**Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency Jet Ventilation (SHFJV)**

Alexander Aloy and Matthaeus Grasl

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/52996

**1. Introduction**

### **1.1. History (an overview)**

#### *1.1.1. Indirect laryngoscopy*

Knowing that almost all laryngeal and tracheal diseases are visible at the surface of the mucous membranes it is of particular interest to visualize these structures.

Endoscopic examinations of the larynx and the trachea are essential in the otorhinolaryngo‐ logical field and had their beginning over 200 years ago. Before the 1800`s only autopsy specimen could clarify laryngotracheal diseases.

In 1807 the physian Phillip Bozzini (Germany) reported about a speculum called "the light conductor, or a simple apparatus for the illumination of the internal cavities and spaces in the living animal body" [1].

In 1816 Ludwig Mende (Germany), a gynaecologist & obstetrician and forensic doctor examined first the inner part of the larynx at a living human being. He looked at a larynx of a suicidal person, who had cut through the soft tissue of the supraglottic area [2].

In 1827 L. Senn (Switzerland) successfully examined the larynx of a child with a small mirrow, cited in [3].

In 1829 Benjamin Guy Babington (Great Britain) developed a larynx-mirrow "glottoscope" and could illuminate the upper parts of the larynx. The instrument combined an epiglottic retractor with a laryngeal mirror. He presented it in the Hunterian Society of London [4].

In 1854 the Spanish singer, voice teacher and scientist Manuel García, living in London, succeeded in performing the auto-laryngoscopy. He first visualized his own larynx, using a dental mirror and a second hand-held mirror to reflect sunlight. Garcia tranfered the method to patients (Figure 1) and could analyse directly the phonation. He presented his invention to the Royal Society in 1855 [5]. The importance of this technique was unrealised first. But in 1862 he was granted an honour of medical degree followed by many international distinctions.

In 1878 Max Joseph Oertel (Germany) describes his invention: the laryngo-stroboscopy via a perforated disc. But the feasibility of this apparatus was not implemented until 1895 when the

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Important milestones for the investigation and treatment of laryngeal diseases were the beginnings of the anaesthesia 1846 using ether by William Morton (USA) [10] and the intro‐ duction of antisepsis by Joseph Lister (Scotland) who performed first 1867 surgery under antiseptic conditions [11]. A fundamental progress was the introduction of the cocain as an anaesthetic and analgetic agent in 1884 by the laryngologist Edmund Jelinek (Austria) [12].

The direct inspection of the larynx is essential in cases of endotracheal intubation and can be performed by spatulate instruments like the straight Miller-spaculate (Robert A. Miller 1941, USA), especiallly for children [13] or the slightly arcuated Macintosh-spatulate (Robert R.

The real interest consists in tube-shaped instruments with lighting for direct inspection of the

The first laryngologist who directly vizualized the larynx using a tongue depressor and a mirror for illumination was Albert von Tobold (Germany) in 1864. He removed with this

In 1895 the laryngologist Alfred Kirstein (Germany) first described direct inspection of the vocal cords. He had modified an oesophagoscope for this purpose and called this device an

In 1897 Gustav Killian a laryngologist (Germany) removed at first with success via a rigid bronchoscope a bronchial foreign body. It was a piece of bone in the right main bronchus [17]. This practical invention was affiliated in professional circles with enthusiasm because the dramatical death rate of 50 percent in case of tracheobronchial foreign bodies could be minimized continuously. This technique persisted for almost 70 years as the standard diag‐

In 1910 Gustav Killian constructed a special laryngoscope, not a tube but a spatula, with a mouth gag (hypopharynx was clear visible) that could be fixed to a supporting construction by a hook, the "suspension-laryngoscopy" (Figure 3). The inspection of the larynx was easier by the hanging position of the head and laryngotracheal surgery could be done with both

Wilhelm Brünings 1910 [19] and Arthur Hartmann 1911 [20] (both Germany) improved

Paul H. Holinger 1947 (USA) created a laryngoscope using an U-shaped handgrip and had a

eletricity has been installed [9].

*1.1.2. Direct laryngoscopy*

Macintosh, 1943, Great Britain) [14].

method laryngeal papilloma [15].

autoscope (electroscope) [16].

hands [18].

But this is not the topic of this historical overview.

larynx, which is only practicable under anaesthesia or deep sedation.

nosis and therapeutic procedure for bronchopulmonar diseases.

Kirsteins electroscope with proximal electric lighting at the handgrip.

better view to the anterior commissure [21].

**Figure 1.** Manuele Garcia`s laryngoscopy.

In 1857 Ludwig Türk, a neurologist and professor of laryngology in Vienna (Austria), unsuc‐ cessfully tried Garcia`s mirror under the use of the ophthalmoscope [6] which was invented by Hermann v. Helmholtz (Germany), a physiologist and physicist in 1851[7].

Johann Nepomuk Czermak, professor of physiology at the University of Pest (Hungary) assumed Türk`s mirror, completed this procedure using light-concentration by a concave head mirror (Figure 2), and presented it 1858 the Viennese medical community [8].

**Figure 2.** Johann Nepomuk Czermak performing the indirect laryngoscopy using natural lighting.

This method propagated rapidly and is still in use, but with electric light source.

In 1878 Max Joseph Oertel (Germany) describes his invention: the laryngo-stroboscopy via a perforated disc. But the feasibility of this apparatus was not implemented until 1895 when the eletricity has been installed [9].

Important milestones for the investigation and treatment of laryngeal diseases were the beginnings of the anaesthesia 1846 using ether by William Morton (USA) [10] and the intro‐ duction of antisepsis by Joseph Lister (Scotland) who performed first 1867 surgery under antiseptic conditions [11]. A fundamental progress was the introduction of the cocain as an anaesthetic and analgetic agent in 1884 by the laryngologist Edmund Jelinek (Austria) [12].

### *1.1.2. Direct laryngoscopy*

In 1854 the Spanish singer, voice teacher and scientist Manuel García, living in London, succeeded in performing the auto-laryngoscopy. He first visualized his own larynx, using a dental mirror and a second hand-held mirror to reflect sunlight. Garcia tranfered the method to patients (Figure 1) and could analyse directly the phonation. He presented his invention to the Royal Society in 1855 [5]. The importance of this technique was unrealised first. But in 1862 he was granted an honour of medical degree followed by many international distinctions.

In 1857 Ludwig Türk, a neurologist and professor of laryngology in Vienna (Austria), unsuc‐ cessfully tried Garcia`s mirror under the use of the ophthalmoscope [6] which was invented

Johann Nepomuk Czermak, professor of physiology at the University of Pest (Hungary) assumed Türk`s mirror, completed this procedure using light-concentration by a concave head

by Hermann v. Helmholtz (Germany), a physiologist and physicist in 1851[7].

mirror (Figure 2), and presented it 1858 the Viennese medical community [8].

**Figure 2.** Johann Nepomuk Czermak performing the indirect laryngoscopy using natural lighting.

This method propagated rapidly and is still in use, but with electric light source.

**Figure 1.** Manuele Garcia`s laryngoscopy.

142 Endoscopy

The direct inspection of the larynx is essential in cases of endotracheal intubation and can be performed by spatulate instruments like the straight Miller-spaculate (Robert A. Miller 1941, USA), especiallly for children [13] or the slightly arcuated Macintosh-spatulate (Robert R. Macintosh, 1943, Great Britain) [14].

But this is not the topic of this historical overview.

The real interest consists in tube-shaped instruments with lighting for direct inspection of the larynx, which is only practicable under anaesthesia or deep sedation.

The first laryngologist who directly vizualized the larynx using a tongue depressor and a mirror for illumination was Albert von Tobold (Germany) in 1864. He removed with this method laryngeal papilloma [15].

In 1895 the laryngologist Alfred Kirstein (Germany) first described direct inspection of the vocal cords. He had modified an oesophagoscope for this purpose and called this device an autoscope (electroscope) [16].

In 1897 Gustav Killian a laryngologist (Germany) removed at first with success via a rigid bronchoscope a bronchial foreign body. It was a piece of bone in the right main bronchus [17]. This practical invention was affiliated in professional circles with enthusiasm because the dramatical death rate of 50 percent in case of tracheobronchial foreign bodies could be minimized continuously. This technique persisted for almost 70 years as the standard diag‐ nosis and therapeutic procedure for bronchopulmonar diseases.

In 1910 Gustav Killian constructed a special laryngoscope, not a tube but a spatula, with a mouth gag (hypopharynx was clear visible) that could be fixed to a supporting construction by a hook, the "suspension-laryngoscopy" (Figure 3). The inspection of the larynx was easier by the hanging position of the head and laryngotracheal surgery could be done with both hands [18].

Wilhelm Brünings 1910 [19] and Arthur Hartmann 1911 [20] (both Germany) improved Kirsteins electroscope with proximal electric lighting at the handgrip.

Paul H. Holinger 1947 (USA) created a laryngoscope using an U-shaped handgrip and had a better view to the anterior commissure [21].

performed an "artificial respiration" by leading in oxygen with a very low flow via a trans‐

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency…

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145

In 1909 Samuel J. Meltzer et al. (USA) enhanced Volhard`s method by applicating the oxygen with high velocity and named it "diffusion respiration". With this high insufflation flow

Clinical application was implemented at first in 1954 by Lothar Barth (Germany) and was used for bronchoscopies and for bridging short apnoea phases over a period of lung resections [29]. Because of insufficient elimination of carbon dioxide it could be applied only 15 -20 minutes.

In 1967 R. Douglas Sanders developed a method enabling a continuously ventilation during bronchoscopy [30]. Two cannulas are placed into the endoscope and 15 to 20 breathing gas portions are applicated periodically during the inspiration phase. Because of the injector effects the primarily very small-sized tidal volumes receive an enhancement. The Venturi effect additionally entrains air through the open proximal end of the endoscope and both result in a sufficient pressure and flow at the end of the endoscope for inflating the lungs. Subsequently gas exchange occurs compareable to conventional breaths (Figure 4). This method simplified general anaesthesia for bronchoscopy and is still in use in surgery of the thorax, published by

In 1971 Jane L. Bradley et al. (Great Britain) described improvements of Sanders` pulmonary ventilation for bronchoscopy. She fixed the proximal injector needle at the bronchoscope and the distal needle became an integral part of the bronchoscope, oxygen feeding was assured

In 1972 Paul Peter Lunkenheimer et al. succeeded a further advancement by oscillating the gas mixture, which was insufflated into the airways. A membrane vibration generator placed at the proximal end of the bronchoscope enabled it. Such oscillations of the breathing gas with

and interruption of the oxygen flow was regulated electronically [33].

This method indeed enabled sufficient oxygenation but hypercapnia occurred rapidly.

laryngeal tracheal tube which did not fill out the diameter of the trachea.

partially elimination of carbon dioxide was practicable.

Therefore a broad distribution did not take place.

E. Gebert et al. [31] and Shaotsu Thomas Lee [32].

**Figure 4.** The injector apparatus of R. Douglas Sanders.

**Figure 3.** Gustav Killian performing a supension laryngoscopy. The patient`s head is suspended by attaching the lar‐ yngoscope to the "gallows".

1961 Oskar Kleinsasser (Germany) published [22] his development of a new instrument for magnified endolaryngeal observation and photography. He used a chest holder. A combina‐ tion of a wide-angle telescope and a telephoto lens guaranteed excellent depth of field for still and motion fotography.

In 1970 Geza J. Jako (USA) refered about his development of a laryngosope, a modified Holinger-Yankauer tube with an ellipsoidal proximal and a round distal aperture. It is made of stainless stell with the inside surface matt to decrease glare. On each side of the instrument there is a built-in tube for the insertion of fiberoptic light pipes. The laryngoscope with a special holder is suspended on an instrument table over the patient`s chest and was developed for laser surgery in the larynx [23].

1970 M. Stuart Strong (USA) coupled the carbon dioxide laser to the surgical microscope. The laser provides precise cutting and also haemostasis of small vessels and is manipulated with a joystick and a foot-pedal [24].

In 1979 Hilko Weerda et al. (Germany) designed an expandable laryngoscope which derived from the Kleinsasser-tube and the Killian-Lynch-suspension laryngoscope consisting of an upper and lower blade. Their distance and angle of twist are variable [25].

The rigid laryngotracheal endoscopy made a qualitative leap with the introduction of the Hopkins-fibreglass-optics with their unachievable splendour and precision with endoscopic resolutions which allow a hundredfold magnification when used additionally. Prof. Harald H Hopkins (Great Britain) developed it the 1960 th with Karl Storz Ltd. Company with limited liability (Germanny) [26].

#### *1.1.3. Jet ventilation*

First attempts to sustain the pulmonary gas exchange without periodical alterations of gas volumes were done by Franz Volhard in an animal experiment with dogs in 1908 [27]. He performed an "artificial respiration" by leading in oxygen with a very low flow via a trans‐ laryngeal tracheal tube which did not fill out the diameter of the trachea.

This method indeed enabled sufficient oxygenation but hypercapnia occurred rapidly.

In 1909 Samuel J. Meltzer et al. (USA) enhanced Volhard`s method by applicating the oxygen with high velocity and named it "diffusion respiration". With this high insufflation flow partially elimination of carbon dioxide was practicable.

Clinical application was implemented at first in 1954 by Lothar Barth (Germany) and was used for bronchoscopies and for bridging short apnoea phases over a period of lung resections [29]. Because of insufficient elimination of carbon dioxide it could be applied only 15 -20 minutes. Therefore a broad distribution did not take place.

In 1967 R. Douglas Sanders developed a method enabling a continuously ventilation during bronchoscopy [30]. Two cannulas are placed into the endoscope and 15 to 20 breathing gas portions are applicated periodically during the inspiration phase. Because of the injector effects the primarily very small-sized tidal volumes receive an enhancement. The Venturi effect additionally entrains air through the open proximal end of the endoscope and both result in a sufficient pressure and flow at the end of the endoscope for inflating the lungs. Subsequently gas exchange occurs compareable to conventional breaths (Figure 4). This method simplified general anaesthesia for bronchoscopy and is still in use in surgery of the thorax, published by E. Gebert et al. [31] and Shaotsu Thomas Lee [32].

**Figure 4.** The injector apparatus of R. Douglas Sanders.

1961 Oskar Kleinsasser (Germany) published [22] his development of a new instrument for magnified endolaryngeal observation and photography. He used a chest holder. A combina‐ tion of a wide-angle telescope and a telephoto lens guaranteed excellent depth of field for still

**Figure 3.** Gustav Killian performing a supension laryngoscopy. The patient`s head is suspended by attaching the lar‐

In 1970 Geza J. Jako (USA) refered about his development of a laryngosope, a modified Holinger-Yankauer tube with an ellipsoidal proximal and a round distal aperture. It is made of stainless stell with the inside surface matt to decrease glare. On each side of the instrument there is a built-in tube for the insertion of fiberoptic light pipes. The laryngoscope with a special holder is suspended on an instrument table over the patient`s chest and was developed for

1970 M. Stuart Strong (USA) coupled the carbon dioxide laser to the surgical microscope. The laser provides precise cutting and also haemostasis of small vessels and is manipulated with

In 1979 Hilko Weerda et al. (Germany) designed an expandable laryngoscope which derived from the Kleinsasser-tube and the Killian-Lynch-suspension laryngoscope consisting of an

The rigid laryngotracheal endoscopy made a qualitative leap with the introduction of the Hopkins-fibreglass-optics with their unachievable splendour and precision with endoscopic resolutions which allow a hundredfold magnification when used additionally. Prof. Harald H Hopkins (Great Britain) developed it the 1960 th with Karl Storz Ltd. Company with limited

First attempts to sustain the pulmonary gas exchange without periodical alterations of gas volumes were done by Franz Volhard in an animal experiment with dogs in 1908 [27]. He

upper and lower blade. Their distance and angle of twist are variable [25].

and motion fotography.

yngoscope to the "gallows".

144 Endoscopy

laser surgery in the larynx [23].

a joystick and a foot-pedal [24].

liability (Germanny) [26].

*1.1.3. Jet ventilation*

In 1971 Jane L. Bradley et al. (Great Britain) described improvements of Sanders` pulmonary ventilation for bronchoscopy. She fixed the proximal injector needle at the bronchoscope and the distal needle became an integral part of the bronchoscope, oxygen feeding was assured and interruption of the oxygen flow was regulated electronically [33].

In 1972 Paul Peter Lunkenheimer et al. succeeded a further advancement by oscillating the gas mixture, which was insufflated into the airways. A membrane vibration generator placed at the proximal end of the bronchoscope enabled it. Such oscillations of the breathing gas with frequences from 1200 to 6000 per minute led in a satisfactory manner to a gas exchange with widely minimisation of intrathoracic pressure fluctuations [34]. An additional integrated carbon dioxide absorber increased elimination of carbon doxide [35].

aerodigestive tract. Absolute indications are the strong suspicion of precancerous or cancerous epithelial diseaes as well as constringent processes. But also benign lesions like polyps, cysts and oedemas have to be operated soon, because it is often found that the opposite vocal chord reacts with a dent, oedema or epithelial thickening. These secondary alterations prolongate healing. Inflammatory epithelial reactions are to be treated with inhalations before in few hard going cases operation is done. Rigid laryngoscopy is a domain for the elimination of foreign bodies in larynx and trachea as well as the surgical treatment of laryngeal or glottic webs. Laryngotracheal injuries and the placement respectively the removal of laryngotracheal endoprosthesis, medialization of vocal chords after palsy of an inferior laryngeal nerve by relining and surgical widening of the glottis are further areas of application of laryngotra‐

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency…

http://dx.doi.org/10.5772/52996

147

Special endangering of patients life by anaesthesia when medical conditions such as apoplectic stroke, heart infarction, aneurysm, severe cardiadic arrhythmias, aggravated pulmonary, liver and renal diseases are contraindication for general anaesthesia and consecutively for micro‐ laryngoscopy. Unfrequent contraindications are severe malformations of the jaws, cervical

The design of the instrumental equipment represents the association of the representational problems and their solution. The present instrumentation indicates the requirement on average in the German-speaking language room and is to be adapted individually for partic‐

The mostly used laryngoscope tube at our institution, the Deaprtment of Ototrhinolaryngol‐ gy of the Medical Universitiy, is that of Kleinsasser with a length of of 80 to 200 mm and a distal diameter of 8 -16 mm (Figure 5). The medium-sized closed coverage type for adults is used predominantly in the endolarynx. An overlong small-bore universal applicable laryngoscope is used in children and adults with difficult adjustabel areas of the endolarynx - especially the anterior commissure, the interary and subglottic region. The proximal end of the tube is differentlyshapedindependencytothe size for adults andchildren.The sideofthe tubes turned to the teeth is flat for spreading the pressure to the teeth as uniform as possible. At both sides of the proximal end mounting parts are placed to fix the cold light rod eighter at the left or right

The spatulated laryngosope of Weerda et al. [46] has an upper and lower blade which is inserted in a closed position and once inside the larynx the distance and angle of twist of the blades is variable. This instrument has adapters for suction and jet stream ventilation and is suitable in particular for the root of the tongue, the vallecula, supraglottis and hypopharynx.

spine diseases like Morbus Bechterew and local spasticity [43].

cheoscopy.

ular purposes:

side [43].

*2.3.1. Laryngoscope*

**2.2. Contraindications**

**2.3. Description of the instruments**

In 1980 Demond J. Bohn et al. published at first a successfully ventilation with this technique in an animal experiment [36]. With a piston pump sinuoidal vibrations with a frequency from 900 to 1500 per minute were tranfered to the breathing gas, elimination of the carbon dioxide is carried out by a cross-flow of fresh mixture. At this way of high frequency oxygenation a superposition of spontaneous breathing is not feasible.

In 1977 and 1980 Ulf H. Sjöstrand (Sweden) published about his invention of high-frequency positive pressure ventilation. He modified a conventional lung ventilator by the application of special valve configuration and could reduce the compressible gas volume. Tidal volumes from 200 to 300 ml with a frequency of 60 to 80 per minute were applicable [37, 38].

Miroslav M. Klain et al. (USA) developed 1976 the high-frequency ventilation. A high pressure jet is conditioned into small-sized single gas quantities by an assessable valve and then applicated via a catheter with a low inner diameter. The breathing gas quantities leave the catheter as a clocked high frequency jet. This jet activates a suction mechanism (entrainment) and the tidal volume is augmented. In a frequency range of 100 to 200 per minute a sufficient gas exchange can be perpetuated in a completely open system towards the atmosphere [39-41].

This high frequency jet ventilation is the initial point of all following developments.

In particular Alexander Aloy and colleagues are engaged practically and scientifically since 1990 over more than twenty years in this field of ventilation [42].

His and contemporarely applicatioins and publications are presented in the next following parts of this chapter.

### **2. Microlaryngoscopy and endolaryngeal microsurgery**

Direct laryngoscopy via the transoral route allows the immediate entry to the inner laryngeal and tracheal structures and has now an extreme importance for the special field of laryngo‐ logical diagnoses and surgical treatments in the otorhinolaryngologic discipline.

A laryngoscope holder is adhered to the chest selfholding by a mount as a supension similar to a gallow.

The binoccular vision and bi-manual manipualtion via the forward spaced microscopy facilitates detailed diagnoses and treatment at the vocal cords and circumjacent areas [43-45].

#### **2.1. Indications**

Microlaryngocopy is particulary helpful in the need of diagnosis and treatment of the vocal chords or surrounding areas, which are first seen by indirect laryngoscopy. The microlar‐ yngoscopy for staging and excision biopsy of tumours is part of a panendoscopy of the upper aerodigestive tract. Absolute indications are the strong suspicion of precancerous or cancerous epithelial diseaes as well as constringent processes. But also benign lesions like polyps, cysts and oedemas have to be operated soon, because it is often found that the opposite vocal chord reacts with a dent, oedema or epithelial thickening. These secondary alterations prolongate healing. Inflammatory epithelial reactions are to be treated with inhalations before in few hard going cases operation is done. Rigid laryngoscopy is a domain for the elimination of foreign bodies in larynx and trachea as well as the surgical treatment of laryngeal or glottic webs. Laryngotracheal injuries and the placement respectively the removal of laryngotracheal endoprosthesis, medialization of vocal chords after palsy of an inferior laryngeal nerve by relining and surgical widening of the glottis are further areas of application of laryngotra‐ cheoscopy.

### **2.2. Contraindications**

frequences from 1200 to 6000 per minute led in a satisfactory manner to a gas exchange with widely minimisation of intrathoracic pressure fluctuations [34]. An additional integrated

In 1980 Demond J. Bohn et al. published at first a successfully ventilation with this technique in an animal experiment [36]. With a piston pump sinuoidal vibrations with a frequency from 900 to 1500 per minute were tranfered to the breathing gas, elimination of the carbon dioxide is carried out by a cross-flow of fresh mixture. At this way of high frequency oxygenation a

In 1977 and 1980 Ulf H. Sjöstrand (Sweden) published about his invention of high-frequency positive pressure ventilation. He modified a conventional lung ventilator by the application of special valve configuration and could reduce the compressible gas volume. Tidal volumes

Miroslav M. Klain et al. (USA) developed 1976 the high-frequency ventilation. A high pressure jet is conditioned into small-sized single gas quantities by an assessable valve and then applicated via a catheter with a low inner diameter. The breathing gas quantities leave the catheter as a clocked high frequency jet. This jet activates a suction mechanism (entrainment) and the tidal volume is augmented. In a frequency range of 100 to 200 per minute a sufficient gas exchange can be perpetuated in a completely open system towards the atmosphere [39-41].

In particular Alexander Aloy and colleagues are engaged practically and scientifically since

His and contemporarely applicatioins and publications are presented in the next following

Direct laryngoscopy via the transoral route allows the immediate entry to the inner laryngeal and tracheal structures and has now an extreme importance for the special field of laryngo‐

A laryngoscope holder is adhered to the chest selfholding by a mount as a supension similar

The binoccular vision and bi-manual manipualtion via the forward spaced microscopy facilitates detailed diagnoses and treatment at the vocal cords and circumjacent areas [43-45].

Microlaryngocopy is particulary helpful in the need of diagnosis and treatment of the vocal chords or surrounding areas, which are first seen by indirect laryngoscopy. The microlar‐ yngoscopy for staging and excision biopsy of tumours is part of a panendoscopy of the upper

logical diagnoses and surgical treatments in the otorhinolaryngologic discipline.

from 200 to 300 ml with a frequency of 60 to 80 per minute were applicable [37, 38].

This high frequency jet ventilation is the initial point of all following developments.

1990 over more than twenty years in this field of ventilation [42].

**2. Microlaryngoscopy and endolaryngeal microsurgery**

parts of this chapter.

146 Endoscopy

to a gallow.

**2.1. Indications**

carbon dioxide absorber increased elimination of carbon doxide [35].

superposition of spontaneous breathing is not feasible.

Special endangering of patients life by anaesthesia when medical conditions such as apoplectic stroke, heart infarction, aneurysm, severe cardiadic arrhythmias, aggravated pulmonary, liver and renal diseases are contraindication for general anaesthesia and consecutively for micro‐ laryngoscopy. Unfrequent contraindications are severe malformations of the jaws, cervical spine diseases like Morbus Bechterew and local spasticity [43].

### **2.3. Description of the instruments**

The design of the instrumental equipment represents the association of the representational problems and their solution. The present instrumentation indicates the requirement on average in the German-speaking language room and is to be adapted individually for partic‐ ular purposes:

### *2.3.1. Laryngoscope*

The mostly used laryngoscope tube at our institution, the Deaprtment of Ototrhinolaryngol‐ gy of the Medical Universitiy, is that of Kleinsasser with a length of of 80 to 200 mm and a distal diameter of 8 -16 mm (Figure 5). The medium-sized closed coverage type for adults is used predominantly in the endolarynx. An overlong small-bore universal applicable laryngoscope is used in children and adults with difficult adjustabel areas of the endolarynx - especially the anterior commissure, the interary and subglottic region. The proximal end of the tube is differentlyshapedindependencytothe size for adults andchildren.The sideofthe tubes turned to the teeth is flat for spreading the pressure to the teeth as uniform as possible. At both sides of the proximal end mounting parts are placed to fix the cold light rod eighter at the left or right side [43].

The spatulated laryngosope of Weerda et al. [46] has an upper and lower blade which is inserted in a closed position and once inside the larynx the distance and angle of twist of the blades is variable. This instrument has adapters for suction and jet stream ventilation and is suitable in particular for the root of the tongue, the vallecula, supraglottis and hypopharynx.

**•** autofocus with 2 visible laser dots - automatic mode with magnetic brakes,

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149

**•** binocular observer ocular,

**•** central user interface,

**•** navigation interface,

**•** laseradapter.

*2.3.4 Instruments*

sidewards.

**•** system setup: autobalance,

**•** interface for micromanipulator,

**•** HD video touchscreen on extended arm,

**•** video-in for external SD video sources, **•** patients data transfer from/to PACS.

**•** intraoperative fluorescence,

**•** integrated HD video camera,

**2.4. Beginning and protection activities**

**•** multifunctional programmable handgrips,

**•** XY robotic movement in 3 axes (variable speed),

**3.** Video, fotography, Television for decumentation and teaching:

**•** integrated SD or HD video recording and editing, **•** adapatation of consumer (SLR) photo/video camera,

Instruments are small at the tip, thin, long (25 cm) and flexible.

All instruments should be manipulated freehanded, which is easily trainable and backing of the arms becomes dispensable. The set of microsurgical instruments should be kept in a basic amount. It includes double-spoon forceps, scissors: straight, laterally and upwards arcuated,

Instruments for laser microlaryngological surgery are of nonreflecting surface. Protectors are neccessary for the subglottic area when tubeless ventilation is applicated. Additional when the vocal chords are treated the false cords and also the contralateral intact side is to be moved

The often "poor risk" patients need preoperatively a careful investigation and treatment to make them capable for anaesthesia. Dental record is essential before insertion of the laryngo‐

acutenaculum, sickle and peeling knifes, suction tubes and coagulation probes.

**•** integrated video still image capturing on HDD and USB-media,

**•** magnetic clutches for all system axes,

**Figure 5.** The Kleinsasser laryngoscope already adapted for jet ventilation (see also part 3 of this chapter).

When laser is used the tubes and spatulas are adapted according to the needs. The inner surface coating should be non-reflecting, opal or black. On the lateral outside cannulas for suction of smoke are mounted.

#### *2.3.2. Laryngoscope holder*

The laryngoscope holder is eighter placed on patient`s chest with a broad rubber ring or it is put on a robust instrument table [43, 47] respectively a holding bow [48] just over his chest to avoid pressure on the anaesthetized chest and to minimize movement of the instrument.

*2.3.3. Example for a configuration of a microscope combining modern vizualisation technologies with a user friendly platform*

	- **•** 2 x 300 W xenon,
	- **•** automatic iris control for adjusting the illumunation to the field of view,
	- **•** individual light treshhold setting,
	- **•** focus light link: working distance controlled light intensity,
	- **•** display of remaining lamp life time.
	- **•** free to move at a tripod or as a ceiling mounted,
	- **•** motorized focus,
	- **•** working distance 200-500 mm,
	- **•** motorized zoom 1:6 zoom ratio,
	- **•** 10 x magnetic widefield eyepieces with integrated eyecups,

When laser is used the tubes and spatulas are adapted according to the needs. The inner surface coating should be non-reflecting, opal or black. On the lateral outside cannulas for suction of

**Figure 5.** The Kleinsasser laryngoscope already adapted for jet ventilation (see also part 3 of this chapter).

The laryngoscope holder is eighter placed on patient`s chest with a broad rubber ring or it is put on a robust instrument table [43, 47] respectively a holding bow [48] just over his chest to avoid pressure on the anaesthetized chest and to minimize movement of the instrument.

*2.3.3. Example for a configuration of a microscope combining modern vizualisation technologies with*

**•** automatic iris control for adjusting the illumunation to the field of view,

**•** focus light link: working distance controlled light intensity,

**•** 10 x magnetic widefield eyepieces with integrated eyecups,

smoke are mounted.

148 Endoscopy

*2.3.2. Laryngoscope holder*

*a user friendly platform*

**•** 2 x 300 W xenon,

**•** motorized focus,

**•** individual light treshhold setting,

**•** display of remaining lamp life time.

**•** working distance 200-500 mm, **•** motorized zoom 1:6 zoom ratio,

**•** free to move at a tripod or as a ceiling mounted,

**1.** Light source:

**2.** Microscope:

	- **•** HD video touchscreen on extended arm,
	- **•** integrated video still image capturing on HDD and USB-media,
	- **•** integrated HD video camera,
	- **•** integrated SD or HD video recording and editing,
	- **•** adapatation of consumer (SLR) photo/video camera,
	- **•** video-in for external SD video sources,
	- **•** patients data transfer from/to PACS.

#### *2.3.4 Instruments*

Instruments are small at the tip, thin, long (25 cm) and flexible.

All instruments should be manipulated freehanded, which is easily trainable and backing of the arms becomes dispensable. The set of microsurgical instruments should be kept in a basic amount. It includes double-spoon forceps, scissors: straight, laterally and upwards arcuated, acutenaculum, sickle and peeling knifes, suction tubes and coagulation probes.

Instruments for laser microlaryngological surgery are of nonreflecting surface. Protectors are neccessary for the subglottic area when tubeless ventilation is applicated. Additional when the vocal chords are treated the false cords and also the contralateral intact side is to be moved sidewards.

#### **2.4. Beginning and protection activities**

The often "poor risk" patients need preoperatively a careful investigation and treatment to make them capable for anaesthesia. Dental record is essential before insertion of the laryngo‐ scope. When indicated patients have to go for remediation preoperatively. Dental impression trays equally spread the pressure of the laryngoscope at the teeth of the upper jaw and can bridge a dental gap.

**2.7. Inspection of the larynx and the circumjacent areas**

**2.8. Microlaryngoscopic diagnoses and surgical therapies**

seen under a magnification of up to 40.

(*most frequent clinical symptom is hoarseness*)

microlaryngoscopy is qualified in particular.

*2.8.1. Tumours*

*2.8.1.1. Precancerous lesions*

*2.8.1.2. Squamous scell carcinomas*

At the begin of the introduction of the laryngocope the structures are inspected by looking with the naked eyes using the lighting inside the laryngoscope: base of the tongue, valleculae, epiglottis: lingual and laryngeal surface area and free margin, aryepiglottic fold, pharyngoepiglottic fold, the processus vocalis and tubercula cuneiformia respectively corniculata, the arytaenoid cartilage, the sinus piriformis bilateral, the posterior hypophar‐ yngeal wall and postcricoid area. After fixation of the laryngoscope under the use of the microscope the false and vocal chord, the sinus Morgagni, the anterior and posterior commissure as well as the subglottic space and the upper parts of the trachea are to be

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency…

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151

Diagnosis and therapy of precancerous lesions and carcinomas of the larynx, especially the vocal chords are still a central domain of laryngoscopy. Any unclear or suspicious epithelial alteration is to be exstirpated and examined by histology. As followup exam after radiotherapy

*Chronichyperplasticlaryngitis*isanepithelialthickeningoflaryngealmucousmembraneaffecting both vocal chords with a spread over their complete length. In this dermatoid epithelium often *leukoplakia* lies as milky area, slightly opacity ofthe surface or as verrucous,thick, white coating. A second group of cornification of the epithelium is the circumscript *keratosis* which is located nearly only at one vocal chord. The surface can be plain, tubercular, verrucous or papillary with all transitions. Histological differentiation of the keratosisis is for all benign types is grade I, when few atypic cells are seen grade II and when a carcinoma in situ is diagnosed grade III. A carcinoma in situ becomes in a high rate an apparent carcinoma and is to be treated as such a malignant tumour. The human papilloma virus induced *solitary hyperceratotic "adult"papillo‐ ma* has a high rate of recurrence after surgery and is to be distinguished from the "*juvenile*" *papilloma* which also occurs in adults but never turns to a malignization. Precancerous lesions

Carcimomas in situ and apparent carcinomas primarily originate bilateral from an enlarged area and are named wallpaper carcimomas respectively superficial spreading carcinomas. Additionally, not infrequently, multiple focuses of seperated carcinomas confluence later. Difficult relocatability, solid or swallen areas and superficial exulceration are important signs of deeper invasion. A relatively rare shape of growth is excessive polypus/exophytic like. Because of tumour infiltration the blood supply suffers and necroses occur. To identify the

are always movable over the muscle of the vocal chord without problems.

Patients lie in dorsal position on the operating table and the correct posture of the head is the dorsal flection in flat bedding. Using adequate laryngoscope types it enables even in patients with a thick and short neck to adjust the larynx. If there are anamnestic indications concerning pathologies at the cervicale spin an orthopaedic specialist has to decide if the head position during laryngoscopy will be tolerated well.

In case of laser application all persons in the operating room have to wear special glasses. When CO2 laser is in use eyeglass lenses are sufficient. Patients face and eyes are to be protected by a humid green woven fabric. The doors to the operating room where laser is used must be signalized.

#### **2.5. Anaesthesia and ventilation during micro laryngotracheoscopy (basic considerations)**

Please see the next part of this chapter.

### **2.6. Insertion of the laryngoscope**

First of all a teeth protector for the lower and upper jaw is placed in position. The insertion of the laryngoscope should be performed not until the patient is full relaxed and in sufficient depth of narcosis. The laryngoscope should be as large as possible enabling best lighting and overview of the larynx. In cases of preexisting laryngotracheal intubation the ventilation tube is moved by two fingers to the left side and the laryngoscope is inserted from the right side under the illumination of a cold light which is piped inside of the tube to the distal end. The tongue should not be pinched between the teeth and the laryngoscope at the same time. The epiglottis is loaded up by the laryngoscope. If the laryngeal skeleton is to be pressed from outside to inward in cases of the need to expose the anterior commissure the laryngoscope should be inserted only into the area of the false cords. In cases of a small, weak or U-shaped epiglottis it can happen that the epiglottis is enrolled and the suprahyoidal part is folded and compressed when the laryngoscope is inserted. Consecutively inspection of the anterior commissure is hindered and a postoperative oedema can occur. Solving of this problem is to clamp the epiglottis when inserting the laryngoscope. The laryngoscope is positioned few millimeters above the anterior commissure. The dorsal lying ventilation tube can be used as a guidance till the exposition of the false and vocal chords.

Next is to underpin the laryngoscope at the mobile laryngoscopy-table and to move it slowly upwards. When a distending laryngoscope is inserted at maximum aperture laterally between the spatulas parts of the tongue can be pinched and it protrudes into the lumen of the laryngoscope. This can be prevented by covering the closed distending-laryngo‐ scope with a finger of a medical glove which is forming a lateral wall when the laryngo‐ scope is opened [49].

### **2.7. Inspection of the larynx and the circumjacent areas**

At the begin of the introduction of the laryngocope the structures are inspected by looking with the naked eyes using the lighting inside the laryngoscope: base of the tongue, valleculae, epiglottis: lingual and laryngeal surface area and free margin, aryepiglottic fold, pharyngoepiglottic fold, the processus vocalis and tubercula cuneiformia respectively corniculata, the arytaenoid cartilage, the sinus piriformis bilateral, the posterior hypophar‐ yngeal wall and postcricoid area. After fixation of the laryngoscope under the use of the microscope the false and vocal chord, the sinus Morgagni, the anterior and posterior commissure as well as the subglottic space and the upper parts of the trachea are to be seen under a magnification of up to 40.

### **2.8. Microlaryngoscopic diagnoses and surgical therapies**

### (*most frequent clinical symptom is hoarseness*)

#### *2.8.1. Tumours*

scope. When indicated patients have to go for remediation preoperatively. Dental impression trays equally spread the pressure of the laryngoscope at the teeth of the upper jaw and can

Patients lie in dorsal position on the operating table and the correct posture of the head is the dorsal flection in flat bedding. Using adequate laryngoscope types it enables even in patients with a thick and short neck to adjust the larynx. If there are anamnestic indications concerning pathologies at the cervicale spin an orthopaedic specialist has to decide if the head position

In case of laser application all persons in the operating room have to wear special glasses. When CO2 laser is in use eyeglass lenses are sufficient. Patients face and eyes are to be protected by a humid green woven fabric. The doors to the operating room where laser is used must be

**2.5. Anaesthesia and ventilation during micro laryngotracheoscopy (basic considerations)**

First of all a teeth protector for the lower and upper jaw is placed in position. The insertion of the laryngoscope should be performed not until the patient is full relaxed and in sufficient depth of narcosis. The laryngoscope should be as large as possible enabling best lighting and overview of the larynx. In cases of preexisting laryngotracheal intubation the ventilation tube is moved by two fingers to the left side and the laryngoscope is inserted from the right side under the illumination of a cold light which is piped inside of the tube to the distal end. The tongue should not be pinched between the teeth and the laryngoscope at the same time. The epiglottis is loaded up by the laryngoscope. If the laryngeal skeleton is to be pressed from outside to inward in cases of the need to expose the anterior commissure the laryngoscope should be inserted only into the area of the false cords. In cases of a small, weak or U-shaped epiglottis it can happen that the epiglottis is enrolled and the suprahyoidal part is folded and compressed when the laryngoscope is inserted. Consecutively inspection of the anterior commissure is hindered and a postoperative oedema can occur. Solving of this problem is to clamp the epiglottis when inserting the laryngoscope. The laryngoscope is positioned few millimeters above the anterior commissure. The dorsal lying ventilation tube can be used as a

Next is to underpin the laryngoscope at the mobile laryngoscopy-table and to move it slowly upwards. When a distending laryngoscope is inserted at maximum aperture laterally between the spatulas parts of the tongue can be pinched and it protrudes into the lumen of the laryngoscope. This can be prevented by covering the closed distending-laryngo‐ scope with a finger of a medical glove which is forming a lateral wall when the laryngo‐

bridge a dental gap.

150 Endoscopy

signalized.

during laryngoscopy will be tolerated well.

Please see the next part of this chapter.

guidance till the exposition of the false and vocal chords.

**2.6. Insertion of the laryngoscope**

scope is opened [49].

Diagnosis and therapy of precancerous lesions and carcinomas of the larynx, especially the vocal chords are still a central domain of laryngoscopy. Any unclear or suspicious epithelial alteration is to be exstirpated and examined by histology. As followup exam after radiotherapy microlaryngoscopy is qualified in particular.

#### *2.8.1.1. Precancerous lesions*

*Chronichyperplasticlaryngitis*isanepithelialthickeningoflaryngealmucousmembraneaffecting both vocal chords with a spread over their complete length. In this dermatoid epithelium often *leukoplakia* lies as milky area, slightly opacity ofthe surface or as verrucous,thick, white coating. A second group of cornification of the epithelium is the circumscript *keratosis* which is located nearly only at one vocal chord. The surface can be plain, tubercular, verrucous or papillary with all transitions. Histological differentiation of the keratosisis is for all benign types is grade I, when few atypic cells are seen grade II and when a carcinoma in situ is diagnosed grade III. A carcinoma in situ becomes in a high rate an apparent carcinoma and is to be treated as such a malignant tumour. The human papilloma virus induced *solitary hyperceratotic "adult"papillo‐ ma* has a high rate of recurrence after surgery and is to be distinguished from the "*juvenile*" *papilloma* which also occurs in adults but never turns to a malignization. Precancerous lesions are always movable over the muscle of the vocal chord without problems.

#### *2.8.1.2. Squamous scell carcinomas*

Carcimomas in situ and apparent carcinomas primarily originate bilateral from an enlarged area and are named wallpaper carcimomas respectively superficial spreading carcinomas. Additionally, not infrequently, multiple focuses of seperated carcinomas confluence later. Difficult relocatability, solid or swallen areas and superficial exulceration are important signs of deeper invasion. A relatively rare shape of growth is excessive polypus/exophytic like. Because of tumour infiltration the blood supply suffers and necroses occur. To identify the superficial spread of the tumours it is additonally necessary to investigate the infraglottic area as well as the ventriculus Morgangni and the false chord via a 30 ˚ and 70˚ rigid fiberoptics.

*Vocal chords nodules* are seen exclusively in women with powerful voice formation. They present as a symmetric swelling of the epithelium of the vocal chords in typical localisation at the border between the first and second third. In up to 50 % the diagnosis of nodules by indirect laryngoscopy is wrong – microlaryngoscopy shows cysts or polyps. Morphodiffentiation compared to polyps is difficult but in any case they are no fibroepithelioma. Microlaryngeal

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In hyperactive children vocal nodes impress as soft spindling swelling in the middle of both vocal chords. Operative resection is not necessary because by no longer than the puberty they involute spontaneously. Phoniatric therapy is useful. Laryngeal papillomas are to be excluded.

The *varix chordis* is found in patients with vocal overstressing at the surface or margin in the middle or posterior part of one vocal chord. Under microscpy one or various capillaries lead to a bloodblaster. Laser coagulation followed by vocal training is a promising therapy.

**1.** *vocal chord cysts* are with about 50 % the most frequent and in most cases as one chamber at the subglottic slope of the anterior third of a vocal chord with a diameter of about 5 mm. Their inner lining is squamous epithelium. The content matter is a muddy aqueousmilky detritus. Under microscopy the subepithelial content glimmers yellowish. They are

**2.** *vestibular fold cysts* are found nearly exclusively in elderly patients. The first mode, originating from the minor salivary glands, presents with one chamber and is peduncu‐ lated at the roof of the ventriculus laryngis (Morgagni) with a prolapse into the glottis. They are neither a real prolapse nor an inner laryngocele and can be mutated oncocytoid, which is a benign age-related metaplastic dyschylic transformation. They can be removed easily by cutting through the peduncle. The second mode is characterized by multiple chambers, often bilateral, inside the vestibular fold and metaplastic transformed epithe‐ lium. The excision is hindered by the deep location and the botryoid extension, which

**3.** *epiglottic cysts* are located always at the same position, deep in the vallecula epiglottica slightly paramedian at the lingual surface of the epiglottis. In ten percent they occur multiple, only the bigger one cause dysphagia and have to be operated. This can be complicated by prominent venes. The inner layer of the wall of the cysts is squamous epithelium enclosing a milky pale yellow fluid. The complete sac of the cyst is to be

The *Reinke-oedema* or *polypoid chorditis* is a frequent disease mostly in heavy smokers. The extention ranges from marginal spindle shaped swelling to bulky floating bulges with stridor. In most cases both vocal chords are involved, but asymmetrically. With longer persistence of the Reinke-oedema the epithelium keratinizes. Patients develop a compensatory phonation by the vestibular folds which are to be reversed by postoperative voice therapy. Surgery begins with plain and clean cutted margins at the tip of the processus vocalis of the arytaenoid cartilage where the oedema is pronounced. The anteroir commissure is not involved and an

resection and postoperative phonatric training is indicated.

*Laryngeal cysts* are frequent and located typically at three areas:

removed gentle under protection of the muscle layer.

promotes relapses.

removed.

A huge advantage of endolaryngeal microsurgery is the possibility to get biopsies from all locations without contusion. In cases of palliative tumour size reduction ("debulking") laryngeal tumour masses can easily be reduced to avoid a tracheotomy. Small-sized tumours can be removed in one piece as an "excision biopsy".

Clear guidelines applied for endoscopic resections of carcinomas include the selective und reluctant production of the indication by a laryngologist experienced in microlaryngologic diagnosis and surgery. Resection is only permitted when the complete tumour circumference over his borders is easily visible with the microscope. Otherwise an external approach is to be chosen allowing simultaneously reconstruction of the glottis. The careful histological investi‐ gation is a condition precedent in cases of microlaryngeal resection. When resection was not in healthy tissue an immediate revision surgery is necessary [43].

Laser surgery in the larynx demands special safety precautions, instruments, anaesthesiolog‐ ical procedures, experiences of the mircosurgeon and knowlegde of histopathological ap‐ praisal. Because bleeding is the most common complication of laser surgery of tumours of the upper aerodigestve tract every clinic performing this surgery should have a clear concept of managing it. When these conditions are respected even enlarged function receiving and organ saving operations in the larynx and hypopharynx with good oncological results are quite practicable [49].

### *2.8.2. Benign lesions*

*Polyps* are only seen at the vocal chords predominantly at one side inserting at the anterior two third at the slope of the vocal chord. They have a diameter on average of 5 mm, bigger one`s are floating in the glottic area. Petiolated pendolous polyps sustain longer, broad based polyps are juvenile and have a thin transparent epithelium (Figure 6). Polyps never degenerate into a carcinoma. If a polyp persists a longer period at the contralaeral side contact reaction in shape of excavation, epithelial thickening or oedematous swelling occurs. This is not to be treated when the polyp is resected.

**Figure 6.** Large vocal chord polyp in the anterior part of the glottis.

*Vocal chords nodules* are seen exclusively in women with powerful voice formation. They present as a symmetric swelling of the epithelium of the vocal chords in typical localisation at the border between the first and second third. In up to 50 % the diagnosis of nodules by indirect laryngoscopy is wrong – microlaryngoscopy shows cysts or polyps. Morphodiffentiation compared to polyps is difficult but in any case they are no fibroepithelioma. Microlaryngeal resection and postoperative phonatric training is indicated.

In hyperactive children vocal nodes impress as soft spindling swelling in the middle of both vocal chords. Operative resection is not necessary because by no longer than the puberty they involute spontaneously. Phoniatric therapy is useful. Laryngeal papillomas are to be excluded.

The *varix chordis* is found in patients with vocal overstressing at the surface or margin in the middle or posterior part of one vocal chord. Under microscpy one or various capillaries lead to a bloodblaster. Laser coagulation followed by vocal training is a promising therapy.

*Laryngeal cysts* are frequent and located typically at three areas:

superficial spread of the tumours it is additonally necessary to investigate the infraglottic area as well as the ventriculus Morgangni and the false chord via a 30 ˚ and 70˚ rigid fiberoptics.

A huge advantage of endolaryngeal microsurgery is the possibility to get biopsies from all locations without contusion. In cases of palliative tumour size reduction ("debulking") laryngeal tumour masses can easily be reduced to avoid a tracheotomy. Small-sized tumours

Clear guidelines applied for endoscopic resections of carcinomas include the selective und reluctant production of the indication by a laryngologist experienced in microlaryngologic diagnosis and surgery. Resection is only permitted when the complete tumour circumference over his borders is easily visible with the microscope. Otherwise an external approach is to be chosen allowing simultaneously reconstruction of the glottis. The careful histological investi‐ gation is a condition precedent in cases of microlaryngeal resection. When resection was not

Laser surgery in the larynx demands special safety precautions, instruments, anaesthesiolog‐ ical procedures, experiences of the mircosurgeon and knowlegde of histopathological ap‐ praisal. Because bleeding is the most common complication of laser surgery of tumours of the upper aerodigestve tract every clinic performing this surgery should have a clear concept of managing it. When these conditions are respected even enlarged function receiving and organ saving operations in the larynx and hypopharynx with good oncological results are quite

*Polyps* are only seen at the vocal chords predominantly at one side inserting at the anterior two third at the slope of the vocal chord. They have a diameter on average of 5 mm, bigger one`s are floating in the glottic area. Petiolated pendolous polyps sustain longer, broad based polyps are juvenile and have a thin transparent epithelium (Figure 6). Polyps never degenerate into a carcinoma. If a polyp persists a longer period at the contralaeral side contact reaction in shape of excavation, epithelial thickening or oedematous swelling occurs. This is not to be treated

can be removed in one piece as an "excision biopsy".

practicable [49].

152 Endoscopy

*2.8.2. Benign lesions*

when the polyp is resected.

**Figure 6.** Large vocal chord polyp in the anterior part of the glottis.

in healthy tissue an immediate revision surgery is necessary [43].


The *Reinke-oedema* or *polypoid chorditis* is a frequent disease mostly in heavy smokers. The extention ranges from marginal spindle shaped swelling to bulky floating bulges with stridor. In most cases both vocal chords are involved, but asymmetrically. With longer persistence of the Reinke-oedema the epithelium keratinizes. Patients develop a compensatory phonation by the vestibular folds which are to be reversed by postoperative voice therapy. Surgery begins with plain and clean cutted margins at the tip of the processus vocalis of the arytaenoid cartilage where the oedema is pronounced. The anteroir commissure is not involved and an epithelial debridment there should be prevented to avoid synechias. The subepthelial mucous is to be sucked carefully.

essential advantage nowadays is that the surgical percedure is performed endolaryngeal and

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http://dx.doi.org/10.5772/52996

155

*Haemangioma* of the larynx are congenital and become symptomatical several months post‐ partal with the general growth. They are treated by laser resection and additional long-term

The incidence of laryngeal *mycosis* is increasing caused by more patients with immunosup‐ pressive therapy and AIDS. In Europe candida albicans and aspergillosis as endomycosis are of clinical relevance. The affection of the larynx is predominantly secondary, the mucous membrane is discrete swollen and reddened, typical off-white coatings are seen only exep‐ tionally and it looks like a chronic laryngitis. The basic concept of the diagnosis is still the microbiological demonstration of the pathogenic agent. Systemic antimycotic drugs are given. Laryngeal *synechia* can be differentiated by location into anterior vocal chords ones, posterior interarytaenoid ones and false chord ones. Anterior synechia can be congenital and are very rare and then aquired more frequent as complication after microlaryngeal surgery. Resection of the narrowing and movement blocking scar tissue is difficile and recurrences many times arise. Cortison and mitomycin is applied additionally. Subglottic annulare stenosis "*pinhole aperture synechia*" are sequels of artificial ventilation and are resectable with out the need of inserting a dilitator. *"Cricoidal stenosis"* caused by diminution of the cricoidal cartilage are funnel-shaped and not to be treated endolaryngeal but resected by an external approach.

*Unilateral pareses* of the i*nferior laryngeal nerv* are treated by a phoniatric training, improvement of voice in defintive unilateral pareses demands an injection of the vocal chord for example with Teflon®. In cases of *acute bilateral paresis* of the *inferior layryngeal nerve* a tracheotmy is only to be avoided when a larynologist performs immediately a posterior chordectomy including a resection of the processus vocalis or partial arytaenoidectomy or a (temporary) laterofixation

General anaesthesia is essential for microscopic laryngoscopy because of the required length of time and the inconveniences to the patient if not applied. Risks of general anaesthesia can be deminished by a close prepoerative examination of all vital functions. It is in the responsi‐ bility of the laryngologist to estimate the practicability of tracheal intubation after the induction of anaesthesia. Patients with compromized airways in a severe degree have to be tracheotom‐ ized in local anaesthesia before microscopic laryngoscopy is performed. A set of instruments for a coniotomy is to be provided. In some cases the anterior larynx cannot be adjusted without the risk of damage of the upper teeth. Exposure can be achieved by using smaller laryngo‐

It is not an unusal finding that cardiadic arrhythmias occur during direct laryngoscopy but they clear all spontaneously. Continuous anaesthetical monitoring discovers them and

therefore the affected children do not need a tracheostomy.

application of cortisone and recently by propranolol alone.

of the vocal chord or applicates Botulinum toxin [50].

scopes and additionally by impressing the larynx.

medication can stop them if necessary.

**2.9. Disadvantages**

**2.10. Complications**

*Chronical hyperplastic laryngitis* is predominantly seen in 90 percent in heavy smoking men. Additional working place associated noxious agents as heat, dust and noice-induced overuse of the voice are said to be at least co-factors. Microlaryngoscopic findings are typical. The thickening of the epithelium begins always at the anterior third of the vocal chords and spreads to the whole vocal chords and inner larynx. In advanced cases of expanse leucoplakia and a pathological secretion of a yellow viscous mucous adheres. Sometimes the disease progresses per acute exacerbation. Signs of this procedure are slit shaped ulcers at the free margin of the vocal chords and crimson bulges of oedema at the border from squamous to cylindrical epithelium. Carcinoma can follow. Resection of nearly all hyperplastic area via microlayngo‐ scope is the symptomatic therapy of choice. It lasts about 4 to 8 weeks till re-epithelisation of a vocal chord is finished. In this period a stingent ban on smoking is to order.

*Contact granuloma* and *contact pachydermia* are two pathogenetic identical but independent diseases caused by vocal abuse and strike of the processus vocales against each other with following formation of granulation tissue. This can be connected with dysphagia, odynopha‐ gia, scratching, sensation of foreign body and haemoptysis. Sometimes granulomas are rejected spontaneously. In other cases the granuloma persists over months and years which are forming bilateral cranial and caudal from the processus vocalis lip-like bulges (in America the Jackson`s "contact ulcer", which is not realy an ulcer - there is no loss of substance) and dash against each other during phonation. All transitions to the typical dish-shaped epithe‐ liazed contact pachyderms are seen. Despite careful microsurgical resection and postoperat‐ vive voice training local recurrences frequently arise.

*Intubation granulomata* are caused by too large sized larynotracheal tubes which excoriate the processus vocales almost one-sided (Figure 7). Depending on their growth they get a pendu‐ alted form and can be rejected and expectorated spantaneously. Recurrences after resection are seen not infrequently, additionally applicaion of cortison should minimize them.

**Figure 7.** Intubation granuloma in the posterior third of the right vocal chord.

*"Juvenile" papillomata* are to be revoved repeatedly because of their tendency of frequent recurrences: optionally by cold instruments, laser, ultrasound, cryocautery or electrocoagula‐ tion. Additional mitomycin is applied. It is of importance to work organ preserving. The essential advantage nowadays is that the surgical percedure is performed endolaryngeal and therefore the affected children do not need a tracheostomy.

*Haemangioma* of the larynx are congenital and become symptomatical several months post‐ partal with the general growth. They are treated by laser resection and additional long-term application of cortisone and recently by propranolol alone.

The incidence of laryngeal *mycosis* is increasing caused by more patients with immunosup‐ pressive therapy and AIDS. In Europe candida albicans and aspergillosis as endomycosis are of clinical relevance. The affection of the larynx is predominantly secondary, the mucous membrane is discrete swollen and reddened, typical off-white coatings are seen only exep‐ tionally and it looks like a chronic laryngitis. The basic concept of the diagnosis is still the microbiological demonstration of the pathogenic agent. Systemic antimycotic drugs are given.

Laryngeal *synechia* can be differentiated by location into anterior vocal chords ones, posterior interarytaenoid ones and false chord ones. Anterior synechia can be congenital and are very rare and then aquired more frequent as complication after microlaryngeal surgery. Resection of the narrowing and movement blocking scar tissue is difficile and recurrences many times arise. Cortison and mitomycin is applied additionally. Subglottic annulare stenosis "*pinhole aperture synechia*" are sequels of artificial ventilation and are resectable with out the need of inserting a dilitator. *"Cricoidal stenosis"* caused by diminution of the cricoidal cartilage are funnel-shaped and not to be treated endolaryngeal but resected by an external approach.

*Unilateral pareses* of the i*nferior laryngeal nerv* are treated by a phoniatric training, improvement of voice in defintive unilateral pareses demands an injection of the vocal chord for example with Teflon®. In cases of *acute bilateral paresis* of the *inferior layryngeal nerve* a tracheotmy is only to be avoided when a larynologist performs immediately a posterior chordectomy including a resection of the processus vocalis or partial arytaenoidectomy or a (temporary) laterofixation of the vocal chord or applicates Botulinum toxin [50].

### **2.9. Disadvantages**

epithelial debridment there should be prevented to avoid synechias. The subepthelial mucous

*Chronical hyperplastic laryngitis* is predominantly seen in 90 percent in heavy smoking men. Additional working place associated noxious agents as heat, dust and noice-induced overuse of the voice are said to be at least co-factors. Microlaryngoscopic findings are typical. The thickening of the epithelium begins always at the anterior third of the vocal chords and spreads to the whole vocal chords and inner larynx. In advanced cases of expanse leucoplakia and a pathological secretion of a yellow viscous mucous adheres. Sometimes the disease progresses per acute exacerbation. Signs of this procedure are slit shaped ulcers at the free margin of the vocal chords and crimson bulges of oedema at the border from squamous to cylindrical epithelium. Carcinoma can follow. Resection of nearly all hyperplastic area via microlayngo‐ scope is the symptomatic therapy of choice. It lasts about 4 to 8 weeks till re-epithelisation of

*Contact granuloma* and *contact pachydermia* are two pathogenetic identical but independent diseases caused by vocal abuse and strike of the processus vocales against each other with following formation of granulation tissue. This can be connected with dysphagia, odynopha‐ gia, scratching, sensation of foreign body and haemoptysis. Sometimes granulomas are rejected spontaneously. In other cases the granuloma persists over months and years which are forming bilateral cranial and caudal from the processus vocalis lip-like bulges (in America the Jackson`s "contact ulcer", which is not realy an ulcer - there is no loss of substance) and dash against each other during phonation. All transitions to the typical dish-shaped epithe‐ liazed contact pachyderms are seen. Despite careful microsurgical resection and postoperat‐

*Intubation granulomata* are caused by too large sized larynotracheal tubes which excoriate the processus vocales almost one-sided (Figure 7). Depending on their growth they get a pendu‐ alted form and can be rejected and expectorated spantaneously. Recurrences after resection

*"Juvenile" papillomata* are to be revoved repeatedly because of their tendency of frequent recurrences: optionally by cold instruments, laser, ultrasound, cryocautery or electrocoagula‐ tion. Additional mitomycin is applied. It is of importance to work organ preserving. The

are seen not infrequently, additionally applicaion of cortison should minimize them.

a vocal chord is finished. In this period a stingent ban on smoking is to order.

vive voice training local recurrences frequently arise.

**Figure 7.** Intubation granuloma in the posterior third of the right vocal chord.

is to be sucked carefully.

154 Endoscopy

General anaesthesia is essential for microscopic laryngoscopy because of the required length of time and the inconveniences to the patient if not applied. Risks of general anaesthesia can be deminished by a close prepoerative examination of all vital functions. It is in the responsi‐ bility of the laryngologist to estimate the practicability of tracheal intubation after the induction of anaesthesia. Patients with compromized airways in a severe degree have to be tracheotom‐ ized in local anaesthesia before microscopic laryngoscopy is performed. A set of instruments for a coniotomy is to be provided. In some cases the anterior larynx cannot be adjusted without the risk of damage of the upper teeth. Exposure can be achieved by using smaller laryngo‐ scopes and additionally by impressing the larynx.

### **2.10. Complications**

It is not an unusal finding that cardiadic arrhythmias occur during direct laryngoscopy but they clear all spontaneously. Continuous anaesthetical monitoring discovers them and medication can stop them if necessary.

Obtruction of the airway by compression or kinking of the flexible intratracheal ventilation tube is a serious problem and the prevention requires constant attention from both, the anaesthesiologist and the endoscopist.

section of the glottic level. Further clinical experience pointed out that this technique is also

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency…

The jet laryngoscope used by us and first described by Aloy et al. 1990 [53] is originally a larynx endoscopy tube [54] which was modified by incorporation of fix jet nozzles (Figure 8).

Carl Reiner Ltd. Company with limited liability, Viennna, Austria) with a connexion for the low-frequency (LF) and high-frequency (HF) jet gas at the left proximal side. Opposite at the right side there is the connexion of the monitor‐ ing. At the basis of the grip of the laryngoscope lies the aperture for the feeding of the moistened and warmed-up

The findings of flow dynamic measurements at the lung simulator served for the basic conception of the construction of this jet laryngoscope. Experiences with nozzles suspend‐ ed in standard laryngoscopes achieved success. To attain a sufficient tidal volume, under the utilization of the Venturi Effect, the size of the jet nozzle as well as its localisation and adjustment play a major role. This was demonstrated in corresponding investigations. The gas jet, entering the laryngoscope, must not be directed to the opposite wall but should be targeted to the caudal direction at the virtual central point of the distal end of the tube finding the continuation median in the trachea. The optimal angle of incidence is 18 degrees. As aperture of the nozzles which influences the effectivity of the jet beam 1.8 mm was chosen. At the right side of the laryngoscope there is a conduction fixed ending at the tip of the laryngoscope used for the measurement of the ventilation pressure and oxygen

according to ALOY (Carl Reiner Jet Laryngoscope,

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implementable in cases of severe stenosis in front of the tip of the endoscope.

**3.1. Construction of the jet laryngoscope**

**Figure 8.** Jet laryngoscope according to KLEINSASSER for SHFJV®

ventilation gas.

concentration (Figure 9).

Post-extubation laryngospasm is a severe complication and are to be kept to a minimum if anaesthetic experts anticipate and prevent them.

Although the incidence of dental fracture is very low the chipping of enamel by friction is seen more especially when the laryngoscope is in contact with unprotected teeth.

If the operative manipulation leads to a dramatic narrowing of the airway by oedema an elective tracheotomy is to be performed. Minor oedemas in the larynx are treated by intrave‐ nious applied cortisone. Cortisone is additionally given to prevent postoperatively the formation of endo-laryngotracheal citatrices and following synechiae and webs.

Tearing, contusion and haematoma of the lips, tongue or pharyngeal wall can be avoided by gentle introduction of the laryngoscope.

In few cases an overexpansion causes a palsy of the hypopharyngeal or glossopharyngeal or lingual nerve. Although very seldom taste disturbances are refered.

Bleedings after biopsies are staunched by swabing with adrenalin resepctively by welldirected monopolar cauterization. Bleeding is the main complication after laser surgery.

#### **2.11. Postoperative procedures**

Untill recover of one`s voice is recured a rest is indicated with avoidance of susurration, coughing and harrumph. Coughing depressing and secretolythic agents are helpful in this phase. A normal theme of speech is considered as possible after healing of the alteration and laryngological investigation. Phoniatric exercises are a useful help for voice rehabilitation especially in cases of functional causation and after removal of a Reinke-oedema or a chronic laryngitis or resection of a vocal chord or an arytaenoidectomy. Antibiotics are prescribed only when enlarged surgical operations like partial endoscopic tumorresection or arytaenoidecto‐ mies were performed. Humid inhalations are to be recommended in any case.

### **3. Low-frequency and high-frequency jet ventilation: Technical basics and special considerations for clinical application**

The supraglottic jet ventilation is a technique whereby the ventilation gas is emitted by a jet injector above the glottic level via an endoscope. The superimposed high-frequency jet ventilation, used by us [51], represents a supraglottical jet ventilation and needs an endoscope, a jet laryngoscope, with two integrated jet nozzles for ventilation. Ng [52] localizes the jet nozzles for the supraglottic jet ventilation at the distal end of the endoscope nearby the tip of the endoscope and thus immediately in front of the glottis. On the contrary we put the jet nozzles more proximal far away from the tip of the endoscope. Initially this ventilation technique was applicated preferential in laryngeal interventions without reduction in cross section of the glottic level. Further clinical experience pointed out that this technique is also implementable in cases of severe stenosis in front of the tip of the endoscope.

### **3.1. Construction of the jet laryngoscope**

Obtruction of the airway by compression or kinking of the flexible intratracheal ventilation tube is a serious problem and the prevention requires constant attention from both, the

Post-extubation laryngospasm is a severe complication and are to be kept to a minimum if

Although the incidence of dental fracture is very low the chipping of enamel by friction is seen

If the operative manipulation leads to a dramatic narrowing of the airway by oedema an elective tracheotomy is to be performed. Minor oedemas in the larynx are treated by intrave‐ nious applied cortisone. Cortisone is additionally given to prevent postoperatively the

Tearing, contusion and haematoma of the lips, tongue or pharyngeal wall can be avoided by

In few cases an overexpansion causes a palsy of the hypopharyngeal or glossopharyngeal or

Bleedings after biopsies are staunched by swabing with adrenalin resepctively by welldirected monopolar cauterization. Bleeding is the main complication after laser surgery.

Untill recover of one`s voice is recured a rest is indicated with avoidance of susurration, coughing and harrumph. Coughing depressing and secretolythic agents are helpful in this phase. A normal theme of speech is considered as possible after healing of the alteration and laryngological investigation. Phoniatric exercises are a useful help for voice rehabilitation especially in cases of functional causation and after removal of a Reinke-oedema or a chronic laryngitis or resection of a vocal chord or an arytaenoidectomy. Antibiotics are prescribed only when enlarged surgical operations like partial endoscopic tumorresection or arytaenoidecto‐

**3. Low-frequency and high-frequency jet ventilation: Technical basics and**

The supraglottic jet ventilation is a technique whereby the ventilation gas is emitted by a jet injector above the glottic level via an endoscope. The superimposed high-frequency jet ventilation, used by us [51], represents a supraglottical jet ventilation and needs an endoscope, a jet laryngoscope, with two integrated jet nozzles for ventilation. Ng [52] localizes the jet nozzles for the supraglottic jet ventilation at the distal end of the endoscope nearby the tip of the endoscope and thus immediately in front of the glottis. On the contrary we put the jet nozzles more proximal far away from the tip of the endoscope. Initially this ventilation technique was applicated preferential in laryngeal interventions without reduction in cross

mies were performed. Humid inhalations are to be recommended in any case.

**special considerations for clinical application**

more especially when the laryngoscope is in contact with unprotected teeth.

formation of endo-laryngotracheal citatrices and following synechiae and webs.

lingual nerve. Although very seldom taste disturbances are refered.

anaesthesiologist and the endoscopist.

156 Endoscopy

gentle introduction of the laryngoscope.

**2.11. Postoperative procedures**

anaesthetic experts anticipate and prevent them.

The jet laryngoscope used by us and first described by Aloy et al. 1990 [53] is originally a larynx endoscopy tube [54] which was modified by incorporation of fix jet nozzles (Figure 8).

**Figure 8.** Jet laryngoscope according to KLEINSASSER for SHFJV® according to ALOY (Carl Reiner Jet Laryngoscope, Carl Reiner Ltd. Company with limited liability, Viennna, Austria) with a connexion for the low-frequency (LF) and high-frequency (HF) jet gas at the left proximal side. Opposite at the right side there is the connexion of the monitor‐ ing. At the basis of the grip of the laryngoscope lies the aperture for the feeding of the moistened and warmed-up ventilation gas.

The findings of flow dynamic measurements at the lung simulator served for the basic conception of the construction of this jet laryngoscope. Experiences with nozzles suspend‐ ed in standard laryngoscopes achieved success. To attain a sufficient tidal volume, under the utilization of the Venturi Effect, the size of the jet nozzle as well as its localisation and adjustment play a major role. This was demonstrated in corresponding investigations. The gas jet, entering the laryngoscope, must not be directed to the opposite wall but should be targeted to the caudal direction at the virtual central point of the distal end of the tube finding the continuation median in the trachea. The optimal angle of incidence is 18 degrees. As aperture of the nozzles which influences the effectivity of the jet beam 1.8 mm was chosen. At the right side of the laryngoscope there is a conduction fixed ending at the tip of the laryngoscope used for the measurement of the ventilation pressure and oxygen concentration (Figure 9).

On the other hand via a second nozzle during the low-frequent inspiration and the subsequent expiration a continous high-frequent gas application is conducted and is additionally super‐ imposed to the low-frequent jet ventilation causing a minimal enhancement of the inspiratory pressure plateau. In the expiration sphase of the low-frequent jet ventilation there exists only the high-frequent jet. The high-frequent jet portion (frequency from 20 to1500 impulses per minute; 0.3 to 25 Hz) produces a lower pressure plateau corresponding to an end-espiratory

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Ventilation via a complete open system with two different pressure plateaus is generated.

Working pressure of the gas leaving the jet nozzle: 0.03-0.04 bar/kg body weight.

Frequency: 12-20 impulses/min (adults), 20-30 impulses/min (children).

Working pressure of the gas leaving the jet nozzle: 0.02 bar/kg body weight.

The periods of inspration and exspiration of the normo-frequent as well as the high-frequent jet gases are to be adjusted variable. It is a *time- and pressure controlled ventilation* at two pressure

The development of the jet ventilation with two jet streams made it mandatory to design a specific respirator (Figure 11). An electronic respirator enabling the low- and highfrequent gas application was developed. Simultaneously the pinside of the endoscope measured ventilation pressures are digital and graphically represented, just as the adjust‐ ed and measured FIO2. Furthermore a laser mode is practicable reducing automatically the FIO2. The ventilation parameters are recorded and an integrated pressure limitation reacts to a too high pressure and also to a pressure drop. Therefore a barotrauma can be avoided with greatest certainty. After the input of patients body weight the ventilation is started with a default setting of the device. The connection with the jet laryngoscope is made by two not confusable jet hose couplings. Moreover the respirator includes different usable ventilation modes for the application of bronchoscopy and infraglottic one-lumen catheter

pressure plateau, corresponding to an end-expiratory pressure (PEEP).

**3.3. Pressure profile in the lung**

plateaus with decelerating flow.

**3.4. Adjustment of the respirator**

*Variable parameter of the low-frequency jet ventilation*:

Inspiration/Exspiration ratio: primary 1:2 or 1:1.

Frequency variable: 100-1500 impulses/min.

**3.5. Respirator**

techniques.

Inspiration/Exspiration ratio: primary 1:2 or 1:1.

*Variable parameter of the high-frequency jet ventilation*:

**Figure 9.** Schematical drawing of the gas flow in the jet laryngoscope (two jet nozzles) and of the pressure measure‐ ment and oxygen concentration (FIO2) at the tip of the endoscope (yellow nozzle).

#### **3.2. Ventilation technique**

The simultaneous application of a jet stream with low- (normo- upto lowfrequent) frequency (12-20 impulses per minute; 0.2 - 0.3 Hz) and a further jet stream with high-frequency is performed via a jet nozzle. The low-frequent jet produces a high, superior pressure plateau representing the inspiration phase with a sufficient tidal volume (Figure 10). This is followed by breathing space of expiration.

**Figure 10.** Relationship of pressure and flow during simultaneous low-frequency and high-frequency jet ventilation.

On the other hand via a second nozzle during the low-frequent inspiration and the subsequent expiration a continous high-frequent gas application is conducted and is additionally super‐ imposed to the low-frequent jet ventilation causing a minimal enhancement of the inspiratory pressure plateau. In the expiration sphase of the low-frequent jet ventilation there exists only the high-frequent jet. The high-frequent jet portion (frequency from 20 to1500 impulses per minute; 0.3 to 25 Hz) produces a lower pressure plateau corresponding to an end-espiratory pressure plateau, corresponding to an end-expiratory pressure (PEEP).

### **3.3. Pressure profile in the lung**

Ventilation via a complete open system with two different pressure plateaus is generated.

The periods of inspration and exspiration of the normo-frequent as well as the high-frequent jet gases are to be adjusted variable. It is a *time- and pressure controlled ventilation* at two pressure plateaus with decelerating flow.

### **3.4. Adjustment of the respirator**

*Variable parameter of the low-frequency jet ventilation*:

Working pressure of the gas leaving the jet nozzle: 0.03-0.04 bar/kg body weight.

Frequency: 12-20 impulses/min (adults), 20-30 impulses/min (children).

Inspiration/Exspiration ratio: primary 1:2 or 1:1.

*Variable parameter of the high-frequency jet ventilation*:

Working pressure of the gas leaving the jet nozzle: 0.02 bar/kg body weight.

Frequency variable: 100-1500 impulses/min.

Inspiration/Exspiration ratio: primary 1:2 or 1:1.

#### **3.5. Respirator**

**3.2. Ventilation technique**

158 Endoscopy

by breathing space of expiration.

The simultaneous application of a jet stream with low- (normo- upto lowfrequent) frequency (12-20 impulses per minute; 0.2 - 0.3 Hz) and a further jet stream with high-frequency is performed via a jet nozzle. The low-frequent jet produces a high, superior pressure plateau representing the inspiration phase with a sufficient tidal volume (Figure 10). This is followed

**Figure 9.** Schematical drawing of the gas flow in the jet laryngoscope (two jet nozzles) and of the pressure measure‐

ment and oxygen concentration (FIO2) at the tip of the endoscope (yellow nozzle).

**Figure 10.** Relationship of pressure and flow during simultaneous low-frequency and high-frequency jet ventilation.

The development of the jet ventilation with two jet streams made it mandatory to design a specific respirator (Figure 11). An electronic respirator enabling the low- and highfrequent gas application was developed. Simultaneously the pinside of the endoscope measured ventilation pressures are digital and graphically represented, just as the adjust‐ ed and measured FIO2. Furthermore a laser mode is practicable reducing automatically the FIO2. The ventilation parameters are recorded and an integrated pressure limitation reacts to a too high pressure and also to a pressure drop. Therefore a barotrauma can be avoided with greatest certainty. After the input of patients body weight the ventilation is started with a default setting of the device. The connection with the jet laryngoscope is made by two not confusable jet hose couplings. Moreover the respirator includes different usable ventilation modes for the application of bronchoscopy and infraglottic one-lumen catheter techniques.

**Figure 11.** Jet respirator for the combined high-frequent and low-frequent jet ventilation (Twin Stream TM multimode respirator, Carl Reiner Ltd. Company with limited liability, Vienna, Austria). The continuous airway pressure is displayed in the left upper corner. The top right part shows the adjustable pressure limitation. In the middle left the digital air‐ way pressure and in the center of the display the inspiratory oxygen concentration is displayed. On the lower left side the low-frequency jet unit can be seen and on the right there is the high-frequency jet unit.

### **3.6. Physical effects during ventilation**

#### *3.6.1. Gas velocity*

The applicated ventilation gas (oxygen/air mixture) is a fluid with 1 to 1.5 bar of pressure of at the nozzle. At the tip of the laryngoscope a decompression of a 100 fold occurs so that there are registrated pressures of 20 mbar. The flow velocity can achieve at the discharge of the nozzle up to 300 m/sec, but at the tip of tube it is also distinctly shortened and represents less than 100 m/sec [55].

#### *3.6.2. Characteristics of the gas flow – Computational fluid dynamics*

The computational fluid dynamics performed by us shows that during application of super‐ imposed high-frequency jet ventilation via the jet laryngoscope an *asymmetric bi-directional gas flow* occurs in the jet laryngoscope (Figure 12).

**Figure 13.** Schema of the characteristics of the free jet as it ejects from the nozzle. A typical deformation of the profile

**Figure 12.** Charactristics of the gas flow in the jet endoscope: flow of the gas leaving the nozzles with high velocity (yellow) towards left side to the virtual tip of the endoscope. Additionally a fluid flow exists towards left side with decreasing velocity (light blue) directed to the tip of the endoscope. At the opposite side of the endoscope there is a

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The described position of the nozzles causes a typical behaviour of the pressure, as shown in Figure 14. In front of the nozzles a negative pressure occurs, which comes to its maximum

Due to the nozzles ending in the first section of the jet laryngoscope the Venturi–effect takes

place far away from the surgical area, suction and spraying of blood is prevented.

Only after the nozzles the pressure in the laryngoscope increases.

of the beams respectively the stream and an entrainment of the (rim) boundary zone is demonstrated.

*3.6.4. Characteristics of pressure in the jet laryngoscope*

flow (dark blue) toward right side outwards.

immediately after the aperture of the jet nozzles.

#### *3.6.3. Free-jet*

The gas stream emitted from the particular jet nozzle is a free jet inducing an entrainment of surrounding air at the rim caused by an occurring discontinuity [56]. This entrainment is also the reason why the oxygen concentration adjusted from the respirator is diminished at the tip of the endoscope. The beams respectively the stream becomes progressively broader and his velocity decelerates (Figure 13).

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**Figure 12.** Charactristics of the gas flow in the jet endoscope: flow of the gas leaving the nozzles with high velocity (yellow) towards left side to the virtual tip of the endoscope. Additionally a fluid flow exists towards left side with decreasing velocity (light blue) directed to the tip of the endoscope. At the opposite side of the endoscope there is a flow (dark blue) toward right side outwards.

**Figure 13.** Schema of the characteristics of the free jet as it ejects from the nozzle. A typical deformation of the profile of the beams respectively the stream and an entrainment of the (rim) boundary zone is demonstrated.

#### *3.6.4. Characteristics of pressure in the jet laryngoscope*

**Figure 11.** Jet respirator for the combined high-frequent and low-frequent jet ventilation (Twin Stream TM multimode respirator, Carl Reiner Ltd. Company with limited liability, Vienna, Austria). The continuous airway pressure is displayed in the left upper corner. The top right part shows the adjustable pressure limitation. In the middle left the digital air‐ way pressure and in the center of the display the inspiratory oxygen concentration is displayed. On the lower left side

The applicated ventilation gas (oxygen/air mixture) is a fluid with 1 to 1.5 bar of pressure of at the nozzle. At the tip of the laryngoscope a decompression of a 100 fold occurs so that there are registrated pressures of 20 mbar. The flow velocity can achieve at the discharge of the nozzle up to 300 m/sec, but at the tip of tube it is also distinctly shortened and represents less

The computational fluid dynamics performed by us shows that during application of super‐ imposed high-frequency jet ventilation via the jet laryngoscope an *asymmetric bi-directional gas*

The gas stream emitted from the particular jet nozzle is a free jet inducing an entrainment of surrounding air at the rim caused by an occurring discontinuity [56]. This entrainment is also the reason why the oxygen concentration adjusted from the respirator is diminished at the tip of the endoscope. The beams respectively the stream becomes progressively broader and his

the low-frequency jet unit can be seen and on the right there is the high-frequency jet unit.

*3.6.2. Characteristics of the gas flow – Computational fluid dynamics*

*flow* occurs in the jet laryngoscope (Figure 12).

velocity decelerates (Figure 13).

**3.6. Physical effects during ventilation**

*3.6.1. Gas velocity*

160 Endoscopy

than 100 m/sec [55].

*3.6.3. Free-jet*

The described position of the nozzles causes a typical behaviour of the pressure, as shown in Figure 14. In front of the nozzles a negative pressure occurs, which comes to its maximum immediately after the aperture of the jet nozzles.

Due to the nozzles ending in the first section of the jet laryngoscope the Venturi–effect takes place far away from the surgical area, suction and spraying of blood is prevented.

Only after the nozzles the pressure in the laryngoscope increases.

**Figure 14.** Characteristics of the pressure in the jet laryngoscope under the application of three different ventilation modes. On the outside (left) of the endoscope a moderate negative pressure originates when gas is emitted at jet nozzles. In the area of the nozzles the pressure becomes strongly negative. Then a positive pressure originates in the direction of the tip of the endoscope (right).

#### *3.6.5. The Joule Thomson effect*

Real gases cool when expanding without performing work (against an external pressure) [57, 58]. The increase of the volume enlarges the median distance of the gas molecules. Work is to be applied against the intermolecular attracting forces. The potential energy of the system grows at the cost of the kinetic energy of the gas molecules and therefore the temperature drops. Due to this effect during prolonged mechanical ventilation, heating and humidification of the respiratory gas is needed to avoid damage to the mucous membrane in the trachea.

Recent developments and clinical experiences with superimposed high-frequency jet ventila‐

**Figure 15.** Device for moistening and warming-up of the respiration gas. The central unit (white) incorporates the electronical control unit. The humidifying chamber (blue) for single or multiple use is fixed at the central unit. The tub‐ ing system (yellow) is splitted in a short tube which transports the ventilation gas coming from the respirator to the humidifying chamber, and in a long tube which transports the now moistioned and warmed-up gas from the humifid‐ ier chamber to the jet laryngoscope. The distal part of the long tube is metallic and is connected to the jet laryngo‐

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This method is suitable for laryngotracheal diseases in adults and also excellent in infants and children [60, 61]. Additional, special indications for jet ventilation are supraglottic, glottic, subglottic and tracheal stenoses. Further applications are the ventilation during bronchoscopy, the percutaneous dilatation tracheostomy (PDT) [62] and the placement of airway stents and

Endolaryngeal and -trachel surgery always burdens from the situation in the operation area which is to share with the anaesthesiologists. An endotracheal tube narrows the view for endoscopic examination and surgery in the larynx and in particular in the trachea. Stenotic areas cause respiratory insufficiency and often can not be passed by a tube however small they may be. A safe ventilation technique, the superimposed high-frequency jet ventilation (SHFJV), which allows the laryngotracheal surgeon optimal conditions for diagnosis and surgical procedures was invented by Aloy 1990 [63].This tubeless method, described in detail before, became rapidly the anaesthetic method of choice for laryngotracheal operations at our Department of Otolaryngology in Viennna [64, 65] (Figure 16). The following report stresses out in general our experiences when laryngotracheal surgery is performed under SHFJV.

tion demonstrate that a broad spectrum of clinical application is practicable [59].

the treatment of acute respiratory distress syndrome (ARDS).

scope.

**4. Tubeless laryngotracheal surgery via jet ventilation**

#### **3.7. Influence on physical effects**

#### *3.7.1. Moistening and warming of the respiratory gas*

Further development of the jet laryngoscopes allows now the continuous moistening and warming of the respiratory gas. The gas is supplied via a so-called bias-flow to a moistening device and is moistened and warmed inside (Figure 15).

#### *3.7.2. Entrainment of the gas*

Due to the installation of an aperture in the grip of the endoscope oxygen enters the laryngo‐ scope replacing the entrainment of surrounding air. Therefore the oxygen concentration remains the same as it leaves the jet nozzles. Thereby at first the entrainment of the air in the laryngoscope is reduced and as second the ventilation gas is moistened and as third it is warmed-up. Although physical effects cannot be eliminated completely, they can be dimin‐ ished in their intensity nevertheless.

**Figure 15.** Device for moistening and warming-up of the respiration gas. The central unit (white) incorporates the electronical control unit. The humidifying chamber (blue) for single or multiple use is fixed at the central unit. The tub‐ ing system (yellow) is splitted in a short tube which transports the ventilation gas coming from the respirator to the humidifying chamber, and in a long tube which transports the now moistioned and warmed-up gas from the humifid‐ ier chamber to the jet laryngoscope. The distal part of the long tube is metallic and is connected to the jet laryngo‐ scope.

Recent developments and clinical experiences with superimposed high-frequency jet ventila‐ tion demonstrate that a broad spectrum of clinical application is practicable [59].

This method is suitable for laryngotracheal diseases in adults and also excellent in infants and children [60, 61]. Additional, special indications for jet ventilation are supraglottic, glottic, subglottic and tracheal stenoses. Further applications are the ventilation during bronchoscopy, the percutaneous dilatation tracheostomy (PDT) [62] and the placement of airway stents and the treatment of acute respiratory distress syndrome (ARDS).

### **4. Tubeless laryngotracheal surgery via jet ventilation**

**Figure 14.** Characteristics of the pressure in the jet laryngoscope under the application of three different ventilation modes. On the outside (left) of the endoscope a moderate negative pressure originates when gas is emitted at jet nozzles. In the area of the nozzles the pressure becomes strongly negative. Then a positive pressure originates in the

Real gases cool when expanding without performing work (against an external pressure) [57, 58]. The increase of the volume enlarges the median distance of the gas molecules. Work is to be applied against the intermolecular attracting forces. The potential energy of the system grows at the cost of the kinetic energy of the gas molecules and therefore the temperature drops. Due to this effect during prolonged mechanical ventilation, heating and humidification of the respiratory gas is needed to avoid damage to the mucous membrane in the trachea.

Further development of the jet laryngoscopes allows now the continuous moistening and warming of the respiratory gas. The gas is supplied via a so-called bias-flow to a moistening

Due to the installation of an aperture in the grip of the endoscope oxygen enters the laryngo‐ scope replacing the entrainment of surrounding air. Therefore the oxygen concentration remains the same as it leaves the jet nozzles. Thereby at first the entrainment of the air in the laryngoscope is reduced and as second the ventilation gas is moistened and as third it is warmed-up. Although physical effects cannot be eliminated completely, they can be dimin‐

direction of the tip of the endoscope (right).

**3.7. Influence on physical effects**

*3.7.2. Entrainment of the gas*

ished in their intensity nevertheless.

*3.7.1. Moistening and warming of the respiratory gas*

device and is moistened and warmed inside (Figure 15).

*3.6.5. The Joule Thomson effect*

162 Endoscopy

Endolaryngeal and -trachel surgery always burdens from the situation in the operation area which is to share with the anaesthesiologists. An endotracheal tube narrows the view for endoscopic examination and surgery in the larynx and in particular in the trachea. Stenotic areas cause respiratory insufficiency and often can not be passed by a tube however small they may be. A safe ventilation technique, the superimposed high-frequency jet ventilation (SHFJV), which allows the laryngotracheal surgeon optimal conditions for diagnosis and surgical procedures was invented by Aloy 1990 [63].This tubeless method, described in detail before, became rapidly the anaesthetic method of choice for laryngotracheal operations at our Department of Otolaryngology in Viennna [64, 65] (Figure 16). The following report stresses out in general our experiences when laryngotracheal surgery is performed under SHFJV.

**Figure 16.** Microlaryngoscopy under superimposed high-frequency jet ventilation (SHFJV)

**Figure 17.** Long micro instruments for the operative procedure in the larynx and in the trachea.

At our department of otorhinolaryngology in Vienna, Austria 2123 micro laryngeal/tracheal surgical interventions were made under SHFJV from 1990 up to December 2011 using micro instruments demonstrated in Figure 17. Diagnoses and number of patients is demonstrated in the following Table 1.

The continuous pressure control of the SHFJV- device could ward a barotrauma in our

**Figure 18.** Cyst at the free margin of the right vocal chord anterior half with free access to the operation area.

**Table 1.** Diagnoses of patients undergoing micro laryngeal/tracheal surgery with superimposed high-frequency jet

The jet ventilation has proven to be most suited for patients with normal, unobstructed airways and normal lung and chest wall compliance (Figure 18). Reduced chest wall compliance such as in obesity (body mass index >35) may lead to unmeant gastric insufflation and distension causing worsening of the respiratory compliance. A significant overbite especially in combi‐ nation with retrognathia makes laryngotracheal placement of the ventilation laryngoscope

**4.1. Contraindications of SHFJV in laryngotracheal surgery**

impracticable and the incidence of accidental gastric hyperinflation is high.

**Diagnoses Total (n=2123) Percent (100%)**

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19.0 12.8 5.7 5.5 12.2 10.4 8.1 2.1 3.4 2.7 3.3 4.4 2.5 3.9 1.5 2.5

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application in any case.

Laryngeal carcinoma Vocal chord leucoplakia Laryngeal papillomatosis Chronic laryngitis Vocal chord polyp Reinke`s oedema

Laryngeal/tracheal stenosis Bilateral vocal chord paralysis Unilateral vocal chord paralysis

Vocal chord nodule Vocal chord granuloma Vocal chord cyst Vocal chords synechia Supraglottic cyst Phonosurgery Others

ventilation (SHFJV).

If it becomes necessary that the vocal chords are in a complete standstill in fine phonosurgical interventions it is easy and hazard-free to interrupt the jet ventilation for a few seconds.

We never saw complications associated with jet ventilation which include inadequate oxygenation and ventilation, severe dehydration of the mucosa, gastric distension, regurgi‐ tation, and even gastric rupture. Pneumomediastinum or pneumothorax have been reported, and occurs mostly when applying jet ventilation with an obstructed airway [66]. Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency… http://dx.doi.org/10.5772/52996 165


**Table 1.** Diagnoses of patients undergoing micro laryngeal/tracheal surgery with superimposed high-frequency jet ventilation (SHFJV).

**Figure 18.** Cyst at the free margin of the right vocal chord anterior half with free access to the operation area.

The continuous pressure control of the SHFJV- device could ward a barotrauma in our application in any case.

#### **4.1. Contraindications of SHFJV in laryngotracheal surgery**

**Figure 16.** Microlaryngoscopy under superimposed high-frequency jet ventilation (SHFJV)

**Figure 17.** Long micro instruments for the operative procedure in the larynx and in the trachea.

the following Table 1.

164 Endoscopy

At our department of otorhinolaryngology in Vienna, Austria 2123 micro laryngeal/tracheal surgical interventions were made under SHFJV from 1990 up to December 2011 using micro instruments demonstrated in Figure 17. Diagnoses and number of patients is demonstrated in

If it becomes necessary that the vocal chords are in a complete standstill in fine phonosurgical interventions it is easy and hazard-free to interrupt the jet ventilation for a few seconds.

We never saw complications associated with jet ventilation which include inadequate oxygenation and ventilation, severe dehydration of the mucosa, gastric distension, regurgi‐ tation, and even gastric rupture. Pneumomediastinum or pneumothorax have been reported, and occurs mostly when applying jet ventilation with an obstructed airway [66]. The jet ventilation has proven to be most suited for patients with normal, unobstructed airways and normal lung and chest wall compliance (Figure 18). Reduced chest wall compliance such as in obesity (body mass index >35) may lead to unmeant gastric insufflation and distension causing worsening of the respiratory compliance. A significant overbite especially in combi‐ nation with retrognathia makes laryngotracheal placement of the ventilation laryngoscope impracticable and the incidence of accidental gastric hyperinflation is high.

Expected massive bleeding is an absolute contraindication. However slight bleeding does not reach the trachea and deeper airways because of the high-frequent gas flow with PEEP-effect pressures the blood to the laryngeal respectively tracheal wall and with the expiration it is tranported externally.

**3.** lesions near or in the laryngeal ventricle.

oxygen/air. Nitrous oxide should not be used.

120 minutes, on the average of 42 minutes.

**5.1. Circumscribed carcinoma**

Haereus, Germany or Sharplan 1050; Vörösmarty, Israel).

Anaesthesia for laryngotracheal interventions can be performed with or without endotracheal tubes [67]. As the most servere complication laser induced combustion is considered. Within 635 laser applications under SHFJV at the Department of Otorhinolaryngology of the Medical University of Vienna we had to see in one case an endlaryngeal fire caused by ignition of an erroneous dry swab which was inserted in the subglottic space for laser prevention of the trachea wall. The fire could be extinguished rapidly. After orotracheal intubation a tracheos‐ tomy was performed for the entrence of ventilation. The patient could be discharged from the intensive care unit within 10 days and from hospital after closure of the tracheostomy after 21 days without further essentially respiration problem deriving from this accident, especially there was no stenotic laryngotracheal process [68]. It is clearly to state, that this ignition was not in a causal connection with the SHFJV. The major complication, airway fire, is avoided by SHFJV itself: there is no flammable material in the airway. Other ventilation devices like plastic tubes do not withstand laser strikes and will ignite the longer the laser exposure lasts. Metallic foil-wrapped plastic tubes may injure pharyngeal and laryngotracheal tissues by sharp edges, loose their elasticity and tend to kink. The protective effect is lost if the foil is detached and airway obstruction may occur when parts of the foil is aspirated. The reflexion from the surface bears the risk of damage of surrounding tissues. For a considerable time laser safe endotra‐ cheal-tubes are put up for sale. The disadvantage of these tubes is the size of its diameter. Because of the required material safety these tubes have a large outer diameter and a small inner diameter. In case of a larger stenosis it is not possible to use these endotracheal tubes. But just in cases of stenoses jet ventilation has a major advantage. No tube - no fire when the applied oxygen concentration is low (< 40%). The jet ventilation is done with a mixture of

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The high gas flow dilutes and eliminates the smoke and therefore additional suction for smoke is redundant. Laser laryngotracheal surgery was perfomed with a CO2 laser (Hercules 5040;

Special indications for CO2 laser application in combination with SHFJV in laryngeal diseases are the early glottic cancer [69, 70], the papillomatosis and the stenoses. Indispensable precaution is the internal approval for general anaesthea, the adjustability of the inner laryngealtracheal structures with special attention to the anterior commissure and the expectation of low bleeding. The laser surgical procedures under SHFJV lasted from 15 up to

The preoperative information of the patients include the postoperative bleeding which depends on the extent of the resection. A revision under endotracheal intubation and general anaesthesia and sometimes a tracheotmy will be necessary. The patient has to know that until the definitve histological findings are evident in case of incomplete resection a re-operation will be necessary. Healing of the wound is delayed with functional consequences like hoarse‐ ness and transient aphonia. Synechiae and stenoses rarely occure. After histological confir‐

### **5. CO2 laser micro laryngotracheal surgery during supraglottic jet ventilation**

Three characteristics are the basics of the high energy density of laser:


With laser light, tissue penetration is mostly a function of wavelight. Long-wavelight laser light such as that from CO2 laser (operation at 10,600 nm) is completey absorbed by water in the first few layers of cells. The thermal effect is therefore largely limited to the point of entry into the target tissue. This results in explosive vaporisation of the surface tissue of the target with surprisingly little damage to underlying cells. When coupled to an operating microscope the laser vaporizes the lesions with precision, causing minimal bleeding and oedema: an obvious advantage, especially in small pediatric airways.


**Table 2.** Technique of CO2 laser microsurgery and advantages of laser surgery.

The pulsed dye laser (PDL) has a shorter wavelength and spares the epithelium, but specifically hits the microvascular supply of the lesion. This has an advantage in the anterior laryngeal commissure because not denuting the epithelium is beneficial, it should limit the occurrence of webs. In certain situations, a laser based resection technique is surgical method of choice for:


### **3.** lesions near or in the laryngeal ventricle.

Expected massive bleeding is an absolute contraindication. However slight bleeding does not reach the trachea and deeper airways because of the high-frequent gas flow with PEEP-effect pressures the blood to the laryngeal respectively tracheal wall and with the expiration it is

**5. CO2 laser micro laryngotracheal surgery during supraglottic jet**

**1.** monochromaticity: in a high degree with very limited range of wavelengths,

**Technique of CO2 laser microsurgery Advantages of CO2 laser microsurgery**

**2.** coherence: in the laser beam the electromagnetic fields of all photons oscillate synchro‐

With laser light, tissue penetration is mostly a function of wavelight. Long-wavelight laser light such as that from CO2 laser (operation at 10,600 nm) is completey absorbed by water in the first few layers of cells. The thermal effect is therefore largely limited to the point of entry into the target tissue. This results in explosive vaporisation of the surface tissue of the target with surprisingly little damage to underlying cells. When coupled to an operating microscope the laser vaporizes the lesions with precision, causing minimal bleeding and oedema: an

The pulsed dye laser (PDL) has a shorter wavelength and spares the epithelium, but specifically hits the microvascular supply of the lesion. This has an advantage in the anterior laryngeal commissure because not denuting the epithelium is beneficial, it should limit the occurrence of webs. In certain situations, a laser based resection technique is surgical method of choice

Contactless operating Precise dosing and control Reduced bleeding Reduced risk of infection Less postoperative pain

Three characteristics are the basics of the high energy density of laser:

**3.** collimated beam: laser light remains in a narrow spectrum.

obvious advantage, especially in small pediatric airways.

**Table 2.** Technique of CO2 laser microsurgery and advantages of laser surgery.

tranported externally.

nously in identical phase, and

Wavelength: ~10.000 nm; infrared - invisible Pilotlaser: red (aiming beam), coaxial Micromanipulator for application Focus diameter: 0.3-0.7 mm at a distance of 40 cm

Microscopic magnification: 4 to 40-fold

**2.** lesions in scared areas and

for:

**1.** sessile lesions,

**ventilation**

166 Endoscopy

Anaesthesia for laryngotracheal interventions can be performed with or without endotracheal tubes [67]. As the most servere complication laser induced combustion is considered. Within 635 laser applications under SHFJV at the Department of Otorhinolaryngology of the Medical University of Vienna we had to see in one case an endlaryngeal fire caused by ignition of an erroneous dry swab which was inserted in the subglottic space for laser prevention of the trachea wall. The fire could be extinguished rapidly. After orotracheal intubation a tracheos‐ tomy was performed for the entrence of ventilation. The patient could be discharged from the intensive care unit within 10 days and from hospital after closure of the tracheostomy after 21 days without further essentially respiration problem deriving from this accident, especially there was no stenotic laryngotracheal process [68]. It is clearly to state, that this ignition was not in a causal connection with the SHFJV. The major complication, airway fire, is avoided by SHFJV itself: there is no flammable material in the airway. Other ventilation devices like plastic tubes do not withstand laser strikes and will ignite the longer the laser exposure lasts. Metallic foil-wrapped plastic tubes may injure pharyngeal and laryngotracheal tissues by sharp edges, loose their elasticity and tend to kink. The protective effect is lost if the foil is detached and airway obstruction may occur when parts of the foil is aspirated. The reflexion from the surface bears the risk of damage of surrounding tissues. For a considerable time laser safe endotra‐ cheal-tubes are put up for sale. The disadvantage of these tubes is the size of its diameter. Because of the required material safety these tubes have a large outer diameter and a small inner diameter. In case of a larger stenosis it is not possible to use these endotracheal tubes. But just in cases of stenoses jet ventilation has a major advantage. No tube - no fire when the applied oxygen concentration is low (< 40%). The jet ventilation is done with a mixture of oxygen/air. Nitrous oxide should not be used.

The high gas flow dilutes and eliminates the smoke and therefore additional suction for smoke is redundant. Laser laryngotracheal surgery was perfomed with a CO2 laser (Hercules 5040; Haereus, Germany or Sharplan 1050; Vörösmarty, Israel).

Special indications for CO2 laser application in combination with SHFJV in laryngeal diseases are the early glottic cancer [69, 70], the papillomatosis and the stenoses. Indispensable precaution is the internal approval for general anaesthea, the adjustability of the inner laryngealtracheal structures with special attention to the anterior commissure and the expectation of low bleeding. The laser surgical procedures under SHFJV lasted from 15 up to 120 minutes, on the average of 42 minutes.

#### **5.1. Circumscribed carcinoma**

The preoperative information of the patients include the postoperative bleeding which depends on the extent of the resection. A revision under endotracheal intubation and general anaesthesia and sometimes a tracheotmy will be necessary. The patient has to know that until the definitve histological findings are evident in case of incomplete resection a re-operation will be necessary. Healing of the wound is delayed with functional consequences like hoarse‐ ness and transient aphonia. Synechiae and stenoses rarely occure. After histological confir‐ mation of the initial diagnosis the surgery by CO2 laser with the soft super pulsed mode a nearly char-free cutting via vaporisation is performed.

Dissecting the soft tissue of the tumour is has proven to perform with the micro manipulator fine serrated hither and thihter movements. With this method laser`s physical properties for cutting and coagulation are utilized most effective [71]. Like the study group of our department could show excellent oncological results can be expected in T1a-glottic cancer in comparison to radiotherapy and conventional surgery [72].

Postoperative stridor is mostly due to a swelling of the local mucous membrane and is easy to be treated by cortisone.

### **5.2. Laryngo/tracheal stenosis**

Congenital and aquired stenoses in all regions of the larynx are a prefered indication for CO2 laser surgery (Figures 19, 20, 21). Tubeless ventilation allows the surgeon to operate in an already narrow area.

**Figure 21.** Star-shaped opening of a glottic/subglottic stenosis with CO2 laser under SHFJV.

Accordingly to their biological behavior with multiple recurrences in juvenile papllomatosis repeated interventions are necessary (Figure 22). The CO2 laser in combination with SHFJV [73] offers the opportunity of a safe procedure with preserving the funtional important vocal

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(We thank Prof. W. Bigenzahn from the Department for Phoniatry and Logopaedia of the

Laryngotracheal surgery in infants and children is handicaped by the narrow anatomical area of operations and often additionally by the pathological substrate itself. A special cooperation

**6. Tubeless laryngotracheal surgery in infants and children via jet**

**5.3. Laryngeal papillomatosis (see also part 6)**

**Figure 22.** Glottic and supraglottic recurrence of a juvenile papillomas.

Medical University of Vienna for providing this figure).

chords.

**ventilation**

**Figure 19.** View through the ventilation laryngoscope in position. Tumour caused massive stenosis. In the area of the posterior commissure a residual lumen exists, enabling patient`s spontaneous but stridulous breathing.

**Figure 20.** High grade subglottic stenosis with a substantially reduced lumen.

**Figure 21.** Star-shaped opening of a glottic/subglottic stenosis with CO2 laser under SHFJV.

### **5.3. Laryngeal papillomatosis (see also part 6)**

mation of the initial diagnosis the surgery by CO2 laser with the soft super pulsed mode a

Dissecting the soft tissue of the tumour is has proven to perform with the micro manipulator fine serrated hither and thihter movements. With this method laser`s physical properties for cutting and coagulation are utilized most effective [71]. Like the study group of our department could show excellent oncological results can be expected in T1a-glottic cancer in comparison

Postoperative stridor is mostly due to a swelling of the local mucous membrane and is easy to

Congenital and aquired stenoses in all regions of the larynx are a prefered indication for CO2 laser surgery (Figures 19, 20, 21). Tubeless ventilation allows the surgeon to operate in an

**Figure 19.** View through the ventilation laryngoscope in position. Tumour caused massive stenosis. In the area of the

posterior commissure a residual lumen exists, enabling patient`s spontaneous but stridulous breathing.

**Figure 20.** High grade subglottic stenosis with a substantially reduced lumen.

nearly char-free cutting via vaporisation is performed.

to radiotherapy and conventional surgery [72].

be treated by cortisone.

168 Endoscopy

already narrow area.

**5.2. Laryngo/tracheal stenosis**

Accordingly to their biological behavior with multiple recurrences in juvenile papllomatosis repeated interventions are necessary (Figure 22). The CO2 laser in combination with SHFJV [73] offers the opportunity of a safe procedure with preserving the funtional important vocal chords.

**Figure 22.** Glottic and supraglottic recurrence of a juvenile papillomas.

(We thank Prof. W. Bigenzahn from the Department for Phoniatry and Logopaedia of the Medical University of Vienna for providing this figure).

### **6. Tubeless laryngotracheal surgery in infants and children via jet ventilation**

Laryngotracheal surgery in infants and children is handicaped by the narrow anatomical area of operations and often additionally by the pathological substrate itself. A special cooperation between the surgeon and the anaesthesist is indispensable. Ventilation via an endotracheal tube with a cuff is most safe to operate. But even this endotracheal tube blocks on the one hand the unobstructed view of the operating field and on the other hand the necessary space for surgical activity and additionally mutates the anatomical structures. In cases of pronounced stenoses in the laryngotracheal area an endotracheal intubation cannot be applied. An alternative procedure is the tracheotomy, especially for infants and children and the postop‐ erative care an enormous burden.

**2.** *infraglottic, transoral jet ventilation:* transoral or nasotracheal positioning of a catheter through the glottis deep enough into the trachea. Available if the glottis is not narrowed.

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**3.** *supraglottic jet ventilation:* as an alternative method the authors, Grasl et al. 1997 [80], have presented their experiences in the first use of tubeless superimposed high- and lowfrequency jet ventilation (SHFJV) with a jet laryngoscope in laryngotracheal surgery in infants and children 28 infants and children. This intervention was spread successively [81]. Because of the absence of an additional jet catheter optimal working conditions with best visibility in primarily narrow areas are created. Nowadays jet laryngoscopes with also two intergrated jet nozzles for children are available in different sizes. The transfer of the jet gas takes place at the proximal section of the laryngoscope and not nearby the glottis. The endoscopes are equipped with an integrated ventilation pressure measure‐ ment positioned at the tip. At the grip of the endoscope (Figure 24) there is an aperture for the connection of the moistening and warming of the ventilation gas. On the left side there of upper section of the laryngoscope there are two jet nozzles, on the right side are located a nozzle for the ventilation pressure measurement and a nozzle for the true FIO2 recording. Additional monitorings are the pulsoxymetry, the electrocardiogram and the noninvasive measurement of the blood pressure. We consider because of our complication

The supraglottic jet ventilation offers the surgeon the opportunity to use the CO2 laser [82].

Not available for children because the diameter of the catheter is often more than 5 mm.

free experiences the invasive arterial monitoring as needless.

**Figure 24.** The proximal section of the ventilation laryngoscope for children with all connexions.

Ventilation is carried out by an air/oxygen mixture. If the CO2 laser is used the inspiratory oxygen concentration is reduced to 40 %. In corresponding dose rate propofol is applied as hynoticum, fentanil or remifentanil as analgesia and rocuronium as short effective relaxant. Anaesthesia starts with manual ventilation by a conventional respirator. When relaxation takes effect the jet laryngoscope is placed and jet ventilation starts. After the end of the surgical

**6.2. Anaesthesia**

A rigid bronchoscope used for ventilation restricts the visibility of the working space and it may occur that it cannot pass a stenosis. Laryngotracheal surgery in the apnea technique is still in use but is associated with the heightened risk of hypoxemia and hypercapnia.

An improvement of ventilation of the patient during laryngotracheal surgery was established by single-frequency jet ventilation techniques applied either per percutaneous insertion of a needle into the trachea or endotracheal tubes or catheters, or application of a jet nozzle into the endocopy tube [74, 75]. All these techniques have the disadvantage of the risk of hypo‐ xaemia and hypercapnia especially in patients underlying pulmonary and cardiadic aggra‐ vated risks and operations with a long continuance. Needles placed transtracheal bear the elevated risk of barotrauma because the gas supply takes place below the stenosis [76].

#### **6.1. Ventilation**

As an alternative ventilation technique the jet ventilation presents themselves with 3 modalities:

**1.** *transtracheal jet ventilation* (Figure 23): for endoscopic laryngeal surgery, also with laser, excellent visibility for the surgeon, even in glottic or supraglottic stenoses with minor complications up to 20 % [77-79]. Very important is the bedding of the child with maxi‐ mum extension of the head. This allows fixing the mobile trachea between middle finger and thumb. The cricoid membrane is narrow and at best to be felt by a fingernail. The punction with ventilation catheter is to be directed in a caudal direction.

**Figure 23.** Percutaneous transtracheal jet ventilation catheter (VBM® -Medizintechnik, Germany) for children with steel punction needle.

**2.** *infraglottic, transoral jet ventilation:* transoral or nasotracheal positioning of a catheter through the glottis deep enough into the trachea. Available if the glottis is not narrowed.

Not available for children because the diameter of the catheter is often more than 5 mm.

**3.** *supraglottic jet ventilation:* as an alternative method the authors, Grasl et al. 1997 [80], have presented their experiences in the first use of tubeless superimposed high- and lowfrequency jet ventilation (SHFJV) with a jet laryngoscope in laryngotracheal surgery in infants and children 28 infants and children. This intervention was spread successively [81]. Because of the absence of an additional jet catheter optimal working conditions with best visibility in primarily narrow areas are created. Nowadays jet laryngoscopes with also two intergrated jet nozzles for children are available in different sizes. The transfer of the jet gas takes place at the proximal section of the laryngoscope and not nearby the glottis. The endoscopes are equipped with an integrated ventilation pressure measure‐ ment positioned at the tip. At the grip of the endoscope (Figure 24) there is an aperture for the connection of the moistening and warming of the ventilation gas. On the left side there of upper section of the laryngoscope there are two jet nozzles, on the right side are located a nozzle for the ventilation pressure measurement and a nozzle for the true FIO2 recording. Additional monitorings are the pulsoxymetry, the electrocardiogram and the noninvasive measurement of the blood pressure. We consider because of our complication free experiences the invasive arterial monitoring as needless.

The supraglottic jet ventilation offers the surgeon the opportunity to use the CO2 laser [82].

**Figure 24.** The proximal section of the ventilation laryngoscope for children with all connexions.

### **6.2. Anaesthesia**

between the surgeon and the anaesthesist is indispensable. Ventilation via an endotracheal tube with a cuff is most safe to operate. But even this endotracheal tube blocks on the one hand the unobstructed view of the operating field and on the other hand the necessary space for surgical activity and additionally mutates the anatomical structures. In cases of pronounced stenoses in the laryngotracheal area an endotracheal intubation cannot be applied. An alternative procedure is the tracheotomy, especially for infants and children and the postop‐

A rigid bronchoscope used for ventilation restricts the visibility of the working space and it may occur that it cannot pass a stenosis. Laryngotracheal surgery in the apnea technique is

An improvement of ventilation of the patient during laryngotracheal surgery was established by single-frequency jet ventilation techniques applied either per percutaneous insertion of a needle into the trachea or endotracheal tubes or catheters, or application of a jet nozzle into the endocopy tube [74, 75]. All these techniques have the disadvantage of the risk of hypo‐ xaemia and hypercapnia especially in patients underlying pulmonary and cardiadic aggra‐ vated risks and operations with a long continuance. Needles placed transtracheal bear the elevated risk of barotrauma because the gas supply takes place below the stenosis [76].

As an alternative ventilation technique the jet ventilation presents themselves with 3 modalities: **1.** *transtracheal jet ventilation* (Figure 23): for endoscopic laryngeal surgery, also with laser, excellent visibility for the surgeon, even in glottic or supraglottic stenoses with minor complications up to 20 % [77-79]. Very important is the bedding of the child with maxi‐ mum extension of the head. This allows fixing the mobile trachea between middle finger and thumb. The cricoid membrane is narrow and at best to be felt by a fingernail. The


punction with ventilation catheter is to be directed in a caudal direction.

**Figure 23.** Percutaneous transtracheal jet ventilation catheter (VBM®

still in use but is associated with the heightened risk of hypoxemia and hypercapnia.

erative care an enormous burden.

**6.1. Ventilation**

170 Endoscopy

punction needle.

Ventilation is carried out by an air/oxygen mixture. If the CO2 laser is used the inspiratory oxygen concentration is reduced to 40 %. In corresponding dose rate propofol is applied as hynoticum, fentanil or remifentanil as analgesia and rocuronium as short effective relaxant.

Anaesthesia starts with manual ventilation by a conventional respirator. When relaxation takes effect the jet laryngoscope is placed and jet ventilation starts. After the end of the surgical intervention the jet laryngoscope is removed and mask ventilation follows till the patient is awake.

extra designed rigid endoscopy tube derived from the Kleinsasser tube [79] during laryngotracheal surgery. Diagnoses were: papillomatosis, subglottic stenoses, laryngeal inspection, web, foreign body, vocal chord cyst, vocal chords granuloma and miscellaneous. Movement of foreign bodies becomes much more easy and elegant during the tubeless ventilation: a Fogarty-Catheters© guided behind the foreign body helps to bring him more proximal where he can be gripped and extracted with a forceps [83]. With this SHFJV technique laryngeal stenoses and cardiopulmonal insufficiences do not present special risks. Laryngotracheal surgery under SHFJV can be applied in any child except special general contraindications.

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As in adults before effective jet ventilation can start, the laryngoscope tube, adjusted to size of the childlike larynx, is inserted and evaluated for suitability for jet ventilation. Immediately afterward the suspension system is installed and the jet injector needles are attached to the laryngoscope. The steadily ventilation can begin. Up to this point of time the manipulation

The procedure of the jet ventilation took from 5 up to 130 minutes, on average about 35 minutes.

Only in a few cases during introduction or recovery of the anaesthesia an endotracheal tube had to replace the ventilation tube temporarily caused by adverse anatomical characteristics. A serve laryngospasm never resulted from SHFJV. To eliminate the danger of pneumothorax in the application of SHFJV it is to state that it is an open system with an air supply always above the existing stenoses. Additionally an intergrated monitoring of pressure in the

Contraindication for SHFJV in infants und children are in principle the same as in grownups.

The technique of SHFJV has helped us to handle the naturally difficult surgery of the larynx

A very special laryngeal disease in children is the recurrent respiratory papillomatosis (RRP)

Only a minority of Human papilloma virus (HPV) carrying mothers will become symptomatic.

There is no cure for RRP at present and no therapy modality that might eradicate the virus

Vaccination against HPV 6 and 11 across the board should decrease the incidence of children

The surgical therapy with a removal of the papillomas as much as possible und preservation of normal structures is the procedure of (Figure 26). Scaring from overagressive resections effects dysphonia and airway comprise. Incomplete resections are accepted under these aspects especially in the anterior commissure. It is not practicable to eradicate all virus particles

The ventilation assured in any case a sufficient oxygenation and CO2 elimination.

laryngoscope is positioned. The surgical procedure could be performed in any case.

and trachea in infants and children and simplified it considerably.

RRP requires a protracted and repeatedly therapy over years.

even when clinically all evident papillomas had been removed.

The route of transmission to the infant in not yet completely understood.

from the respiratory mucosa. Local recurrences are therefore frequently seen.

happens in an anaesthetized but apnoeic patient.

[84-86].

in future.

**Figure 25.** Procedure of an endoscopic surgical intervention under a continuous superimposed high-frequency jet ventilation.

The physiology of the infantile lung offers several specifics. The compliance and also the resistence of the lung make age-related fluctuations. The compliance is significantly lower and the resistance higher than in adults. Due to the resulting time constant a higher ventilation frequence exists. With increasing age an approximation to the values up to that of adults occurs. Subsequently the following considerations for the adjustment of the respirator are: higher frequency of ventilation, ventilation pressure low but not too low, the start calibration of the respirator with body weight specification, orientation at the displayed and measured values of ventilation pressure. As in adults the supraglottic jet ventilation is performed at two different pressure plateaus. With the superior pressure plateau CO2 is eliminated, the inferior pressure plateau produces the positive end-expiratory pressure (PEEP).

Contraindications for the jet ventilation are: impracticality to bring the jet laryngoscope in the right position, bleeeding in larynx and trachea and the absence of patient`s sobriety.

The superimposed jet ventilation offers the anaesthesist and the surgeon optimal working conditions (Figure 25). Anaesthesia has as advantage the continuous mechanical ventilation with integrated limitation of pressure. The surgean has optimal conditions of visibility with no displacement of anatomical structures by a catheter or endotracheal tube. A further advantage is the safe application of laser surgery.

The youngest patient was two week old. Therefore no age-related limitation exist for the superimposed high-frequency jetventilation.

Up to now at the Department of Otorhinolaryngology of the Medical Universitiy of Vienna 230 infants and children with an age below 14 years were ventilated sufficiently by a therefore extra designed rigid endoscopy tube derived from the Kleinsasser tube [79] during laryngotracheal surgery. Diagnoses were: papillomatosis, subglottic stenoses, laryngeal inspection, web, foreign body, vocal chord cyst, vocal chords granuloma and miscellaneous. Movement of foreign bodies becomes much more easy and elegant during the tubeless ventilation: a Fogarty-Catheters© guided behind the foreign body helps to bring him more proximal where he can be gripped and extracted with a forceps [83]. With this SHFJV technique laryngeal stenoses and cardiopulmonal insufficiences do not present special risks. Laryngotracheal surgery under SHFJV can be applied in any child except special general contraindications.

intervention the jet laryngoscope is removed and mask ventilation follows till the patient is

**Figure 25.** Procedure of an endoscopic surgical intervention under a continuous superimposed high-frequency jet

The physiology of the infantile lung offers several specifics. The compliance and also the resistence of the lung make age-related fluctuations. The compliance is significantly lower and the resistance higher than in adults. Due to the resulting time constant a higher ventilation frequence exists. With increasing age an approximation to the values up to that of adults occurs. Subsequently the following considerations for the adjustment of the respirator are: higher frequency of ventilation, ventilation pressure low but not too low, the start calibration of the respirator with body weight specification, orientation at the displayed and measured values of ventilation pressure. As in adults the supraglottic jet ventilation is performed at two different pressure plateaus. With the superior pressure plateau CO2 is eliminated, the inferior pressure

Contraindications for the jet ventilation are: impracticality to bring the jet laryngoscope in the

The superimposed jet ventilation offers the anaesthesist and the surgeon optimal working conditions (Figure 25). Anaesthesia has as advantage the continuous mechanical ventilation with integrated limitation of pressure. The surgean has optimal conditions of visibility with no displacement of anatomical structures by a catheter or endotracheal tube. A further

The youngest patient was two week old. Therefore no age-related limitation exist for the

Up to now at the Department of Otorhinolaryngology of the Medical Universitiy of Vienna 230 infants and children with an age below 14 years were ventilated sufficiently by a therefore

right position, bleeeding in larynx and trachea and the absence of patient`s sobriety.

plateau produces the positive end-expiratory pressure (PEEP).

advantage is the safe application of laser surgery.

superimposed high-frequency jetventilation.

awake.

172 Endoscopy

ventilation.

As in adults before effective jet ventilation can start, the laryngoscope tube, adjusted to size of the childlike larynx, is inserted and evaluated for suitability for jet ventilation. Immediately afterward the suspension system is installed and the jet injector needles are attached to the laryngoscope. The steadily ventilation can begin. Up to this point of time the manipulation happens in an anaesthetized but apnoeic patient.

The procedure of the jet ventilation took from 5 up to 130 minutes, on average about 35 minutes. The ventilation assured in any case a sufficient oxygenation and CO2 elimination.

Only in a few cases during introduction or recovery of the anaesthesia an endotracheal tube had to replace the ventilation tube temporarily caused by adverse anatomical characteristics. A serve laryngospasm never resulted from SHFJV. To eliminate the danger of pneumothorax in the application of SHFJV it is to state that it is an open system with an air supply always above the existing stenoses. Additionally an intergrated monitoring of pressure in the laryngoscope is positioned. The surgical procedure could be performed in any case.

Contraindication for SHFJV in infants und children are in principle the same as in grownups.

The technique of SHFJV has helped us to handle the naturally difficult surgery of the larynx and trachea in infants and children and simplified it considerably.

A very special laryngeal disease in children is the recurrent respiratory papillomatosis (RRP) [84-86].

Only a minority of Human papilloma virus (HPV) carrying mothers will become symptomatic. The route of transmission to the infant in not yet completely understood.

There is no cure for RRP at present and no therapy modality that might eradicate the virus from the respiratory mucosa. Local recurrences are therefore frequently seen.

Vaccination against HPV 6 and 11 across the board should decrease the incidence of children in future.

RRP requires a protracted and repeatedly therapy over years.

The surgical therapy with a removal of the papillomas as much as possible und preservation of normal structures is the procedure of (Figure 26). Scaring from overagressive resections effects dysphonia and airway comprise. Incomplete resections are accepted under these aspects especially in the anterior commissure. It is not practicable to eradicate all virus particles even when clinically all evident papillomas had been removed.

**Figure 26.** Laryngeal papillomatosis. View through the jet laryngoscope.

We have experiences about 122 surgical interventions under SHFJV in children with RRP.

Near all of them received papilloma ablation by CO2 laser.

In addition the adjuvant medical therapy plays an increasing role: a-Interferon, and various antiviral agents, of which the most commonly used is the intralesional sidovir.

If the glottis is not obstructed any form of jet ventilation can be applied. The narrower the glottic space becomes because of a pathological process the more attention is to be applied to

**Figure 27.** Schematical drawing of the supraglottic jet ventilation with a stenosis in front of the tip of the laryngo‐

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In principle three options are available for jet ventilation with stenosis: *i)* the *transcricoidal punction* – not usable in cases of long-stretched stenoses where the trachea is not to be local‐ ized, *ii)* the *transoral infraglottic jet catheter* – not to be inserted through high-grade stenoses and *iii)* the *jet laryngoscope* – a supraglottic jet ventilation with jet gas emission above the glottic area (Figure 27). The first and second techniques are in terms of the location of the jet nozzles

Initially the application of the supraglottic jet ventilation was applied cautious in obstructive pathologies but at an early stage the advantages in severe airway obstructions emphasized [90, 91]. It became apparent that the increasing ventilation pressure, measured at the tip of the

Therefore this technique is best suited for all kinds of to be expected difficult airway. However

If a stenosis is produced at the lung simulator in the level of the fictitious glottis immediately ahead of the laryngoscope the following characteristics with regard to the tidal volumes are

Increasing of the working pressure of the device for both types of ventilation, the low- and

With decrease of the compliance (0.05 l/mbar, **red columns**) the tidal volume without stenosis is already low and decreases dramatically with increase of a stenosis, at the identical original

absolute requirement is to place the jet laryngoscope ahead the expected obstruction.

high-frequent jet, produces a sufficient respiratory tidal volume (**blue columns**).

laryngoscope, behind an obstruction can not be higher than in front of it.

the chosen jet ventilation.

scope.

infraglottic jet ventilations.

observed (Figure 28).

setting of the jet ventilator.

We cannot confirm, based on our experiences, the theoretical risk in clinical practice that the applicated jet is forcing papilloma fragments deeper into the airways. Our preliminary results provide no indication that the risk of spread of papillomas by jet ventilation into the trachea has increased. A spread of papillomas by an endotracheal tube cannot be entirely excluded.

### **7. Supraglottic jet ventilation in laryngotracheal stenoses**

High degree stenoses in the larynx and trachea represent an acute alarming situation for the affected patients. In a slow increasing stenotic process the narrowing of the laryngeal or tracheal lumen up to 80 % is clinically well tolerated by the patients [87-89]. A further increase of the stenoses, for example caused by a local swelling, is associated with life-threatening dyspnoea and hypoxia. In these cases a tracheotomy is necessary to maintain gas exchange. If an endotracheal intubation is impossible due to the massive narrowing of the laryngotracheal area and ventilation via mask provides sufficient oxygenation tracheotomy is performed under local anaesthesia. An extreme dyspnoea requires oxygenation via a percutaneous transtracheal puncture or surgical cricothyrotomy.

#### **7.1. Applications of the jet ventilation in obstructive supraglottic respectively glottic or infraglottic narrowing of the airways**

According to the local spread of pathologies the following anatomical localisations of obstruc‐ tions exist: *i) supraglottic*, *ii) glottic*, *iii) subglottic* and *iv) tracheal*.

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency… http://dx.doi.org/10.5772/52996 175

We have experiences about 122 surgical interventions under SHFJV in children with RRP.

In addition the adjuvant medical therapy plays an increasing role: a-Interferon, and various

We cannot confirm, based on our experiences, the theoretical risk in clinical practice that the applicated jet is forcing papilloma fragments deeper into the airways. Our preliminary results provide no indication that the risk of spread of papillomas by jet ventilation into the trachea has increased. A spread of papillomas by an endotracheal tube cannot be entirely excluded.

High degree stenoses in the larynx and trachea represent an acute alarming situation for the affected patients. In a slow increasing stenotic process the narrowing of the laryngeal or tracheal lumen up to 80 % is clinically well tolerated by the patients [87-89]. A further increase of the stenoses, for example caused by a local swelling, is associated with life-threatening dyspnoea and hypoxia. In these cases a tracheotomy is necessary to maintain gas exchange. If an endotracheal intubation is impossible due to the massive narrowing of the laryngotracheal area and ventilation via mask provides sufficient oxygenation tracheotomy is performed under local anaesthesia. An extreme dyspnoea requires oxygenation via a percutaneous transtracheal

**7.1. Applications of the jet ventilation in obstructive supraglottic respectively glottic or**

According to the local spread of pathologies the following anatomical localisations of obstruc‐

antiviral agents, of which the most commonly used is the intralesional sidovir.

**7. Supraglottic jet ventilation in laryngotracheal stenoses**

puncture or surgical cricothyrotomy.

**infraglottic narrowing of the airways**

tions exist: *i) supraglottic*, *ii) glottic*, *iii) subglottic* and *iv) tracheal*.

Near all of them received papilloma ablation by CO2 laser.

**Figure 26.** Laryngeal papillomatosis. View through the jet laryngoscope.

174 Endoscopy

If the glottis is not obstructed any form of jet ventilation can be applied. The narrower the glottic space becomes because of a pathological process the more attention is to be applied to the chosen jet ventilation.

In principle three options are available for jet ventilation with stenosis: *i)* the *transcricoidal punction* – not usable in cases of long-stretched stenoses where the trachea is not to be local‐ ized, *ii)* the *transoral infraglottic jet catheter* – not to be inserted through high-grade stenoses and *iii)* the *jet laryngoscope* – a supraglottic jet ventilation with jet gas emission above the glottic area (Figure 27). The first and second techniques are in terms of the location of the jet nozzles infraglottic jet ventilations.

Initially the application of the supraglottic jet ventilation was applied cautious in obstructive pathologies but at an early stage the advantages in severe airway obstructions emphasized [90, 91]. It became apparent that the increasing ventilation pressure, measured at the tip of the laryngoscope, behind an obstruction can not be higher than in front of it.

Therefore this technique is best suited for all kinds of to be expected difficult airway. However absolute requirement is to place the jet laryngoscope ahead the expected obstruction.

If a stenosis is produced at the lung simulator in the level of the fictitious glottis immediately ahead of the laryngoscope the following characteristics with regard to the tidal volumes are observed (Figure 28).

Increasing of the working pressure of the device for both types of ventilation, the low- and high-frequent jet, produces a sufficient respiratory tidal volume (**blue columns**).

With decrease of the compliance (0.05 l/mbar, **red columns**) the tidal volume without stenosis is already low and decreases dramatically with increase of a stenosis, at the identical original setting of the jet ventilator.

**Figure 28.** Diagram of the respiratory tidal volume (ml) to be achieved by a supraglottic jet ventilation via a jet lar‐ yngoscope in a default setting on the lung simulator: with a narrowing of the cross section for ventilation, at first with‐ out stenosis (0 %, left), then with a 50 % stenosis (centre) and at last with a 80 % stenosis (right) all **yellow columns**. The lung compliance was adjusted at 0.1 liter per millibar (l/mbar).

**Figure 30.** Characteristics of pressure in front and behind the stenosis in the jet laryngoscope. Note the pressure be‐

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These experimental results show that the pressure behind a stenosis is not higher than the

This simulation of the gas flow at a stenosis at the tip of the endoscope shows in the case of a reduction of the cross-section immediately in front of the tip of the endoscope the occurrence of an impact pressure. This pressure increases continuously at the shock front up to the stagnation point, but the velocity decreases. However the pressure behind the stenosis is lower

The supraglottic jet ventilation via the jet laryngoscope guarantees even in high grade stenoses (grade II-III according to RT Cotton [92] a sufficient ventilation. The development of a barotrauma can be excluded like experimental results demonstrated. Only in stenosis grade IV when in no way a lumen exists the SHFJV via a jet laryngoscope cannot be applied.

An essential advantage of this technique is that the surgeon has in these difficult situations an absolutely free approach to the larynx and trachea. Because of the absence of inflammable material laser is safe to applicate. The high gas flow avoids the smoke induced obstruction of

> Long-time Short-time High High

Experimental results demonstrate if supraglottic jet ventilation is applicated the ventilation pressure behind a stenosis cannot be higher than in front of a stenosis. The pressure measure‐

fore the stenosis (left) and behind the stenosis (right).

**Parameter Setting**

**Table 3.** Setting of the respirator in stenosis and supraglottic jet ventilation.

pressure in front of the stenosis.

than ahead the stenosis.

vision.

Inspiration time Expiration time Driving pressure Ventilation frequency

The increase of the working pressures of the ventilators succeeds in achievement of sufficient tidal volumes even in 80 % stenosis (**green column**).

#### **7.2. Computational fluid dynamic**

In a jet laryngoscope a flow simulation with ANSYS fluent® was carried out. First, the creation of a three-dimensional image of the jet laryngoscope with the preprocessor Gambit was performed. This was followed by the definition of boundary conditions and input parameters in the solver and the iterative calculation in fluent.

**Figure 29.** Distribution of pressure in the jet laryngoscope in case of a stenosis. Note the impact pressure in front of the stenosis (Figures 29, 30). The pressure behind the stenosis is lower than the pressure before the stenosis.

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**Figure 30.** Characteristics of pressure in front and behind the stenosis in the jet laryngoscope. Note the pressure be‐ fore the stenosis (left) and behind the stenosis (right).

These experimental results show that the pressure behind a stenosis is not higher than the pressure in front of the stenosis.

This simulation of the gas flow at a stenosis at the tip of the endoscope shows in the case of a reduction of the cross-section immediately in front of the tip of the endoscope the occurrence of an impact pressure. This pressure increases continuously at the shock front up to the stagnation point, but the velocity decreases. However the pressure behind the stenosis is lower than ahead the stenosis.

The supraglottic jet ventilation via the jet laryngoscope guarantees even in high grade stenoses (grade II-III according to RT Cotton [92] a sufficient ventilation. The development of a barotrauma can be excluded like experimental results demonstrated. Only in stenosis grade IV when in no way a lumen exists the SHFJV via a jet laryngoscope cannot be applied.

An essential advantage of this technique is that the surgeon has in these difficult situations an absolutely free approach to the larynx and trachea. Because of the absence of inflammable material laser is safe to applicate. The high gas flow avoids the smoke induced obstruction of vision.


**Table 3.** Setting of the respirator in stenosis and supraglottic jet ventilation.

The increase of the working pressures of the ventilators succeeds in achievement of sufficient

**Figure 28.** Diagram of the respiratory tidal volume (ml) to be achieved by a supraglottic jet ventilation via a jet lar‐ yngoscope in a default setting on the lung simulator: with a narrowing of the cross section for ventilation, at first with‐ out stenosis (0 %, left), then with a 50 % stenosis (centre) and at last with a 80 % stenosis (right) all **yellow columns**.

In a jet laryngoscope a flow simulation with ANSYS fluent® was carried out. First, the creation of a three-dimensional image of the jet laryngoscope with the preprocessor Gambit was performed. This was followed by the definition of boundary conditions and input parameters

**Figure 29.** Distribution of pressure in the jet laryngoscope in case of a stenosis. Note the impact pressure in front of the stenosis (Figures 29, 30). The pressure behind the stenosis is lower than the pressure before the stenosis.

tidal volumes even in 80 % stenosis (**green column**).

The lung compliance was adjusted at 0.1 liter per millibar (l/mbar).

in the solver and the iterative calculation in fluent.

**7.2. Computational fluid dynamic**

176 Endoscopy

Experimental results demonstrate if supraglottic jet ventilation is applicated the ventilation pressure behind a stenosis cannot be higher than in front of a stenosis. The pressure measure‐ ment at the tip of the endoscope allows the detection of elevated airway pressures. At the ventilator a pressure limitation can be adjusted and the ventilation stops when the pressure limit is reached. Clinical results with the absence of any complications caused by ventilation confirm this. The supraglottic jet ventilation can be applied in severe high-grade stenoses [93] (Figures 31, 32, 33). All these results are only valid for the type of supraglottic jet ventilation where the jet nozzles are positioned in the proximal section of the jet laryngoscope and not at the tip of the endoscope. Only in the case of grade IV stenosis after Cotton, in which no lumen in the area of the larynx is more available, the SHFJV on the jet laryngoscope cannot be applied.

**Figure 33.** Extended subglottic stenosis. The use of a jet catheter through the glottis would make the outflow of the

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Central airway obstruction is caused by lung cancer, esophageal carcinoma, thyroid carcino‐ ma, malignant lymphoma, and rather rare carcinoma of the larynx, trachea and hypopharynx. If the airway constriction is not yet in the focus external-beam radiation therapy, endoluminal

If curative treatment fails and progessive extended tumour growth infiltrates and advances intraluminal or external compression the effective lumen of the airway becomes dramatically

Palliative surgical tumour reduction methods are intraluminal laser ablation, electrocautery or mechanical removal. This is followed by implantation of tracheal or bronchial stents for to

Indications for insertion of tracheobronchial stents are severe stridor and dyspnea in patients with tracheobronchomalacia and extraluminal compression, intraluminal tumour growth and tracheoesophageal fistulas. Airway stents have proved as best practical environmental option to renew and to perpetuate airways in such patients with a serious central airway obstruction.

[94-97]. Endotracheal intervention can be performed under local anaesthesia by fiberoptical bronchoscopy or under general anaesthesia using rigid bronchoscopy or supension laryngo‐ scopy [98]. From the consideraton of anaesthesia a conventional ventilation or jet ventilation

Suspension laryngoscopy and jet ventilation offers an ideal setting with directly visual control

Low-frequency jet ventilation provides adequate ventilation as well as a non obstructed field

for the precise placement of tracheal and bifurcational airway stents [101].

during fibre optic bronchoscopy and stent insertion [102].

**8. Superimposed high-frequency jet ventilation (SHFJV) for**

jet gas impossible.

narrow.

improve ventilation.

can be performed [99, 100].

**tracheobronchial stent insertion**

brachytherapy and photodynamic therapy can be applied.

**Figure 31.** A severe subglottic stenosis: a jet-catheter (Hunsaker Mon® -Jet-Ventilation Tube, Medtronic Xomed® Inc. Jacksonville USA) is placed through this stenosis. Although the visibility conditions are good, the working conditions are difficult for the surgeon caused by the catheter.

**Figure 32.** Schematic drawing of a long-segment 90% laryngeal stenosis. The diameter of the stenosis was 3 mm. In this clinical case, it was realizable to achieve a sufficiently ventilation. A transoral jet ventilation with a catheter would not have been possible. The diameter of a jet catheter is more than 3 mm. In the case of transtracheal jet ventilation, it would not have been possible to find the trachea in a simple way.

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**Figure 33.** Extended subglottic stenosis. The use of a jet catheter through the glottis would make the outflow of the jet gas impossible.

### **8. Superimposed high-frequency jet ventilation (SHFJV) for tracheobronchial stent insertion**

ment at the tip of the endoscope allows the detection of elevated airway pressures. At the ventilator a pressure limitation can be adjusted and the ventilation stops when the pressure limit is reached. Clinical results with the absence of any complications caused by ventilation confirm this. The supraglottic jet ventilation can be applied in severe high-grade stenoses [93] (Figures 31, 32, 33). All these results are only valid for the type of supraglottic jet ventilation where the jet nozzles are positioned in the proximal section of the jet laryngoscope and not at the tip of the endoscope. Only in the case of grade IV stenosis after Cotton, in which no lumen in the area of the larynx is more available, the SHFJV on the jet laryngoscope cannot be applied.

Jacksonville USA) is placed through this stenosis. Although the visibility conditions are good, the working conditions

**Figure 32.** Schematic drawing of a long-segment 90% laryngeal stenosis. The diameter of the stenosis was 3 mm. In this clinical case, it was realizable to achieve a sufficiently ventilation. A transoral jet ventilation with a catheter would not have been possible. The diameter of a jet catheter is more than 3 mm. In the case of transtracheal jet ventilation, it


**Figure 31.** A severe subglottic stenosis: a jet-catheter (Hunsaker Mon®

would not have been possible to find the trachea in a simple way.

are difficult for the surgeon caused by the catheter.

178 Endoscopy

Central airway obstruction is caused by lung cancer, esophageal carcinoma, thyroid carcino‐ ma, malignant lymphoma, and rather rare carcinoma of the larynx, trachea and hypopharynx. If the airway constriction is not yet in the focus external-beam radiation therapy, endoluminal brachytherapy and photodynamic therapy can be applied.

If curative treatment fails and progessive extended tumour growth infiltrates and advances intraluminal or external compression the effective lumen of the airway becomes dramatically narrow.

Palliative surgical tumour reduction methods are intraluminal laser ablation, electrocautery or mechanical removal. This is followed by implantation of tracheal or bronchial stents for to improve ventilation.

Indications for insertion of tracheobronchial stents are severe stridor and dyspnea in patients with tracheobronchomalacia and extraluminal compression, intraluminal tumour growth and tracheoesophageal fistulas. Airway stents have proved as best practical environmental option to renew and to perpetuate airways in such patients with a serious central airway obstruction.

[94-97]. Endotracheal intervention can be performed under local anaesthesia by fiberoptical bronchoscopy or under general anaesthesia using rigid bronchoscopy or supension laryngo‐ scopy [98]. From the consideraton of anaesthesia a conventional ventilation or jet ventilation can be performed [99, 100].

Suspension laryngoscopy and jet ventilation offers an ideal setting with directly visual control for the precise placement of tracheal and bifurcational airway stents [101].

Low-frequency jet ventilation provides adequate ventilation as well as a non obstructed field during fibre optic bronchoscopy and stent insertion [102].

Airway stent placement requires a combination of surgical techniques and skills with safety and perpetuated ventilation during manipulation. The procedure is to be planned carefully, a constant communication between the surgeon and anaesthesiologist is an indispensable condition.

Stents are made from either metallic expandable prostheses or flexible silicone, with each type having their special indications according to the requirements and are placed either temporary or permanent.


Anaesthesia is performed as totally intravenous, as hypnoticum propofol continuous, as shortacting relaxant serves rocuronium as a bolus and as short-acting analgesic remifentanil. This

**Figure 34.** Application of a Y-stent under guidance of two catheters (right and left main bronchus) under superim‐

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If the stent is to be positioned as a distal Y stent or a tube, it is essential to check that both limbs are patient. The ventilation laryngoscope allows a lot of space for manipulation. Folding and or creasing of a limb of a T or Y tube can disable ventilation with the need of emergent removal of the stent. Additionally, when jet ventilation is used, a totally stent blockage can cause high airway pressures with the risk of a tension pneumothorax. After the placement of a stent, the

At this moment all equipment and personnel should stay at call in the operating room until

If a stent reaches into the upper trachea, standard intubation in following anaesthesia should be avoided, because this second endotracheal tube may adhere to the stent and remove it

**Wallstent**: small-meshed grating, self expanding, for extraluminal caused stenosis.

**Gianturco-Z-stent**: broad-meshed grating, for example for tracheobronchial malacia.

For application various sizes and types can be adapted to the particular located situation (Figures 34, 35, 36). Their application is descibed in numerous publications [106, 107]. That includes also the Montgomery -T-tubes [108], the Dumona-Artemis-Stent and also the Orlowski-stent [109] and also the Polyflex® stent is to be allocated to the silicone stents. In the silicone grating polyester fibres are integrated. The application of all these stents can be done

kind of anaesthesia has well proven in adults and children [105].

the patient is completely awake and ready for transport.

during extubation.

posed high-frequency jet ventilation.

**8.3. Types of stents**

**Selfexpanding stents**

under continuous jet ventilation.

**Silicone stents**

laryngoscope is removed and the patient may awaken with mask ventilation.

**Table 4.** Indication for temporary and permanent tracheobronchial stents.

#### **8.1. Technique of stent implantation**

Usually the stent implantation is carried out under general anaesthesia in most cases via a bronchoscope under conventional ventilation or via a tracheoscope with the opportunity for jet ventilation or with growing extent via a jet laryngoscope [101]. Even in severe tracheal stenosis the jet ventilation is recommended [102, 103]. First at all inspection and then meas‐ urement of the stenosis is performed. If necessary a surgical debulking for the enlargement of the tracheal lumen is made.

#### **8.2. Anaesthetic management**

During execution of these steps and the placement of the stent a continuous ventilation of the patient is applied, preferential with jet ventilation [104] without phases of apnoea.

Often we really succeed to create a straight axis between the trachea and the jet laryngoscope and under certain circumstances the view extends to the carina.

The advantage of jet ventilation especially via the jet laryngoscope is the continuous automat‐ ically ventilation and the operation area with no limitation of visibility. Ventilation is arranged by an air/oxygen mixture applicated via the bronchoscope or the jet laryngoscope.

Through the jet laryngoscope or the rigid bronchoscope a simultaneous low- and highfrequency jet ventilation is applicated.

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**Figure 34.** Application of a Y-stent under guidance of two catheters (right and left main bronchus) under superim‐ posed high-frequency jet ventilation.

Anaesthesia is performed as totally intravenous, as hypnoticum propofol continuous, as shortacting relaxant serves rocuronium as a bolus and as short-acting analgesic remifentanil. This kind of anaesthesia has well proven in adults and children [105].

If the stent is to be positioned as a distal Y stent or a tube, it is essential to check that both limbs are patient. The ventilation laryngoscope allows a lot of space for manipulation. Folding and or creasing of a limb of a T or Y tube can disable ventilation with the need of emergent removal of the stent. Additionally, when jet ventilation is used, a totally stent blockage can cause high airway pressures with the risk of a tension pneumothorax. After the placement of a stent, the laryngoscope is removed and the patient may awaken with mask ventilation.

At this moment all equipment and personnel should stay at call in the operating room until the patient is completely awake and ready for transport.

If a stent reaches into the upper trachea, standard intubation in following anaesthesia should be avoided, because this second endotracheal tube may adhere to the stent and remove it during extubation.

#### **8.3. Types of stents**

Airway stent placement requires a combination of surgical techniques and skills with safety and perpetuated ventilation during manipulation. The procedure is to be planned carefully, a constant communication between the surgeon and anaesthesiologist is an indispensable

Stents are made from either metallic expandable prostheses or flexible silicone, with each type having their special indications according to the requirements and are placed either temporary

Benig: long-segment stenosis

functional inoperative patients

(lenghts of stenosis, tumour spread,

Malign: anatomical and functional inoperative patients

complicated injuries

overall condition).

Usually the stent implantation is carried out under general anaesthesia in most cases via a bronchoscope under conventional ventilation or via a tracheoscope with the opportunity for jet ventilation or with growing extent via a jet laryngoscope [101]. Even in severe tracheal stenosis the jet ventilation is recommended [102, 103]. First at all inspection and then meas‐ urement of the stenosis is performed. If necessary a surgical debulking for the enlargement of

During execution of these steps and the placement of the stent a continuous ventilation of the

Often we really succeed to create a straight axis between the trachea and the jet laryngoscope

The advantage of jet ventilation especially via the jet laryngoscope is the continuous automat‐ ically ventilation and the operation area with no limitation of visibility. Ventilation is arranged

Through the jet laryngoscope or the rigid bronchoscope a simultaneous low- and high-

patient is applied, preferential with jet ventilation [104] without phases of apnoea.

by an air/oxygen mixture applicated via the bronchoscope or the jet laryngoscope.

and under certain circumstances the view extends to the carina.

condition.

180 Endoscopy

or permanent.

Decay of a post-stenotic pneumonia Improvement of the overall condition Stabilization of a tracheobronchomalcia

**Temporary Permanent**

**Table 4.** Indication for temporary and permanent tracheobronchial stents.

Pretherapeutic until radio/chemotherapy is effective.

**8.1. Technique of stent implantation**

the tracheal lumen is made.

**8.2. Anaesthetic management**

frequency jet ventilation is applicated.

#### **Selfexpanding stents**

**Wallstent**: small-meshed grating, self expanding, for extraluminal caused stenosis.

**Gianturco-Z-stent**: broad-meshed grating, for example for tracheobronchial malacia.

#### **Silicone stents**

For application various sizes and types can be adapted to the particular located situation (Figures 34, 35, 36). Their application is descibed in numerous publications [106, 107]. That includes also the Montgomery -T-tubes [108], the Dumona-Artemis-Stent and also the Orlowski-stent [109] and also the Polyflex® stent is to be allocated to the silicone stents. In the silicone grating polyester fibres are integrated. The application of all these stents can be done under continuous jet ventilation.

**Figure 35.** Various forms of silicone stents to be inserted according the respective local anatomical situation. From W. Klepetko et al. Endoluminal Stenting of the Tracheobronchial System. Acta Chirurgica Austriaca 1991;23(3)124-129 [11] with friendly permission of Springer Verlag, Vienna-New York.

**Figure 37.** Polyflex®

jet laryngoscope.

**Figure 39.** Tracheal stent (Polyflex®

loader can be placed through each jet laryngoscope.


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**Figure 38.** Application of a Polyflex® stent with a stent loader under superimposed jet ventilation. The patient is venti‐ lated continuously by the jet laryngoscope. The stent loader can be adapted and placed into the trachea passing the


**Figure 36.** A typical T-tube according Montgomery in correct position.

The T-tube according Montgomery serves to bridge tracheal stenoses in the presence of a tracheotomy.

#### **Polyflex®-Stent**

The application of a Polyflex® stent is made with a special application system (Fa. Rüsch®). The stent is produced from silicone with a polyester meshwork and is X-ray shadow giving. The Polyflex® stent includes a stent loader with an insertion tube (Figures 37, 38). Suitable stent dimensions are: diameter: 8-22 mm; length: 2-8 cm.

The most frequently and dangerous complications of anaesthesia (SHFJV) and surgery for patients with airway pathology and stent insertion are listed in Table 5. Bleeding can occur from the underlying pathology or manipulation of the laryngoscope or when tissue is ablated (e.g. by laser). If bleeding originates from friable tissue a significant compromise of ventilation results. Then rapid suction is as necessary as the control of bleeding which reqires a variety of interventions, including epinephrine solution, tamponade with a bronchoscope or balloonEndoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency… http://dx.doi.org/10.5772/52996 183

**Figure 37.** Polyflex® -stent in regular size (left) and after potential expansion with the stent-loader (right). The stent loader can be placed through each jet laryngoscope.

**Figure 38.** Application of a Polyflex® stent with a stent loader under superimposed jet ventilation. The patient is venti‐ lated continuously by the jet laryngoscope. The stent loader can be adapted and placed into the trachea passing the jet laryngoscope.

**Figure 39.** Tracheal stent (Polyflex® -stent) in the trachea.

**Figure 36.** A typical T-tube according Montgomery in correct position.

[11] with friendly permission of Springer Verlag, Vienna-New York.

dimensions are: diameter: 8-22 mm; length: 2-8 cm.

tracheotomy.

182 Endoscopy

**Polyflex®-Stent**

The T-tube according Montgomery serves to bridge tracheal stenoses in the presence of a

**Figure 35.** Various forms of silicone stents to be inserted according the respective local anatomical situation. From W. Klepetko et al. Endoluminal Stenting of the Tracheobronchial System. Acta Chirurgica Austriaca 1991;23(3)124-129

The application of a Polyflex® stent is made with a special application system (Fa. Rüsch®). The stent is produced from silicone with a polyester meshwork and is X-ray shadow giving. The Polyflex® stent includes a stent loader with an insertion tube (Figures 37, 38). Suitable stent

The most frequently and dangerous complications of anaesthesia (SHFJV) and surgery for patients with airway pathology and stent insertion are listed in Table 5. Bleeding can occur from the underlying pathology or manipulation of the laryngoscope or when tissue is ablated (e.g. by laser). If bleeding originates from friable tissue a significant compromise of ventilation results. Then rapid suction is as necessary as the control of bleeding which reqires a variety of interventions, including epinephrine solution, tamponade with a bronchoscope or balloontipped catheter. Pieces of necrotic or fragmentary tissue as well as clots from bleeding can block the distal airway. SHFJF is not be to be interrupted when they are removed. Airway perforation can be caused by the manipulation at the walls of the trachea or bronchii when the stent is inserted, a subcutaneous emphysema results. An injury of the inner larynx, especially the vocal chords, happens prevalently when difficulties of insertion of the laryngosope tube occur and is rarely severe.

applicable types of high-frequency ventilations like High-Frequency-Pulsation (HFP), Forced Diffusion Ventilation (FDV) [111, 112] and High Frequency Jet Ventilator (HFJV) only the High Frequency Positive Pressure Ventilation (HFPP), the High Frequency Jet Ventilation (HFJ), the HighFrequencyOscillation(HFO)andcombinedhigh-frequencyventilationtechniquesbecame

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From the aspect of a lung protective ventilation with the option to reduce the end-inspiratory lung volume the risk of ventilation-induced damage of lungs [113] when conventional

However higher end-exspiratory lung volumes can be applied [114]. Simultaneously these tidal volumes are transferred with only marginally pressure variations at a higher frequency and thus the average airway pressure is to be kept at a higher level as it is in conventional ventilation. The high average airway pressure seems to optimize the end-exspiratory lung volume and is protective against the periodic collapse and therefore also avoiding an atalectatic trauma. The perfect mode of application of high-frequency ventilation should permit lung recruitment manoeuvre and thereby shifting the lung under optimizing of the compliance and oxygenation to the exspiratory arm of the pressure/volume relationship. The opened lung is ventilated then with small-sized tidal volumes and slight fluctuation of pressure. This results also in a diminished alveolar distension and a reduced collapse of alveolar tissue. In an experimental laboratory animal study the high-frequency oscillation shows in comparison to a lung protective conventional ventilation an attenuation of activation of alveolar macrophages

All types of pulmonary reduction of ventilation with no improvement under conventional ventilation therapy

Lunkenheimer and co-workers observed already 1994 [116] that normocapnea can be achieved when small gas volumes rates are applicated into the airway of animals with a ventilation frequency of more than 40 Hertz. Using a piston pump sinus-like variations of pressure are

**Table 6.** Clinical indications for high-frequency ventilation in adult distress syndrom (ARDS).

**9.2. High-frequency oscillatory ventilation (HFO)**

ventilation is performed should be reduced by the high- frequency ventilation.

widely accepted and are used in clinical field (Table 7).

and neutrophils in lung injury [115].

Bronchopulmonary fistula

Acute lung insuffiency (ALI)

Adult respiratory distress syndrome (ARDS)

Atalectasis Pneumonia

Inhalation injury

**Clinical indications for high frequency ventilation**

**9.1. Theoretical advantages of the high-frequency ventilation**

A barotauma occurs suddenly when a mass causes a ball-valve effect or in a distal airway the route of air exit is blocked by a mass and the air pushed behind causes a tension pneumothorax. Typical signs are absence of chest excursion, sudden tachycardia and hypotension. A rapid decompression to prevent a cardiavascular collapse is essential.

The occurrence of inadequate oxygenation and ventilation are always to be observed and this is best to be done by strictly attention to a loud pulsoxymeter which allows quickly an adequate reaction and correction.


**Table 5.** Complications of tracheobronchial stent insertion.

The application of the described stents like silicone stents, wall stents and Polyflex® stents via the jet laryngoscope enables the surgeon due to the excellent field conditions a fast and safe intervention (Figure 39). The anaesthesiologist takes care of an unproblematic ventilation. A ventilation caused barotrauma under supraglottic jet ventilation did not occur in any case at our department. Inside the jet laryngoscope a continuous ventilation pressure measurement with pressure limitation under connection to the respirator is conducted.

### **9. High-frequency ventilation techniques in adult respiratory distress syndrom (ARDS)**

The high frequency ventilation is characterized as a type of artificialrespiration where low tidal volume is applicated with a hyper-physiological frequency. Different types of high-frequency jet ventilations weredevelopedandusedin the last 30 years [110]. From the numerouspotential applicable types of high-frequency ventilations like High-Frequency-Pulsation (HFP), Forced Diffusion Ventilation (FDV) [111, 112] and High Frequency Jet Ventilator (HFJV) only the High Frequency Positive Pressure Ventilation (HFPP), the High Frequency Jet Ventilation (HFJ), the HighFrequencyOscillation(HFO)andcombinedhigh-frequencyventilationtechniquesbecame widely accepted and are used in clinical field (Table 7).

### **9.1. Theoretical advantages of the high-frequency ventilation**

tipped catheter. Pieces of necrotic or fragmentary tissue as well as clots from bleeding can block the distal airway. SHFJF is not be to be interrupted when they are removed. Airway perforation can be caused by the manipulation at the walls of the trachea or bronchii when the stent is inserted, a subcutaneous emphysema results. An injury of the inner larynx, especially the vocal chords, happens prevalently when difficulties of insertion of the laryngosope tube occur and

A barotauma occurs suddenly when a mass causes a ball-valve effect or in a distal airway the route of air exit is blocked by a mass and the air pushed behind causes a tension pneumothorax. Typical signs are absence of chest excursion, sudden tachycardia and hypotension. A rapid

The occurrence of inadequate oxygenation and ventilation are always to be observed and this is best to be done by strictly attention to a loud pulsoxymeter which allows quickly an adequate

The application of the described stents like silicone stents, wall stents and Polyflex® stents via the jet laryngoscope enables the surgeon due to the excellent field conditions a fast and safe intervention (Figure 39). The anaesthesiologist takes care of an unproblematic ventilation. A ventilation caused barotrauma under supraglottic jet ventilation did not occur in any case at our department. Inside the jet laryngoscope a continuous ventilation pressure measurement

**9. High-frequency ventilation techniques in adult respiratory distress**

The high frequency ventilation is characterized as a type of artificialrespiration where low tidal volume is applicated with a hyper-physiological frequency. Different types of high-frequency jet ventilations weredevelopedandusedin the last 30 years [110]. From the numerouspotential

with pressure limitation under connection to the respirator is conducted.

**Long-term complications** Displacement of the stent Granulation tissue

Mucosa impaction of the stent Oesophagotracheal fistula

decompression to prevent a cardiavascular collapse is essential.

is rarely severe.

184 Endoscopy

reaction and correction.

**Acute complications**

Bleeding Occlusion Perforation Vocal chord injury Subcutaneous emphysema

Pneumothorax Hypoxaemia Hypercapnia

**syndrom (ARDS)**

**Complications of tracheobronchial stent insertion**

**Table 5.** Complications of tracheobronchial stent insertion.

From the aspect of a lung protective ventilation with the option to reduce the end-inspiratory lung volume the risk of ventilation-induced damage of lungs [113] when conventional ventilation is performed should be reduced by the high- frequency ventilation.

However higher end-exspiratory lung volumes can be applied [114]. Simultaneously these tidal volumes are transferred with only marginally pressure variations at a higher frequency and thus the average airway pressure is to be kept at a higher level as it is in conventional ventilation. The high average airway pressure seems to optimize the end-exspiratory lung volume and is protective against the periodic collapse and therefore also avoiding an atalectatic trauma. The perfect mode of application of high-frequency ventilation should permit lung recruitment manoeuvre and thereby shifting the lung under optimizing of the compliance and oxygenation to the exspiratory arm of the pressure/volume relationship. The opened lung is ventilated then with small-sized tidal volumes and slight fluctuation of pressure. This results also in a diminished alveolar distension and a reduced collapse of alveolar tissue. In an experimental laboratory animal study the high-frequency oscillation shows in comparison to a lung protective conventional ventilation an attenuation of activation of alveolar macrophages and neutrophils in lung injury [115].


**Table 6.** Clinical indications for high-frequency ventilation in adult distress syndrom (ARDS).

#### **9.2. High-frequency oscillatory ventilation (HFO)**

Lunkenheimer and co-workers observed already 1994 [116] that normocapnea can be achieved when small gas volumes rates are applicated into the airway of animals with a ventilation frequency of more than 40 Hertz. Using a piston pump sinus-like variations of pressure are

**9.3. Parameters to be adjusted on the apparatus for high frequency oscillatory ventilation**

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**Inspiratory time (I:E) of the pulsation (a single breath cyclus) in %:**

**Mean airway pressure (MAP - Paw = PEEP – post end-expiratory pressure):**

**Figure 41.** Parameters to be adjusted on the apparatus for high-frequency oscillatory ventilation.

At the first time in 1983 El-Baz et al. introduced the Combined High Frequency Ventilation Technique [118]. Two types of high-frequency ventilation (HFPPV and HFO) were combined.

At a basic frequency of 60 breaths per minute high-frequent gas pulses up to 3000 were superimposed. Further developments combined different types of high frequency ventilation.

**9.4. Combined high-frequency ventilation (CHFJV)**

**(Figure 41)**

3-15 f = Hz

33-50%

3-55 cm H2O

**Bias flow:**

0-60L/min

up to 10 cm H2O

**Oscillations frequency**

**Oscillation pressure –amplitude –delta P:**

**Figure 40.** A piston pump puts an oscillation membrane in vibration.

produced and directed to into the lungs (Figure 40). An auxiliary flow of gas (bias-flow) crosses the oscillating gas flow to provide fresh gases. This was followed by the application and further developments of the high frequency oscillation with numerous clinical applications. Although the high frequency oscillation has established in paediatrics it could not be implemented in adults with ARDS because of limited elimination of CO2. With the improvement of the technical devices this problem of CO2 elimination could be resolved.

High-frequency oscillation differs from high-frequency jet ventilation by the fact that in addition to the inspiration the expiration is also active, the tidal volume is less.

The frequencies could be higher, however, they are today similar to the jet ventilation usually under 10 Hz. Recently the interest in the high-frequency oscillation has risen again especially for the acute respiratory distress syndrome. The high-frequency pressure oscillations allow the use of a high mean airway pressure to achieve a recruitment of atalectatic lung tissue. At the same time the high mean airway pressure prevents a collapse of lung tissue and high peak airway pressure during inspiration can be avoided.

Different mechanisms of gas transport have been described, like: direct alveolar ventilation in the lung units situated near the airway opening, bulk convective mixing in the conducting convective transport of gases as a result of the asymmetry between inspiratory and expiratory velocity profiles, longitudinal dispersion caused by the interaction between axial velocities and radial transports due to turbulent eddies, molecular diffusion near the alveolo-capillary membrane [117].

#### **9.3. Parameters to be adjusted on the apparatus for high frequency oscillatory ventilation (Figure 41)**

**Oscillations frequency**

3-15 f = Hz

**Inspiratory time (I:E) of the pulsation (a single breath cyclus) in %:**

33-50%

**Mean airway pressure (MAP - Paw = PEEP – post end-expiratory pressure):**

3-55 cm H2O

**Oscillation pressure –amplitude –delta P:**

up to 10 cm H2O

#### **Bias flow:**

0-60L/min

produced and directed to into the lungs (Figure 40). An auxiliary flow of gas (bias-flow) crosses the oscillating gas flow to provide fresh gases. This was followed by the application and further developments of the high frequency oscillation with numerous clinical applications. Although the high frequency oscillation has established in paediatrics it could not be implemented in adults with ARDS because of limited elimination of CO2. With the improvement of the

High-frequency oscillation differs from high-frequency jet ventilation by the fact that in

The frequencies could be higher, however, they are today similar to the jet ventilation usually under 10 Hz. Recently the interest in the high-frequency oscillation has risen again especially for the acute respiratory distress syndrome. The high-frequency pressure oscillations allow the use of a high mean airway pressure to achieve a recruitment of atalectatic lung tissue. At the same time the high mean airway pressure prevents a collapse of lung tissue and high peak

Different mechanisms of gas transport have been described, like: direct alveolar ventilation in the lung units situated near the airway opening, bulk convective mixing in the conducting convective transport of gases as a result of the asymmetry between inspiratory and expiratory velocity profiles, longitudinal dispersion caused by the interaction between axial velocities and radial transports due to turbulent eddies, molecular diffusion near the alveolo-capillary

technical devices this problem of CO2 elimination could be resolved.

airway pressure during inspiration can be avoided.

**Figure 40.** A piston pump puts an oscillation membrane in vibration.

membrane [117].

186 Endoscopy

addition to the inspiration the expiration is also active, the tidal volume is less.

**Figure 41.** Parameters to be adjusted on the apparatus for high-frequency oscillatory ventilation.

#### **9.4. Combined high-frequency ventilation (CHFJV)**

At the first time in 1983 El-Baz et al. introduced the Combined High Frequency Ventilation Technique [118]. Two types of high-frequency ventilation (HFPPV and HFO) were combined.

At a basic frequency of 60 breaths per minute high-frequent gas pulses up to 3000 were superimposed. Further developments combined different types of high frequency ventilation. The application of an additive, mostly conventional breath with an enlarged tidal volume enables the enhancement of CO2 elimination. A disadvantage is the usually need of combina‐ tion of two devices.

The gas delivered by the respirator is first transmitted to the so-called Phasitron® (Figure 43)

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The mobile Venturi-body in the Phasitron® is moved forward in the inspiratory phase. This causes a closure of the expiratory aperture and now warmed-up and moisturized air is sucked

This prepared column of air lying in front of the Phasitron® is now applied to the lung according

: movement of the Venturi-body during a) inspiration an b) exspiration. During the inspiration

moistened and warmed air is drawn in by the entrainment port. During the exspiration the entrainment port is closed.

The high-frequency oscillatory ventilation is recently moved in the centre of interest especially for application at the acute lung failure [125]. However bronchopulmonal fistulas are indica‐ tions for this method [126] and from the theoretical point of view for all purposes of lung protection. Without controversy high-frequency oscillatory ventilation is applied in paediatric

where its augmentation of volume, humidification and warming takes place.

in by the jet effect.

to the jet frequency.

**Figure 43.** Phasitron®

a)

b)

**9.6. Clinical experiences with high-frequency ventilation**

intensive care since a longer period and has become a routine method.

*9.6.1. High-frequency oscillatory ventilation*


**Table 7.** Authors and their use of combinations of predominately conventional types of ventilation with different high-frequency ventilation techniques. HFPPP… High-Frequency Positive Pressure Ventilation; HFO… High-Frequency Oscillation; IMV… (Intermittend mandatory Ventilation); HFJV… High- Frequency Jet Ventilation; PCV… (Pressure Controlled Ventilation); CMV… (Controlled Mechanical Ventilation); HFV… (High-Frequency Ventilation).

#### **9.5. High-frequency percussive ventilation**

Can be considered as a special type of the combined high-frequency ventilation. The highfrequency jet pulse produced by the respirator are superimposed by a apparently conventional pressure controlled higher pressure plateau. A pulsatile jet ventilation with two different high pressure plateaus is generated by only one respirator (Figure 42).

**Figure 42.** Characteristics of pressure and flow during ventilation with the VDR-4 ventilator. Peak airway pressure: 21 cm/H2O; PEEP: 9 cm/H2O; low-frequency: 12 cycles/min; high-frequency 500 cycles/min; inspiration:exspiration ratio = 1:2.

**Phasitron**® (Percussionaire® Corporation, Sandpoint, Idaho, USA)

The gas delivered by the respirator is first transmitted to the so-called Phasitron® (Figure 43) where its augmentation of volume, humidification and warming takes place.

The mobile Venturi-body in the Phasitron® is moved forward in the inspiratory phase. This causes a closure of the expiratory aperture and now warmed-up and moisturized air is sucked in by the jet effect.

This prepared column of air lying in front of the Phasitron® is now applied to the lung according to the jet frequency.

**Figure 43.** Phasitron® : movement of the Venturi-body during a) inspiration an b) exspiration. During the inspiration moistened and warmed air is drawn in by the entrainment port. During the exspiration the entrainment port is closed.

#### **9.6. Clinical experiences with high-frequency ventilation**

#### *9.6.1. High-frequency oscillatory ventilation*

The application of an additive, mostly conventional breath with an enlarged tidal volume enables the enhancement of CO2 elimination. A disadvantage is the usually need of combina‐

> HFPPV HFO IMV HFO IMV HFJV IMV HFO IMV HFPPV PCV HFO CMV HFV

**Author Frequency (LF/HF) Mode (Combination)**

**Table 7.** Authors and their use of combinations of predominately conventional types of ventilation with different high-frequency ventilation techniques. HFPPP… High-Frequency Positive Pressure Ventilation; HFO… High-Frequency Oscillation; IMV… (Intermittend mandatory Ventilation); HFJV… High- Frequency Jet Ventilation; PCV… (Pressure Controlled Ventilation); CMV… (Controlled Mechanical Ventilation); HFV… (High-Frequency Ventilation).

Can be considered as a special type of the combined high-frequency ventilation. The highfrequency jet pulse produced by the respirator are superimposed by a apparently conventional pressure controlled higher pressure plateau. A pulsatile jet ventilation with two different high

**Figure 42.** Characteristics of pressure and flow during ventilation with the VDR-4 ventilator. Peak airway pressure: 21 cm/H2O; PEEP: 9 cm/H2O; low-frequency: 12 cycles/min; high-frequency 500 cycles/min; inspiration:exspiration ratio

60/3000 2/250 5-7/200 5-10/1200 1-5/130-170 15-20/900-1200

15/360

pressure plateaus is generated by only one respirator (Figure 42).

**Phasitron**® (Percussionaire® Corporation, Sandpoint, Idaho, USA)

**9.5. High-frequency percussive ventilation**

tion of two devices.

El Baz et al. [118] Yeston et al. [119] Keszler et al. [120] Boynton et al. [121] Barzilay et al. [122] Borg et al. [123] Jousela et al. [124]

188 Endoscopy

= 1:2.

The high-frequency oscillatory ventilation is recently moved in the centre of interest especially for application at the acute lung failure [125]. However bronchopulmonal fistulas are indica‐ tions for this method [126] and from the theoretical point of view for all purposes of lung protection. Without controversy high-frequency oscillatory ventilation is applied in paediatric intensive care since a longer period and has become a routine method.

The best references for their indicated application at ARDS results from two prospective studies [127, 128] and a retrospective clinical trial with application of high-frequency oscilla‐ tion in combination with a recruitment manoeuvre [129], all showing significantly increase of oxygenation in comparison to conventional ventilation.

area of otorinolaryngology, but this Ventilation can be applied also due to ventilation techni‐ que of the respirator in the intensive care unit. So we could show in a clinical study [131] that this ventilation technique can lead to a quicker recruitment of the lungs in patients with a respiratory insuffiency. However, further studies are necessary to make more precise and

Endoscopy of Larynx and Trachea with Rigid Laryngo-Tracheoscopes Under Superimposed High-Frequency…

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191

First clinical results show that under high-frequency ventilation potentially a fast recruitment of dependent areas of the lung occurs without a simultaneous massive overexpansion of nondependent areas of the lungs. It is conceivable that the under high-frequency ventilation observed enhanced gas exchange is not so much to be explained by mechanism of increasing

The authors thank Mr. Heinrich Reiner from the Carl Reiner Corp. in Vienna, Austria, for his understandingful and dynamic help in implementation and propagation of our jet ventilation program at the Medical University of Vienna. Mr. Reiner supported not only the clinical and

\*Address all correspondence to: alexander@aloy.co.at, matthaeus.grasl@meduniwien.ac.at

This chapter deals with the history of laryngoscopy and the fruitful scientific and clinical collaboration of anaesthesiologists and laryngologists in development and application of jet

[1] Bozzini, Ph. Der Lichtleiter oder die Beschreibung einer einfachen Vorrichtung inner‐ er Höhlen und Zwischenräume des lebenden animalischen Körpers. Weimar: Verlag

1 Department of Anaesthesia and General Intensive Care Medicine, Vienna, Austria

2 Department of Otorhinolaryngology, Head & Neck Surgery, Vienna, Austria

ventilation for surgical laryngotracheal interventions via a rigid laryngoscope.

diffusion but by pulsatile mechanism leading to a fast recruitment of lung tissue.

definitive statements.

**Acknowledgements**

**Author details**

**References**

practical issues but also the scientific ones.

Alexander Aloy1\* and Matthaeus Grasl2

des Industrie Compoir; (1807).

*9.6.6. Potential effects of high-frequent ventilation techniques*

### *9.6.2. Combined high-frequency jet ventilation (CHFJV)*

The use of the conventional part of ventilation with low ventilation frequencies with conven‐ tional PEEP but higher volume tides guarantees a sufficient CO2 elimination.

A high-frequent ventilation mode superimposes the conventional mode. Predominantly the oxygenation is enhanced by the high-frequent pulsatile fraction of ventilation.

#### *9.6.3. High-frequency percussive ventilation*

In literature concerning the implementation of the high-frequency percussive ventilation in patients with acute lung failure was reduced over a long period to paediatric and adult. More descriptions exist about successful application in patients with ARDS, after inhalation trauma and taumata [130]. In paediatric patient polpulation with an inhalation trauma a lower rate of infection and mortality could be observed. Surprisingly a greater extent of departments apply the high-frequency percussive ventilation in clinical use even though they do not publizise their results.

### *9.6.4. High-frequency jet ventilation*

The high-frequency jet ventilation has become widely accepted in operative interventions in the larynx and trachea. Optimal working conditions with best view for the surgeons are achieved under the application of thin jet catheter and the absence of an endotracheal tube.

Application of high-frequency ventilation in intensive care units in premature patients with respiratory distress syndrome and interstitial pulmonary emphysema is a safe procedure and dimishes peak pressures. In relation to the outcome and mortality from the high-frequenecy jet ventilation did not derive a benefit in comparison to conventional ventilation.

The exclusive application of high-frequency jet ventilation in adults did not prevail. Usually is is applicated as combined high-frequency jet ventilation in cases when the conventional ventilation fails. The literature refers only about case reports or not randomized trials with few cases. However it demonstrates that these ventilation techniques are in use, although expen‐ sive, safe in application with a high potential to increase the oxygenation.

#### *9.6.5. Superimposed high-frequency jet-ventilation (SHFJV)*

SHFJV is a special type of combined high-frequency ventilation. A respirator produces a lowfrequent jet ventilation with a higher pressure level. Simultaneously a superposition with a high-frequent jet ventilation takes place which ensures for itself alone a lower plateau of pressure analogous a positive end-expiraratory pressure (PEEP). Only one respirator generates these two plateaus of pressure. This ventilation technique is primarily used in the operative area of otorinolaryngology, but this Ventilation can be applied also due to ventilation techni‐ que of the respirator in the intensive care unit. So we could show in a clinical study [131] that this ventilation technique can lead to a quicker recruitment of the lungs in patients with a respiratory insuffiency. However, further studies are necessary to make more precise and definitive statements.

### *9.6.6. Potential effects of high-frequent ventilation techniques*

First clinical results show that under high-frequency ventilation potentially a fast recruitment of dependent areas of the lung occurs without a simultaneous massive overexpansion of nondependent areas of the lungs. It is conceivable that the under high-frequency ventilation observed enhanced gas exchange is not so much to be explained by mechanism of increasing diffusion but by pulsatile mechanism leading to a fast recruitment of lung tissue.

### **Acknowledgements**

The best references for their indicated application at ARDS results from two prospective studies [127, 128] and a retrospective clinical trial with application of high-frequency oscilla‐ tion in combination with a recruitment manoeuvre [129], all showing significantly increase of

The use of the conventional part of ventilation with low ventilation frequencies with conven‐

A high-frequent ventilation mode superimposes the conventional mode. Predominantly the

In literature concerning the implementation of the high-frequency percussive ventilation in patients with acute lung failure was reduced over a long period to paediatric and adult. More descriptions exist about successful application in patients with ARDS, after inhalation trauma and taumata [130]. In paediatric patient polpulation with an inhalation trauma a lower rate of infection and mortality could be observed. Surprisingly a greater extent of departments apply the high-frequency percussive ventilation in clinical use even though they do not publizise

The high-frequency jet ventilation has become widely accepted in operative interventions in the larynx and trachea. Optimal working conditions with best view for the surgeons are achieved under the application of thin jet catheter and the absence of an endotracheal tube. Application of high-frequency ventilation in intensive care units in premature patients with respiratory distress syndrome and interstitial pulmonary emphysema is a safe procedure and dimishes peak pressures. In relation to the outcome and mortality from the high-frequenecy

The exclusive application of high-frequency jet ventilation in adults did not prevail. Usually is is applicated as combined high-frequency jet ventilation in cases when the conventional ventilation fails. The literature refers only about case reports or not randomized trials with few cases. However it demonstrates that these ventilation techniques are in use, although expen‐

SHFJV is a special type of combined high-frequency ventilation. A respirator produces a lowfrequent jet ventilation with a higher pressure level. Simultaneously a superposition with a high-frequent jet ventilation takes place which ensures for itself alone a lower plateau of pressure analogous a positive end-expiraratory pressure (PEEP). Only one respirator generates these two plateaus of pressure. This ventilation technique is primarily used in the operative

jet ventilation did not derive a benefit in comparison to conventional ventilation.

sive, safe in application with a high potential to increase the oxygenation.

*9.6.5. Superimposed high-frequency jet-ventilation (SHFJV)*

tional PEEP but higher volume tides guarantees a sufficient CO2 elimination.

oxygenation is enhanced by the high-frequent pulsatile fraction of ventilation.

oxygenation in comparison to conventional ventilation.

*9.6.2. Combined high-frequency jet ventilation (CHFJV)*

*9.6.3. High-frequency percussive ventilation*

*9.6.4. High-frequency jet ventilation*

their results.

190 Endoscopy

The authors thank Mr. Heinrich Reiner from the Carl Reiner Corp. in Vienna, Austria, for his understandingful and dynamic help in implementation and propagation of our jet ventilation program at the Medical University of Vienna. Mr. Reiner supported not only the clinical and practical issues but also the scientific ones.

### **Author details**

Alexander Aloy1\* and Matthaeus Grasl2

\*Address all correspondence to: alexander@aloy.co.at, matthaeus.grasl@meduniwien.ac.at

1 Department of Anaesthesia and General Intensive Care Medicine, Vienna, Austria

2 Department of Otorhinolaryngology, Head & Neck Surgery, Vienna, Austria

This chapter deals with the history of laryngoscopy and the fruitful scientific and clinical collaboration of anaesthesiologists and laryngologists in development and application of jet ventilation for surgical laryngotracheal interventions via a rigid laryngoscope.

### **References**

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[2] Mende, L. Von der Bewegung der Stimmritze beym Athemholen; eine neue Entdeck‐ ung; mit beygefügten Bemerkungen über den Nutzen und die Verrichtung des Kehl‐ deckels. Greifswald; (1916).

[19] Brünings W. Direct Laryngoscopy: Criteria determinating the appliccability of auto‐ scopy. Direct laryngoscopy, brochoscopy and esophagoscopy. London: Bailliere, Tin‐

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[20] Hartmann A. Zur Behandlung der Larynxtuberkulose. In: Hoffmann R (Hrsg) Verh d

[21] Holinger P. A new anterior commissure laryngoscope. Ann Otol Rhinol Laryngol.

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[23] Jako GJ. Laryngoscope for microscopic observation, surgery and photography. The

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**Chapter 10**

**Bronchology – A Well Branched Tree**

Bogdan Oprea, Raluca Marinas, Mimi Floarea Nitu,

Lung cancer is responsible for 1.3 million deaths worldwide annually, and it is the most common cause of cancer-related death in men and the second most common in women. Lung cancer staging is the assessment of the degree to which a lung cancer has spread from its original source. As with most cancers, for lung cancer staging is of paramount impor‐ tance for the treatment planning process and prognosis. Two primary methods of lung can‐ cer staging are available: clinical staging and pathologic staging. In clinical staging, information is provided by noninvasive or minimally invasive techniques, such as physical examination, radiologic examination, endoscopic ultrasound, bronchoscopy, mediastinosco‐ py, and thoracoscopy. In pathologic staging, information obtained from clinical staging is combined with findings from both the invasive surgical procedure and the pathologic evalu‐ ation of excised tissue. Clinical staging is important and can help to determine the next ap‐ propriate step in therapy, such as the decision to proceed with pathologic staging, which remains the reference standard because the overall level of agreement between the two sys‐

Definition of the stage is an essential part of the approach to patients with lung cancer, and it has led to the development of a universally accepted stage classification systems for most tumors. The Union Internationale Contre le Cancer (UICC) and the American Joint Commit‐ tee on Cancer (AJCC) periodically define, review, and refine the stage classification systems. Nearly half of all patients with lung cancer have mediastinal disease at diagnosis, and this implies metastases to ipsilateral or subcarinal nodes (N2) that are classified as stage IIIA dis‐

and reproduction in any medium, provided the original work is properly cited.

© 2013 Olteanu et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

Additional information is available at the end of the chapter

Mihai Olteanu, Costin Teodor Streba,

Emilia Crisan and Tudorel Ciurea

http://dx.doi.org/10.5772/52748

**1.1. Lung cancer – Stadialization**

tems only ranges from 35% to 55% [1].

**1. Introduction**

