**Abstract**

Difficult airway management in critically ill patients has serious implications, as failing to secure a stable airway can lead to a brain injury or even death. Early recognition of a difficult airway can allow the clinician to minimize the potential morbidmortality. In this chapter, we describe all about the common scenarios that we may tackle when we need to secure a patent airway. It is important to know common definitions about the airway, pre-visualize potential problems and knowing how to be aware of the different pathways on managing and solving the different problems that clinicians may face. It is highlighted to know all the different medical equipment and medication used when an airway is suspected not to be easy to manage or when problems arrive without warning and the practitioner needs to rapidly change the plan on the go. We discuss the current most relevant guidelines and literature about this subject trying to give a practical approach.

**Keywords:** difficult airway, airway management, ventilation, intubation, airway devices

## **1. Introduction**

One of the most stressful situations that all anesthetists, intensivists and emergency physicians can face is the management of a difficult airway (DA). That stressful situation can turn into a tragedy if the team is not well trained, not ready, and the plans are not well established or known.

The prediction of a DA is essential to anticipate all the strategy that the team has to deploy to successfully manage that situation.

Different guidelines and much literature have been published on this topic in recent years, all these articles try to establish a structured approach and facilitate in the simplest way the different steps to follow in this problematic scenario.

Airway management was considered inappropriate in a high percentage of complaints, including inadequate evaluation, lack of planning for difficult intubation, failure to use the supraglottic airway for rescue, delay in requesting help, and perseveration in failed techniques.

A thoroughly well-designed plan needs to be established and summarized in the airway approach algorithm and foresight all possible situations that may be encountered during the clinical practice of a serious and threatening airway crisis, all of them should be discussed in advance. Awake intubation, intubation after induction of anesthesia, and the "can't intubate, can't oxygenate" (CICO) situation should be planned and well known to all team members.

#### **2. Definition of difficult airway**

There is no universal definition of difficult airway in the literature. However, We can define the DA such as some clinical factors that make ventilation of the mask difficult or some anatomical factors that make tracheal intubation difficult for a trained specialist [1]. Difficult airway encompasses the interaction of various circumstances: patient factors, clinical settings, and specialized skills.

Difficult ventilation is the inability of an experienced specialist (intensivist or anesthesiologist) to maintain oxygen saturation above 90% with a 100% FiO2 face mask. We know that with some indirect signs such as absence or inadequate respiratory sound, inadequate chest movement, haemodynamic changes such as hypertension or hypotension, arrhythmias associated with hypoxaemia, cyanosis, etc.

Difficult orotracheal intubation (DOTI) is defined as three or more attempts to perform tracheal intubation or more than ten minutes to perform it. It occurs in 1.5–8% of general anesthesia procedures [2, 3]. The cause of these may be due to difficulty in laryngoscopy: we cannot visualize any portion of the vocal cords, failed intubation: the place of the endotracheal tube is incorrect after multiple attempts, presence of tracheal pathology that prevents correct tracheal intubation.

## **3. Purposes of the guidelines for difficult airway management**

DOTI is a common cause of anesthetic morbidity and mortality, so it is important to anticipate these difficulties before the process. Up to 30% of death from anesthesia could be due to a difficult airway. That is why it is very important to have high prognosis tests to identify difficulties in the airways [4, 5] and make a universal definition to classify the DA and teach the management of this. The main adverse outcomes include brain injuries that can be related to dental damage, trauma to the airways, unnecessary surgical airways or some injuries related to cardiopulmonary arrest, hypoxia, brain injury, or even death. The use of one method and another for the management of the DA, the hierarchy of categories made according to the level of scientific evidence collected will be carried out hereunder.

#### **4. Assessment of the airway**

The experienced clinician can anticipate when intubation may be difficult by taking a proper history and complete physical examination. In emergencies, a brief but comprehensive airway assessment is essential to treat patients who require advanced airway management.

#### **4.1 History of the respiratory tract**

The physician should take a history of the patient's airway, investigating in detail the medical, surgical, and anesthetic factors that may indicate the presence of a

**287**

*Management of New Special Devices for Intubation in Difficult Airway Situations*

Morbid obesity Acromegaly

Rheumatoid arthritis Ankylosing spondylitis Obstructive sleep apnea Tumors involving the airway

Radiation of face or neck

Pregnancy after 12 to 20 weeks gestation (gestational age for increased risk is controversial) Symptomatic

Trauma or burns of the face, head, or neck

etc.)

DA. Many disease states have been associated with DA (**Table 1**). Additionally, lung problems such as asthma, chronic obstructive pulmonary disease (COPD), bronchitis, recent upper respiratory infection, or the presence of pneumonia can affect oxygenation and ventilation. Most patients presenting for emergency procedures

Infections involving the airway (Ludwig's angina, epiglottitis, croup,

The purpose of this evaluation is to detect physical characteristics that may

Mouth. The jaw opening should be at least 4 centimeters in adults, which is roughly three to four fingers. A mouth opening of fewer than three fingers is considered limited. Patients with temporomandibular joint (TMJ) disease or previous surgery may have a very limited mouth opening or trismus. The movement of the TMJ must allow at least a maximum opening of the mouth of 50 to 60 mm. A small or large jaw can affect vision when intubated. The dentition should be evaluated, paying particular attention to the presence of caps, crowns, implants, veneers, dentures, braces, or loose teeth. The small space between incisors suggests possible DA management [7–9]. The Mallampati classification was first described in 1985 as a test to predict difficult laryngoscopy [10]. The Mallampati classification involves the size of the tongue concerning the oral cavity. The more the tongue obstructs the view of the pharyngeal structure, the more difficult the migration of the device: Class I: The entire tonsillar pillars, uvula, hard and soft palates are visualized.

and short neck, and neck collars are immediately apparent and suggest a pos-

Class II: Partial uvula and soft palate are visualized.

The sight assessment provides very useful information. Obesity, facial hair, thick

*DOI: http://dx.doi.org/10.5772/intechopen.97400*

are at increased risk of aspiration (**Table 2**) [6].

**Congenital Acquired**

*Diseases associated with difficult airway management.*

Full stomach – nonfasted, emergency surgery or trauma

Increased intra-abdominal pressure – ascites, abdominal mass

Pierre Robin syndrome Treacher-Collins syndrome Goldenhar syndrome Mucopolysaccharidoses Achondroplasia Micrognathia Down syndrome Cretinism Beckwith syndrome

gastroesophageal reflux Diabetic or another gastroparesis

Gastric outlet obstruction Oesophagal pathology Bowel obstruction

Hiatal hernia

**4.2 Examination of the respiratory tract**

indicate the presence of a DA.

*Conditions that increased risk of aspiration.*

sible DA.

**Table 2.**

**Table 1.**

*Management of New Special Devices for Intubation in Difficult Airway Situations DOI: http://dx.doi.org/10.5772/intechopen.97400*

DA. Many disease states have been associated with DA (**Table 1**). Additionally, lung problems such as asthma, chronic obstructive pulmonary disease (COPD), bronchitis, recent upper respiratory infection, or the presence of pneumonia can affect oxygenation and ventilation. Most patients presenting for emergency procedures are at increased risk of aspiration (**Table 2**) [6].


#### **Table 1.**

*Special Considerations in Human Airway Management*

planned and well known to all team members.

**2. Definition of difficult airway**

A thoroughly well-designed plan needs to be established and summarized in the airway approach algorithm and foresight all possible situations that may be encountered during the clinical practice of a serious and threatening airway crisis, all of them should be discussed in advance. Awake intubation, intubation after induction of anesthesia, and the "can't intubate, can't oxygenate" (CICO) situation should be

There is no universal definition of difficult airway in the literature. However, We can define the DA such as some clinical factors that make ventilation of the mask difficult or some anatomical factors that make tracheal intubation difficult for a trained specialist [1]. Difficult airway encompasses the interaction of various

Difficult ventilation is the inability of an experienced specialist (intensivist or anesthesiologist) to maintain oxygen saturation above 90% with a 100% FiO2 face mask. We know that with some indirect signs such as absence or inadequate respiratory sound, inadequate chest movement, haemodynamic changes such as hypertension or hypotension, arrhythmias associated with hypoxaemia, cyanosis, etc. Difficult orotracheal intubation (DOTI) is defined as three or more attempts to perform tracheal intubation or more than ten minutes to perform it. It occurs in 1.5–8% of general anesthesia procedures [2, 3]. The cause of these may be due to difficulty in laryngoscopy: we cannot visualize any portion of the vocal cords, failed intubation: the place of the endotracheal tube is incorrect after multiple attempts,

circumstances: patient factors, clinical settings, and specialized skills.

presence of tracheal pathology that prevents correct tracheal intubation.

**3. Purposes of the guidelines for difficult airway management**

of scientific evidence collected will be carried out hereunder.

**4. Assessment of the airway**

advanced airway management.

**4.1 History of the respiratory tract**

DOTI is a common cause of anesthetic morbidity and mortality, so it is important to anticipate these difficulties before the process. Up to 30% of death from anesthesia could be due to a difficult airway. That is why it is very important to have high prognosis tests to identify difficulties in the airways [4, 5] and make a universal definition to classify the DA and teach the management of this. The main adverse outcomes include brain injuries that can be related to dental damage, trauma to the airways, unnecessary surgical airways or some injuries related to cardiopulmonary arrest, hypoxia, brain injury, or even death. The use of one method and another for the management of the DA, the hierarchy of categories made according to the level

The experienced clinician can anticipate when intubation may be difficult by taking a proper history and complete physical examination. In emergencies, a brief but comprehensive airway assessment is essential to treat patients who require

The physician should take a history of the patient's airway, investigating in detail

the medical, surgical, and anesthetic factors that may indicate the presence of a

**286**

*Diseases associated with difficult airway management.*

#### **Table 2.**

*Conditions that increased risk of aspiration.*

#### **4.2 Examination of the respiratory tract**

The purpose of this evaluation is to detect physical characteristics that may indicate the presence of a DA.

The sight assessment provides very useful information. Obesity, facial hair, thick and short neck, and neck collars are immediately apparent and suggest a possible DA.

Mouth. The jaw opening should be at least 4 centimeters in adults, which is roughly three to four fingers. A mouth opening of fewer than three fingers is considered limited. Patients with temporomandibular joint (TMJ) disease or previous surgery may have a very limited mouth opening or trismus. The movement of the TMJ must allow at least a maximum opening of the mouth of 50 to 60 mm. A small or large jaw can affect vision when intubated. The dentition should be evaluated, paying particular attention to the presence of caps, crowns, implants, veneers, dentures, braces, or loose teeth. The small space between incisors suggests possible DA management [7–9]. The Mallampati classification was first described in 1985 as a test to predict difficult laryngoscopy [10]. The Mallampati classification involves the size of the tongue concerning the oral cavity. The more the tongue obstructs the view of the pharyngeal structure, the more difficult the migration of the device:

Class I: The entire tonsillar pillars, uvula, hard and soft palates are visualized. Class II: Partial uvula and soft palate are visualized.

Class III: Only the soft palate is visualized. Class IV: No visualization of any structures beyond the tongue.

Neck range of motion decreases with age, neck arthritis, cervical spine disease, or previous spinal surgery. Patients with restricted neck extension may be more difficult to position optimally for induction of anesthesia and intubation [11]. Airway management must be based on the fact that DA cannot be predicted reliably. This is a particularly important consideration in the intensive care setting [12]. Recognition of patients at particular risk of DA management helps planning and is recommended, even in the most urgent situations. The only validated airway assessment tool in critically ill patients is the MACOCHA score (**Table 3**). A score of ≥3 predicts difficult intubation in critically ill patients. However, to reject difficult intubation with certainty, the main value of the score comes from the negative predictive value of the parameter. It is wise to be prepared for DOTI, even if intubation is ultimately not difficult [13].


**Table 3.** *MACOCHA score.*

## **5. Basic preparation for difficult airway management**

A difficult airway management protocol includes several well-organized strategies to achieve sufficient ventilation and apply various intubation techniques to have the best chance of success and decrease the chance of injury to the patient. Although the airway approach is a challenge for the emergency team, airway management is even more difficult in critically ill patients. Decision-making, interaction within the team, use of resources, and motor skills can all be affected under stress. The goal is to ensure oxygenation in life-threatening and rapidly changing situations that require agile decision making, thereby reducing the number and severity of critical incidents and complications.

#### **5.1 Recommendations for the management of the difficult airway**

There should be at least one portable storage unit containing all specialized equipment for managing DA. A variety of standard and alternative airway devices should be readily available, including masks, appropriate sizes and types of laryngoscopes (direct, indirect, flexible), oral and nasal airways, supraglottic airways (SGA), spark plugs and equipment. For the front of the mouth neck access (FONA). Make sure there is at least one additional person who must be immediately available to serve as an assistant in managing DA.

All patients must be pre-oxygenated before induction of general anesthesia. Pre-oxygenation increases oxygen reserve delays the onset of hypoxia and allows

**289**

*Management of New Special Devices for Intubation in Difficult Airway Situations*

more time for laryngoscopy, tracheal intubation, and airway rescue in the event of intubation failure [14]. The duration of apnea without desaturation can also be prolonged by passive oxygenation during the apneic period (apneic oxygenation). This can be achieved by administering up to 15 liters/min of oxygen through nasal cannulas. Nasal administration of oxygen during intubation management has been shown to prolong apnea time in obese patients with a DA [15]. High-flow nasal cannulas (with humidified high-flow oxygen (up to 70 liters/min) have been shown to prolong apnea time, although their ability to improve preoxygenation has not yet

There should be a portable chart unit containing all specialized pieces of equipment for the management DA. The following steps are highly recommended [16]: • Inform the patient (or responsible person, if possible) about the risks and special procedures related to the management of DA. • Make sure there is at least one person available to operate as an assistant. • Pre-oxygenate with a mask before starting DA management. In the uncooperative or pediatric patient may result impossible to achieve. • Actively seek any opportunity to supply supplemental oxygen throughout the DA management. These include the delivery of oxygen via nasal cannulas, mask or LMA, and oxygen supply through any applied device. Airway management is safer when potential problems are identified in advance in case of urgent intubation, allowing planning and reducing the risk of complications [17]. Airway assessment should be performed routinely to identify factors that may cause difficulties with face mask ventilation, SAD insertion, tracheal intubation, or front neck access (FONA). The prediction of DA management is not always completely reliable. Basic management preparation for DA management includes (1) availability of DA management equipment, (2) informing the patient or relatives of a known or suspected DA, (3) assigning a person for help and assistance, (4) mask pre-oxygenation, and

(5) supplemental oxygen administration throughout the DA management.

A well pre-planned strategy before induction includes several interventions, designed to facilitate intubation in the event of DA. Non-invasive maneuvers targeted at treating DA include [17]: (1) awake intubation, (2) video-assisted laryngoscopy, (3) intubation stylet or tube changers, (4) SGA for ventilation (eg. LMA, laryngeal tube), (5) PEG for intubation (eg. ILMA), (6) rigid laryngoscopy, (7) fibreoptic-guided intubation, and (8) stylets with light or light wands. Following the Difficult Airway Society, we will proceed with a structured detailed plan that

The very essence of Plan A is to maximize the chance of successful intubation on the first attempt or, failing that, limit the number and duration of laryngoscopy attempts to prevent airway injury and progression to a " cannot intubate, cannot oxygenate "(CICO). Patients must be in an optimal position and well pre-oxygenated before the administration of anesthetic medication. The use of neuromuscular blockade facilitates mask ventilation and tracheal intubation. Any attempt at laryngoscopy and tracheal intubation is potentially harmful. A suboptimal attempt is a vain attempt and carries the possibility that success diminishes with each

*DOI: http://dx.doi.org/10.5772/intechopen.97400*

**5.2 Recommendations for basic DA management**

**6. Difficult airway intubation strategy**

**6.1 Plan A. Mask ventilation and tracheal intubation**

consists of several considerations.

been elucidated [16, 17].

*Management of New Special Devices for Intubation in Difficult Airway Situations DOI: http://dx.doi.org/10.5772/intechopen.97400*

more time for laryngoscopy, tracheal intubation, and airway rescue in the event of intubation failure [14]. The duration of apnea without desaturation can also be prolonged by passive oxygenation during the apneic period (apneic oxygenation). This can be achieved by administering up to 15 liters/min of oxygen through nasal cannulas. Nasal administration of oxygen during intubation management has been shown to prolong apnea time in obese patients with a DA [15]. High-flow nasal cannulas (with humidified high-flow oxygen (up to 70 liters/min) have been shown to prolong apnea time, although their ability to improve preoxygenation has not yet been elucidated [16, 17].

#### **5.2 Recommendations for basic DA management**

*Special Considerations in Human Airway Management*

Class III: Only the soft palate is visualized.

tion is ultimately not difficult [13].

of critical incidents and complications.

to serve as an assistant in managing DA.

Class IV: No visualization of any structures beyond the tongue.

**M**allampati 3 or 4 5 Obstructive Sleep **A**pnea 2 **C**ervical-spine movement limited 1 Mouth **O**pening < 3 cm 1 **C**oma 1 **H**ypoxemia (<80%) 1 Non-**A**nesthetist intubator 1

**5. Basic preparation for difficult airway management**

**5.1 Recommendations for the management of the difficult airway**

There should be at least one portable storage unit containing all specialized equipment for managing DA. A variety of standard and alternative airway devices should be readily available, including masks, appropriate sizes and types of laryngoscopes (direct, indirect, flexible), oral and nasal airways, supraglottic airways (SGA), spark plugs and equipment. For the front of the mouth neck access (FONA). Make sure there is at least one additional person who must be immediately available

All patients must be pre-oxygenated before induction of general anesthesia. Pre-oxygenation increases oxygen reserve delays the onset of hypoxia and allows

A difficult airway management protocol includes several well-organized strategies to achieve sufficient ventilation and apply various intubation techniques to have the best chance of success and decrease the chance of injury to the patient. Although the airway approach is a challenge for the emergency team, airway management is even more difficult in critically ill patients. Decision-making, interaction within the team, use of resources, and motor skills can all be affected under stress. The goal is to ensure oxygenation in life-threatening and rapidly changing situations that require agile decision making, thereby reducing the number and severity

Neck range of motion decreases with age, neck arthritis, cervical spine disease, or previous spinal surgery. Patients with restricted neck extension may be more difficult to position optimally for induction of anesthesia and intubation [11]. Airway management must be based on the fact that DA cannot be predicted reliably. This is a particularly important consideration in the intensive care setting [12]. Recognition of patients at particular risk of DA management helps planning and is recommended, even in the most urgent situations. The only validated airway assessment tool in critically ill patients is the MACOCHA score (**Table 3**). A score of ≥3 predicts difficult intubation in critically ill patients. However, to reject difficult intubation with certainty, the main value of the score comes from the negative predictive value of the parameter. It is wise to be prepared for DOTI, even if intuba-

**288**

**Table 3.** *MACOCHA score.*

There should be a portable chart unit containing all specialized pieces of equipment for the management DA. The following steps are highly recommended [16]: • Inform the patient (or responsible person, if possible) about the risks and special procedures related to the management of DA. • Make sure there is at least one person available to operate as an assistant. • Pre-oxygenate with a mask before starting DA management. In the uncooperative or pediatric patient may result impossible to achieve. • Actively seek any opportunity to supply supplemental oxygen throughout the DA management. These include the delivery of oxygen via nasal cannulas, mask or LMA, and oxygen supply through any applied device. Airway management is safer when potential problems are identified in advance in case of urgent intubation, allowing planning and reducing the risk of complications [17]. Airway assessment should be performed routinely to identify factors that may cause difficulties with face mask ventilation, SAD insertion, tracheal intubation, or front neck access (FONA). The prediction of DA management is not always completely reliable. Basic management preparation for DA management includes (1) availability of DA management equipment, (2) informing the patient or relatives of a known or suspected DA, (3) assigning a person for help and assistance, (4) mask pre-oxygenation, and (5) supplemental oxygen administration throughout the DA management.

#### **6. Difficult airway intubation strategy**

A well pre-planned strategy before induction includes several interventions, designed to facilitate intubation in the event of DA. Non-invasive maneuvers targeted at treating DA include [17]: (1) awake intubation, (2) video-assisted laryngoscopy, (3) intubation stylet or tube changers, (4) SGA for ventilation (eg. LMA, laryngeal tube), (5) PEG for intubation (eg. ILMA), (6) rigid laryngoscopy, (7) fibreoptic-guided intubation, and (8) stylets with light or light wands. Following the Difficult Airway Society, we will proceed with a structured detailed plan that consists of several considerations.

#### **6.1 Plan A. Mask ventilation and tracheal intubation**

The very essence of Plan A is to maximize the chance of successful intubation on the first attempt or, failing that, limit the number and duration of laryngoscopy attempts to prevent airway injury and progression to a " cannot intubate, cannot oxygenate "(CICO). Patients must be in an optimal position and well pre-oxygenated before the administration of anesthetic medication. The use of neuromuscular blockade facilitates mask ventilation and tracheal intubation. Any attempt at laryngoscopy and tracheal intubation is potentially harmful. A suboptimal attempt is a vain attempt and carries the possibility that success diminishes with each

subsequent attempt [18–20]. Repeated attempts at tracheal intubation reduce the likelihood of effective airway rescue with SAD [21]. Current guidelines recommend a maximum of three intubation attempts; a fourth attempt can be done by a more experienced colleague. If unsuccessful, a failed intubation should be stated and proceed to Plan B.

#### **6.2 Plan B. SAD**

Maintaining of oxygenation: supraglottic airway device (SAD) insertion is in the guidelines. The emphasis of Plan B is to maintain oxygenation using a SAD. If we succeed in the placement of a SAD, it brings the opportunity to stop and consider whether to wake the patient, try a new attempt at intubation, continue without a tracheal tube, or, in rare cases, proceed to a cricothyroidotomy. If we cannot achieve oxygenation via SAD after a maximum of three attempts, proceed to Plan C.

#### **6.3 Plan C. Awakening or total paralysis**

Final attempt at mask ventilation. If effective ventilation has not been established after three attempts at SAD insertion, Plan C proceeds directly. At this stage, several possible scenarios can be developed. During Plans A and B, it will be determined whether mask ventilation was easy, difficult, or impossible, but the situation may have changed if attempts at intubation and SAD placement have traumatized the airway. If mask ventilation results in inadequate oxygenation, the patient should be awakened in all but exceptional circumstances, and this situation will require total antagonism of the neuromuscular block. If oxygenation cannot be maintained using a face-mask, ensuring complete paralysis before critical hypoxia develops and we will have one last chance to rescue the airway without resorting to Plan D. Sugammadex has been used to antagonize neuromuscular block during the situation of CICO, but does not guarantee a patent and manageable upper airway. Residual neuro-depressant medication, airway laceration, or pre-existing upper airway disease may contribute to airway obstruction [17, 21].

#### **6.4 Plan D. Front neck emergency access (FONA)**

A CICO situation arises when attempts to manage the airway by tracheal intubation, mask ventilation, and SAD have failed. Hypoxic brain damage and death can occur if the situation is not resolved quickly. NAP4 report provided feedback on a cohort of emergency surgical airway and cannula cricothyroidotomies performed when other methods of securing the airway had failed [22, 23]. The report highlighted several issues, including decision making (delayed progression to cricothyroidotomy), knowledge gaps (not understanding how the available equipment worked), system failures (specific equipment not available), and technical failures (not placing a cannula in the airway). After NAP4, the discussion focused largely on the choice of technique and equipment used when airway rescue failed, but the report also highlighted the importance of human factors (discussed elsewhere) [16, 17]. Regular training in technical and non-technical elements is needed to reinforce and retain skills. Success depends on decision-making, planning, preparation, and skill acquisition, all of which can be developed and refined with repeated practice [24, 25].

FONA consists of surgical airway access employing an emergency cricothyroidotomy. This technique is presented and discussed elsewhere in this book.

**291**

**Table 4.** *Stylets.*

*Management of New Special Devices for Intubation in Difficult Airway Situations*

**7. Different techniques and devices for approaching intubation in DA**

We define the classic stylet as a malleable metal wire designed to be inserted into the endotracheal tube to facilitate tracheal placement at the time of intubation with difficult laryngoscopy. Mild mucosal bleeding and a sore throat are complications

We can find several commercialized types that differ in curvature and size. There are also specialized stylets available known as endotracheal tube introducers or "rubber elastic plug" which consist of a 50 to 60 cm stylet with the distal tip bent at a 30-degree angle. They are indicated in a grade III Cormack-Lehane view because they allow the physician to direct forward under the epiglottis and through the vocal cords and then a tracheal tube can be inserted over it. Some of them are single-use like **Frova,** whose tip is fenestrated to allow oxygenation. However,

Today there are also disposable optical lighted stylets or light wands that incorporate a video or fiber-optic display element at the distal end. The viewing element provides the clinician with an adequate view from outside the mouth with direct laryngoscopy to the region near the glottis. Common examples include; the **Clarus video system**, the **Shikani video system**, the **Bonfires retromolar intubation fibrescope**, and the **Leviton FPS telescope** (**Table 4**) [27, 28]. They are not indicated for use in patients with laryngeal trauma, tumors, and foreign bodies. It is also

Introduce the ET over the stylet having previously lubricated the inner face of the ET. Choose the desired stylet angle. Using the index finger of the left hand or the laryngoscope, move the tongue to the left and insert the tip of the pencil into the right side of the mouth with the right hand. Try to direct the tip of the stylet towards the midline of the neck trying to pass the glottis. Once the tip of the stylet passes the glottis, we will appreciate light in the midline of the neck by transillumination. We then advance the ETT through the stylet to the trachea.

**SPECIALIZED** LIGHTED BOUGIE OPTICAL

Eschmann introducer can be sterilized and reused [26].

Instructions for use [28]:

not indicated for patients with thick necks or limited neck extension.

**CLASSICAL** SINGLE USED REUSED

*DOI: http://dx.doi.org/10.5772/intechopen.97400*

**7.1 Intubation stylets or tube exchangers**

associated with stylets (**Figure 1**).

*7.1.1 Stylets*

**Figure 1.** *Classical stylets.* *Management of New Special Devices for Intubation in Difficult Airway Situations DOI: http://dx.doi.org/10.5772/intechopen.97400*
