**2.3 Aiding blind and fiberoptic-guided endotracheal intubation**

SGAs can be used as a conduit for blind and fiberoptic-guided intubation for rescue of failed direct laryngoscopy or failed intubation [27–29]. After inserting the LMA, a well lubricated ETT with deflated cuff is passed over the fiberscope. The fiberscope is then advanced through the LMA. The ETT is advanced around 1.5 cm past the mask aperture. The tip of the ETT lifts the fiberscope away from the bowl of the mask and exposes the glottis. The fiberoptic scope is then advanced up to the distal end of the tracheal tube. The ETT is advanced until the glottis is brought into view and then further advanced into the trachea.

A specific advantage of using an SGA is the ability to continue ventilating and anaesthetising the patient through the SGA until formal tracheal intubation is achieved. The Aintree catheter, a modification of the Cook's airway exchanger may be used to intubate through the SGA. It is loaded over a fiberoptic bronchoscope (FOB) and the trachea is visualised through the SGA [30, 31]. Leaving the Aintree catheter in place, the SGA is then removed. The ETT is then loaded over the catheter and advanced into the trachea.

#### **2.4 Rescue airway**

The difficult airway algorithm made by the American Society of Anesthesiologists (ASA) has a prominent place for the use of SGAs in airway rescue [32]. The Difficult Airway Society (DAS) 2015 guidelines suggests the use of SGAs as first line rescue airway for management of a failed intubation [33]. Several case reports support the use of SGAs for supporting ventilation in difficult airways with failed intubation [34–37]. SGAs also aid successful tracheal intubation in situations in which conventional methods have failed.

**3. Contraindications**

Disease, hiatus hernia)

• Maxillo facial trauma

• Upper airway trauma

• Cough and laryngospasm

• Gastric insufflation

**4. Insertion technique**

create a seal.

**253**

**3.1 Complications**

• Morbidly obese patients

• Regurgitation and aspiration

• Restricted mouth opening (< 2.5 cm)

*Second Generation Supraglottic Airway (SGA) Devices DOI: http://dx.doi.org/10.5772/intechopen.93947*

• Prolonged duration of surgery (>2 hrs)

• Surgery involving the upper airway

• Distorted airway anatomy and airway obstruction

• Misplacement of mask and airway obstruction

• Malposition or dislodgement of LMA

• Inadequate sealing of airway and leaks

• Patients with risk of gastric aspiration (non-fasted, Gastro Oesophageal Reflux

• Patients with airway morbidities (Respiratory tract infections, COPD etc.)

• Vocal cord palsy and nerve injuries (Lingual nerve, Recurrent Laryngeal

All LMAs consist of four parts, a hollow tube (shaft) continuous with a hollow mask or cuff, inflation line with pilot balloon and drain (gastric access) tube. The broad elliptical inflatable cuff has a smooth upper surface that prevents pharyngeal secretions from entering the airway and an under surface that sits over the larynx to

The patient's neck is flexed and head is extended (sniffing position) (**Figure 1**). The LMA is partially deflated and the backside of the LMA is lubricated. The shaft is grasped with the dominant hand like a pen, as near to the mask as possible. The deflated flattened mask is inserted against the hard palate downward into the mouth along the curvature of the back of the pharynx. The index finger follows the tube into the mouth to keep pressing "back" and "down" until the aperture faces the laryngeal inlet. If at any time during insertion the mask fails to stay flattened or starts to fold back, it should be withdrawn and reinserted. Another technique is to

Nerve, Hypoglossal Nerve, Glossopharyngeal Nerve)

#### **2.5 Procedures in the critical care units**

## *2.5.1 Paediatric bronchoscopies*

Flexible bronchoscopies comprise the major airway procedures performed including bronchoalveolar lavage, transbronchial biopsies, and foreign body removal [38]. LMA use during paediatric bronchscopies is associated with ease of insertion during general anaesthesia with spontaneous or assisted ventilation, as well as a net decrease in procedure time.

#### *2.5.2 Adult bronchoscopies*

Certain patients who cannot tolerate the procedure with conscious sedation (i.e., excessive gag response or discomfort) may require general anaesthesia. An LMA is an ideal device in such a scenario.

#### *2.5.3 Percutaneous tracheostomies*

Percutaneous tracheostomies are increasingly performed in the critical care setting. It is indicated in patients who are ventilator dependent due to acute illnesses, or if duration of ETT use is expected to exceed 2 weeks [39]. Cattano et al. conducted a study on patients undergoing percutaneous tracheostomy using dilating forceps approach where ETT was replaced by an SGA [40]. They concluded that intubation through SGAs offered a superior view of the trachea without the risk of the bronchoscope or the ETT getting needle punctured.

#### **2.6 Aide to tracheal extubation**

Since SGAs cause less cough and rise in intracranial or intraocular pressures compared to the ETT, they may be used for smooth emergence from anaesthesia. The device may be placed after removal of the ETT. This is helpful in situations in which airway and hemodynamic reflexes are undesirable.

#### **2.7 Pre or outside the hospital airway**

In the field, securing an airway is of paramount importance. SGAs are lifesaving in the "can't ventilate, can't intubate" situation. An SGA can be used for transport until a definitive airway can be obtained [41]. The placement of an SGA is easily mastered by the inexperienced hands with minimal training.

During cardio pulmonary resuscitation (CPR), the first part of the secondary survey includes securing an airway device as soon as possible [42]. SGA use during CPR has increased since SGA insertion is easier to learn than tracheal intubation and feasible with fewer and shorter interruptions in chest compression [43]. Use of SGAs during CPR is associated with a lower incidence of regurgitation of gastric contents than bag-mask ventilation [44].
