Airway Management

Jayashree  Sood; Pradeep  Jain; Deepanjali  Pant

Airway Management1

This chapter is designed to cover management of the pediatric airway under four subheadings:

Differences between pediatric and adult airway
Armamentarium of pediatric airway devices and associated equipment
Special airway techniques in children
Management of the difficult airway.

Normal Pediatric Airway

The area of greatest anatomic difference between an infant and an adult is in the airway (Fig. 1.1).

Fig. 1.1: Anatomical differences

Table 1.1 Anatomical differences and their significance

Parts	Infant	Adult	Considerations in infant
Head and neck	Large head, short neck, occipital protuberance	Normal	Hyperflexion of neck in supine position a roll under the neck offsets this (Figs 1.2A and B)
Nares	Obligatory nasal breather, narrow nares, inclined floor of nasal cavity	Normal	Nasal secretions obstruct breathing Tongue contacts posterior wall of pharynx—obstructs airway
Tongue	Relatively large and posteriorly placed	Normal	Less roomy oral cavity – airway obstruction during mask holding Laryngoscopy and intubation more difficult
	Enlarged adenoids		Compounds airway obstruction
Epiglottis	Large, floppy, angled posteriorly over laryngeal inlet	Firm, less posterior angle	Control with laryngoscope blade more difficult. Folding of epiglottis during LMA insertion is frequent
Glottis	Anterior and higher, C₃ level in premature babies, C₃-C₄ level in newborn	C₅ level	Excess neck extension interferes with good visualization of glottis
Vocal cords	Inclined, slant anteriorly, prominent arytenoids	Flat	Insertion of endotracheal tube (ETT) more difficult especially for blind endotracheal intubation
Narrowest portion	Cricoid level	Glottis level	Significant while selecting size of ETT
Trachea	Short, mobile, posterior displacement into thorax	Long, stationary, vertical descent into thorax	Short trachea predisposes to accidental dislodgement of ETT or endobronchial intubation
Carinal angle	55 degrees both sides	25 degrees right and 45 degrees left side	Endobronchial intubation possible on either side
Lungs	Less elastic, smaller diameter of alveoli	Normal	Even a small amount of secretion can increase resistance
Diaphragm	Type II muscle fibers	Type I muscle fibers	Ability to perform repeated exercise is less, so respiratory muscle fatigue is common

Knowledge of these anatomical differences is essential for every practitioner to understand pediatric airway management (Table 1.1).

The salient physiological differences are mentioned in Table 1.2.

Pediatric Airway Devices and Associated Equipment

There are many airway devices available to manage the pediatric airway. However, choosing the right airway device is a critical decision which depends on the experience and familiarity with the device.

These devices can be grouped into three main categories:

Face masks and airways
Tracheal tube and its alternatives
Conventional rigid laryngoscope and its alternatives.

Figs 1.2A and B: Roll under neck: (A) Obstructed airway; (B) Patent airway

Table 1.2 Physiological considerations

Factors	Infant	Adult
O₂ Consumption	7 mL kg)⁻¹ min⁻¹	3.5 mL kg⁻¹ min⁻¹
Minute ventilation	200 mL kg⁻¹ min⁻¹	100 mL kg⁻¹ min⁻¹
Respiratory rate	24–30 min⁻¹	10–15 min⁻¹
Pleural pressure	−1 to −2 cm H₂O	−5 cm H₂O
Vital capacity	35 ml kg⁻¹	70 ml kg⁻¹
FRC	30 ml kg⁻¹	35 ml kg⁻¹
Tidal volume	7 ml kg⁻¹	7 ml kg⁻¹
Dead space	2–2.5 ml kg⁻¹	2.2 ml kg⁻¹
Resistance to gas flow	10 × of adults	Normal
pH	7.34–7.40	7.36–7.44
PaO₂ (mm of Hg)	60–85	85–95
PaCO₂ (mm of Hg)	30–36	36–44

FACE MASKS

The face mask is an essential adjunct for airway management in almost all situations. It is frequently used prior to laryngeal mask airway (LMA) or endotracheal tube (ETT) insertion and also for non-invasive positive pressure ventilation for treatment of respiratory failure. These masks are made up of non-conductive black rubber (neoprene), clear plastic or elastomeric material. Scented disposable PVC cushion face masks are commonly used in contemporary pediatric practice (Fig. 1.3), but the anatomical black rubber face mask (Connell mask) is preferred in larger patients. Circular pediatric masks are available in silicone or black rubber versions (Fig. 1.4).

The face mask has a body, a seal and a connector. A transparent body is more acceptable to the patient and also allows observation of vomitus, secretions, blood, lip color and exhaled moisture.4

Fig. 1.3: Scented disposable PVC face masks

Fig. 1.4: Circular pediatric mask

The seal is either an air-filled cushion or a flap which conforms to the contour of the face. The connector part consists of a thickened fitting of ID 22 mm. A ring with hooks around the connector allows fixation with a harness or strap. The Rendell-Baker-Soucek (RBS) mask is specially designed for neonates and has a triangular body with minimal dead space (one quarter of the anatomical face mask) (Fig. 1.5). It can also be used to achieve controlled or assisted ventilation over a tracheostomy stoma with its nasal end pointing caudally.

The endoscopic mask has a port for insertion of a fiberscope through nose or mouth while allowing simultaneous mask ventilation. The available sizes are usually for children more than four years of age (Fig. 1.6).

Selection of a face mask of appropriate size and shape ensures a proper mask-fit for optimal ventilation with the least increase in dead space (Table 1.3). The commonly used methods of holding a mask to maintain a patent airway with a tight seal are (Figs 1.7A to C):

(i) One-hand method, (ii) Two-hand method, (iii) Claw-hand method.

One-hand method (E-C clamp technique): The thumb and index finger of the left hand are placed on the mask body to form a ‘C’ to hold the mask on the patients’ face while the remaining three fingers are placed on the inferior surface of the mandible to form an ‘E’ to lift the jaw into the mask. Care should be taken to avoid pressure on the eyes and compression of the submental soft tissues, since in young children the tongue can be pushed up to cause airway obstruction.5

Fig. 1.5: Rendell-Baker-Soucek (RBS) masks

Fig. 1.6: Disposable endoscopic mask
Two-hand method: This method is used when the one-hand method is ineffective. A second person is required if manual assisted or controlled respiration is needed.
Claw-hand method: This method is useful in short duration ophthalmic procedures where the anesthesiologist stands on the side facing the child. The face mask is applied in such a manner that the ring finger and middle finger go under the angle of the jaw on the opposite side and the thumb and index finger encircle the body of the mask to achieve a good seal.

Figs 1.7A to C: Mask holding methods: (A) One-hand method; (B) Two-hand method; (C) Claw-hand method

The palmar surface of the anesthesiologist's hand faces upwards unlike in the previous methods where it faces downwards.

Table 1.3 Different types of face masks

Age group	Rendell-Baker- Soucek mask	Circular mask
Premature	0	00
Infant	1	0
Small child	2	0A
Child	3 with hook	0B

Advantages

Lower incidence of sore-throat
Requires less anesthetic depth
Cost-efficient method to manage the airway for short cases.

Disadvantages

User fatigue
Higher fresh gas flow required
Not useful in remote anesthesia (i.e. MRI/CT scan)
More episodes of oxygen desaturation
PaCO₂-EtCO₂ gradient higher particularly with small tidal volume because of large dead space ventilation
May require more frequent intraoperative airway manipulations
Work of breathing increases during spontaneous breathing.

Complications

Gastric inflation during controlled ventilation
Skin allergy to the material or residue from chemical or gas sterilization
Eye injury due to ill-fitting mask and undue pressure applied
Nerve injury due to pressure from mask or strap, stretching from extreme forward jaw displacement or unstable cervical spine.

AIRWAYS

Airways lift the tongue and epiglottis away from the posterior pharyngeal wall thus preventing obstruction of the space above the larynx. Airways always require a face mask as a ventilatory device and decrease work of breathing during spontaneous respiration. The airway may be 7inserted via the oral or nasal route. The nasopharyngeal airway is used in a pediatric patient with gag reflex while an oropharyngeal airway is for patients without gag reflex. Sizing of the airway is in the same way as for an adult. Measurement landmarks are from the corner of the mouth or nose to the tip of the ear lobule.

Complications

Airway obstruction by the tongue or epiglottis due to incorrect size or improper insertion
Trauma to nose, lip, tongue, teeth and pharynx
Tissue edema, ulceration and necrosis of nose or tongue when airway is in situ for an extended period
Coughing and laryngospasm if airway is introduced during inadequate depth of anesthesia.

Oropharyngeal Airways

These are made of PVC or elastomeric material. Each airway has a flange at the buccal end to prevent over-insertion. The bite portion is straight, fits between the teeth or gums and is reinforced to prevent occlusion by biting. The curved portion extends backwards to correspond to the shape of the tongue and palate. Oral airway insertion does not cause movement of cervical spine. The oral airway does not need to be inverted when inserted into the mouth of an infant or small child. It should never be inserted in case of epiglottitis as total airway obstruction may be precipitated. The most popular oral airway is the Guedel airway which has its bite-portion color-coded according to size (Fig. 1.8) (Table 1.4). The dual channel design of Berman oral airway allows access of a suction catheter and a color coded version is also available for easy identification (Fig. 1.10).

Table 1.4 Sizes available for pediatric age group (Fig. 1.9)

Age group	Color code	Order size	Length (mm)	ISO size
Newborn	Transparent	000	30	3
	Pink	00	40	4
Children	Blue	0	50	5
	Black	1	60	6
	White	2	70	7

Advantages

Maintains an open airway
Facilitates oropharyngeal suctioning

Fig. 1.8: Guedel oropharyngeal airways

8

Fig. 1.9: Sizing of oral airway

Fig. 1.10: Berman oropharyngeal airways
Protects tongue or orotracheal tube from being bitten
Provides a pathway for inserting device into pharynx or esophagus.

Nasopharyngeal Airways

Nasopharyngeal airways are made of rubber or plastic and are available in various sizes (Figs 1.11A and B). The anatomic constraints of the nasal passages limit the scope for various designs of nasal airways. Most consist of a flange and a curved cylindrical tube. The flange, sometimes aided with a safety-pin, prevents it from slipping deep into the nose.9

Figs 1.11A and B: (A) Nasopharyngeal airways; (B) Different sizes of disposable nasal airways

Fig. 1.12: Binasal airway

The tube is curved to follow the anatomic shape of the nasal floor and nasopharynx. Most nasal airways are uncuffed and use one nostril, but some are cuffed. A binasal airway consists of two nasal airways joined together by an adapter for attachment to a breathing system or CPAP machine (Fig. 1.12).

Nasal airway should be lubricated thoroughly along its entire length. A vasoconstrictor may be applied to the nostril before insertion of airway to reduce trauma. Insert the airway gently without resistance, in a perpendicular direction with the curve oriented towards the mouth. Too deep an insertion may stimulate the laryngeal reflex and too short an insertion may not relieve airway obstruction. Ideally, when fully inserted, the pharyngeal end should be below the base of the tongue, but above the epiglottis (Table 1.5). The ideal size is 0.5-1 mm smaller than the appropriate orotracheal tube. Nasopharyngeal airway is available in sizes 2 to 8.5 mm which indicate the internal diameter in millimeters (Fig. 1.13).

Indications

Situations where access to the mouth is limited
Avoidance of the oral cavity is desirable (loose /bad dentition, lingual frenulum)10

Fig. 1.13: Different sizes of nasal airways with adjustable flange

Table 1.5 Size of nasal airways with adjustable flange (Fig. 1.14)
Size/ID (mm)
OD (mm)
Length (mm)
2
4
95
2.5
4.7
3
5.3
3.5
6
4.5
6.7
125
5
7.3
170
5.5
8
6
8.7

Fig. 1.14: Sizing of nasopharyngeal airway
Useful back-up when orally inserted airway fails
Awake, semi-comatose or lightly anesthetized patients—better tolerated and less easy to dislodge
Cuffed nasal airway for ventilation
Guidance of fiberoptic instruments, suction catheters, and nasogastric tube into the laryngopharynx.

Contraindications

Nasal pathology
Fracture base of the skull
Bleeding disorders
Large adenoids or tonsils.

AIRWAY DEVICES

Airway devices can be further divided into:

Supraglottic devices
Infraglottic devices.

SUPRAGLOTTIC DEVICES

These cuffed devices are inserted blindly via the oral route, to secure airway in case of elective or emergency situations. The tip of the device sits in the hypopharynx and its cuff or base forms a seal incorporating the supraglottic area. These devices can be used for spontaneous as well as positive pressure ventilation, but do not provide adequate protection against aspiration. They can be further grouped as:

Laryngeal mask airway (LMA)
Non-LMA supraglottic devices
1. Cuffed oropharyngeal airway
2. Laryngeal tube and laryngeal tube suction device
3. Cobra perilaryngeal airway
4. Combitube.

Laryngeal Mask Airway

The LMA is the most frequently used and tested supraglottic airway device. It consists of a curved shaft and an elliptical spoon shaped cup surrounded by an inflatable cuff with an inflation tube along with a self-sealing pilot balloon (Fig. 1.15) (Table 1.6).

The LMA family now includes a variety of LMAs and the advanced use of special purpose LMAs requires an impeccable technique and good communication with the operating surgeon (Table 1.7).

Fig. 1.15: Parts of laryngeal mask airway (LMA)

Table 1.6 Cuff volume and size of LMA

Mask size	Patient size	Maximum cuff volume (ml)	Largest ETT (ID) mm	Largest fiberscope (ED) mm
1	Neonates (<5 kg)	4	3.5	2.7
1.5	Infants (5–10 kg)	7	4.0	3.0
2	Child (10–20 kg)	10	4.5	3.5
2.5	Child (20–30 kg)	14	5.0	4.0
3	Child (30–50 kg)	20	6.0 cuffed	4.5

Too large a size is difficult to place whereas too small a size predisposes to gas leak during positive pressure ventilation.

One size smaller and one size larger than the chosen size should always be immediately available. The inflating syringe should be dry and contain only air. Method of insertion can be the classic insertion with deflated cuff or partially deflated with the lateral insertion technique or with mask opening facing the palate till base of tongue is bypassed and then rotated 180° into the final position. Since there is no statistical difference between the different methods of LMA insertion, it is better to change to another when one method is not working.

Advantages

Easy insertion
Reliable performance
Less invasive than intubation
Decreased incidence of trauma, sore throat
Facilitates smooth emergence
Cost-effective as requires lesser anesthetic depth.

Disadvantages

Epiglottic downfolding
Malpositioning
Inadequate protection against aspiration.

Uses

Provides airway under anesthesia during elective operative procedures, for spontaneous or controlled ventilation
In procedures outside the operating room such as GI endoscopy, flexible bronchoscopy, interventional radiology, radiation therapy
As a conduit for ETT in the management of the difficult airway
Provides airway during resuscitation (ASA guidelines)
Conduit for drug administration (i.e. surfactant to neonate with respiratory distress syndrome)
Useful alternative for airway control in children with an upper respiratory infection.

Cuffed Oropharyngeal Airway (COPA)

This supraglottic device is a modified Guedel oral airway with a cuff at its distal end, which creates a seal between the patient's upper airway and the anesthesia delivery system (Fig. 1.29). When the cuff is inflated, it displaces the base of the tongue anteriorly and passively elevates the epiglottis away from the posterior pharyngeal wall. The proximal end has a standard 15 mm connector for connecting the device to the anesthesia circuit, an integrated bite-block (tooth-lip guard) and two posts for attaching the elastic fixation strap.13

Table 1.7 Supraglottic devices (LMA family)

S. No.	Name	Description	Size (Pediatric use)	Ciinicai application	Special features
1.	Classic LMA (1991) (Figs 1.16A to E)	Original prototype, made up of silicone, latex-free, reusable upto 40 times	5 sizes (1, 1.5, 2, 2.5, 3)	Maintenance of airway	Soft silicone cuff Less chance of throat irritation and stimulation
2.	LMA Unique (1997) (Fig. 1.17)	Disposable classic LMA, made up of medical grade PVC	5 sizes (1, 1.5, 2, 2.5, 3)	Used where a reusable device not practical or economical (infective cases in OR, ambulance, ER, crash carts)	Stiffer tube and less compliant cuff-ideal to warm it prior to use to make it softer. Intracuff pressure increases less with use of N₂O in comparison to classic LMA
3.	LMA ProSeal (PLMA) (2000) (Figs 1.18A to E)	Most versatile member of LMA family Airway tube shorter, narrower Integral drain tube with opening at tip allows passage of a gastric tube and venting of gastric gas and liquid Integrated bite-block Bowl deeper, no bar Cuff softer and larger proximally, higher sealing pressure Second dorsal cuff present in sizes ≤3	5 sizes (1, 1.5, 2, 2.5, 3)	Preferred in controlled ventilation	Reusable, autoclavable Facilitates PPV, provides airway protection Method of insertion: Introducer tool method Finger – insertion method Guided method (stylet/bougie/ fiberscope) in difficult airway
4.	LMA Supreme (2008) (Fig. 1.19)	Disposable PLMA Made up of PVC and polycarbonates, anatomically shaped airway tube-easy insertion	Size 3 for children 30-50 kg	Situations where reusable device not advisable	Hybrid of PLMA and ILMA Smaller sizes are currently under development
5.	Flexible LMA (1993) (Fig. 1.20)	Longer, narrower, flexible wire-reinforced shaft, but cuff size is same. Available in both reusable and disposable version More difficult to insert, may require a stylet to stiffen	3 sizes (2, 2.5, 3)	Adenotonsillectomy, oral surgery, head and neck surgery, ophthalmic and dental procedures, radiation therapy Unsuitable for MRI/prolonged spontaneous ventilation (due to narrow tube)	Less likely to be displaced during head rotation or tube repositioning Kink-proof, but does not prevent obstruction from biting. Malposition less easily diagnosed as tube does not give clear indication of cuff orientation
14
6.	Intubating LMA (ILMA, Fastrach) (1997) (Fig. 1.21)	Mask attached to a rigid stainless steel short tube curved to align the aperture to glottis Attached metal handle aids one-handed insertion, adjustment and stabilization during ETT insertion Does not need finger insertion into mouth	Size 3 for 30-50 kg (can accommodate 6 mm ETT)	True pediatric size requires the curve to be re-configured to fit airway in a small child Unsuitable in MRI unit Adequate mouth opening with difficult laryngoscopy (high anterior larynx) For ventilation To aid intubation (blind/ visually guided)	Single, movable epiglottic elevating bar present Available in silicone/disposable version ETT is non-disposable, silicone -reinforced, high pressure low volume cuff, not for prolonged use Expensive
7.	LMA C-Trach (2005) (Fig. 1.22)	Similar to ILMA, but with two built-in fiberoptic channels which emerge under epiglottic bar. One channel transmits light, the other conveys image to monitor at proximal end attached via a magnetic latch connector	Same as ILMA	Awake intubation Very useful in unstable cervical spine Indication and insertion technique same as ILMA	Battery operated, rechargable Autoclavable upto 20 times Real-time image of glottis -improves first-attempt intubation rate
8.	Soft seal LMA (Fig. 1.23)	Similar to LMA unique but large oval cuff, deeper bowl, no tapering at tip. No epiglottic bar, clear shaft allows easier visualization of secretion and exhaled condensation Embedded blue pilot line exits proximally, so remains out of way and less irritation	Size and cuff volume same as classic LMA	Disposable, cost-effective, eliminates risk of cross-infection – Easy access for flexible fiberoptic devices	made of PVC – less permeable to N₂O pilot balloon labeled with size and maximum cuff volume
9.	Ambu LMA (Fig. 1.24)	Cuff tapered at the tube. Extra-soft cuff, reinforced tip does not bend during insertion, no aperture bar	Size and cuff volume same as classic LMA	Disposable, cost-effective in infected cases – Reusable version also available	Shaft larger, more rigid and precurved which replicates human anatomy, especially in smaller babies
10.	LMA classic Excel (Fig. 1.25)	Similar to classic LMA, soft silicone cuff, removable connector for easy fiber-optic assisted intubation	Size 3 for 30-50 kg	6.5 mm cuffed ETT can be negotiated	Maximum cuff inflation volume up to 20 ml
15
11.	Solus LMA (Figs 1.26A to C)	Includes standard, MRI compatible and flexible tube LMA	Size and cuff volume same as classic LMA	Disposable	MRI compatible – ferrous free option with MRI logo
12.	I-gel (Figs 1.27A and B)	Named after the unique soft -gel like material (SEBS: Styrene Ethylene Butadiene Styrene) of which it is made up Epiglottis blocker present Buccal cavity stabilizer aids insertion and prevents rotation Gastric channel and integral bite block enhances safety	Four sizes (1, 1.5, 2, 2.5)	Both for spontaneous or controlled ventilation In sniffing position, glide it downwards and backwards along hard palate with a continuous but gentle push until a definitive resistance is felt –	Easy to use and a safe and rapid airway management solution, less trauma Single use, latex-free No cuff inflation is required, so avoids compression trauma No finger insertion is required Color coded polypropylene ‘protective cradle’ Size 1 without gastric channel
13.	Intubating Laryngeal Airway (ILA) (Fig. 1.28)	A dark blue oval bowl with a clear curved silicon tube. Hypercurved airway tube approximates anatomy, Easy insertion Opening into bowl has ridges on top and sides to prevent trapping of epi-glottis. Ridges below outlet improves mask seal	Disposable sizes (1, 1.5, 2, 2.5) Reusable size (2.5)	Primary airway Aid for intubation in difficult airway situation	Autoclavable upto 40 times Downward tilt at tip of bowl helps to slip below epiglottis Keyhole shaped airway outlet directs the ETT in midline towards the laryngeal inlet, facilitates intubation Reusable removal stylet available in 2 sizes which allows controlled removal of ILA after intubation

Figs 1.16A to E: (A) Classic LMA (sizes 1, 1.5, 2, 2.5); (B to E) Technique of using deflator

Fig. 1.17: LMA-unique

Figs 1.18A to E: (A) LMA ProSeal (sizes 1, 1.5, 2, 2.5); (B) PLMA with cuff deflator; (C) PLMA with deflated cuff; (D) PLMA with introducer; (E) PLMA in situ with cuff pressure measurement

Fig. 1.19: LMA supreme

Fig. 1.20: Flexible LMA

Fig. 1.21: Intubating LMA

Fig. 1.22: LMA C-trach

Fig. 1.23: Soft seal LMA (sizes 1, 1.5, 2, 2.5)

Fig. 1.24: Disposable ambu LMA

Fig. 1.25: LMA classic excel

Figs 1.26A to C: Solus LMA: (A) Flexible; (B) Standard; (C) MRI compatible

Figs 1.27A and B: (A) I-gel; (B) I-gel in situ

Fig. 1.28: Intubating laryngeal airway

Fig. 1.29: Cuffed oropharyngeal airway (COPA)

The number of sizes available refers to the distance in centimeters between the tooth-lip guard and the distal tip. The bite block is color coded for size. The smallest size available is suitable for bigger children only (Table 1.8).

Table 1.8 Sizes of COPA

Size	Color	Volume of air
8	Green	25 cc
9	Yellow	30 cc
10	Red	35 cc
11	Light green	40 cc

Cuffed oropharyngeal airway (COPA) size can be determined by measuring the distal tip of the device at the angle of the jaw with the COPA perpendicular to the patient's head (as for oral airway). Selecting the right size is the most important step in using the COPA. The technique of insertion is the same as that for an oral airway. After insertion the COPA should be strapped with colored bite block between the teeth in the midline. Then the jaw thrust/chin lift is done and cuff is inflated with the appropriate volume of air.

Indication: Obese pediatric patients with small mouth undergoing general anesthesia with spontaneous ventilation for minor surgery or any painful procedure.

Advantages

Easy insertion even in inexperienced hands
Less anesthetic depth required when compared to LMA
Allows hands free anesthesia.

Disadvantages

Frequent airway manipulations may be necessary intraoperatively
Not suitable for controlled ventilation as the airway seal pressure is low.

Laryngeal Tube (LT)

This newly developed supraglottic device consists of a relatively wide and curved single lumen tube with two anterior facing, oval-shaped ventilation outlets in between its two low pressure high volume cuffs'a large proximal oropharyngeal cuff near the middle of the tube and a small distal esophageal cuff near the blind distal tip.

It is available in both reusable (silicone) and disposable (PVC) versions. It is available in six sizes with color coded connector according to size. One inflation tube inflates both light blue cuffs simultaneously. The approximate inflation volume is indicated on syringe with color coding (Table 1.9).

Table 1.9 Sizes of LT/LTS for pediatric age-group (Figs 1.30A and B)

Size	Max. cuff volume (ml)	Color of connector	Patient size
0	10	Transparent	Neonate < 5 kg
1	20	White	Infant 5-12 kg
2	35	Green	Child 12-25 kg
2.5	60	Orange	Child 125-150 cm

In neutral or sniffing position, the fully deflated device is inserted in midline and slid along the palate into the hypopharynx until resistance is felt. The three black marks on the shaft should align with the upper incisors (thicker middle line for orientation, thinner lines for eventual repositioning). The cuffs are inflated to a pressure of 60 cm H₂O. The inflated proximal cuff stabilizes the tube and blocks oropharynx and nasopharynx.23

Figs 1.30A and B: (A) LT and LTS; (B) Color coded connector and syringe

Advantages

Easy insertion
Useful for both spontaneous and controlled ventilation
Ventilatory holes act as a guide for airway exchange catheter placement or fiberscope and also allow suction.
Risk of gastric inflation is low as distal cuff blocks esophageal inlet, so protects against aspiration
Higher ventilation pressure can be used when required
Especially useful for resuscitation in the difficult airway scenario
Low laryngopharyngeal morbidity.

Disadvantages

PLMA proves superior to LT
In manual in-line neck stabilization, ILMA proves superior to LT.

Laryngeal Tube Suction (LTS) Device

This device is identical to LT in terms of its size and method of insertion. It is available in both reusable and disposable version. It has an additional (esophageal) lumen posterior to the respiratory lumen that ends just distal to the esophageal cuff for suction and gastric tube placement. LTS has been recommended as the first line device to secure the airway in a difficult airway. However, as with all supraglottic devices, familiarity and clinical experience with the device and its insertion technique is essential for safe and successful use, especially in an emergency.

Cobra Perilaryngeal Airway (Cobra PLA)

This disposable supraglottic device is a single lumen breathing tube with a wide, tapered distal end (cobra head design). It has a low pressure, high volume, oval cuff attached just proximal to the wide part.24

Figs 1.31A and B: (A) Cobra perilaryngeal airway; (B) Distal end

It is termed perilaryngeal because when positioned in hypopharynx, the distal end abuts the aryepiglottic folds and directly sits on the laryngeal inlet. The distal ventilatory end has a unique design such that the series of slots prevent the ventilatory hole from being obstructed by the epiglottis and soft tissue (Figs 1.31A and B).

Inflation of cuff to a pressure less than 25 cm H₂O seals off the distal end from the upper airway and allows positive pressure ventilation. The device is available in eight sizes, out of which five sizes are for pediatric age group (Table 1.10).

Table 1.10 Pediatric sizes of Cobra PLA

Size	Patient weight (kg)	Tube (ID/mm)	Cuff volume (ml)	ETT (ID/mm)
0.5	>2.5	5.0	<8	3.0
1.0	>5	6.0	<10	4.5
1.5	>10	6.0	<25	4.5
2.0	>15	10.5	<40	6.5
3.0	>35	10.5	<50	6.5

With the patient in a sniffing position, the deflated and lubricated device is inserted in midline back into the mouth (not towards the hard palate) until resistance is felt. The cuff is inflated with enough air to obtain an adequate seal.

Advantages

Useful alternative in “Cannot ventilate cannot intubate” (CVCI) situation
Easy insertion, less sore throat
Large lumen as a conduit for ETT or fiberscope
Short breathing tube allows ETT to pass below vocal cords without removing it.

Disadvantages

No protection against aspiration
Cuff leak
Possible airway obstruction.

Esophageal Tracheal Combitube (ETC)

It is a disposable double-lumen tube that combines the features of a conventional ETT and that of an esophageal obturator airway. It has a large proximal latex oropharyngeal balloon and a distal esophageal low-pressure cuff with eight ventilatory holes in between.25

Fig. 1.32: Esophageal tracheal combitube (ETC)

Ventilation is possible with either tracheal or esophageal intubation(Fig. 1.32). It can be inserted blindly, quickly and with a relatively low level of skill. It enters the esophagus in 99% of insertions. It reduces the likelihood of aspiration.

Indications

Elective or emergent situations, both in and out of hospital environment
Situations where neck movement is contraindicated
Limited access to airway
CVCI situation
Massive airway bleeding or regurgitation.

Limitation

The smallest (37 F) size can only be used in children taller than 4 feet.

INFRAGLOTTIC DEVICES

These include: (a) Endotracheal tubes, (b) Tracheostomy tubes.

Endotracheal Tubes (ETTs)

Traditionally, uncuffed tracheal tubes were routinely used in children. They are available for both nasal and oral use in various sizes, the smallest being 2 mm ID. In recent years, cuffed tracheal tubes are preferred, mostly in small children, especially in the pediatric ICU and emergency department (Fig. 1.33) (Table 1.11).

Cuffed Endotracheal Tube

Advantages

Less gas leak around tracheal tube
Reduced need to exchange inappropriately sized ETT
More consistent ventilation
Ventilation with higher inspiratory pressure possible
Decreases risk of aspiration
Less use of oversized uncuffed tube

Table 1.11 Size of ETT and Depth of insertion
Age
Weight (kg)
Size (mm)
Depth (cm)
Premature newborn
< 1
2–2.5
7
< 3 months
1-2
3
8
3-9 months
2-3
3.5
9
> 9 months

26

Fig. 1.33: Endotracheal tube ID 3 mm (cuffed and uncuffed)
Low flow anesthesia
More reliable end-tidal carbon dioxide monitoring
Reduces atmospheric pollution.

Disadvantages

Cuff hyperinflation leading to tracheal mucosal injury
Risk of post extubation stridor
Reduced ID of tube—higher resistance and work of breathing, difficulty in suctioning
Frequent cuff pressure monitoring is required
Subglottic stenosis.

Ultra thin high-volume, low-pressure polyurethane cuff results in lower sealing pressure than the conventional cuff. There are considerable differences in the outer tube diameter for a given ID and in length of cuff from different manufacturers. A pressure of 20 cm H₂O is sufficient to provide a seal without compromising tracheal mucosal blood flow, which is compromised at 30 cm H₂O and completely obstructed at 45 cm H₂O.

When the child's age is unknown, the tube size approximates to the external diameter of distal phalanx of little finger or diameter of external nares. Age is recognized as the most reliable indicator of appropriate ETT size selection.

Penlington's Formula:

ETT half a size larger and half a size smaller than calculated should be available as well. Cuffed ETT should always be half size smaller than the above calculated uncuffed diameter.

Depth of insertion (cm) oral:

3 × ETT (ID in mm)

Rule of 7–8–9–10 in infant (depth of insertion at lips):

1 kg–7 cm, 2 kg–8 cm, 3 kg–9 cm, 4 kg–10 cm27

Fig. 1.34: Cole tube

The desired depth of a nasotracheal tube is 20% more than oral tube. The practical formula is simplified as nasal tube depth = oral depth + 2 cm.

SPECIAL TYPES OF ETT

Cole Tube (Fig. 1.34)

Its distal portion (2.5-4.5 cm) is smaller in diameter than the rest of the tube. It is sized according to the ID of the tracheal portion. The shoulder (transition from oral to laryngotracheal portion) protects against inadvertent bronchial intubation. It cannot be used nasally as the larger segment will not pass through the nares. It is recommended for resuscitation but not long-term intubation.

Flexometallic Tube (Armoured/Reinforced/Spiral Embedded Tube) (Fig. 1.35)

These tubes have nylon or metal spiral reinforcing wire covered internally and externally by rubber, PVC or silicone. The spirals may not extend into proximal or distal ends. They are available in both cuffed and uncuffed forms.

Fig. 1.35: Flexometallic endotracheal tube (cuffed and uncuffed)

Advantages

Resistant to kinking or compression
Portion of tube outside can be angled away from surgical field.

Disadvantages

Requires a forceps or stylet for intubation
Nasal insertion may be difficult
Length cannot be shortened, so leads to increase in dead space
Tendency to dislodge from secured position
Not suitable for ventilation beyond operating room as once compressed due to teeth-bite, does not revert back to normal, so increases resistance to breathing
Cuff deflation or failure of cuff to deflate.

Uses

Prone position
Head and neck surgery
Surgery on trachea
Patient with tracheostomy undergoing anesthesia.

Preformed Tube (Ring-Adair-Elwyn Tube/RAE Tube) (Figs 1.36A and B)

Both cuffed and uncuffed versions are available for oral or nasal use. As the diameter increases, the distance of the bend from distal tip also increases. There is a mark at the bend which should be at the teeth or nares when ideally positioned. Oral tubes (south pole tube) are shorter and have the bend at an acute angle so that it rests on patient's chin when positioned. A nasal preformed tube (north pole tube) has a curve opposite to oral tube; the outer portion is directed over the patient's forehead.

Figs 1.36A and B: Preformed tubes: (A) North pole tube; (B) South pole tube

Figs 1.37A and B: (A) Parker flex-tip tube (3 mm ID); (B) Distal tip

Advantages

Easy to secure and less chance of accidental extubation
Breathing system connected away from surgical field.

Disadvantages

Difficulty in passing suction catheter
More resistance than conventional tube
When inappropriately sized it may lead to bronchial intubation or accidental extubation.

Uses

ENT surgery
Dental surgery
Plastic surgery.

Parker Flex-tip Tube (Pft Tube) (Figs 1.37A and B)

It has a “hooded” curved, flexible tapered tip that points towards the center of the distal lumen on the concave surface of the tube so that the bevel faces posteriorly. It reduces the gap between the fiberscope and inside of the tube. There are Murphy eyes on the right and left side of the tube. The tube cuff is very thin. The PFT tube is available in both cuffed and uncuffed version.30

Fig. 1.38: Hi-Lo jet tracheal tube

Advantages

Easier to advance over intubating guide or fiberscope
Less likely to impinge on vocal cord.

Hi-Lo Jet Tracheal Tube (Fig. 1.38)

This specially designed tube has a main lumen for ventilation, an insufflation lumen integrated within the tube wall for delivery of jet ventilation and a distal monitoring/irrigation lumen used to monitor airway pressure, sample respiratory gases and irrigate the airway. It is used specifically for high frequency jet ventilation (HFJV) in neonatal/pediatric surgery.

The outer diameter of this tube is 0.8 mm larger than the conventional tube with same internal diameter. Thus, a 2.5 mm conventional tube has an outer diameter of 3.5 mm whereas the outer diameter of a similar triple lumen tube is 4.3 mm, which limits its use in infants weighing less than 900 gm. It is available in sizes starting from 3.0 mm onwards.

Options for One-Lung Ventilation

Single lumen ETT
Bronchial blocker
Double lumen tube (DLT).

Single lumen ETT: The conventional single lumen ETT is intentionally pushed into the right or left main bronchus. For left bronchus to be intubated, the bevel of ETT is rotated 180° and the head is turned to the right (Table 1.12).

Table 1.12 Single lumen endotracheal tube

Internal diameter (mm)	External diameter (mm)^*
2.5	3.4
3	4.2
3.5	4.8
4	5.4
4.5	6.2
5	6.8
5.5	7.4
6	8.2
6.5	8.8
7	9.6
^*cuffed tubes have approximately 0.5 mm additional outer diameter.

Fig. 1.39: Balloon-tipped embolectomy catheter

Advantages

Simple, requires a fiberscope to confirm
Preferred technique in airway hemorrhage or contralateral pneumothorax.

Disadvantages

Failure to achieve adequate bronchial seal in case of uncuffed ETT leads to incomplete collapse of operated lung or failure to protect the healthy lung from contamination.
Hypoxia from obstruction of upper lobe bronchus, when the right bronchus is intubated.

Bronchial blockers: Because many children are too small for DLTs, different bronchial blockers are often required for single-lung ventilation (SLV) in pediatric patients.

Balloon-tipped bronchial blockers (Fig. 1.39)
1. Fogarty embolectomy catheter
2. End-hole, balloon wedge catheter
Univent tube
Arndt bronchial blocker.

Balloon-tipped bronchial blockers

Fogarty embolectomy catheter: Its placement is facilitated by bending the tip of the stylet towards the bronchus on the operative side. Fiberscope is used to confirm or reposition for appropriate placement.
End-hole balloon wedge catheter: The bronchus on the operative side is initially intubated with an ETT. A guidewire is advanced into that bronchus through the ETT. The ETT is then removed and the blocker catheter is advanced over the guidewire into the bronchus. The ETT is reinserted into the trachea along the side of the blocker catheter.32

Table 1.13 Balloon wedge catheters
Size (F)
Length (cm)
Maximum inflating volume (cc)
Inflated balloon diameter (mm)
Guidewire size (inches)
5
60
0.75
8
0.025
6
60
1.0
10
0.035
7
110
1.25
11
0.038

The catheter balloon is positioned in proximal mainstem bronchus under fiberoptic visual guidance (Table 1.13).

Advantage of balloon-tipped blockers: More predictable lung collapse with optimal operating conditions is achieved than an ETT in bronchus.

Disadvantages

Dislodgement of blocker balloon into trachea
Being low-volume and high-pressure, overdistention can damage or rupture the airway
With close tip bronchial blockers, operated lung cannot be suctioned and CPAP cannot be provided.

Univent tube: It consists of a conventional ETT with a second lumen containing a flexible small balloon-tipped tube which can be advanced into a bronchus to serve as a blocker. It requires a fibrescope for successful placement (Table 1.14) (Fig. 1.40).

Advantages

As bronchial blocker is firmly attached to main ETT, displacement is less likely than other blocker techniques
High torque control blocker can block either left or right bronchus
Easier to insert and position correctly than a DLT in difficult intubations because of its reduced bulk and anatomic angulation

Table 1.14 Univent tube
Size-ID in mm
OD (sagittal/transverse) in mm
Age recommended (years)
3.5
7.5/8.0
6–10
4.5
8.5/9.0
10–14
6
10.0/11.0
14–16
6.5
10.5/11.5
16–18

Fig. 1.40: Univent tube

33
Can be used for postoperative ventilation
Possible to use suction, apply CPAP, insufflate oxygen through blocker lumen.

Disadvantages

Failure to achieve adequate bronchial seal
Not recommended for children < 6 years of age
Fixed shape causes difficulty in sliding over bronchoscope
Does not soften in warm water bath
Small lumen gets easily blocked by blood or pus
Low volume high pressure cuff may cause mucosal injury
Larger outer diameter makes it difficult to pass between cords.

Arndt bronchial blocker (wire-guided endobronchial blocker, WEB) (Figs 1.41A and B): It is designed to be used with a single lumen ETT already in place. It consists of two parts: a blocking catheter and a special airway (multiport) adapter. A 5F blocker can be inserted through ETT #x2265; 4.5 mm ID. The innovative guide loop at the end of Arndt blocker's silicone balloon enables precise placement with a pediatric bronchoscope. Both bronchoscope and blocker can be introduced simultaneously through the multiport adapter while maintaining ventilation.

Advantages

Can be used in already intubated or tracheostomized patients
Has been used successfully in infants and small children

Figs 1.41A and B: (A) Arndt bronchial blocker; (B) Inflated tip

34

Fig. 1.42: Double lumen tube
Allows larger internal cross-sectional area than a DLT or Univent tube of similar OD
May require fewer insertion attempts than a DLT
If the wire is removed, the lumen can be used for suctioning or administering oxygen or CPAP.

Disadvantages

Once the wire loop is removed, it cannot be reinserted through the channel to allow repositioning of blocker
Placement requires availability of fiberscope and skill to use it
Takes longer to position and achieve complete lung collapse compared with Univent or DLT
Balloon may get sheared while being removed from blocker port.

Double-lumen tube (dlt) (Fig. 1.42): It consists of a shorter tracheal tube and a longer bronchial tube moulded together. Technique of insertion is the same as in an adult and requires a fiberscope to confirm placement. Left DLT is preferred to right DLT (Table 1.15).

Table 1.15 Double Lumen tube

Size (F)	Age (years)	Bronchial lumen OD (mm)	Main body OD (mm)
26	8–10	5.1	9.3
28	10–12	6.9	10.2
32	12–14	8.1	11.2
35	14–16	9.7	13.5
Cuff thickness = 0.049 mm, therefore cuff adds to 0.1 mm to overall OD of the tube.

Advantages

Ease of insertion
Suction and CPAP with oxygen possible.

Disadvantages

Often too large for small children
Rigidity and width makes intubation difficult
Tube malposition from head movement and surgical manipulation
Trauma to the respiratory tract
Needs to be changed in case of requirement of post-operative ventilatory support.

TRACHEOSTOMY TUBES (TT) (Figs 1.43A to C)

Various types of TT are available for intended use (Table 1.16).

Cuffed, uncuffed or fenestrated
Single cannula or double cannula
Metal, plastic or silicone.

Plastic and silicone tubes are increasingly popular due to less weight and less crusting of secretions. Fenestrated tube has an opening that permits speech through the upper airway when the external opening is blocked. It is not recommended for small children as the opening can get obstructed with granulation tissue. The silicone tracheostomy tubes are available with air cuff or foam cuff and adjustable neck flange or extended connect.

Table 1.16 Neonatal and pediatric tracheostomy tube

Size	ID (mm)	OD (mm)	Length (mm)
Size	ID (mm)	OD (mm)	Neonatal	Pediatric
3.0	3.0	4.5	30	39
3.5	3.5	5.2	32	40
4.0	4.0	5.9	34	41
4.5	4.5	6.5	36	42
5.0	5.0	7.1		44/50
5.5	5.0	7.7		46/52
6.0	6.0	8.3		54
6.5	6.5	9.0		56

Indications of Tracheostomy

Congenital or acquired airway obstruction (i.e. Pierre Robin syndrome, subglottic stenosis, tracheomalacia)
Long-term ventilation
Neuromuscular diseases.

ALTERNATIVES TO CONVENTIONAL RIGID LARYNGOSCOPY IN CHILDREN

Gum elastic bougie aided endotracheal intubation
Lighted stylet aided endotracheal intubation
LMA/ILMA/LMA-C Trach aided endotracheal intubation
Indirect rigid fiberoptic laryngoscope assisted endotracheal intubation (i.e. Bullardoscope/Glidescope/Truview/C-MAC)
Flexible fiberoptic aided endotracheal intubation

Figs 1.43A to C: (A) Neonatal tracheostomy tube; (B) Cuffed tracheostomy tube; (C) Metallic tracheostomy tube
36
Invasive airway access
- Emergency needle cricothyrotomy
- Transtracheal needle jet ventilation
- Retrograde intubation
- Tracheostomy

Endotracheal Tube Guides

A number of ETT guides including stylets, introducers and airway exchange catheters (AECs) have been used to aid intubation. The stylets and introducers are always an adjunct to direct laryngoscopy to provide directional control when the laryngeal inlet is not completely visible. A blind technique with these guides, even through the LMA, in difficult airway situations should be avoided (Table 1.17).

Lighted Stylets

Depending on the structure and principle involved they can be broadly divided into two types (Table 1.18):

Light wand (stylet with built-in light source): Functioning is based on transillumination of the soft tissues of the neck, does not require visualization of larynx, i.e. Trachlight
Intubating FO stylet (malleable stylet with built-in fiberscope and light source): based on visualization of larynx, i.e. SOS, FAST, etc.

Lighted stylets are portable, light-weight, easily cleaned and sterilized. They produce less sympathetic stimulation than direct laryngoscopy. The possible complications are minor airway trauma, arytenoid subluxation or instrument disarticulation that may be overcome by newer sturdier integral bulbs or FO bundle.

Trachlight

Indication: Difficult airway where fiberscope is unavailable or predicted to be difficult because of blood or secretions in the airway.

Contraindications

Upper airway tumor or foreign body
Retropharyngeal abscess
Infection with friable tissue along intubation course
Laryngeal injury
Subglottic stenosis.

Caution: Transillumination may not be useful in emaciated or extremely obese children.

Technique: After lubricating the distal end of trachlight (TL) an ETT with a tube connector is loaded on. The tip of the stylet of TL should remain just inside the ETT without protrusion and locked with a clamp. The ETT-TL unit is shaped to 90°-120° “hockey-stick” at 3-6 cm from the distal end (i.e. just proximal to the cuff). The OR light is dimmed. In supine with head in neutral or sniffing position, perform jaw-lift and insert ETT-TL in midline to advance gently in a rocking motion. If resistance is felt, the TL is rotated backward, then the tip is redirected towards the thyroid prominence using the ‘glow’ as a guide. The initial well-circumscribed light just above the thyroid cartilage changes to a cone-shaped light projecting caudally at the suprasternal notch when it passes the vocal cords. Then the stylet is retracted 10 cm and the ETT-TL is advanced until the glow disappears at the sternal notch. Following the release of the locking clamp, the trachlight is removed from the ETT. In infants and small children, the feel of the lightwand is as important as the visual part.37

Table 1.17 ETT guides

S. No.	Name	Description	Size /Length (cm) (OD)	Ciinicai applications	Special features
1.	Stylet (Fig. 1.44)	Made of malleable aluminium, so adapts easily to desired shape. Its smooth high density polyethylene outer sleeve permits easy insertion and withdrawal	2.2 mm/22.5 4 mm/33.5, 67.3 5 mm/36.5, 69.3	for ETT (2.5-4.5 mm) for ETT (> 5 mm)	Meant for single use only Walking-stick design
2.	Eschmann tracheal introducer (Gum Elastic Bougie) (Fig. 1.45)	Made from a polyester woven base, angled 40° at its distal end (coude tip), calibrated at both ends at 10 cm increments for easy and accurate insertion. Marking indicate the direction of deflected tip	10 F/70 15 F/60, 70	ETT (4-5.0 mm) ETT (≥ 5.5 mm) Deflected tip should angle anteriorly to prevent posterior tracheal wall dissection by ETT during threading	May cause trauma if excess force is applied or passed beyond carina Both reusable and single use versions available
3.	Arndt airway exchange catheter (AEC)	Polyethylene, tapered end, multiple side ports, yellow in color, packaged with a stiff guidewire, bronchoscope port and Rapi-fit adapters	8 F/50 14 F/65, 78	ETT (3-5 mm) ETT (≥ 5.5 mm) –^* Exchange of LMA and ETT using a fiberscope	Single use Allows both IPPV or jet ventilation
4.	Cook AEC (Fig. 1.46)	Polyethylene ID of catheter (mm) 1.6 2.3 3.0	8 F/45 11 F/83 14 F/83	ETT (≥ 3 mm) ETT (≥ 4 mm) ETT (≥ 5 mm)
5.	Endotracheal tube guides	Straight, both single use and reusable versions available No hollow lumen or coude tip	5 F/50 10 F/70 15 F/70	ETT (≥2 mm)	5 F size available only for single use Used for exchange of ETT with a new ETT or speciality ETT in a known or suspected difficult airway.
^* Fogarty catheter can be tried for its increased stiffness and its lumen allowing oxygen insufflation or jetted when smaller size AEC is not available.

Table 1.18 Lighted stylets

S. No.	Name / Manufacturer	Description	Sizes	Ciinicai application	Special features
1.	Trachlight (Fig. 1.47)	3 parts: a plastic reusable handle, a flexible wand with a bright bulb at distal end, a stiff retractable stylet. A proximal locking clamp secures ETT connector at the adjusted length	3 sizes: infant, child, adult Accommodates ETT ≥ 2.5-10 mm ID	Fiberscope unavailable (ambulance or emergency dept.) Fiberscopy difficult (Blood or secretions in airway) War-time casualties	Semi-blind technique After 30 sec the bulb blinks off and on to prevent heat damage and also indicates 30 sec apnea time Reusable 10 times
2.	Seeing optical stylet system (SOS) (Fig. 1.48)	High-resolution, stainless-steel, rigid FO stylet with preformed J-shape. Adjustable tube stop and integral oxygen port	Pediatric (ETT 3-5 mm) Adult (ETT ≥ 5.5 mm)	Similar to flexible fiberscope Comfortable for less experienced users with fiberscope	Reusable Simple form of a standard stylet with advantage of FO view and maneuverability of its tip. 6V Halogen battery or fiberscope light-source is required
3.	Flexible airway scope tool (FAST) (Fig. 1.49)	Similar to SOS, but has a malleable section and an atraumatic tip, easily adjusted manually to confirm patient's anatomy	Same as SOS	Same as SOS	Recently modified to use nasally (FAST – Plus)
4.	Bonfils retromolar intubation fiberscope (Fig. 1.50)	High-resolution, rigid, FO stylet with fixed 40° curve distally. Adapter for fixation of ET and oxygen insufflatior	Pediatric (2 mm) Adult (5 mm)	Similar to fiberscope Retromolar/transoral route – positions ETT directly in front of vocal cords with minimal manipulation of epiglottis	Movable eyepiece allows ergonomic movement during intubation Better maneuverability than flexible fiberscope fast, atraumatic, reliable intubation in difficult airways
5.	Video-optical intubation stylet (VOIS) (Fig. 1.51)	Stylet malleable to 90° Angle of view 50°	Stylet diameter − 2.8 mm − 3.8 mm	Reliable and effective tool for management of difficult airway	Used like a conventional stylet, but with a good view from the tip of tracheal tube Needs least time and effort to learn

Fig. 1.44: Endotracheal tube stylet

Fig. 1.45: Gum elastic bougie

Fig. 1.46: Airway exchange catheter (cook)

Fig. 1.47: Trachlight

Fig. 1.48: Seeing optical stylet system (SOS)

Fig. 1.49: Flexible airway scope tool (fast)

Fig. 1.50: Bonfils retromolar fiberscope

Fig. 1.51: Chhiber intubation fiberscope

A click is often felt when the ETT/stylet is advanced past the epiglottis. It is easier to pass a slightly smaller ETT than the maximal age predicted diameter.

Laryngoscopes

A laryngoscope enables medical practitioners to approach the larynx, vocal cords, trachea and adjacent structures and provides a lighted view of the airway. Its use is primarily for inserting an endotracheal tube by intubating the trachea and also for examination of the throat to evaluate diseases of the larynx such as infection, congenital defects, growths, etc.

Laryngoscopy can be divided into: (a) Direct laryngoscopy, (b) Indirect laryngoscopy.

Direct laryngoscopy: It is a technique wherein the vocal cords are visualized using a handle with a detachable blade such as the Macintosh (curved) or the Miller (straight) blade. Choosing the correct size laryngoscope blade is critical to successful endotracheal intubation (Table 1.19) (Figs 1.52A and B). The tip of Macintosh blade is placed in the vallecula and lifts the base of the tongue, thereby indirectly lifting the epiglottis for visualization of the vocal cords. The Miller blade directly lifts the epiglottis by being placed posterior to the epiglottis, so it is preferred in infants and younger children who have a large, floppy epiglottis (Figs 1.53A and B). Excessive cricoid pressure should be avoided as it results in collapse of airway structures during intubation.

The best conventional laryngoscopic view is dependent on the optimal positioning of the patient, an experienced practitioner with capable assistance for optimal external laryngeal manipulation (OELM) and backward upward right pressure (BURP) maneuver if required.

Table 1.19 Size of laryngoscope blade
Miller Blade
Age Group
Macintosh Blade
Size
Length (mm)
Size
Length (mm)
00
65
Premature neonate
0
75
Term neonate
0
80
1
102
Infant
1
87
2
155
Child
2
108

42

Figs 1.52A and B: Pediatric laryngoscope blade: (A) Miller blade (0, 1, 2) size; (B) Macintosh (1, 2) size

Figs 1.53A and B: Methods of laryngoscopy: (A) Miller blade; (B) Macintosh blade
Indirect laryngoscopy: The vocal cords are visualized through an optical or electronic imaging system. Modifications of the traditional laryngoscope blades are primarily designed for difficult airway situations such as limited mouth opening, anterior larynx, sternal space restriction, small intraoral cavity and unstable cervical spine. The most recently developed blades suitable for pediatric use are:
1. Truview evo2
2. Glidescope
3. Bullard elite laryngoscope
4. C-MAC video laryngoscope
5. Airtraq optical laryngoscope.

Truview evo2 (Figs 1.54A and B): This rigid, indirect laryngoscope has a unique blade tip angulation which provides a wide and magnified laryngeal view at 46° anterior refracted angle.

43

Figs 1.54A and B: (A) Truview evo2; (B) Truview in use

It has an integrated optical lens and an attachment for connecting oxygen (2-5 liters/min) which provides insufflation, prevents misting and improves safety. The narrow blade tip is suitable for a small mouth.

In the neutral position the laryngoscope is inserted centrally over the tongue or from the right side of the mouth, pushing the tongue to the left while visualizing through the optical eyepiece. First the uvula is seen, then the epiglottis becomes visible after advancing a little further. Here the blade can be used as MAC or Miller blade to lift the epiglottis and view the vocal cords. The endotracheal tube over the provided stylet is advanced along the side of the blade till seen in the eyepiece.

44

Fig. 1.55: Glidescope

Then the ETT is advanced slightly upwards and to the left toward the tip of the blade to pass the cords. The ETT is further advanced into the trachea after removing the stylet.

Available in 2 sizes:
1. Infant size (1-10 kg)
2. Adult size (>10 kg).
A new generation upgrade called Truview PCD is available in total 5 blade sizes out of which size 0, 1, 2 are for pediatric use.

Advantages
1. Effective in all intubation grades
2. Requires little or no neck movement
3. Reduced force required.
Glidescope (Fig. 1.55): This videolaryngoscope consists of a laryngoscope blade with a high-resolution digital camera in the middle of the tip of the blade and a LCD light source embedded along the inferior border. The blade is curved at 60° angle to match the anatomical alignment and the camera aids in video-assisted intubation by providing an outstanding view of the supraglottic area on the high-resolution display unit to the viewers. The overall thickness of the blade is reduced to 18 mm and it has an embedded anti-fogging mechanism. Midline approach is essential. A styletted ETT provides the needed curvature for insertion. It is available in 3 sizes—neonatal, pediatric and standard. The latest version called Cobalt uses a disposable blade and has an infant size with a smaller (10 mm) laryngoscope blade for use in neonates.
Bullard elite laryngoscope (Fig. 1.56): This indirect rigid fiberoptic laryngoscope combines the benefits of rigid direct laryngoscopy and fiberoptic intubation. It is available in three sizes – neonate - infant, child and adult. Its anatomically curved blade requires minimal mouth opening for insertion. Unlike in the adult Bullard, tip or blade extender is not used in children. Its power source can be a conventional laryngoscope blade with batteries and a halogen bulb or a fiberoptic light source attached through an adapter. It has a bifurcated channel: one working channel for oxygen insufflation, suction, instillation of local anesthetics or saline, passage of an airway exchange catheter or jet ventilation catheter and the other channel accepts the dedicated, non-malleable stylet.

Two stylets are available for use:
1. Introducing (intubating) stylet: It follows the blade contour to reach the field of vision at the 4 o'clock position. It facilitates the passage of the tracheal tube into the laryngeal inlet.
  
  45
  
  Fig. 1.56: Bullard elite laryngoscope
2. Multifunctional stylet: It is a long, hollow tube which follows the blade contour when attached. Its hollow core guides the flexible fiberoscope, tracheal tube exchanger or small catheter to instill local anesthetic into trachea. Its maneuverability is much less than the introducing stylet.
Its eyepiece is at 45° angle from the handle and can get attached to a video camera for remote viewing.

Recommendations for use: Six methods of intubation have been described. The blade-stylet assembly with premounted tracheal tube should be inserted into mouth in perfect midline over the tongue with the handle horizontal without looking through eyepiece. Then the handle is made vertical as it slides over the tongue to reach the pharynx. Here, for the first time the viewer has to look through the eyepiece to view the epiglottis and lift it directly or indirectly to slide the ETT over the introducer into the glottis.

Advantages
- Requires neutral head position
- Can be used for rapid sequence intubation in experienced hands
- Cheaper than fiberscopes, while indications are the same
- Quicker than flexible fiberoptic intubation
- Less trauma and discomfort in awake patient than direct laryngoscopy.
Disadvantages
- Requires skill and experience
- Expensive compared to conventional laryngoscope
- Takes slightly longer than conventional laryngoscopy
- Special tubes like DLT or laser tube cannot be inserted
- View less panoramic than regular intubation
- Not useful in distorted upper airway anatomy or foreign body obstruction or blood and secretions in the upper airway.
C-MAC video laryngoscope: This video laryngoscope can be fitted with laryngoscope blades that are similar to Macintosh 1 or 2 blade and Miller 0 or 1 blade and are applicable in premature neonates (Figs 1.57A and B). This unit is available with LCD monitor of 2.4” screen size which is movable via two rotation axes and rechargeable Li-ion batteries. It is light-weight, compact and very easy to use even by less-experienced practitioners.
Airtraq optical laryngoscope: Unlike other laryngoscope, it provides a channel for directing the ETT through the vocal cords. It is available in a variety of sizes, i.e. infants (gray), pediatric (pink).

46

Figs 1.57A and B: (A) MAC 2 and Miller 1 blade; (B) C-MAC video-laryngoscope in use

The relatively large blade height (12-13 mm) precludes its use in infants with limited mouth opening.

Special Airway Techniques

Flexible fiberoptic intubation
Retrograde intubation
Cricothyrotomy
Tracheostomy.

FLEXIBLE FIBEROPTIC INTUBATION (FFI) (Figs 1.58A AND B)

Flexible fiberoptic bronchoscopy remains the mainstay of airway assessment and difficult airway management. Indeed, it has become an integral part of neonatology, pediatric pulmonology, anesthesiology, critical care, laryngology and cardiothoracic surgery. The fiberscope is available in different sizes (Table 1.20).

Advantages

It is less traumatic as it is manipulated under vision
It can be used orally or nasally for both upper and lower airway problems.

Table 1.20 Flexible fiberoptic bronchoscope

S. No.	Type	Size (OD in mm)	LMA size/ETT (ID in mm)	Indications
1.	Neonatal (no suction port)	2.2	1 / 2.5	Premature neonates, infants
2.	Pediatric (most versatile)	2.9-3.1	2/3.5-4.5	Infant to 6-8 yr of age
3.	Adult	4-5.6	3 / ≥ 4.5	Older children and adolescents

Figs 1.58A and B: (A) Flexible fiberoptic bronchoscope; (B) Fiberoscopy through PLMA

Disadvantages

It requires skill and experience
In case of abnormal anatomy, FFI may be impossible especially under deep sedation.

Indication

Diagnostic and treatment modality in airway management

Key-points for Procedure

The discrepancy between the OD of scope and ID of ETT should be kept to a minimum to prevent the ETT from getting stuck at the arytenoids while railroading over the scope.
For diagnostic bronchoscopy, the scope size should not be more than two-thirds of the diameter of the trachea as the patient has to breathe around the scope.
The neonatal fiberscope lacks a working channel which generates adequate suction. While using this scope secretions must be aspirated with a normal suction catheter. The neonatal fiberscope has very delicate ultra-thin optic fibers which get easily damaged and requires more skill to control.
During the oral approach in infants, the scope needs to make an acute anterior bend to approach the anteriorly placed laryngeal inlet, this problem is mitigated during nasal intubation.
The vocal cords in infants are slanted anteriorly, so it is ideal to approach the anterior commissure at the inlet and then make an acute posterior deflection to enter the trachea.
For FFI, the ETT is loaded on the scope before endoscopy and the tube is advanced after positioning the scope just above the carina and without having any slack on the scope.
If the child's trachea is too small for available scope, the suction channel of bronchoscope is used for passage of an extra-long J-tip guidewire into trachea under direct vision while the fiberscope sits above the vocal cords. The scope is then removed and the ETT can be advanced over the guidewire into the trachea. Alternatively, a stiffening device such as a ureteric dilator or Cooks airway exchange catheter can be railroaded over the guidewire. Next, the guidewire is removed and position of the catheter is confirmed by capnography. 48Then an ETT can be railroaded over the stiffening device (However, the adult size fiberscope cannot be used in infants for railroading technique).
In case of any resistance during advancement of the ETT, it should be withdrawn and twisted 90° in counter-clockwise direction to make the tip free from the arytenoid cartilage. Reinforced ETT are preferable to minimize this problem.
Unlike in adults, an awake technique is not preferred in children since cooperation is required to gain a clear bronchoscopic view. A variety of regimens have been used for maintaining spontaneous ventilation in children undergoing FFI. Premedication with atropine helps to dry up secretions. Benzodiazepine with a relatively smaller dose of narcotic are preferred. Midazolam and remifentanil are the ideal agents for sedation as they are short acting and can be reversed with flumazenil and naloxone respectively. Ketamine and propofol are the most commonly recommended anesthetics, often supplemented with local anesthetic instillation and volatile anesthetics.
Nasal FFI is easier but nasal bleeding is a disadvantage and cannot be used in situations as cleft palate or adenotonsillectomy where oral intubation is required. Otherwise, the approach remains a personal preference.
Fiberscope through the LMA as a conduit and ventilation device is safe in neonates and infants.
Rescue techniques such as placing a retrograde guidewire through the suction channel may be employed if the glottis cannot be located with the scope or if blood and secretions are present. Once the fiberscope reaches the trachea, the ETT can be advanced. When the fiberscope is introduced through the LMA as a conduit, LMA has to be of split type or shortened or telescoping the tube over fiberscope is to be done to remove the scope and LMA. Telescoping involves pushing the tube of choice onto a larger one which acts as a holding device while removing LMA and scope without accidentally pulling out ETT.
FFI should be used early as an aid in a difficult airway scenario as presence of blood or secretions limit its use.

Contraindications

Absolute – lack of time
Relative – blood and secretions in oral cavity, edema of tongue, pharynx.

RETROGRADE INTUBATION

Retrograde intubation is an excellent technique for securing a difficult airway for both elective and emergency situations either alone or in conjunction with fiberscope and a tube exchanger. The technique is simple with a high success rate and should be a skill practiced by every anesthesiologist.

Indications

Restricted cervical spine mobility
Airway trauma.

Technique

Cricothyroid puncture is done with a small catheter-over-needle device with an attached syringe with cephalad angulation. A flexible J-tip guidewire (0.021 inch diameter, 140 cm) or an epidural catheter is introduced through the catheter to exit spontaneously through the mouth or nostril (in cases with difficult mouth opening, suction can be used to retrieve the retrograde catheter). The catheter at the cricothyroid membrane is removed and the guide is clamped at the skin. 49The guidewire can be threaded through the ETT or AEC or working channel of a fiberscope sheathed with a reinforced ETT. The scope and tube assembly or AEC can be advanced following the wire through abnormal and collapsed tissues. Once the tip of the scope gets just below the vocal cords, the guidewire is removed with caudad traction. Then the scope is threaded into the distal trachea and ETT is slid into place. The airway exchange catheter will allow patient's oxygenation as well as confirmation of tracheal placement by capnography. The ETT can then be advanced over AEC.

Limitations

It may not be suitable for immediate intubation and ventilation as the procedure may take time for completion.
It may cause bleeding at the skin-puncture site, pretracheal abscess.
Trauma to the airway is possible, especially in infants, because of the poorly defined cricothyroid membrane and the proximity of the vocal cords to the puncture site.

CRICOTHYROTOMY

Cricothyrotomy is a life-saving procedure in CVCI situation. It can be performed by 3 techniques.

Needle cricothyrotomy
Percutaneous dilatational cricothyrotomy
Surgical cricothyrotomy.

Needle Cricothyrotomy

Needle cricothyrotomy with small catheters of at least 4 cm length with percutaneous translaryngeal ventilation (PTLV) is quicker, simpler and safer than the other two techniques. The jet ventilation catheter is available in 3 sizes (babies, children and adults). Catheter length is important, because if too short, it may come out and gas will escape into the subcutaneous tissue of the neck. It is essential for every emergency physician to be familiar with the indications, contraindications, techniques and complications of this type of rescue airway.

Indications: “CVCI situation”

Facial or cervical trauma, uncontrollable oral hemorrhage
Oropharyngeal edema from infection, anaphylaxis or chemical inhalation injuries.
Trismus or anatomic variants
Rescue from profound hypoxemia during FFI under deep sedation, followed by urgent tracheostomy.

Contraindications

Where nasal or oral intubation possible and safe
Acute laryngeal trauma or infection
Obstruction at or below the cricoid level, as the obstructing element may get pushed deeper
Avoided if patient recently intubated
Inability to locate the cricothyroid membrane
Upper airway obstruction not allowing the gas to escape.

Technique

Identify the cricothyroid membrane in the midline between thyroid and cricoid cartilage. Prepare skin with betadine.
Use a small 25 G needle with syringe to aspirate air through the cricothyroid membrane and inject 0.3 ml lignocaine (2%) transtracheally.50
Next use a large 12-14 G angiocath (catheter over needle) with syringe directed at a 45° angle caudally to puncture the membrane.
Once air is aspirated into the syringe, remove the needle from angiocath while advancing the catheter smoothly in a caudad direction, taking care not to perforate the posterior tracheal wall.
Confirm the position of the catheter by air aspiration with a syringe.
Then attach the catheter hub to an oxygen source or jet ventilator through an appropriate connector.

This technique is a temporary measure which allows 30-40 minutes of uninterrupted oxygenation and ventilation while allowing unhurried access to secure the airway. Significant barotrauma is a risk with tracheal jet insufflation. A high-flow oxygen source and an adequate expiratory time are the appropriate ventilatory parameters to limit barotrauma.

Complications

Exsanguinating hematoma
CO₂ retention in spite of adequate oxygenation
Perforation of esophagus, posterior wall of trachea, thyroid gland
Inadequate oxygenation
Subcutaneous or mediastinal emphysema
Infection.

Percutaneous Dilatational Cricothyrotomy (PDC)

This technique uses the Seldinger method to gain access to the cricothyroid membrane. The track around the guidewire can be enlarged by using serial dilators to accommodate the cricothyrotomy tube which may have a cuff. There are a number of commercial kits available. For example, Quicktrach 2 mm for children, Arndt emergency cricothyrotomy cath set (9F/6 cm length, coil reinforced kink- resistant catheter with a standard 15 mm connector and luer-lock) (Fig. 1.59).

Fig. 1.59: Percutaneous dilatational cricothyrotomy set

Surgical Cricothyrotomy

In this technique a transverse incision is made through the cricothyroid membrane using a scalpel, through which an ETT is inserted. It should be performed rapidly when equipment for less invasive technique is unavailable. It is a more definitive airway than the PDC.

TRACHEOSTOMY

Tracheostomy may be defined as establishing transcutaneous access to the trachea below the level of cricoid cartilage.

Indications

Emergent—acute airway loss in <6 yr of age where the cricothyroid space is too small for cannulation
Elective—distorted laryngeal anatomy, prolonged ventilatory support.

Percutaneous dilatational tracheostomy is not recommended in the pediatric age group as the tracheal tissue is markedly elastic in children. Pressure applied on the anterior tracheal wall during dilatation of stoma can cause compressive obstruction of tracheal lumen and increased chance of perforation of the posterior wall of the trachea.

Translaryngeal tracheostomy is preferable in children as its approach is retrograde and requires minimum pressure on the pretracheal tissue and trachea. Under bronchoscopic guidance, insertion of a J-shaped wire percutaneously in the trachea passes retrograde into the mouth. The specially designed conal dilator with tracheostomy tube is threaded over the guidewire and pulled through the oral cavity, larynx, trachea and out through the anterior tracheal wall. Then the cone is removed and TT is rotated from a cephalad to caudal direction by using an obturator and then advanced caudally to its final position. During the procedure, the trachea is ventilated with a small diameter tracheal tube positioned co-axial to the original airway and its distal end is positioned distal to tracheostomy site. The ETT is removed after or just before rotation and securing of tracheostomy tube. Since dilatation is achieved by tracheal cannula itself (tracheal rings are simply divaricated), it fits snugly with the wound edges. This newer technique is safe in children and specially beneficial in coagulopathic babies.

The subcricoid region has the advantage of absence of bleeding as no major blood vessel is present on the cricotracheal membrane and also reduction in possible development of subglottic edema and stenosis.

Surgical tracheostomy is more invasive. In the supine position, maximal extension of the head and neck is done with a towel roll. A 1 cm transverse skin incision is made in the second tracheal ring. The incision is dilated and deepened. A longitudinal tracheal incision is made over the second and third tracheal ring and a tracheostomy tube is inserted through the opening. The tracheal cartilage should not be excised as this leads to stricture formation. A metal tube is avoided. Ideally intubation should be done prior to tracheostomy unless an obstructive lesion precludes its use. Sedation and analgesia is strongly recommended to minimize movement of the head and neck for 3-5 days.

Difficult Airway

Management of a difficult airway is a fundamental part of clinical practice. Fortunately, the incidence of unexpected difficult pediatric airway is low since most of them are associated with congenital syndromes.52

Recognizing a difficult airway is thus the first step in handling these cases. A detailed preoperative evaluation and accordingly a plan of action of how to proceed with the available resources and equipment, usually prevents a CVCI situation. A child's airway anatomy may get modified with growth or get worsened in some syndromes, thus a previous successful intubation does not guarantee success in the future. Airway assessment is very difficult in an uncooperative child. Every child's airway should be evaluated in the lateral profile. A full and frank discussion of the risks with parents (and child if appropriate) and the possibility of tracheostomy and indeed, of failure to secure the airway should always be mentioned.

Preparing these patients is the next step. Premedication and duration of preoperative fasting plays an important role in preventing a crying child, as upper airway obstruction worsens when the child cries or struggles and generates a greater negative intrathoracic pressure. Premedication with atropine is recommended, to dry up secretions and to prevent bradycardia associated with airway manipulation.

COMMON CAUSES OF DIFFICULT AIRWAY

Congenital craniofacial abnormalities
1. Maxillary hypoplasia: Apert syndrome, Crouzon disease
2. Mandibular hypoplasia (micrognathia): Pierre-Robin syndrome, Treacher-Collins syndrome, Goldenhar syndrome, Nager syndrome
3. Mandibular hyperplasia: Acromegaly, Cherubism
Temporomandibular joint ankylosis: Congenital, mucopolysaccharidoses (MPS)
Microstomia: Ludwig's angina, burns, trauma scarring, hemangioma tongue, Freeman-Sheldon syndrome.
Macroglossia: Down's syndrome, hypothyroidism, MPS, Beckwith-Wiedeman syndrome
Nose: Narrow nares due to MPS, choanal atresia
Pharynx: Hypertrophic tonsils and adenoids, retropharyngeal abscess
Palate: Cleft palate, soft palatal swelling
Larynx: Glottic-laryngomalacia, MPS, Infraglottic- congenital stenosis, MPS
Neck-vertebral anomalies: MPS, Klippel-Feil anomaly.

Any of the above can lead to a difficult airway due to:

Difficult access, i.e. limited mouth opening, obstruction by soft tissue mass
Difficult to visualize, i.e. small mandible with less submandibular space to accommodate tongue.
Challenges on target tissue, i.e. inspite of glottic visualization, unable to ventilate or intubate as in foreign body trachea or laryngeal tumor.

MANAGEMENT STRATEGIES (FIG. 1.60)

The principles of airway care in the adult population are applicable to pediatric patients. However, the techniques available in adult care may not be available because of size and technological limitations.

The degree of cooperation in the pediatric age group is variable, so awake intervention may not always be an option.
Loss of patency of child's airway rapidly results in hypoxemia and desaturation due to a low FRC with a high basal oxygen consumption. Oxygen supplementation throughout the intervention is critical in children.53

Fig. 1.60: Difficult pediatric airway algorithm
In certain cases, mask ventilation is difficult but airway access via LMA or ETT is achieved readily. In such situations, an attempt with LMA insertion or tracheal intubation should be a prudent first intervention.
A patent airway is the ultimate goal, hence direct laryngoscopy attempts must not be persistent because of associated morbidity and mortality and other choices should be offered as an alternative according to algorithm.
Transtracheal techniques should be considered early if alternate transoral techniques are either not available or do not achieve ventilation.
Maintenance of spontaneous breathing allows a way out in case of inability to secure the airway. Muscle relaxants should be withheld until the airway is secure and intubation should be preferably be done under deep inhalation anesthesia. In case muscle relaxant has led to a “CVCI” situation, surgical airway should be rapidly accessed.
For the neonatal difficult airway, the presence of a third competent person is advisable. When bag and mask ventilation, LMA and tracheal intubation all fail to establish effective ventilation, the possibility of a laryngotracheal anomaly calls for an immediate surgical access as the only way to save the baby.
Planned extubation of a trachea that presented difficulty at intubation, should take place in the presence of not only an experienced laryngoscopist but also a surgeon competent in providing surgical access to the airway.

Fig. 1.61: Difficult airway cart

DIFFICULT AIRWAY CART FOR PEDIATRICS (FIG. 1.61)

One should ideally have all the desired equipment on a designated difficult airway cart. However, it is far more important that the kit contains tools with which the physician is familiar and skilled, than containing a large number of items. All equipment should be clearly labeled and functionally well-maintained.

A Standard Airway Kit

A Standard airway kit should contain as a minimum:

Face-masks of all sizes and shapes
Nasopharyngeal airways and oropharyngeal airways- of all sizes
ETT - uncuffed and cuffed (2.5-6 mm)
Tracheal tube stylet (6F, 8F)
Magill forceps—small, medium
Laryngoscope blades - Miller (00, 0,1,2), Macintosh (0,1,2), short laryngoscope handle
LMA classic (1,1.5,2,2.5,3), ProSeal (1, 1.5,2,2.5, 3) disposable LMA
Suction catheters (6F, 8F, 10F, 12F) (Fig. 1.62)
Manual resuscitation bag (0.5L and 1 Liter)
Miscellaneous—spare batteries, lignocaine spray, lubricant, bite-block, syringes, decongestant.

Fig. 1.62: Color coded suction catheters

A Difficult Airway Cart

A difficult airway cart should contain:

Lighted stylet (Trachlight) - Pediatric and infant size
Gum elastic bougie (GEB)
Airway exchange catheter (AEC)
Alternative to direct laryngoscope
- Flexible fiberscope
- C-MAC video laryngoscope } Pediatric size
- Retromolarscope
Transtracheal airway kit - l6/18G IV catheter (1.5-2 inches long jet ventilation device)
Cricothyrotomy equipment
Tracheostomy set
Oxygen source
ILMA # 3, Combitube (37F).

Chapter Notes

Airway Management1