A newborn with small bowel obstruction is taken to the operating room for an exploratory laparotomy. You are called to assist with a potentially difficult airway. Initial assessment of the newborn demonstrates a “small chin” and obvious signs of respiratory distress including tachypnea and upper airway obstruction. The baby’s oxygen saturation is 91% in the supine position. The primary anesthesia practitioner suggests an “awake” intubation in light of the potential for aspiration and high likelihood of a difficult airway. What are your concerns and how would you manage this child’s airway?

When I See the Patient for the First Time, What Should I be Looking for?

A thorough assessment of the patient’s anatomic features can yield significant information. Features associated with a difficult airway include a narrow inter-incisor distance, restricted head extension, mandibular hypoplasia, midface hypoplasia, macroglossia, and microstomia.^1,2 Furthermore, determine whether the patient has been diagnosed with any syndromes. One study showed that half of the patients with difficult intubations were diagnosed with a syndrome, and the other half had extremely anterior airways and micrognathia.³ Another large study identified that micrognathia, a weight less than 10 kg, greater than two tracheal intubation, and three direct laryngoscopy (DL) attempts before an indirect technique were independently associated with an increased risk of severe airway complications.⁴ It is important to evaluate the patient while lying supine at rest, and look for signs of upper airway obstruction, such as paradoxical chest wall movement and/or stridor while observing any change in oxygen saturation.

What Are Some of the Most Common Syndromes Associated with a Difficult Airway?

There are several syndromes that are well known to be associated with a difficult airway. Each syndrome presents its own functional or anatomic challenges. Classic examples include Pierre Robin sequence (micrognathia), Treacher Collins (mandibular hypoplasia), Goldenhar syndrome (mandibular hypoplasia), Hunter and Hurler syndromes (mucopolysaccharidosis), and more.¹ It is important to be familiar with these syndromes as these patients may be at risk for difficult bag-mask-ventilation, difficult tracheal intubation, or both.⁵

When Should I Consider Doing an Awake Intubation on a Neonate?

An awake intubation should be strongly considered in a neonate if there is a clinical picture suggestive of difficult bag-mask-ventilation, difficult laryngoscopy, high aspiration risk with severe upper airway obstruction at rest.⁶ An awake patient has the ability to maintain their own life-saving oxygenation and ventilation, and is more able to protect themselves from aspiration of regurgitated gastric contents.

What Basic Components Are Needed to Perform an Awake Tracheal Intubation in a Neonate with Airway Obstruction?

Basic components include reliable intravenous access, gastric decompression, and various airway tools readily available for your initial and backup airway plans. The decision to administer anti-sialagogues and/or topicalization must be tailored to each patient scenario. The goals, however, are always the same and include: maintenance of spontaneous ventilation and oxygenation, avoidance of worsening airway obstruction, and an assurance that the patient can potentially protect their own airway from aspiration of gastric contents.

What Airway Techniques Are Available to Secure the Airway of an Awake Neonate with a Difficult Airway?

There are a number of techniques that have been successfully employed in this scenario.

Direct Laryngoscopy

Consider using a straight blade in the paraglossal/retromolar technique where the blade enters the right side of the mouth along the buccal mucosa and lifting the epiglottis from the side, with the tongue avoided altogether.⁷

Video-Laryngoscopy (VL)

Commercially available video-laryngoscopes for neonatal use include the GlideScope^® (Verathon, Bothell, WA) and the pediatric video-laryngoscope (Karl Storz, Tuttlingen, Germany). These indirect devices come in variable sizes but incorporate a camera lens at the distal end of the intubating blade that provides a wider magnified view of the laryngeal inlet. VL eliminates the need for the practitioner to align different axes of the upper airway and minimizes the need for lifting force or neck manipulation.^8,9 In both difficult and normal pediatric airways, the GlideScope^® has repeatedly demonstrated a faster time to glottic view, however, required longer time to successful intubation.^8–11 Premature baboon model studies¹² and case reports involving difficult infant airways demonstrated that implementation of VL is both feasible and valuable for successful difficult airway management.^13–15

Flexible Bronchoscopy

This technique remains the “gold standard” for management of the difficult airway and will be discussed more in section “Is Tracheal Intubation Using a Flexible Bronchoscope the Gold Standard for Difficult Airways in Neonates?” of this chapter.

Would You Attempt DL First in an Anticipated, Yet “Untested” Difficult Airway?

Practitioners must make this decision based on their own expertise, comfort level, and patient factors. However, be aware that persistence in DL leads to increased complications. Results of the Pediatric Difficult Intubation Registry found that multiple attempts (defined as greater than two) at DL in pediatric patients with difficult airways were associated with greater rates of failed intubation and severe complications.⁴ Severe complications included cardiac arrest, hypoxemia, bronchospasm, esophageal intubation, and severe airway trauma. Additional risk factors for complications include weight <10 kg and a short thyromental distance (i.e., micrognathia).

Is Tracheal Intubation Using a Flexible Bronchoscope the Gold Standard for Difficult Airways in Neonates?

Tracheal intubation using a flexible bronchoscope is the “gold standard” for tracheal intubation of the pediatric patient with a difficult airway.^5,16,17 The utility of the flexible bronchoscope derives from its ability to traverse the passageway of the patient’s airway under indirect visualization. Intubation can be achieved through various routes—the mouth, nose, or through an extraglottic device. Anatomic reasons for a difficult airway can possibly be overcome with this device, such as small mouth openings, anterior larynx, and airway masses.

What Are the Limitations to Flexible Bronchoscopic Intubation?

Limitations include: lack of training by the practitioner using the device; lack of patient cooperation; small amounts of blood and secretions can easily hinder views from its small camera; expensive equipment; and complex and time-consuming sterilization process (please also see section “What Are the Limitations and Complications of Bronchoscopic Intubation?” in Chapter 10). In order for the device to be a useful airway tool, frequent use and practice are required for the practitioner to maintain a proficient skill level in children.^16–18 In novices, bronchoscopic intubation in children was achieved more quickly through the nasal route than the oral route.¹⁹ Therefore, depending on the expertise of the practitioner, the nasal route should be considered.

What Is Required to Perform an Awake Tracheal Intubation Using a Flexible Bronchoscope in a Free-Handed Manner for a Neonate?

A number of different sizes of flexible bronchoscopes are available for neonates. The smallest is 2.2 mm in diameter.¹⁶ The bronchoscope should be preloaded with an appropriately sized endotracheal tube (ETT) (for a full-term neonate consider using a cuffed 3.0 ETT or smaller). Make sure the scope is white-balanced and examined for proper functioning before use.

Consider administering medications such as anti-sialagogues or anti-muscarinics (in the scenario where the neonate has a vagal response with subsequent bradycardia during intubation). Provide passive oxygenation during the process of intubation by nasal cannula or via nasal trumpet.

After adequate denitrogenation, an assistant can provide bilateral jaw thrust and manual tongue traction to facilitate entry and passage of the scope into the oropharynx. To pull the tongue out, the practitioner can consider holding the tongue using sterile gauze or tongue-holding forceps (Babcock forceps), or stitching the tongue with a suture to pull and anchor the tongue out.

The bronchoscope should be inserted midline, if the anatomy allows, and landmarks should be identified as the scope is advanced until the laryngeal inlet is encountered. Once the epiglottis is visualized, the scope should be retroflexed underneath the epiglottis and then subsequently retroflexed to bring the glottic opening into view.

Alternatively, a nasal bronchoscopic approach may be considered. The nasal approach has the advantage of keeping the bronchoscope relatively midline during tracheal intubation. Prior to nasotracheal intubation, a vasoconstrictor should be instilled in the nares and a thermosoftened tracheal tube should be used to minimize the risk of epistaxis.²⁰ It has been shown that this approach is faster than the oral bronchoscopic intubation in small children for practitioners inexperienced with using pediatric flexible bronchoscopes.¹⁹

Each practitioner should decide whether to use induction agents and/or muscle relaxant at this point, with the purpose to minimize reflex laryngeal and pharyngeal activation. However, be aware that optimizing intubation conditions with such medications come at the cost of ablating the protection of these airway reflexes if the ETT is unable to be passed successfully over the bronchoscope. Topicalization of the posterior pharynx to facilitate awake intubation also can be performed and is covered in section “How Would You Place an Extraglottic Device in an Awake Neonate? Is Topicalization Necessary?” of this chapter.

Once the scope is in the trachea, the ETT should be guided over the bronchoscope into the trachea. Confirmation of tracheal placement and adequate ventilation should be confirmed with the bronchoscope as well as end-tidal capnography.

Why Use an Extraglottic Airway Device as a Conduit for Tracheal Intubation in Neonates?