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Technique Utilizing a Modified Oral Ring-Adair-Elwyn Tube to Provide Continuous Oxygen and Sevoflurane Delivery During Nasotracheal Intubation in an Infant With a Difficult Airway: A Case Report

Man, Janice Y. MD*; Fiadjoe, John E. MD; Hsu, Grace MD

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doi: 10.1213/XAA.0000000000000677
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Patients with Pierre Robin sequence (PRS) have the triad of micrognathia, glossoptosis (a posterior and inferior displacement of the tongue), and airway obstruction. The incidence of PRS ranges from 1 in 5000 to 1 in 85,000,1 with the actual incidence unclear because of obscurity in the pathophysiology of the disease. Neonates with PRS vary in how they present—from asymptomatic to suffering from severe respiratory obstruction that impairs feeding and leads to failure to thrive. They may also not tolerate the supine position as their glossoptosis worsens while supine. Because PRS patients with severe symptoms are also likely to be difficult to mask ventilate, they are at risk for hypoxemia after induction and before tracheal intubation.2 In addition, because of their craniofacial abnormalities, they are also often difficult to intubate by traditional means.3 This places these children at risk for a situation in which they can neither be oxygenated nor intubated.

Several airway management strategies have been described for intubating patients with PRS. One important consideration in the airway plan is delivering oxygen continuously during intubation. This has been described by using a high-flow nasal cannula, a modified nasopharyngeal airway (NPA), or a supraglottic airway (SGA).4–6 Techniques using high-flow nasal cannula and SGA are most applicable for oral intubations, but will cause mechanical obstruction during nasal intubations.7 We describe a simple technique to administer continuous oxygen and volatile anesthetic during nasal intubation in an infant with PRS.

Written consent was obtained from the parents of the patient for publication of this case report.


A 4.08-kg, 4-month-old male infant with PRS was scheduled for mandibular osteotomies with distractor placement. Mandibular distraction osteogenesis is performed to decrease upper airway obstruction in infants.8 The patient had 2 prior anesthetics: a laparoscopic fundoplasty with gastric tube placement and an inguinal hernia repair. A prior anesthesia team successfully performed a trans-SGA fiberoptic oral intubation when the patient was 3 months old.

Surgery for mandibular distraction osteogenesis requires a nasal endotracheal tube (ETT). The first technique in the airway management plan was a mask induction with spontaneous ventilation, then transitioning to oxygenation via a modified NPA, and finally the last step of nasal intubation guided by a fiberoptic scope in the contralateral naris. A peripheral intravenous line was placed in the preoperative holding area. Standard American Society of Anesthesiologists monitors were placed in the operating room before induction. Glycopyrrolate 15 µg/kg was given as an antisialagogue. Dexmedetomidine 1 µg/kg bolus was given before the administration of volatile anesthetic for balanced anesthesia care. The dexmedetomidine had little visible effect on the patient’s consciousness or respiratory effort. Mask induction with 8% sevoflurane and oxygen at fraction of inspired oxygen 1.0 was initiated. The patient maintained spontaneous ventilation with moderate obstruction, which was relieved with aggressive jaw thrust.

Sizing and sequential dilation of bilateral nares with NPAs were attempted to determine which naris was optimal for intubation. The left naris accepted up to a 14F NPA. The modified NPA was connected to the anesthesia circuit, and end-tidal carbon dioxide (Etco2) and end-tidal sevoflurane were detected. Sizing and sequential dilation were attempted on the right naris. However, even the smallest NPA available, the 12F NPA, could not be passed. The decision was made to intubate through the left nare and to provide an alternate means of continuous oxygenation.

A 4.0 oral Ring-Adair-Elwyn (RAE) ETT was chosen based on the patient’s age. The oral RAE was then cut to specific length such that the distal tip would approximate the location above the glottic opening and remains supraglottic. The bend of the oral RAE ETT was placed alongside the lateral corner of the patient’s mouth, and this was utilized to estimate the length needed to such that the tip would remain supraglottic. The hyoid bone was used as an external marker to approximate the location of the epiglottis and glottic opening (Figure 1). The ETT was cut just proximal to this location. This modified oral RAE ETT was then placed in the lateral oropharynx and was connected via a flexible circuit connector to the anesthesia circuit (Figure 2). Once connected, there was continual end-tidal O2, Etco2, and end-tidal sevoflurane monitoring during spontaneous ventilation. To further optimize intubating conditions, an assistant was giving jaw thrust and applying gentle suction to the tip of the tongue, to aid in moving the tongue anteriorly and to relieve any obstruction to spontaneous ventilation (Figure 3).

Figure 1.
Figure 1.:
An oral RAE ETT placed alongside the mouth. The hyoid bone is used as an external marker to approximate the location of the epiglottis and the glottic opening. The distal end of the oral RAE ETT is then cut to become the modified oral RAE ETT to be placed inside the oropharynx. ETT indicates endotracheal tube; RAE, Ring-Adair-Elwyn.
Figure 2.
Figure 2.:
The modified oral RAE ETT is placed inside lateral to the tongue and is connected via an accordion device to the anesthesia circuit. This allows for continuous end-tidal sevoflurane, oxygen, and carbon dioxide monitoring. ETT indicates endotracheal tube; RAE, Ring-Adair-Elwyn.
Figure 3.
Figure 3.:
Gentle suction is applied to relieve airway obstruction from the tongue. A fiberoptic bronchoscope loaded with an ETT can then enter the naris. ETT indicates endotracheal tube.
Figure 4.
Figure 4.:
View of the distal tip of the modified oral RAE ETT from the fiberoptic bronchoscope. ETT indicates endotracheal tube; RAE, Ring-Adair-Elwyn.

A 3.0 Microcuff nasal ETT (Halyward, Alpharetta, GA) was loaded onto a 2.2-mm fiberoptic bronchoscope and placed gently into the left nare. The ETT and scope were advanced into the nasopharynx, and then the scope advanced into the oropharynx until the epiglottis, tip of the modified oral RAE ETT, and glottic opening were in view (Figure 4). The scope was advanced with ease into the trachea and nasotracheal tube advanced over the fiberoptic shaft, into the trachea. ETT position was verified with visualization via fiberoptic bronchoscope, presence of Etco2, and chest auscultation. There were no episodes of hypoxemia or oxygen desaturation during inhalational induction, insertion of the modified oral RAE, and management of the airway with fiberoptic intubation. After confirmation of successful endotracheal intubation, vecuronium 0.2 mg/kg was given and the ETT was sutured at 13 cm at the nare. The surgical procedure proceeded without complication. The patient was taken to the neonatal intensive care unit intubated. The patient received daily mandibular distraction in the neonatal intensive care unit for 6 more days and remained intubated for airway protection during analgesia and sedation. The patient was extubated on postoperative day 7.


It is estimated that 2–5 difficult intubations occur in every 1000 pediatric anesthesia cases in the United States, with 3% of these patients experiencing severe complications as a result of the intubation.9 Patients with PRS, especially neonates, are a significant airway challenge. Preparation of the patient and the equipment for difficult airway management is both key and essential. A difficult airway cart should be readily available with a variety of appropriately sized laryngoscope blades, SGAs, oral and nasal airways, and fiberoptic and video laryngoscope instruments. Anticipation of a difficult airway should be a team-based approach. Elicitation of assistance from experienced anesthesiology and otolaryngology colleagues is of upmost importance in difficult airway management before induction. An otolaryngologist should be available when an emergency or surgical airway need arise.

Passive oxygenation during intubation via a nasal cannula, modified NPA, and SGA are traditional approaches described to prevent hypoxemia. We present a simple and alternative technique to effectively administer oxygen and volatile anesthetic during nasotracheal intubation in an infant with PRS. There are several major advantages and disadvantages to this modified or supraglottic oral RAE technique compared to the use of a nasal cannula, SGA, or NPA techniques for the management of the difficult airway in pediatric patients (Table). A major advantage of this technique for continuous oxygenation versus use of a modified NPA is that the free nostril does not have to be entered, thus decreasing risk of epistaxis.10–12 This is also an effective technique to deliver continuous oxygenation during nasal intubation in the setting of unilateral choanal atresia or other causes of unilateral nasal obstruction.13,14 The use of a supraglottic oral RAE ETT versus use of a nasal cannula situated at the mouth opening allows for concomitant delivery of volatile anesthetic and oxygen at a location closer to the trachea, thus potentially improving oxygenation and minimizing contamination of volatile anesthetic into the operating room. With a nasal cannula technique, it allows for continuous delivery of oxygen as well as monitoring of continuous Etco2 and end-tidal oxygen, but does not allow for continuous delivery of sevoflurane or end-tidal sevoflurane monitoring. Use of the nasal cannula for oxygenation requires a total intravenous anesthetic technique to allow for the patient to be spontaneously breathing and to prevent light anesthesia.

Advantages and Disadvantages of Different Difficult Airway Techniques for Delivery of Continuous Oxygen

The supraglottic oral RAE occupies little space in the oropharyngeal cavity allowing visualization of the glottic opening as opposed to techniques using an SGA.15 Additionally, this technique is easily and quickly reproducible and requires minimal modification of the oral RAE ETT. By using the hyoid bone as an external marker for the location of the epiglottis and glottic opening, one can cut the oral RAE to fit the patient’s oropharynx.

A potential disadvantage of this method is if the practitioner leaves the oral RAE for an extended duration and risking that the tip of the ETT may reach the larynx. This may result in irritation of the larynx and may even lead to laryngospasm. In addition, similar to a nasal cannula or NPA technique, air entrainment occurs that can result in a diluted fraction of inspired oxygen and light anesthesia if a total intravenous anesthetic technique is not utilized. Similarly, contamination of the operating room with inhalation agent occurs if utilizing inhalational agent. Finally, Etco2 monitoring may be unreliable especially in neonates and infants. A variety of techniques has been previously described in intubating an infant with a difficult airway with continuous oxygen delivery. We have described a simple and easily reproducible method of administering oxygen and volatile anesthetic during tracheal intubation in infants with difficult airways. Potential future directions include prospectively evaluating the time to desaturation with continuous oxygenation and sevoflurane delivery via modified oral RAE compared to other difficult airway techniques in the pediatric patient population.


Name: Janice Y. Man, MD.

Contribution: This author helped identify and manage the presented case, and draft and revise the manuscript.

Name: John E. Fiadjoe, MD.

Contribution: This author helped draft and revise the manuscript.

Name: Grace Hsu, MD.

Contribution: This author helped identify and manage the presented case, and draft and revise the manuscript.

This manuscript was handled by: Raymond C. Roy, MD.


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