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Sudden Hypoxemia in GI Procedure Relieved by a New Distal Pharyngeal Airway (DPA): Case Report

July 16, 2023

James DuCanto, MD

Airway management challenges such as upper airway obstruction and hypoxemia occur frequently in gastrointestinal (GI) endoscopy cases despite the use of supplemental oxygen administration from purpose-built oxygen masks. Recent closed claims analysis indicate that GI endoscopy cases are associated with the highest number of malpractice claims for anesthesia providers, highlighting the need for improvement in upper airway patency and oxygenation1. The Distal Pharyngeal Airway (DPA) is a narrow-tubular oral airway that can be placed alongside an esophagogastroduodenoscopy (EGD) endoscope to relieve distal pharyngeal airway obstruction that can occur during endoscopy and thus facilitate effective airway management under monitored anesthesia care (MAC) sedation.


As a result of sharing the airway with the endoscopist, airway management challenges can occur during gastrointestinal (GI) endoscopy. Hypoxemia occurrence during an upper endoscopy is multifactorial and manifested with low oxygen saturations of < 90% for ≥ 15 seconds. One prospective trial suggested that the rate of hypoxemia maybe as high as 51% among ASA 1 and 2 patients.2 Airway complications resulting in hypoxemia can lead to apnea, bradycardia, and cardiac arrest.3

Deep sedation administered by anesthesia professionals for GI procedures (i.e., sedation that exceeds the definition of ‘moderate’ sedation with preservation of spontaneous ventilation) is steadily increasing worldwide with 50 million cases performed in 2016 in the U.S.4 Providers choose Monitored Anesthesia Care (MAC) with propofol to increase patient comfort, improve the quality of examination, provide rapid recovery, and to save time and money.5 Deep sedation blunts the gag reflux while keeping the patient spontaneously breathing during an upper endoscopy esophagogastroduodenoscopy (EGD)—a challenging balance. Further complicating the anesthesia professional’s job is the need to share the airway with the endoscopist. The EGD bite block is placed in the middle of the mouth, making intraoral airway support with instrumentation extremely difficult if needed.


A 60-year-old, 137 kg male with a BMI of 53 and a medical history of hypertension, type 2 diabetes, obstructive sleep apnea (OSA) and hepatic steatosis presented for an EGD at an ambulatory surgery center. Routine monitors and 8L oxygen via endoscopy mask were placed. The patient was in a left lateral position with the head of the bed elevated 30 degrees. Sedation was initiated with careful titration of propofol until the patient became unresponsive to verbal or gentle physical stimuli. EGD endoscope insertion was uncomplicated with a jaw thrust assist, and the endoscopist began the examination. Apnea occurred with the start of the procedure, which led to an episode of hypoxemia (SpO2 dropped from 99% to 60%), which was not amenable to a vigorous jaw thrust maneuver. Without procedure interruption, the endoscopy mask was lifted briefly by the chin to quickly place the distal pharyngeal airway (DPA) alongside the EGD bite block (Fig. 1 & 2). The patient’s hypoxemia resolved with the reversal of airway obstruction and the procedure was completed without any complication.

Fig. 1 Depicts a commercially available DPA (McMurray Medical, Minneapolis, Minnesota) placed through lateral hole of standard GI Endoscopy Bite Block.

Fig. 1 Depicts a commercially available DPA (McMurray Medical, Minneapolis, Minnesota) placed through lateral hole of standard GI Endoscopy Bite Block.

Fig. 2 This figure depicts a DPA in an airway mannequin showing its use next to an endoscope.

Fig. 2 This figure depicts a DPA in an airway mannequin showing its use next to an endoscope.


Hypoxemia is common in upper GI endoscopy procedures.8 Prompt identification and treatment is important to prevent serious complications. Risk factors for hypoxemia during sedation for EGD include OSA, obesity, and age 60 or older.9 These factors contribute to the risk of airway obstruction from redundant distal pharyngeal tissue.2,6 Comorbidities contribute to decreased respiratory reserve volumes as well.2,6 Hypoxemia due to apnea can occur from oversedation, upper airway obstruction by the large EGD endoscope, anesthesia-induced myorelaxation of the distal pharynx and tongue, and respiratory depression.6,7

Steps that may reduce the risk of hypoxemia during EGD procedures include upper pharyngeal topicalization prior to the procedure (to reduce the amount of sedation used), as well as less aggressive and rapid administration of sedative agents, such as propofol. In patients who possess multiple risk factors for hypoxemia during EGD procedures, assisted face mask ventilation with a bag-mask ventilation prior to endoscope insertion can facilitate lung recruitment and reduce the phenomena of hypoventilation prior to and following the endoscopy (author’s personal experience and expert opinion).

As demonstrated in this case, a DPA can effectively resolve an upper airway obstruction during an upper GI endoscopy procedure to mitigate risk of apnea, hypoxemia and associated adverse events. The oral DPA can allow an EGD procedure in which airway obstruction has occurred to continue in some cases without requiring the endoscopist to remove the endoscope for rescue ventilation, and possibly, aborting the procedure completely. As with any device, there is the risk of potential injuries to the lips, tongue, teeth, and palate, which are similar to traditional oropharyngeal airways. Multiple modalities are currently under evaluation to attain the goal of “zero tolerance for hypoxemia during upper endoscopies”7 and indeed, distal pharyngeal airways represent another cost effective and simple tool to assist in basic airway management during EGD procedures. Improved GI anesthesia practice requires simple and effective methods and tools that can be employed when needed to manage upper airway obstructions recalcitrant to jaw thrust maneuvers and head and neck repositioning. The Distal Pharyngeal Airway presented in this case represents a potential tool that can be utilized during an EGD procedure to improve basic airway management. Further clinical studies are warranted to validate the DPA’s role in improving patient safety in those undergoing endoscopy.


James DuCanto is a Staff Anesthesiologist in the Aurora Healthcare Medical Group in Milwaukee Wisconsin as well as an adjunct clinical professor with the University of Wisconsin School of Medicine and Public Health.

James DuCanto, MD has no conflicts of interest.


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