Airway management remains a fundamental skill for all emergency physicians. Extraglottic airway devices (EGAs) have become a widely accepted means of airway management along with rescue airway devices. We aim to clarify the role of these devices in the prehospital setting and discuss considerations surrounding the most frequently used devices in current practice. Although we discuss the benefits of various commercial products, none of the authors endorse any individual device detailed below.

Historically, the endotracheal tube (ETT) has been considered the definitive airway of choice in both the prehospital and in-hospital setting. Emergency medical services (EMS) scope of practice is governed by the state, but national scope of practice guidelines are available for the four different EMS provider levels. The guidelines, updated most recently in 2019, note that endotracheal intubation is reserved for paramedics. Extraglottic devices, however, are in the scope of practice for both advanced emergency medical technicians (AEMTs) and paramedics, making the devices more widely applicable.¹ Prehospital endotracheal intubation and EGAs are typically placed without paralytics and are reserved for unconscious, apneic, and out-of-hospital cardiac arrest patients. With more recent studies such as the AIRWAYS-2 and PART trials showing no significant benefit to using ETTs over EGAs and even possible evidence of benefit with EGAs, the role of the prehospital ETT may be further restricted in the coming years.^2,3,4 With the current prehospital emphasis on EGAs, it is important for emergency physicians to understand which current extraglottic devices are commercially available and the role each plays in the management of the compromised airway in the prehospital setting.

Proposed benefits to EGAs include ease and speed of placement, reduced need for training, reduced need for sedation and paralytic medications to facilitate placement, and reduced risk of complications during the procedure.⁵ Due to these benefits, many protocols (both prehospital and hospital-based) list EGAs as a key step in both standard and failed airway management; however, potential risks come with using EGAs in lieu of ETTs. Because EGAs do not isolate the trachea as the ETT does, the risk of aspiration events increases, and due to the blind placement of many of these devices, unidentified airway occlusion can occur.⁶ Additionally, EGAs are not generally considered to be “definitive” airways and are typically exchanged for an ETT at patient hospital presentation, although they can be used with mechanical ventilation for up to 24 hours.⁷

Laryngeal Mask Airway (LMA)

Developed in the 1980s and first introduced into the prehospital setting in 1992, the LMA spearheaded the broader introduction of extraglottic devices into prehospital practice.⁸ Initially developed as a surgical adjunct, the LMA proved to be easily adaptable to the less controlled environments of the prehospital setting.⁹ LMAs use an inflatable mask expanded using a similar technique to the endotracheal tube cuff. LMAs are intended to cover the laryngeal inlet, thus isolating the airway from the esophagus. These devices are currently manufactured by several companies and have multiple variants, including the LMA Supreme (manufactured by The Laryngeal Mask Company Ltd) and the LMA-Proseal and LMA-Fastrach (manufactured by LMA North America), which aim to improve certain aspects of the LMA device, such as ease of placement or improved isolation of the respiratory tract.⁶ Because LMAs require inflation to function appropriately, they are at risk of balloon rupture or loss of seal pressure. While not unique to LMAs, the potential risk of airway occlusion is higher than it is for other EGAs.⁷

Esophageal-Tracheal Combitube

The Esophageal-Tracheal Combitube (manufactured by Covidien-Nellcor in Colorado), a device designed to be inserted blindly, was created to be used with less prerequisite training. The Combitube features two lumens, proximal and distal, with two associated cuffs that allow for ventilation of the patient regardless of esophageal or tracheal insertion. If the distal lumen is placed in the esophagus, the patient is ventilated via the proximal lumen. If the Combitube is inserted and breath sounds are heard when ventilating through the distal lumen, the distal lumen was likely inserted into the trachea. Similar to the LMA, the Combitube can be used without significant neck manipulation in patients who require C-spine precautions. It has the added advantages of aspiration risk reduction and stomach decompression given its two cuffs and lumens.¹⁰ The Combitube is contraindicated in patients with upper esophageal abnormalities, such as esophageal varices, or caustic ingestions.¹¹ As with LMAs, Combitubes are at risk of balloon rupture as well, and attention is needed to avoid damaging the inflating sections of the device both while in storage and during placement. The variation in using the two lumen can also cause confusion.

Laryngeal Tube/King Airway

First invented in Europe in 1999, laryngeal tubes were popularized in the United States by King Systems and are commonly referred to as King airways.⁸ The King LT has distal and proximal cuffs that function to seal the esophagus and hypopharynx, respectively, with a ventilatory lumen located between these cuffs. In contrast to the Combitube, the King LT utilizes one line to inflate both cuffs. The benefits of a King LT include lower inflation pressure and soft distal end, which decrease trauma during insertion and use.¹¹ Due to the presence of inflatable sections, balloon rupture and degradation remain a potential complication, similar to LMAs and the Combitube.

I-Gel

The i-gel was designed in the UK in 2003 and features a gel-style cuff that surrounds the larynx.⁸ Constructed with thermoplastic material, it can take the shape of the patient’s larynx, a design intended to optimize ventilation and minimize aspiration.¹¹ The i-gel features a smaller, secondary lumen running the length of the device, through which a nasogastric tube can be passed. Commonly used in prehospital and hospital settings, the i-gel can facilitate endotracheal intubation and bronchoscopy given its large unobstructed main lumen.¹¹ First-pass success rates are similar when compared to cLMAs and pLMAs and better when compared to the King airway.¹² As a result, the i-gel has found itself in the hands of many prehospital and hospital workers, both in initial and difficult airway management. As there is no inflation step in the placement of i-gel devices, balloon rupture is not a concern and syringes are not required to place the device.

Conclusion

EGAs offer multiple benefits in managing patient airways and have found generally wide acceptance in the protocols of numerous EMS provider levels. Regardless of the device used, continuous ventilation and oxygenation assessment must be performed, because EGAs constitute only one aspect of airway management. Frequent training and skill verification are needed to ensure that these devices are utilized appropriately, regardless of the care setting. While each EGA device type features proposed benefits, ultimately, the greatest predictor of success is likely to be the thoughtful incorporation of these devices into protocolized care structures and emphasis on both initial and ongoing personnel training.

Dr. Glauser is professor of emergency medicine at Case Western Reserve University at MetroHealth Cleveland Clinic in Cleveland, Ohio.

Dr. Hillman is a third-year resident at the MetroHealth/Cleveland Clinic Emergency Medicine Residency in Cleveland, Ohio.

References

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