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number of occasions for casualties who were unconscious Extraglottic Airways
from hemorrhagic shock or traumatic brain injury (TBI),
but who had no direct maxillofacial injuries or documented The esophageal obturator airway (EOA) was developed in the
airway problems. In unconscious casualties without an ob- 1970s and included a large tube with a balloon that occluded
served airway obstruction, EGA use should be attempted the esophagus and a mask attached to the tube that had an
to manage the airway before undertaking a surgical airway. opening to allow for ventilation. As the patient was ventilated
3. In individuals who are unconscious from hemorrhagic via bag-valve-mask (BVM), air could only go into the trachea
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shock or TBI, but who do not have direct trauma to airway since the esophagus was occluded. EOA use was associated
structures, the only airway interventions other than surgi- with a number of complications such as tracheal occlusion and
cal airways recommended in the TCCC Guidelines for use esophageal perforation. It never became popular in emergency
during Tactical Field Care (TFC) have been the chin-lift, departments, although many EMS units used them. One of the
jaw-thrust manuever, nasopharyngeal airways (NPAs), and skills required for an emergency physician in the past was the
the use of the recovery position. Although intracranial in- ability to tracheally intubate a patient with an EOA in place.
sertion of NPAs is rare and has not, to the authors’ knowl-
edge, occurred in US casualties from Iraq and Afghanistan, The first extraglottic airway (EGA) was invented by Archie
it has been reported in the literature. 19–23 EGAs do not entail Brain in 1981 and became commercially available in the
the risk of intracranial misplacement and are an important, United States in 1991. It was called the laryngeal mask airway
safe, and easy-to-use item that can be added to the combat (LMA) and became widely used in anesthesia and prehospi-
medic’s kit to help manage the airway during TFC. tal care. The LMA was designed to provide ventilation while
4. The i-gel was introduced in 2007 and has a number of positioned above the glottis with an inflated mask that seals
characteristics that make it favorable for use on the battle- the esophagus, allowing for air to enter the trachea. Currently
field. Notably, the cuff that fits over the laryngeal inlet there are many similar devices that use the same principle and
is filled with a soft gel rather than air. This feature has attempt to improve on the ease of placement and protection
four advantages on the battlefield: (1) the combat medical from aspiration while still providing oxygenation and venti-
provider does not have to carry a syringe for the purpose lation. Several articles have discussed the advantages of the
of inflating the cuff; (2) not having to fill the cuff with air EGA over endotracheal intubation in the OR and these advan-
saves the medic, corpsman, or PJ from having to take the tages, especially the ease of insertion and training, also make
12,39,40
time required for that action during airway insertion; (3) EGAs an ideal airway for prehospital use. EGAs are now
the gel does not expand at altitude during evacuation on frequently used in the OR, ED, and prehospital practice as a
aircraft, as air-filled cuffs do, thus making it unnecessary routine airway device as well as a rescue and difficult airway
2–4,7–13,15,17,18
to monitor EGA cuff pressure during air transport; and device.
(4) the lack of increased cuff pressure relative in the EGA
cuff relative to ambient lowers the potential for iatrogenic The 1996 TCCC Guidelines included a recommendation to
damage to neural structures in the oropharynx secondary use the LMA as an option to assist in securing the airway in
to EGA use. the Tactical Evacuation (TACEVAC) phase of care. A variety
5. The emerging literature has shown the i-gel EGA to be as of EGAs have subsequently been used in combat casualty care
good or better than other EGAs in multiple studies. 5,10,13,24–30 over the past 20 years. The US Army has used the King LT
41
6. Overpressurization of EGA cuffs is associated with palsies EGA during the conflicts in Iraq and Afgahnistan after a
of the cranial nerves that pass through the oropharynx. 31–34 study by McManus et al. showed this device to be quickly and
42
This can occur even without a change in ambient pressure, easily placed by combat medics. Adams and his coauthors
but the decrease in atmospheric pressure associated with further noted that “In the combat setting, medical direction in
helicopter transport of combat casualties results in increas- far-forward Army units is not standardized and training can
41
ing relative pressure inside the volume-limited EGA cuff and vary widely between units and individuals. . . .”
an increased risk of barotraumatic neuropraxia. A study
done on a Combat Casualty Aeromedical Transport Team In May 2012, one of the authors (E.J.O.) presented evidence
(CCATT) training mission that examined 4 methods of to the CoTCCC that other SGAs were similar to the LMA
managing cuff pressures during flight concluded that none with respect to training time, efficiency of ventilation, speed of
were sarifactory and that new technology or techniques insertion, and complications. The CoTCCC and the Defense
need to be developed. As noted here earlier, the i-gel has a Health Board (DHB) subsequently reaffirmed support for the
35
gel-filled cuff that does not increase in volume or cause ele- use of SGAs in the TACEVAC phase of TCCC, but changed
vated cuff pressures at altitude. This lowers the potential for the recommendation from the LMA to a generic SGA recom-
cuff overpressurization and resultant cranial nerve palsies. mendation based on the available evidence at that point in
43
7. The i-gel was found to be the fastest EGA to insert in in- time. Note that this paper will use the alternate term “ex-
dividuals who are wearing chemical, biological, radiation, traglottic airway” (EGA) instead of the term “SGA” that was
nuclear–personal protective equipment (CBRN-PPE). 36 used in the DHB memo in order to be more anatomically pre-
cise about the location of the device.

Background The DHB went on to recommend that if an EGA device was
Airway obstruction was the second leading cause of prevent- found to be superior to other options based on the best avail-
able death in the prehospital phase of care for US combat able evidence, then that device should be standardized across
43
fatalities during the conflicts in Iraq and Afghanistan, thus the military services. The evaluation criteria that is used to
37
emphasizing the need for combat medical personnel to be guide decisions regarding a particular item of combat casu-
proficient in managing casualties with airway injuries on the alty care equipment as evaluated by by the CoTCCC New
battlefield. Technology Subcommittee consists of the following: (1) it

20 | JSOM Volume 17, Edition 4/Winter 2017