American Journal of Emergency Medicine 37 (2019) 349-373

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Correspondence

Airway management in a Prehospital combat setting

To the Editor,

In a retrospective review of US Army medical evacuation patient care records, Hardy et al. [1] compared outcomes of US military injured that received prehospital advanced airway interventions. The authors con- clude that patients who received a supraglottic airway devices (SAD) had higher morbidity demonstrated by fewer ventilator, hospital, and ICU free days than those receiving cricothyrotomy or mask ventilation. We would like to add several appreciations. The authors do not spec- ify the SADs used. This data is essential to make an accurate analysis of the data. It is well known that Second-generation SADs, although they do not completely protect the airway from aspiration, provides better efficacy and safety compared with first-generation devices [2]. The first-generation SADs (e.g. the classic laryngeal mask airway) have sev- eral limitations, fundamentally providing only a moderate pharyngeal seal that may be associated with inadequate ventilation, gastric infla- tion, regurgitation and pulmonary aspiration. The design of second- generation Supraglottic airways allows for greater pharyngeal seal pres- sures and they contain an oesophageal port which provides functional separation of the respiratory and gastrointestinal tracts and allows for the draining or aspiration of gastric contents. Second-generation SGAs are also more likely to enable oxygenation and ventilation [3]. Thus, only second-generation SADs are recommended in the recent guide- lines [3-5]. Likewise, each second-generation SAD has specific attributes as the time of placement, seal pressure, type of separation of gastroin- testinal and respiratory tracts and use as a conduit for endotracheal in-

tubation (blind or fibre-optically guided tracheal intubation).

The competence and experience of the operator with the device also play a relevant role since they influence the success of insertion and cor- rect placement. Different studies indicate a low failure rate in the clinical use, although the consequences of failure included an increase in hospi- tal admission and ICU admission [6].

All of this justifies the need to specify the kind of SAD since they con- stitute a heterogeneous group of non-equated devices. Therefore, it is necessary to take all these data into account. Otherwise, the conclusions of this interesting work could be misleading.

Manuel Angel Gomez-Rios* Department of Anesthesia and Perioperative Medicine, Complejo Hospitalario Universitario de A Coruna, A Coruna, Galicia, Spain Anesthesiology and Pain Management Research Group, Institute for Biomedical Research of A Coruna (INIBIC), A Coruna, Spain

Spanish Difficult Airway Group (GEVAD)

*Corresponding author at: Department of Anesthesia and Perioperative Medicine, Complejo Hospitalario Universitario de A Coruna, Xubias de

Arriba, 84, A Coruna 15008, Spain

E-mail address: [email protected]

Jose Maria Calvo-Vecino Department of Anesthesia, Complejo Asistencial Universitario de Salamanca, Universidad de Salamanca (CAUSA), Salamanca, Spain

6 June 2018

https://doi.org/10.1016/j.ajem.2018.06.050

References

1. Hardy GB, Maddry JK, Ng PC, et al. Impact of prehospital airway management on com- bat mortality. Am J Emerg Med 2018;36(6):1032-5.
2. Gomez-Rios MA, Gaitini L, Matter I, Somri M. Guidelines and algorithms for managing the difficult airway. Rev Esp Anestesiol Reanim 2018;65(1):41-8.
3. Higgs A, McGrath BA, Goddard C, et al. Guidelines for the management of tracheal in- tubation in critically ill adults. Br J Anaesth 2018;120(2):323-52.
4. Rehn M, Hyldmo PK, Magnusson V, et al. Scandinavian SSAI clinical practice guideline on pre-hospital airway management. Acta Anaesthesiol Scand 2016;60(7):852-64.
5. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for man-

   agement of unanticipated difficult intubation in adults. Br J Anaesth 2015;115(6):827-48.

   Cook TM, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth 2012;109(Suppl 1):i68-85.

   Impact of prehospital airway management on combat mortality

   Response to Letter to Editor,

   We appreciate the inquiry regarding our publication and thank you for the letter. We were unable to determine the type or generation of Supraglottic airway devices used in the prehospital combat setting from the MEDEVAC documentation. An additional consideration affect- ing patient outcomes regarding supraglottic airway devices in the prehospital combat setting is the difference in the combat environment versus the hospital environment. As mentioned in our discussion sec- tion, combat medics do not carry paralytics, the patients are not fasting, and the environment is considerably different than that of the hospital. Furthermore, the primary causes of injury in our patient population are improvised Explosive devices and high velocity rifles which result in in- juries significantly different from those in the US civilian setting. This is in addition to the differing types of supraglottic airway and varying competence of the operator that you mentioned. Regardless, further re- search comparing the different supraglottic airway devices is necessary to draw more definitive conclusions.

   Funding source

   Defense Joint Program Committee — 6.

   Garrett Hardy, MD, MC, US Army

   Department of Emergency Medicine, San Antonio Military Medical Center,

   JBSA Ft. Sam Houston, TX, United States

   0735-6757/(C) 2018