obstruction, all of the above techniques are useful, including sitting the patient up to allow blood and secretions to drain. If unsuccessful, the military recommends a supraglottic airway (if unconscious) or surgical cricothyroidotomy. TECC recommends the same, with considerations for oral or nasotracheal intubation and placement of supraglottic airway devices.
In the evacuation phase of field care, the clinician and patient are normally on their way to higher levels of care via air, ground, or sea. Airway management interventions at this point more closely mirror the normal prehospital environment. TCCC and TECC recommend expanding options, including supraglottic airway placement, endotracheal intubation, and surgical cricothyroidotomy.
The choice of airway management technique can affect the exposure of the tactical clinician above cover or concealment. In one study, the time to first ventilation was relatively similar for both King LT and standard intubation (59.7 seconds and 63.3 seconds, respectively). The time to ventilation was longer for digital intubation (125.4 seconds), and there was greater risk due to exposure over a concealment barricade (23.5 inches above the barricade for digital intubation vs. 17.7 inches for King LT placement) [20].
Tactical operations may occur under low light or near‐blackout conditions. Night vision goggles can be used, but times to intubation are much longer than in typical lighting situations [21].
A study assessing prehospital airway interventions during the wars in Iraq and Afghanistan noted that roughly 4.9% of patients in the data set had prehospital airway interventions. These interventions consisted of nasal airways, cricothyroidotomy, endotracheal intubation, and supraglottic airway placement. Of such interventions, endotracheal intubation and cricothyroidotomy were the most common procedures [22].
Surgical airways in the tactical setting
United States military personnel often proceed directly to surgical airway placement due to complex facial injuries or the need to expedite care during various tactical scenarios [23]. A study of 72 battlefield prehospital cricothyroidotomies noted a success rate of 68%, with a 21% rate of miscannulating the trachea [24]. Combat medics performed most of these procedures. Patients undergoing cricothyroidotomy had a high mortality rate of 66%. The authors recommend that tactical EMS clinicians should be well versed in surgical airway techniques before attempting them [25].
A study of Israeli defense forces revealed that intubation success rates fall with each subsequent attempt [26]. Therefore, rescuers should determine thresholds for abandoning initial intubation efforts in favor of surgical airway placement.
Otolaryngologic airway emergencies
Any condition that results in airway edema and bleeding may create significant challenges. Post‐tonsillectomy bleeding is an example. Brisk bleeding may threaten to obstruct the airway. Effective measures to control bleeding include direct pressure with gauze, which may be moistened with 1:1000 epinephrine. Exceptional care must be taken not to precipitate airway obstruction with the gauze. For example, it may be held with a hemostat so that it doesn’t fall into the airway. If definitive airway control is necessary because of profuse bleeding, difficulties should be anticipated and appropriate contingency plans ready. Surgical airway may be necessary, but again, should only be attempted by experienced clinicians.
Pandemic airway management
The novel human coronavirus SARS‐CoV‐2, or COVID‐19, has introduced new complexities to prehospital airway management. Many victims of COVID‐19 experience cardiac or respiratory arrest requiring prehospital airway interventions. Experience from the prior SARS pandemic highlights that those health care personnel providing airway management and endotracheal intubation are vulnerable to viral exposure and contracting the illness. For EMS clinicians performing airway interventions for potentially infectious individuals, attention should focus on use of appropriate personal protective equipment (PPE) and application of pandemic‐specific airway management measures to minimize risk of viral transmission.
PPE for communicable disease airway management should include at least the following measures: a surgical facemask, gloves, eye protection, and gowns. Most EMS personnel will opt for N95 or higher levels of protection when dealing with such high‐risk patients. Higher levels above the N95 level of protection include N100 masks/half face piece respirators, and powered air‐purifying respirators. All persons on the EMS team providing care should be using the same level of protection. All equipment coming into contact with the patient’s face or airway should be considered infectious and either appropriately disposed or decontaminated.
If the patient is not in frank respiratory failure, protective measures can help to limit pathogen spread. For example, all spontaneously breathing patients should be placed in surgical masks. Data from cough simulation studies suggests that placing the patient in an N95 mask will further limit the distance of respiratory particle transmission [27]. A facemask can be placed over the nose and mouth of a patient receiving nasal cannula oxygen.
The approach to intubation can be modified to minimize respiratory droplet transmission. Consider preoxygenation techniques that minimize aerosolization. When possible, bag‐valve‐mask ventilation should be minimized, but when needed, a HEPA filter may minimize pathogen exposure. The use of video laryngoscopy may help to optimize intubation success while distancing the operator from the patient [28, 29]. After intubation, a HEPA filter should be used to decrease viral exposure.
Several protective devices have been proposed to mitigate pathogen spread during intubation. For example, draping a clear plastic bag over the patient’s head or using clear a plexiglass enclosure with or without a negative pressure suction mechanism, has been proposed [30]. While widely advocated, the net benefits of these measures are unclear. The ability of a box or shield devices to minimize viral spread is unproven. Some studies suggest that, in the absence of negative pressure, pathogen spread may actually be worsened by the use of enclosure devices [31]. Furthermore, these measures have markedly altered the ergonomics of intubation, prolonging laryngoscopy and reducing first‐pass intubation success [32]. The Food and Drug Administrative revoked an Emergency Use Authorization allowing the use of passive protective barrier enclosures in airway management [33].
Conclusion
EMS clinicians may need to manage patients’ airways in unusual prehospital situations. Important considerations include the following.
Ground‐level intubation. Many different intubation positions are described for ground‐level intubation. Left lateral decubitus positioning may prove the best approach in this situation.
Face‐to‐face intubation. The “tomahawk” approach may be viable in this situation.
Low light intubation. Optimizing available ambient light may help to facilitate intubation in low light conditions.
Minimize field equipment. A minimal airway management kit may be necessary. New miniaturized technology provides options for minimizing the airway kit.
Telemedicine assistance. Remote airway management guidance may be possible with new telemedicine technology.
Tactical airway management. Airway management is best deferred until the intensity of the threat has decreased. Operational constraints may force the operator to consider early surgical airway.
Communicable disease. Focus on minimizing the risk to the clinician during airway management through adequate preparation, PPE, and tactics to decrease exposure during airway procedures.
Acknowledgment
Special thanks to Scott Poynter, CRNA, for assistance with the photos.
References
1 1 Pinchalk M, Roth RN, Paris PM, Hostler D. Comparison of times to intubate a simulated trauma patient in two positions. Prehosp Emerg Care. 2003; 7:252–7.
2 2