The Edge: Preemptive Airway Decontamination

The past 15 years of prehospital medicine have seen several major advances in clinical airway management, including improvements in monitoring through waveform capnography, CPAP and BiPAP therapy, video laryngoscopy, and, of course, improved extraglottic devices. As the innovator who brought the Suction-Assisted Laryngoscopy Airway Decontamination (SALAD) technique to the attention of hospital and prehospital clinicians, my insight on these innovations is that until recently preemptive airway decontamination has not been routinely discussed and practiced in simulation, and even less so in clinical practice. 

The importance of “closing the loop” on this aspect of airway management during BLS and ALS care is thus: If the prehospital clinician cannot deliver resuscitated and viable patients to the hospital, then hospital-based clinicians cannot hope to help these patients. When partial or full ventilatory support of a patient is necessary by face mask ventilation, extraglottic device, or endotracheal intubation, what is becoming clear is that preemptive airway decontamination is essential to ensure success. 

In a 2013 prospective observational study of the incidence of regurgitation during the management of out-of-hospital cardiac arrest, the incidence of regurgitation among 3,104 patients was 25%,¹ underscoring the need for preparation to manage airway contamination in prehospital scenarios. Peer-reviewed literature on the sequelae of massive aspiration dates back to the original publication describing Mendelson’s syndrome in 1946, in which obstetrician Curtis Mendelson described the clinical signs and symptoms of massive pulmonary aspiration in women who had Caesarean deliveries utilizing face mask ventilation for anesthesia. The definitive publication on the prevention of pulmonary aspiration during anesthetic care dates to 1970 with the description of “Rapid Sequence Induction/Intubation” by Peter Safar, MD, and William J. Stept, MD.² 

A review of the American Society of Anesthesiology closed claims database reveals the leading cause of death and serious patient injury from respiratory causes in U.S. anesthesiology practice is massive aspiration.³ Similarly, the NAP4 study indicated that same source of morbidity and mortality from adverse respiratory events: massive aspiration of gastrointestinal fluids and other material.⁴ To quote the NAP4, “Aspiration was the single commonest cause of death in anesthesia events.”  

A review of prehospital and critical care literature reveals that airway contamination is one of the principal causes of failure of first-attempt tracheal intubation utilizing video laryngoscopy.^5–7 I am unable to find any literature discussing the contribution of airway contaminants to the failure of face mask ventilation and extraglottic airway ventilation other than the aforementioned NAP4 study, in which a large proportion of patients who experienced aspiration during anesthetic care were ventilated with extraglottic devices during the incident.

Better First-Pass Success

Since the initial publication describing the SALAD technique,⁸ there have been multiple simulation-based studies of it that overwhelmingly demonstrate increased first-attempt success in tracheal intubation in simulated contaminated airways, as well as reduced times to intubation and increased confidence in participants. 

Recently the first peer-reviewed case report describing the management of a patient with massive regurgitation during tracheal intubation utilizing video laryngoscopy and the SALAD technique was published, and it provides us with clinical evidence that preemptive airway decontamination is vitally important in such cases.⁹ The case report describes a patient with known gastric cancer with a large amount of gastric content present prior to surgical resection that unfortunately was not adequately decompressed prior to the anesthesia, leaving a large intragastric volume. The anesthesiologist in this case elected to proceed with rapid sequence induction and airway management following thorough preoxygenation and a steep head-down position in the event of airway contamination. Those authors reported that utilizing the head-down position along with rigid suction as described in the SALAD technique allowed for hypopharyngeal decontamination during endoscopy and successful endotracheal intubation on the first attempt. Specifically, they describe the use of a rigid suction catheter positioned to the left of the video laryngoscope during tracheal tube delivery as a feature of this procedure that allowed successful intubation.

Over the past several years I have received anecdotal case reports of the effectiveness of the SALAD technique from colleagues. I’d like to share one. 

My paramedic unit was dispatched to a neighboring jurisdiction for a motor vehicle accident with entrapment. On arrival I was directed to a patient who was already in another ambulance. My patient was a mature adult female who was responsive to painful stimuli and had extensive injuries. They included several deep lacerations to her extremities (bleeding controlled with bandaging), but the most concerning were the maxillofacial injuries. They included a Le Fort fracture, mandible fracture (open), obvious orbital fractures (one open), and uncontrolled bleeding from the mouth. Due to her positioning and level of consciousness, securing her airway was a priority. 

I began with aggressive suctioning as tolerated to divert blood flow from the nasal passages away from the airway or esophagus, which would contribute to vomiting if she continued to swallow the blood. At the same time we established a high concentration of oxygen with nasal cannula and simple mask, both at 15 lpm. We drew medications and, due to her low systolic pressure (80/40) and accelerated heart rate, chose ketamine as the induction agent, rocuronium as the paralytic. 

During increased oxygenation for the ET attempt, we considered backup airway management. Mask ventilation was not an option due to the loss of facial structure integrity. We set aside a supraglottic device as a backup and employed the King Vision video laryngoscope with channeled blade and 7.5 ET. 

The SALAD technique was employed by using the large-diameter rigid suction catheter in front of the blade to clear blood and teeth from the area of the cords. A small blood clot was visualized and removed prior to intubation. The suction was then parked in the esophagus to contain any additional emesis.

There were no complications, and the patient was intubated on the first pass. If I had not known of the SALAD technique, my approach would have been vastly different, and my airway attempt most likely would have failed due to visual obstruction. 

Conclusion

In conclusion, it is appropriate to ask if a technique such as SALAD can be scrutinized with the tools of evidence-based medicine beyond the publication of case reports. I offer that principal indicators of the effectiveness of this technique in prehospital airway management will be a steady improvement in the rate of first-attempt success at tracheal intubation, followed by a reduction in the incidence of massive aspiration during respiratory care.   

References

1. Jost D, Minh PD, Galinou N, et al. What is the incidence of regurgitation during an out-of-hospital cardiac arrest? Observational study. Resuscitation, 2015 Nov; 96(Suppl 1): 70.

2. Stept WJ, Safar P. Rapid induction-intubation for prevention of gastric-content aspiration. Anesth Analg, 1970 Jul–Aug; 49(4): 633–6.

3. Peterson GN, Domino KB, Caplan RA, et al. Management of the difficult airway: a closed claims analysis. Anesthesiology, 2005 Jul; 103(1): 33–9.

4. Cook TM, Woodall N, Frerk C. A national survey of the impact of NAP4 on airway management practice in United Kingdom hospitals: closing the safety gap in anaesthesia, intensive care and the emergency department. Br J Anesth, 2016 Aug; 117(2): 182–90.

5. Trimmel H, Kreutziger J, Fitzka R, et al. Use of the GlideScope Ranger Video Laryngoscope for Emergency Intubation in the Prehospital Setting. A Randomized Control Trial. Crit Care Med, 2016 Jul; 44(7): 470–6.

6. Joshi R, Hypes CD, Greenberg J, et al. Difficult Airway Characteristics Association with First-Attempt Failure at Intubation Using Video Laryngoscopy in the Intensive Care Unit. Ann Am Thorac Soc, 2017 Mar; 14(3): 368–75.

7. Sakles JC, Corn GJ, Hollinger P, et al. The Impact of a Soiled Airway on Intubation Success in the Emergency Department When Using the GlideScope or the Direct Laryngoscope. Acad Emerg Med, 2017 May; 24(5): 628–36.

8. DuCanto J, Serrano KD, Thompson RJ. Novel Airway Training Tool that Simulates Vomiting: Suction-Assisted Laryngoscopy Assisted Decontamination (SALAD) System. West J Emerg Med, 2017 Jan; 18(1): 117–20.

9. Choi I, Choi YW, Han SH, Lee JH. Successful Endotracheal Intubation Using Suction-Assisted Laryngoscopy Assisted Decontamination Technique and a Head-Down Tilt Position During Massive Regurgitation. Soonchunhyang Medical Sci, 2020; 26(2): 75–9. 

James “Jim” DuCanto, MD, is the associate medical director of airway and ventilation for FlightBridgeED, LLC.