Airway Management 2019: More Options, Same Physiology

As paramedic Wes Ogilvie responded to a “diabetic male” north of Houston in 2010, he wasn’t too concerned about managing the airway. “I figured the sugar was either too high or too low,” the Austin native recalls.

That was before Ogilvie and his crew found their obese patient in cardiac arrest. “We weren’t sure how long he’d been down,” Ogilvie says. “My partner tried to intubate but couldn’t see the cords, so I inserted a King.”

The King Airway is one example of extraglottic or supraglottic airways (SGAs). They differ from endotracheal tubes (ETTs) mostly because they’re inserted blindly and their distal ends sit in the hypopharynx or esophagus, rather than in the trachea. Wes should have been able to ventilate his patient through a properly placed King but couldn’t.

“When I tried nothing happened,” he says. “I couldn’t get any air in. Maybe we should have considered a cric, but we were close to the hospital. It was frustrating.”

Although Ogilvie keeps up with the literature and seeks advice from EMS veterans like Gene Gandy and Dr. Jeffrey Jarvis, he wishes his 2007 airway training had been more comprehensive. “Most of our practice was on manikins,” he says. “Our OR time was discontinued midway through the course. I did get two or three tubes, but the only comment I heard from the CNAs (certified nurse anesthetists) who monitored us was something like, ‘Yeah, that looks OK.’

“Field clinicals were even less helpful. I rode with a very rural service and didn’t have a single chance to intubate. I realized I was just going to have to learn what I could on my own.”

Gaining endotracheal intubation (ETI) experience became even more of a challenge for most prehospital providers after revised ACLS algorithms rendered cardiac arrests less-likely opportunities for practice. As devices like the King and Combitube became alternatives to ETTs in many systems, Wes wasn’t the only paramedic wondering whether SGAs and changing priorities would one day relegate laryngoscopes to the same storage locker as MAST pants.

Mastering the Tools, Embracing the Research

Darren Braude, MD—EMS physician, professor of emergency medicine at the University of New Mexico, and medical director of “Difficult Airway Course: EMS”—became interested in SGAs when he noticed an ends-justify-the-means philosophy about ETI among his residents and flight crews. “They were making too many attempts,” he says. “It was a matter of getting the tube in one way or another and not really thinking about the harm we might be causing.”

Braude, who began as a paramedic in 1991 and still retains that certification, remembers carrying EOAs (esophageal obturator airways) and Combitubes that were rarely used because they were considered inferior to ETTs, particularly as a means of preventing aspiration. Now he feels that concern was overstated.

“What we discovered was that many of our patients had already aspirated by the time we got to them,” the 49-year-old author and speaker says. “And for those who hadn’t, extraglottic airways provided substantially more protection than most providers realized.”

Braude cites retrospective research comparing prehospital aspiration associated with SGAs and ETTs.¹ Eight percent of SGA patients aspirated, versus 12% of those who’d been intubated. “It’s a small study—by no means definitive—but I never would have guessed the rates would have been so close, or even better for the extraglottic group,” Braude says.

“There’s lots of evidence that those devices do much of what we want from endotracheal tubes and may be a better option in the field for cardiac arrests. They’re certainly used extensively in ORs. It becomes a matter of weighing the security of endotracheal intubation against the difficulty of maintaining that skill.”

Research by emergency physician Henry Wang, et al., supports Braude’s assertion that SGAs are robust airway management tools. Wang and his team showed improved cardiac arrest survival and neurological outcomes after prehospital insertion of SGAs versus ETTs.² Before promoting a reduced role for ETI, though, Braude feels educators have to confront practitioners’ unrealistic expectations of SGAs as fail-safe instruments.

“We’ve implied these tools are so easy to use, you don’t have to think about what you’re doing,” he says. “No device is that good.

“Providers grab an extraglottic airway, and when it doesn’t do exactly what they want the very first second, they’re like, This thing is worthless! It confirms all my suspicions, and I’m going back to intubating! But that’s not how it works. You have to be patient and focus on the basics, the physiology.”

Braude suggests starting with a moment of contemplation and a realization that you won’t succeed 100% of the time. “Consider the patient, the anatomy, the device, and the technique,” he offers. “Understand there’s a ‘fiddle factor’ involving fine adjustments. That should relieve some of the stress. Remember, none of us are perfect at this.”

Ogilvie buys into Braude’s philosophy. “I try to have a plan and a backup to the plan before I start (placing an airway),” the 43-year-old volunteer explains. “Maybe even a backup to the backup. I just wish my school had gone further than, ‘Put the blade in the mouth, move the tongue, and find the right hole.’”

Accentuate the Basics, Get the Reps

Paul Werfel understands the imperatives of airway management from the perspectives of both teacher and pupil. In fact, the director of Stony Brook University’s paramedic program says his students have to work harder than he did as a paramedic candidate at Beekman Downtown Hospital in New York City 35 years ago.

“Back then it was about how many hours you did,” the Long Island native recalls. “Now it’s about competencies: 50 airway interventions in our program, including at least five endotracheal intubations. You can sign up for whatever ambulance and hospital rotations you like, but you’re going to keep going until you meet those criteria.”

Like Braude, Werfel believes airway proficiency begins with the basics: “We start with EMT stuff people didn’t learn properly or don’t use often enough: manual maneuvers, OPAs, NPAs, BVM ventilation. You’d better know the anatomy, too, or you might as well stay home.

“Then we move on to more advanced levels. We address endotracheal intubation pretty aggressively—the indications, contraindications, and pitfalls, plus RSI and DFI (drug-facilitated intubation)—but we’re also teaching that not everyone needs a tube.”

The Stony Brook program covers SGAs such as LMAs, King Airways, and Combitubes with the caveat that inflatable cuffs can impede cerebral perfusion.^3,4 “Properly placed and monitored endotracheal tubes are still the gold standard,” says Werfel, who often serves as an expert witness on airway mismanagement cases. “If a board-certified anesthesiologist has to have waveform capnography to confirm tube placement in the OR, you better believe that should be happening prehospitally too.”

Werfel acknowledges paramedics have long considered ETI to be a specialty, if not a privilege of the position. “That’s one of the reasons they aren’t always up to date on the research,” he says. “They think they know it already. The attitude becomes, You’ll have to pry that laryngoscope from my cold, dead hands.”

Even diligent paramedics who know what they don’t know sometimes struggle with ETI. When that happens Werfel says it might be because they’re rushing: “Medics can develop tunnel vision and think it’s a measure of professionalism to get the tube within a certain number of seconds. That’s when you forget to prepare—to have everything ready so you don’t have to reach for a stethoscope or a stylet.

“Intubation can be like a golf swing,” the 62-year-old professor adds. “Sometimes it turns out better when you slow it down a bit.”

Werfel encourages students to see target-rich environments like ORs as good places to practice airway management that doesn’t necessarily include ETI. “If you happen to get a tube, great, but you should be manipulating airways and bagging every patient you see. If it were up to me, I’d send EMT students there too,” he says. 

Beyond Psychomotor Skills

Ogilvie’s diabetic male was pronounced at the ED soon after arrival. Wes thinks the patient’s trachea may have been obstructed. Braude wonders if the King had been inserted too far into the esophagus and needed to be pulled back a few centimeters. We’ll never know because hospitals were not yet sharing diagnoses and dispositions routinely with EMS.

Braude highlights outcome data collection and analysis as key elements of improved airway management and sees EMS agencies as eventual contributors and beneficiaries of such information. Meanwhile, he urges paramedics to value clinical knowledge over cool tools.

“We’ve come a long way,” he says, “but we still have to get past the point where prehospital airway management is defined by a specialized procedure or device. Invasive techniques in EMS rarely save lives. Instead we should focus on the basics: a knowledge of the physiology and how we can best maintain that physiology.”

References

1. Steuerwald M, Braude D, Petersen T, et al. Preliminary report: Comparing aspiration rates between prehospital patients managed with extraglottic airway devices and endotracheal intubation. Air Medical Journal, 2018; 37(4): 240–3.

2. Wang H, Schmicker R, Daya M, et al. Effect of a strategy of initial laryngeal tube insertion vs endotracheal intubation on 72-hour survival in adults with out-of-hospital cardiac arrest. JAMA, 2018; 320(8): 769–78.

3. Segal N, Yanopoulos D, Mahoney B, et al. Impairment of carotid artery blood flow by supraglottic airway use in a swine model of cardiac arrest. Resuscitation, 2012; 83(8): 1,025–30.

4. Michalek P, Donaldson W, Vobrubova E, Hakl M. Complications associated with the use of supraglottic airway devices in perioperative medicine. BioMed Research International, 2015; 2015(6): 1–13.

Mike Rubin  is a paramedic in Nashville and a member of EMS World’s editorial advisory board. Contact him at mgr22@prodigy.net.