A History of Airway Hardware

“You should be thinking airway, airway, airway.”

That’s what a paramedic told me after my first cardiac arrest as an EMT in the early 1990s. He was critiquing my performance—the part that happened before he arrived. My patient got O₂, defibrillation, and CPR, but no oropharyngeal airway.

That medic was right to remind me that my top priority, before the ABCs became the CABs, was airways. Sure, they’re naturally occurring in most people, but paramedics and EMTs were supposed to open them when their owners couldn’t. We still do that with a variety of appliances that have two things in common: a lineage that goes back almost two centuries, and modern versions that are best known by acronyms such as OPA, NPA, ETT, and SGA.

We can’t cover every invention and brand without getting annoyingly encyclopedic, but it’s entertaining to compare today’s airway devices to their prototypes. That means starting in the 19th century—right around the time anesthesia was discovered. Thank God for that. Airways weren’t merely inserted then; they were inflicted. Some primitive equipment looks like it was invented by a deranged plumber.

‘I think I left my tube kit by the patient’s chamber pot.’

That’s how I could have explained a missing airway bag in the mid-1800s if there had been such a thing as forgetful paramedics in those days. Assuming I commandeered a fast horse and stealthy buggy to retrieve my tube roll, here’s what we might have found inside (note: see all the images here):

Leroy’s intubation aid (Figure 1): This 1827 endotracheal-tube introducer is even scarier when we learn its inventor was a urologist. The good news is, the French Academy of Science and the Royal Humane Society had the decency to ban the contraption. The bad news? They prescribed “warming, tickling, [and] rubbing” instead. For patients too.

Babington’s glottiscope (Figure 2): That 1829 diagram may be more frightening than the actual scope. It’s supposed to show a tongue depressor attached to one end and a mirror on the other, but it’s hard to tell which is which. Were people’s throats bigger back then? The only way I can imagine using this instrument of terror is on decapitation victims.

Garcia’s laryngoscope (Figure 3): In 1854, with direct laryngoscopy still half a century away, Manuel Garcia invented an indirect laryngoscope—just a couple of mirrors, one of which deflected sunlight toward another one above the glottis. It’s easier if you’re using an oropharynx that happens to be your own, as the gagless Garcia demonstrates.

O’Dwyer’s airway (Figure 4): Joseph O’Dwyer’s apparatus, introduced around 1885, resembles a modern supraglottic airway, except the variable-size tip is meant to sit in the glottis. Hmm…this gizmo needs its own acronym.

O’Dwyer’s intubation set (Figure 5): Joey O is back with a pediatric kit that features metal cylinders and blind introducers. The “blind” part demanded tactile skills and a willingness to use one’s favorite fingers as bite blocks.

Kuhn endotracheal tube (Figure 6): Hans Kuhn enhanced O’Dwyer’s equipment at the turn of the century by developing a flexible metal ETT with its own introducer. I bet those metal rings did more soft-tissue damage than a cactus bougie.

Kirstein autoscope (Figure 7): Finally, a way to visualize the cords! Alfred Kirstein’s 1895 invention began as an endoscope accidentally placed in a patient’s trachea. Who knew the opposite circumstances would become a worst-case outcome of airway management?

Roosevelt or Hoover? Miller or Mac?

You could call the first half of the 20th century the OPA era. 

The first modern oral airway adjunct—a metal mouthpiece attached to a straight rubber tube—was introduced in 1908 by anesthesiologist Frederic Hewitt (Figure 8). Hewitt soon tweaked his design by curving the tube and lengthening it, which gave other anesthesiologists the idea of administering drugs through it. Where those meds ended up was as precise as an IV stick in the dark.

Hewitt’s invention led to development of curved, plastic, disposable OPAs that remain popular today: the Guedel unit in 1933 and the Berman model with side channels in 1952. I wasn’t a big fan of either until very late in my useful medic life, when I inserted one—I forget which—in the oropharynx of an elderly male in ventricular fibrillation refractory to two shocks. The guy woke up (without gagging) and wanted to know why someone was beating on his chest. I had to convince him he still needed a hospital.

Later I explored possible connections between OPA insertion and ROSC. I found two studies linking vagal stimulation to a rise in v-fib threshold (see the Yoon and Waxman papers in the resources). Why aren’t medics taught about that?

I envisioned an ad campaign about the lifesaving properties of OPAs, with me as the national spokesperson. I settled for a cup of coffee with my boss instead.

The early 1900s saw major advancements in laryngoscopy too, beginning with Chevalier Jackson’s 1920 scope (Figure 9). The photo shows three views—not three parts—of the same instrument. What you can’t see is the tip with a tungsten bulb that enhanced the Kirstein design.

Jackson’s laryngoscope was probably the inspiration for a couple of famous Roberts—Miller and MacIntosh—who introduced straight and curved blades in 1941 and ’43, respectively. MacIntosh felt his model was superior because it had less contact with the epiglottis, but choosing between the two remains a matter of personal preference for the rest of us.

As endotracheal intubation became more sophisticated, so did supraglottic airways. The first that closely resembled a contemporary SGA was Beverly Leech’s Pharyngeal Bulb Gasway of 1937 (Figure 10). Mostly metal and relatively inflexible, Leech’s “bulb” was the inspiration for modern inflatable plastic seals.

Stayin’ Alive

By the time the Bee Gees were peddling disco fever from Brooklyn to Brisbane, supraglottic no longer accurately described most blind-insertion airways. Because those implements were designed to block the esophagus below the level of the glottis, extraglottic became more precise. I’m just laying that all out for you in case you say “SGA” instead of “EGA” to an MD or RT with OCD.

The first SGA—sorry, EGA—carried by prehospital caregivers was the esophageal obturator airway (EOA, Figure 11), introduced in 1968. That was followed by the esophageal gastric tube airway (EGTA) in 1979. They were similar to today’s popular King units.

EOAs and EGTAs were already on the way out by the time I started riding in 1992. I never used them, but I know someone who did. Meet Roger Swor, a paramedic at the Mayo Clinic in Duluth, Minn. for 45 years. By way of perspective, Swor’s NREMT number is 308. It would have been even lower if numbers weren’t assigned alphabetically that first year.

I asked Roger what he remembers most about early airways.

“That’s easy,” he replied. “Vomit.”

He elaborated: “We weren’t very good at keeping BVM ventilations out of the abdomen. It had to do with equipment, education, and experience. We didn’t know to tilt the head, watch the chest and abdomen, listen for lung sounds.

“Those original airways weren’t as pliable as the King models we use now. The side openings in the King are better placed too.”

Swor feels airway education has improved as much as the tools. “We have a training ambulance with special manikins that cost thousands of dollars each,” he says. “They breathe, they have pulses—they’re amazing. It’s night and day compared to what we used to have.”

It’s tempting to call EGAs like the King or Combitube or LMA the most versatile airway hardware popularized during my 29 years in EMS, but I’m going with video laryngoscopy, introduced in 2001. Swor agrees…sort of. “I just wish some of those medevac crews would spend less time on the ground with those fancy toys when they’re out in the boonies with us,” he says.

Visualizing Cords and the Future

When I became a medic in 1995, endotracheal intubation was the gold standard of airway management. It still is, only not so much for EMS providers. Disappointing results and fewer opportunities to practice on live patients leave prehospital responders more dependent on EGAs. Is there a practical way for paramedics to regain their 20th-century standing as airway experts while minimizing risks?

I’m thinking point-of-care ultrasound (POCUS). I’m not the only one. A 2019 paper by Osman et al. highlights these benefits of POCUS as an airway management monitor:

• POCUS is noninvasive.
• It can help evaluate anatomy and predict difficult intubations.
• The learning curve is shallow.
• The technology has many other clinical uses.

My only experience with ultrasound is being on the receiving end of a deep cleaning at my dentist. I haven’t analyzed the pros and cons of adding another pricey piece of equipment to our ambulances, but I wouldn’t mind being on the leading edge of a noninvasive initiative to improve prehospital airway control.

And I’m still open to an OPA endorsement deal. 

Resources

Donen N, Tweed WA, Dashfsky S, Guttormson B. The esophageal obturator airway: an appraisal. Canadian Anaesthesia Society Journal, 1983 Mar; 30(2): 194–200.

Doyle J. A brief history of clinical airway management. Anestesiologia, 2009 Apr–Jun; 32(1): 164–7.

Goldenberg IF, Campion BC, Siebold CM, et al. Esophageal gastric tube airway vs endotracheal tube in prehospital cardiopulmonary arrest. Chest, 1986 Jul; 90(1): 90–6.

Hernandez M, Klock PA, Ovassapian A. Evolution of the Extraglottic Airway: A Review of Its History, Applications, and Practical Tips for Success. International Anesthesia Research Society, 2012 Feb; 114(2): 349–68.

Matioc AA. An Anesthesiologist’s Perspective on the History of Basic Airway Management: The “Modern” Era, 1960 to Present. Anesthesiology, 2019 May; 130(5): 686–711. 

Matioc AA. An Anesthesiologist’s Perspective on the History of Basic Airway Management: The “Preanesthetic” Era—1700 to 1846. Anesthesiology, 2016 Feb; 124(2): 301–11. 

Matioc AA. An Anesthesiologist’s Perspective on the History of Basic Airway Management: The “Progressive” Era, 1904 to 1960. Anesthesiology, 2018 Feb; 128(2): 254–71. 

McIntyre JWR. History of Anaesthesia—Oropharyngeal and nasopharyngeal airways: I (1880–1995). Can J Anaesthesia, 1996; 43(6): 629–35.

Osman A, Kok MS, Wahab SFA. Focused airway ultrasound: an armamentarium in future airway management. J Emerg Crit Care Med, 2019 Aug; 3.

Reilly E, Walters B. A Brief History of the Endotracheal Tube. Emergency Physicians Monthly, 2020 Nov 9; https://epmonthly.com/article/a-brief-history-of-the-endotracheal-tube/. 

Waxman MB, Sharma AD, Asta J, et al. The protective effects of vagus nerve stimulation on catecholamine-halothane-induced ventricular fibrillation in dogs. Can J Physiol Pharmacol, 1989 Jul; 67(7): 801–9.

Yoon MS, Han J, Tse WW, Rogers R. Effects of vagal stimulation, atropine, and propranolol on fibrillation threshold of normal and ischemic ventricles. Am Heart J, 1977 Jan; 93(1): 60–5.

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