Stethoscopes, Oxygen, and Heart Monitors: The EMS History of 3 Key Tools

Before I started in EMS, I signed up for an advanced first-aid class. I had to. So did anyone else who wanted to volunteer at my town’s rescue squad in 1991.

I wasn’t the first member of my family to bandage boo-boos. My mother took a Red Cross course in the mid-1950s, when nuclear war was still considered winnable. “Duck and cover” was the protocol for pesky gamma rays. Mom knew better; she focused on peacetime therapeutics and practiced her skills in our Boston living room on a consenting, anatomically correct preschooler: me. 

It was a low-budget operation. Our most sophisticated tools were safety pins to fasten cravats. During Mom’s most ambitious sessions, she’d have me splinted, dressed, and bandaged from ankles to occiput. I looked like a midget mummy in a sling and swathe.

As an EMT student 35 years later, I talked my way through similar scenarios. The biggest difference was the equipment, which included stethoscopes, oxygen, and defibrillator/monitors. Not only did that authentic gear lend legitimacy to our curriculum, but its evolution continues to influence modern health care.

A New Pair of Ears

Do you remember your first stethoscope? I don’t mean the cheap plastic one you shared at your own risk with dozens of sweaty EMT students during manikin assessment. I’m talking about the first steth you owned.

Mine was a gray Sprague Rappaport—the one with parallel tubes. Somebody, I don’t remember who, bought it for me in the mid-‘90s, 50 years after it was introduced by two guys who named it after themselves. They get no points for modesty, but their novel design included a 2-sided bell that rotated to accommodate low- and high-frequency sounds.

The Sprague Rappaport was a huge improvement over French physician Rene Laennec’s original stethoscope, an 1816 invention whose name comes from stithos, Greek for chest. Tyligmenos chartinos solinas, Greek for rolled-up paper tube, would have been more precise because that’s all it was (Figure 1). Laennec improvised the instrument allegedly because he was embarrassed to place an ear directly on a Rubenesque patient’s chest. I bet that story sounds more romantic in the original French.

Laennec’s three-part wooden upgrade (Figure 2) looked more like a modular saltshaker than a serious medical device, but it led to enhancements by Pierre Piorry, who used a tapered tube to connect a conical bell to a more ergonomic earpiece long before the word ergonomic had been invented (Figure 3). Another auscultator/innovator was George Cammann, whose binaural 1855 model was the first to resemble a modern steth (Figure 4).

To me the stethoscope is still a work in progress because it gets caught on something or someone no matter how we carry it. To address that issue, I turned to the greatest all-purpose problem solver in the history of earth: my smartphone. It has a stethoscope app that supposedly auscultates heart and lung sounds. Neither feature worked, but the app did record all the ambient noise in the room, including my wife telling our cat to shut up.

Go With the Flow

Imagine a world where fire is a distinct element that causes matter to burn until air absorbs all the flames. Sounds bizarre, doesn’t it? Well, that oxygen-ignorant theory of combustion was proposed by Johann Becher, a 17th-century German physician. If Becher hadn’t been outed as a quack by chemist Antoine Lavoisier 100 years later, we’d still have no BVMs, no nonrebreathers, and no expressions like “What a waste of oxygen.”

Lavoisier, who was guillotined by French revolutionaries during their purge of smart people, inspired various forms of O₂ therapy. Take George Holtzapple’s apparatus for treating pneumonia in 1885 (Figure 5). That contraption pioneered respiratory care while discouraging the practice of administering oxygen through…uh…pelvic orifices. Every one of them. It would take another 30 years to establish the trachea as a more effective and less humiliating route for resuscitation.

During World War I, while well-to-do civilians inhaled recreational vapors (Figure 6), British physicians developed supplementary oxygen systems for soldiers recovering from poison-gas attacks. The early 20th century also saw major advances in peacetime O₂ delivery, including oxygen tents, nasal cannulas, and face masks (Figure 7). The popular but flawed practice of intermittent oxygenation, characterized by Scottish scientist John Haldane as “bringing a drowning man to the surface of the water occasionally,” continued until the 1960s.

Rhythm Section

I was going to start this part by introducing the father of EKGs, Willem Einthoven. Then my friend Jimmy Garside, a New York paramedic and police officer, sent me some literature on Bernard Lown, a physician Jimmy claims is an underappreciated architect of cardiac care. Jimmy’s pretty smart for a Mets fan, so I agreed to publicize both scientists’ contributions.

Einthoven, who’s best known in the prehospital community for having a triangle named after him, was the first to display the heart’s electrical activity as a printed waveform. His electrocardiogram of 1901 was generated by a 600-pound machine attached to a human subject with three limbs immersed in buckets of saline (Figure 8). The Dutch doctor also originated the PQRST system for naming EKG components.

Lown’s experiments with electricity began in the 1950s, when state-of-the art treatment for ventricular fibrillation included alternating current (Figure 9)—fine for household appliances but for defibrillators, not so much. Lown switched to battery-powered (direct-current) shocks in 1961 and added lidocaine to the mix. Then he discovered a synchronized shock right before the heart repolarized could terminate life-threatening tachyarrhythmias in perfusing patients. Figure 10 shows his “cardioverter.”

Frank Pantridge, another player in the nascent monitor/defibrillator market of the ’60s, developed an ambulance-based 150-lb defibrillator powered by a car battery. In 1968, after Pantridge trimmed the weight to 6 lbs, his machine became the prototype for today’s portable units (Figure 11). Four years later a Pantridge device was used to defibrillate former president Lyndon Johnson during one of his MIs.

The first heart-focused hardware I handled as a new EMT was Physio-Control’s Lifepak 5 (Figure 12). That 1976 design had detachable modules for EKGs and defibrillation. Woe betide the minimalist paramedic who’d separate the two and bring only one on a cardiac call.

Dynamic Trio

A lot has happened to our three basic tools since my dotcom-era introduction to EMS:

• Stethoscopes, which used to rely only on plastic and pressure to detect faint sounds beneath skin and bones, now have digital amplifiers.
• Heart monitors have become sophisticated multitaskers with BP, SpO₂, end-tidal CO₂, ventilation, and chest compression analytics.
• Although oxygen hasn’t changed in 13 billion years, our understanding of its potentially toxic effects has. Now we know blasting ACS patients with 25 lpm can be as reckless as accelerating through intersections.

Continued evolution of EMS gear reminds us that our industry is dynamic, with high-tech improvements paving the way for enhanced service. And yet…

Twenty-five years ago, I bought a state-of-the-art Littmann Cardiology III stethoscope for roughly 15 times what my old Sprague Rappaport had cost. The money didn’t matter; I considered it the price of admission to EMS 2.0. I was going to hear secret sounds, interpret them for less-sophisticated caregivers, and raise the bar on prehospital assessment.

None of that happened.  

Resources

Heffner J. The Story of Oxygen. Respir Care. 2013; 58(1): 18–27. doi: 10.4187/respcare.01831

Mihm S. History of medical oxygen: How the key to Covid fight used to be a feared thing. The Economic Times. Posted February 12, 2022 

Roguin A. Rene Theophile Hyacinthe Laennec (1781–1826): The Man Behind the Stethoscope. Clin Med Res. 2006; 4(3): 230–5. doi: 10.3121/cmr.4.3.230

Salam A. The Invention of Electrocardiography Machine. Heart Views. 2019; 20(4): 181–3. doi: 10.4103/HEARTVIEWS.HEARTVIEWS_102_19

Nashville paramedic Mike Rubin is the author of Life Support, a collection of EMS-oriented essays about patient care, personal growth, and career development. Contact Mike at mgr22@prodigy.net.