Doctor's Review: Medicine on the Move

October 23, 2017
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Stereo sound

The first stethoscope was a simple tube, but docs soon discovered that two earpieces were twice as nice

One of medicine’s most recognizable instruments is the stethoscope, particularly the biaural version. Today, every child’s doctor kit contains one, but up until the early 19th century, physicians only had the very basics to evaluate heart health: a tap here and there, a hand held over a patient’s chest or an ear pressed up against it. This presented numerous logistical and ethical problems, especially when overweight or female patients were concerned.

And so 1816 was a banner year for medical instrumentation. It was then that French wonderdoc and accomplished flutist René Laënnec (1781-1826) invented the stethoscope. After observing kids experimenting with sounds using hollow sticks, he was struck by an idea: why not try the same trick with a heartbeat? His groundbreaking device wasn’t much to look at — a wooden tube with a progressively widening hole bored through its centre — but it worked well. It was heralded as useful, if not revolutionary, by most physicians, and eventually caught on.

Discretion perfection

Laënnec’s simple solution simultaneously addressed a couple of age-old problems: obesity and modesty. After encountering a “young woman labouring under general symptoms of diseased heart, and in whose case percussion and the application of the hand were of little avail on account of the great degree of fatness,” Laënnec applied what was tantamount to a toilet paper roll to her chest and made his mark on medical history.

No longer would doctors be afraid to approach female patients or be hindered by weight. He published De l'Auscultation Médiate in 1819, his amplification technique launching a new era of diagnostic possibility. In addition, the particularities of various cardiac sounds could now be identified and catalogued, and their correlating conditions explored with greater ease.

For more than a decade after Laënnec’s monaural stethoscope was introduced, physicians were content simply to soak up the success. Granted, the design evolved from a simple cylinder to curvier shapes resembling trumpets and hourglasses with bells to augment amplification, but it remained a glorified tube. When it came to hearing the heartbeat in stereo, surround sound was just around the corner.

Personal space

The first to suggest a binaural stethoscope was an Edinburgh med student. But Nicholas P. Comins — who introduced the concept in 1929 in a text he brilliantly titled “New Stethoscope” — had as his inspiration doctors’ postures and not their diagnoses. His monaural model was a series of interlocking curved tubes on hinges that allowed doctors to sit upright. More significantly, Comins also described a model that would wound its way to both of the listener’s ears. It was never produced or, at least, no prototype has ever been found.

Amazingly, it would be decades before stereo sound took root, but advances in materials led to improvements in monaural stethoscopes, primarily in the form of more flexible tubing. This made for longer apparatuses, which provided more distance between doctors and patients, reducing the risk of contagion of transmissible diseases like tuberculosis.

It also granted physicians even greater discretion when examining female patients, since they could now theoretically be in the next room during exams, with the modest patient placing the cupped end of the device on her bosom herself. The French doctor Marc-Hector Landouzy introduced one such device made out of soft metal in 1841 and it actually was binaural in the sense that it was designed for one patient and two listeners!

Double duty

It was Irish doctor Arthur Leared (1822-1879) who introduced the first true “double stethoscope” in 1851 at the Great Exhibition in London. It was made of gutta-percha: an early form of rubber derived from natural latex. The stethoscope didn’t attract the attention it rightly deserved, perhaps because its earpieces didn’t work so well, offering only a muffled version of a heartbeat, or perhaps because Leared was more mad scientist than salesman. Within a year, however, the idea of this first binaural device made its way to the US where one prescient physician picked it up and ran with it.

George Cammann, a New York City doctor, introduced and produced for sale the first effective binaural stethoscope in 1852. While treating the poor at the city’s Northern Dispensary, Cammann culled the best of the devices then in use to create one that was actually fairly similar to the stethoscopes of today. It had a pair of silk-covered flexible tubes that were capped with ivory earpieces. The tubes led into a hollow sphere that amplified the sounds leading from an ebony-wood trumpet-shaped chest piece ringed with rubber to provide suction. Cammann’s stethoscope was also notable in that it featured a connector between its two arms to provide tension, first with an elastic band, then a hinge joint, then with coiled wire in later models.

Philanthropic physician

Cammann was modest about his creation, saying simply that he built on older ideas to suit his needs. He didn’t patent his binaural device, either, since he felt that anything in the public’s best interest should be made available to any doctor who wanted one. The invention was tweaked, mass-produced and marketed by the medical instrument-maker George Tiemann. Although it was quickly embraced by many forward-thinking doctors, Cammann’s stethoscope really took off in 1866, when Austin Flint — the influential professor of medicine at Bellevue Hospital and eventual president of the American Medical Association — endorsed the device.

Many different makes of stethoscope hit the market in the latter half of the 19th century, though the Cammann Stethoscope remained the gold standard. Interestingly, a new invention in 1878 — the microphone — caused a slight drop in the acceptance of the stethoscope since the stethoscope models that incorporated microphone technology distorted chest sounds. Once stethoscopes came back to basics, however, their popularity surged once again.

Despite brief periods of skepticism in which these newfangled devices were considered untrustworthy, the binaural stethoscope had become the primary symbol of the physician by the end of the 19th century. In the early part of the 20th century, a few improvements were added, most notably a taut diaphragm that stretched over the cup of the chest piece. Advances in manufacturing and materials also allowed for greater malleability in rubber and metal providing greater workability.

And, for the sake of greater suction and the comfort of patients everywhere, the now-indispensable “anti-chill” ring could arguably be considered the final piece of the puzzle in the invention of this most ubiquitous tool in the physician’s diagnostic arsenal.

This article was accurate when it was published. Please confirm rates and details directly with the companies in question.

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