Stethoscope: An integral tool in medical practice

Index Home

First stethoscope was invented only in 1816. While this 200 year old instrument, is quite synonymous with medical practice, it is more of a physician’s tool. It has evolved, both in its appearance, as well as its utility. It has the same mysticism, as the symbol of medicine – the staff and the intertwined serpent. Postage stamps are a testimony to how stethoscope has changed with the times. So let’s embark on this remarkable journey.

Birth

Rene Theophile Hyacinthe Laënnec (1781-1826) a French Physician, invented the first stethoscope. He was helped by concerns of modesty, and execution of an almost immediate thought. In Laennec’s time physicians used to hear lung and heart sounds by directly placing their ear against a patient’s chest. This was immediate or direct auscultation. In 1816, Laennec was called to examine a young girl with a ‘malady of the heart’. Modesty held him back, but innovation was quick to step in. He rolled a thick paper, and fashioned it as a tube. Lo and behold, this rapid invention worked and he could hear heart as well as lungs. This was the first indirect auscultation, and the first stethoscope.

Laennec improved his device further. He made the lumen of the tube a bit narrow, and its wall thicker. Further he fashioned patient’s end as a funnel to improve the quality of sound. This concept has stayed on with us till date.

From one ear to both

Our next versions followed between 1850-55. NB Marsh, George Cammann, and Arthur Leared led subsequent improvements. The patient end (or the chest piece) was fashioned like a funnel, and the sound was led to through two tubes, one for each ear. Hence we had two head-ends or the ear-pieces. This was the first bi-aural stethoscope.

The biaural (or two-ear) stethoscope ruled for more than a hundred years. Biaural stethoscopes were heavy, these were often carried in a brief-case and were not worn around necks. This instrument might have led to a doctor’s bag that placed stethoscope with other useful medicines. This was the next most important ‘scope’ in medicine. First one being the micro-scope.

A Modern Stethoscope

In 1961, Dr. David Littmann an American Cardiologist argued in favour of a new stethoscope. He suggested an improved chest piece where we could toggle funnel-shaped bell, with a bell covered with a thin membrane or a diaphragm. He argued that bell is for softer or low pitched sounds, and diaphragm for louder or high pitched sounds. These thoughts helped him create a modern-day stethoscope. We know this as Littman’s stethoscope. In 1967, 3M took over Littmann Brand in its portfolio.

The modern stethoscope has two ear-tips both connected to a metallic aural-tube. Metallic tubes quickly join a T-piece, and a single tube leads to the chest piece. Aural tubes have a spring, that makes stethoscope snugly fit our ears.

Stethoscope becomes a wearable ornament

As stethoscopes became lighter, and its chest-piece tube was now single, they became wearable. This probably was an unintended outcome. We started wearing them, around our necks. This development probably took place in the late 1960’s, and some postage stamps bear testimony to this phenomenon.

While some physicians debate that a neck-worn stethoscope means more infection, yet this instrument of utility, worn in this manner, is also a status symbol. Some decades ago, it was a prerogative of the doctors and those in training were barred from its display.

Instrument in use

While common use of a stethoscope is to listen to lung and heart sounds, a more common use is now on a decline. By 1920s, we had discovered that we can also use stethoscope to correctly measure blood pressure. By the turn of the century, we switched on to digital devices. Again, two postage stamps below, show this huge change.

Any change in medical practice, has an acceptance cycle. When Laennac’s monoaural stethoscope became biaural, we debated if two ears were really better than one. Similarly, as blood pressure measurement has become stethoscope free, we often debate if this is right way to go. Nonetheless, this digital change has empowered all to measure blood-pressure. Empowerment cannot be a bad idea after all !!

Mysticism and Rituals

Despite all the medical progress, stethoscopes seem to be holding on. While, we have better instruments to know what is wrong with our lungs, heart, vessels or intestines, none is still as handy as a stethoscope. Sheer joy of giving a sound an appreciative ear, still mesmerises medical and nursing students.

Sounds can be deceptive, and medical teachers often proclaim that “most important part of stethoscope, lies between the two ears”. We often hear what we think, and sometimes think about what we hear. This is a complex two-way dependence. However, as we practice this hearing ritual, again and again, we tune our mind to the signal and try to filter out the noise.

Budding doctors are often mesmerised, by what the more trained ones proclaim to have heard. None-the-less, the mysticism of stethoscope, and the hearing ritual (which doctors call auscultation) lives on !!!