Saturday, August 20, 2016

Technology and the Cardiac Exam

The stethoscope is the iconic symbol of medicine. There so much I love about it: how it was conceived, the panoply of obscure sounds that indicate specific pathologies, the synecdoche of listening to a patient's heart for the patient-doctor relationship. But I also imagine a time where the stethoscope is relegated to history. Why do we still use an instrument invented in the early 19th century? Physicians are notoriously slow to adopt new technologies, but I can think of two inventions that should replace the stethoscope.

If listening to heart sounds is crucial to medicine, why don't we develop a microphone that we can place on a patient's chest that will record the patient's heart and lung sounds? We have the electronic ability to filter extraneous noises and amplify relevant sounds. Computers can analyze the sounds to dissect out what fledgling medical students struggle to discern. In the same way that the computer reads EKGs, programs can be developed to detect an extra S3 or S4, the type of murmur, or the presence of a rub. Recordings can be saved and compared to prior captures; wouldn't it be fantastic if we could compare today's lung crackles to yesterday's?

And this may be anathema, but I'm not sure listening to the heart offers that much diagnostic value. I definitely think it's important for the patient-doctor relationship and has interpersonal, even therapeutic, value. But it's pretty rare that what I hear on heart or lung exam changes my decision making. This is definitely because of my clinical specialty; in the intensive care unit, I'll often order chest X-rays and echocardiograms, and in the operating room, few heart sounds will cause me to cancel a case. But still, there's less medical utility in the stethoscope than we might wish.

This leads me to wonder when bedside echocardiograms will replace the stethoscope. Handheld echo probes are starting to drop into the affordable range. There's certainly a learning curve, but once bedside echo is mastered, it gives a lot more information than listening to the heart. One day, I think this will become the cardiac exam.

Image is in the public domain, from Wikipedia.

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