In the context of human evolution, a vestigial organ is defined as one that has lost all or most of its original function through evolution. Charles Darwin provided a list of vestigial human organs in “The Descent of Man,” including the muscles of the ear, wisdom teeth, the appendix, the coccyx, body hair and the semilunar fold in the corner of the eye. If you had told me 19 years ago when I graduated from medical school that I would one day compare my stethoscope to a vestigial organ, I would have smiled politely and discounted everything you subsequently said. But back then, beta-blockers were contraindicated for heart failure — so who could predict what two decades in medicine could bring?

My first stethoscope was a gift from my parents that arrived shortly after my medical school acceptance letter. I imagined myself striding down hospital hallways with my Littman slung around my neck, flinging words like “stat” over my shoulder as I inserted chest tubes in the ICU. Of course, being a careful student of human nature, I soon realized that serious doctors never wore their stethoscopes as leashes or necklaces, but rather curled sedately in the pocket of their white coats, and I dutifully followed suit.

But over time, the stethoscope has become more of a prop than a vital organ. My golden rules of medicine are to: 1) Never order a test that will not change management, and 2) Never perform an intervention that will not help a patient feel better and/or live longer. More often than not, the stethoscope has little impact on the outcomes of my patients.

Consider an asymptomatic patient. If a patient has no cough, wheeze or dyspnea, will auscultation of the lungs change the patient’s management? Will a finding on the lung examination of a patient without pulmonary symptoms help the patient feel better or live longer? If the patient has no nausea, vomiting or abdominal pain, does auscultation of bowel sounds really matter?

Now consider a patient with a known aortic stenosis, with a recent echocardiogram documenting normal left ventricular function and a valve area of 1.2 cm squared. Let’s say the patient has no symptoms of angina, dyspnea or syncope and exercises regularly with no limitations. How is cardiac auscultation going to change my management or improve the patient’s quality of life or survival?

A third example of the stethoscope as useless appendage: the hospitalized patient. When a patient is admitted for urosepsis or pancreatitis or atrial fibrillation with rapid ventricular response and is responding appropriately to the prescribed ministrations, does daily auscultation of various thoracic and abdominal viscera actually make a difference?

When I encounter patients like these, I still auscultate. But as I’m listening, I’m wondering why. Partly, it’s because the rhythm of the physical examination is so deeply ingrained that I feel out of sorts if I don’t perform one. Partly, it’s because I know the patient expects to receive a cardiopulmonary examination from the cardiologist. Partly, it’s because the billing algorithm mandates a physical exam (see: tailing wagging dog). And sometimes, it’s because the patient is so anxious that pausing to take four to six deep breaths is just what it takes to break the torrent of a nervous history and calm the patient down.

That’s not to say the physical examination is unimportant. The physical exam is amazing, and it starts when the patient enters the room; initial observation can often identify the doctor’s most important differential: sick or not sick. The history then points the physical examination in one direction or another. An elevated jugular venous pressure steers me away from dyspnea caused by deconditioning and towards dyspnea from decompensated heart failure. If the JVP is elevated, then the presence of an S3 gallop makes me worry about poor perfusion, the kind of heart failure hospitalization that involves cardiorenal syndrome and inotropic support. On the other hand, if the JVP is elevated and there is no S3 gallop, I’m anticipating a set-it-and-forget-it approach of a few days of IV Lasix until the patient easily achieves euvolemia and all is right in the world again. So, the stethoscope is useful in context, not in isolation.

The stethoscope is a tool, but don’t take it on a fishing expedition, never sure if you’ll hook a bluefin tuna or a rusty tin can. Instead, use your stethoscope as a safecracker would. A safecracker puts the stethoscope over the lock as if it were a heart and turns the dial. He tries to feel and hear the notches lining up on the series of interlocking wheels inside. A safecracker patiently listens and evaluates what he hears; to my mind, that’s the role of the stethoscope in the 21st century.

Maybe Osler could diagnose complete heart block by a history and physical examination, but modern doctors have skills he didn’t — couldn’t — acquire. We can harness a powerful armamentarium of diagnostic and therapeutic tools ranging from laboratories to imaging studies to gene expression profiling. We use these varied tools to find the right fit for the right patient. We not only fashion the appropriate algorithm, but translate the complicated technical lingo into plain language so patients can understand. Not only that, but we can do battle with insurance companies to make sure everyone who needs to get paid does, and no one gets billed who shouldn’t.

Is the stethoscope a vestigial organ? Perhaps it has lost some of its original function through evolution, but so have doctors. Still, we’ve gained new functions, like reassuring the wearers of Apple watches and persuading the proponents of Dr. Google that we truly know more than their monitors and internet searches. Like us, the stethoscope has taken on new roles. I might not take it out for every patient, but it will always remain, curled sedately in the lower left pocket of my white coat. While the stethoscope may be heralded by laymen as an essential accouterment of the physician, the judgment and experience that are the hallmarks of a good physician are less tangible. As I’m constantly assessing and pondering the ultimate question of sick-or-not-sick, while these almost unconscious algorithms run through my head, I know it is there, just one of my many tools to crack the code from chief complaint to diagnosis to management plan.

Michelle M. Kittleson is a cardiologist.

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