Saturday, July 14, 2012

Your Next Stethoscope Should Be Electronic. Here's Why.

Last month, I reluctantly entered the market for a new stethoscope. (My old one broke. Don’t ask.)

For doctors, choosing a stethoscope is not a decision made lightly: it requires laying out a significant amount of cash for a device you might carry in your pocket for years. So, after researching stethoscopes online for a few days, I surprised myself by buying an electronic model — the 3M Littmann Electronic Stethoscope Model 3000 — and I couldn’t be happier.

“Why an electronic stethoscope?” is a reasonable question, but a better one might be: “What prevented you from buying one before?” Here are the most common objections:

  • Electronic stethoscopes are expensive.
  • Unless you have a hearing problem, you should be able to hear just fine without one.
  • Physicians have gone without electronic stethoscopes for almost two hundred years — why switch now?
The price of electronic stethoscopes has fallen dramatically in recent years. As of this writing, the Littmann Model 3000 is $287 on Amazon. Compare this with the price of the Littmann Cardiology II, which is $156. What does this $131 difference get you? The amplification of the Model 3000, according to the website, is “up to 18 times greater than the best non-electronic stethoscope.” And the ambient noise reduction technology cancels out “an average of 75% of distracting room noise.”

That sounds great, but does it actually make a difference? To test the performance of the Model 3000, an internal medicine resident and I listened to the heart of a patient with hypertrophic obstructive cardiomyopathy. We each auscultated the patient’s murmur with both a conventional acoustic stethoscope and the Model 3000 — but to level the playing field, we placed the electronic stethoscope on the patient’s hospital gown and placed the acoustic stethoscope directly on the patient’s skin. We heard the patient’s murmur better with the electronic stethoscope on the patient’s clothes than we did with the acoustic stethoscope on bare skin.

In an ideal situation, could you pick up all the murmurs you might hear with the electronic Model 3000 with a conventional acoustic stethoscope? Sure — but there are no ideal situations. Hospitals are noisy, it’s sometimes difficult to position patients properly to listen to their heart and lungs, and doctors are often rushed. At the very least, the electronic stethoscope provides an added level of assurance that you haven’t missed any significant findings. If you view the physical exam as a test, then the electronic stethoscope significantly increases the test’s sensitivity without decreasing its specificity.

If you see 20 patients a day, 5 days a week, for 48 weeks a year, in 2 years you will have used your stethoscope on patients 9600 times. For the Littman Model 3000, that is the equivalent of an extra 2 cents per physical exam. Is this worth it? If the average physician makes $50 per hour — and feel free to check my math, here — 2 cents is worth about a second of their time. So if an electronic stethoscope saves you more than a second per patient — and I would argue that it does — it’s worth buying.

Even so, I wasn’t fully convinced the Model 3000 was worth it until I showed it to another resident. She placed the chestpiece on her heart — over her clothes, mind you — and listened. Her eyes widened. “Oh my god,” she said, “I have mitral valve prolapse. I was never able to hear it before.” And I listened too. She was right. Even through her clothes, you could clearly hear the mid-systolic click.

What do you think? Has anyone else had positive or negative experiences with electronic stethoscopes? Are there compelling reasons not to get one?

(Also posted on The Efficient MD.)
This was originally written for the Tech Medicine Blog in 2008.

Posted on infosnack.

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