“It must be confessed that there is something even ludicrous in the picture of a grave physician formally listening through a long tube applied to the patient’s thorax, as if the disease within were a living being that could communicate its condition to the sense without.” — Dr. John Forbes, 1821

As the Covid-19 pandemic reshapes how medicine is practiced in the U.S., one iconic tool could be relegated to the dustbin of medical history: the stethoscope.

For generations, there has been no better physician archetype than the quintessential black rubber stethoscope donned confidently over a crisp white coat. This highly recognizable image evolved from experiments conducted in 1816, when Dr. René Laennec listened through a paper cylinder placed on a patient’s chest, revealing a treasure trove of muted thumps, crackles, and wheezes that comprise the cacophony of physical exam findings clinicians rely on today.

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Two centuries later, as the world suffers through a cataclysmic pandemic, many hospitals and clinicians have conspicuously decided that the ratio of useful information to infection risk does not favor employing a stethoscope on any patient with even a whiff of Covid-19 related illness. In its place has risen a budding dark horse of modern bedside medicine: the portable, and increasingly affordable, ultrasound.

We are entering the era of point-of-care ultrasound, which relies on higher-frequency sound waves than its stethoscope predecessor. It is a hand-held device equipped with the ability to both emit sound waves and interpret them as they reflect off structures of interest, similar to how a bat uses sonar to navigate its surroundings.

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This technology could usher in an epoch in health care that does not rely on the spectrum of audible noise that the ears of aging doctors increasingly cannot discern. Instead, we should be looking ahead to the widespread use of a pocket-sized and radiation-free device that peers into the body in real time and explores the inner organs in a “Magic School Bus“-like fashion. Point-of-care ultrasound enables a clinician to digitally peel back the skin and observe the ecosystem of internal organs functioning in real time, an ability our forefathers and stethoscope-monogamous colleagues could infer only through skin changes, audible noises, and subjective symptoms.

So far, point-of-care ultrasound has been embraced mainly by emergency and intensive care clinicians, and has yet to crack my internal medicine colleagues’ morning rounds. Lack of formal training and cost — a basic point-of-care ultrasound system costs between $2,000 and $50,000, compared to $400 for a top-of-the-line stethoscope — are certainly barriers to adoption. Yet if medical students with only 18 hours of ultrasound training can more accurately diagnose heart problems with point-of-care ultrasound than experienced cardiologists can with a stethoscope, it is time to admit that our trusty analog listening device should be put out to pasture.

The art of auscultation using a stethoscope is a right-of-passage skill learned by all medical trainees on their journeys to becoming clinicians. Yet as with any other medical test or physical exam, auscultation requires adequate scrutiny and understanding of its limitations. The American Roentgen Ray Society once published 10 criteria for an ideal screening test. Two of them, affordability/availability and high accuracy, are most relevant to the stethoscope vs. point-of-care ultrasound debate. While the stethoscope is certainly more available and affordable, it fails to provide accurate data, the most crucial measure of a good screening assessment.

While there are many clinical scenarios in which point-of-care ultrasound provides more and better information than a stethoscope, the lung examination may be the most telling.

Take as an example pulmonary edema, a buildup of fluid in the lungs often caused by congestive heart failure. When this fluid is present, it can cause a crackling sound to be present as the patient takes a breath. Listening for these characteristic “crackles” picks up only about 4 out of 10 cases, and only 67% of patients in whom crackles are heard actually have congestive heart failure. In contrast, point-of-care ultrasound is almost perfect, accurately detecting 97% of cases with only 2% of false positives. Point-of-care ultrasound also outperforms auscultation in diagnosing asthma, COPD, and pleural effusion, a buildup of fluid between the lung and chest cavity (see table).

 

Condition Auscultation Point-of-care ultrasound
Sensitivity Specificity Sensitivity Specificity
Fluid buildup in the lungs due to congestive heart failure 46% 67% 97% 98%
Asthma / COPD 30% 90% 89% 97%
Pleural effusion with 200 or more milliliters of fluid 42% 90% 100% 100%
Pleural effusion with less than 200 milliliters of fluid Cannot detect Cannot detect 93% 96%

As the authors of a meta-analysis on lung auscultation published in the journal Nature concluded, “When better diagnostic modalities are available, they should replace lung auscultation. Only in resource limited settings, with a high prevalence of disease and in experienced hands, lung auscultation still has a role.” Point-of-care ultrasound could certainly represent one of those “better diagnostic modalities.”

On top of their poor utility for screening and diagnosis, stethoscopes have already been linked to a Covid-19 outbreak in a South African hospital, are known to carry dangerous Staphylococcus aureus and MRSA bacteria, and the majority of them are cleaned rarely — or never.

In this ultra-heightened era of infection prevention, these shortcomings certainly beg the questions: Why are we clinging to this medical relic with minimal utility and known infection risk? If it does not provide enough useful information to warrant its risk in Covid-19 infections, then does it ever?

In the Covid-19 era, point-of-care ultrasound has proven invaluable. While it also carries significant risk of transmitting infection, multiple studies have confirmed that there are ultrasound lung findings for Covid-19 that can be used to triage patients with respiratory symptoms. It is more sensitive than the chest X-ray in detecting Covid-19 and conserves PPE and limits health care worker exposure by allowing one physician to both assess the patient and perform the imaging. In patients with a high suspicion for Covid-19 but a negative nasal swab test, ultrasound provides valuable objective information to determine if that negative test warrants a repeat, as these tests still have notoriously high false negative rates.

The art and tradition of medicine should be learned and respected. But with the high-stakes, time-sensitive decisions that physicians make on a daily basis, art and tradition should take a backseat to precision and certainty. Interventional cardiologists like to say that “time is heart” when referring to how quickly they need to open a blocked coronary artery. Neurologists prefer the “time is brain” axiom when referring to treating strokes. For the ultrasound-wielding clinician who can peer inside you with near-perfect accuracy for many diseases and see your fate as soon as you barge through the hospital doors with shortness of breath, “time is life.”

Time is life when you can find in a patient with plummeting blood pressure a large pericardial effusion compressing the heart, making it difficult for it to pump blood to the body and brain. Time is life when you can detect a large blood clot brewing in the leg before it has broken off and traveled to the lung, causing a life-threatening pulmonary embolism.

I believe that given the remarkable diagnostic accuracy of point-of-care ultrasound, every patient presenting to a clinic or hospital should have a focused ultrasound to augment their clinician’s physical exam findings. There is just no excuse not to.

With the advent of small ultrasound probes that connect to a smartphone and cost 20 times less than their traditional ultrasound counterparts, we are finally in a position where we can make point-of-care ultrasound as routine as auscultation. That means pivoting residency training and continuing education to ensure that all clinicians in every health care setting worldwide have this skill so one day soon we can see the adored stethoscope reach its final resting place: collecting dust inside the medical exam room drawer labeled “wheeze-detector.”

Larry Istrail is a hospitalist physician and is point-of-care ultrasound certified by the Society of Hospital Medicine. He is a champion of point-of-care ultrasound and a contributor to pocusmeded.com. He has no financial ties with any standard or point-of-care ultrasound companies.

  • Hi Dr Dave,

    Thanks for the comment. I appreciate your forward thinking. Yes that is certainly possible with the butterfly and other handheld devices! Yes the billing aspect unfortunately complicates things but I’m confident this is a train that cannot he stopped now.

    • The ”standard of care” when I started 35+ years ago for thyroid cancer was radiology then we went to MRI then of course nuclear medical uptake now we can tell in 100 seconds or even less with a POCUS what is going on with no need to wait or to in many cases even biopsy the tissue. We have take what was 4-6 weeks plus a few ten thousand dollars and reduced it to one visit and ready to hit the OR. Sure another departments are upset especially the medicolegal department but my position is we pay them enough to protect us after the fact so let them do it meanwhile we save lives and time and more importantly we keep the machine moving forward so that people don’t have to suffer. Can’t tell you how many times we made a mental diagnosis day k e only to never see the patient again because the pathway to health was either too expensive or difficult.
      POCUS cuts that cost and time dow to seconds and pennies rather than weeks or dollars
      Every ED has them now as the standard of care to the point that many are used even before the attending is even called in to see the patient.

  • After a night of horrific pain near right kidney and heart, and desperately gasping for air, a stethoscope exam in Hospital Emergency led to a lung X-ray and lab-work that “showed nothing” and I was sent home on Percocet (for “muscle spasms”). Two days later (day 3) turning slightly blue and still gasping for air with more flank pain it was my young Doctor’s stethoscope in her clinic that led to an ECG, a negative triponen test, and another chest X-ray now with “pleurisy” diagnosis, and I was sent home with Biaxin. On day 4 with excruciating flank pain and no air, young Doc’s stethoscope led to more “kidney” labwork (NAF) and an Xray at the local lab for kidney stone (non-existent). A senior doctor to whom I owe my life saw my grey complexion crawling out of their clinic, perused my file, sent me back to the Hospital ER for CT scan he had set up. So on day 5 (a Friday) with 7 emboli in both lungs (those near right kidney and behind heart were large marble size) I was carted off to the ICU stat. I would not have survived the weekend without that diagnosis, I am very lucky to be alive.
    This diagnosis would have occurred on day 1 with ultrasound Point-of-Care rather than the stethoscope in ER and clinic. So thank you, Dr. Istrail, and your support Dr. Dave L, for seeking this vast improvement for correct and quick diagnostics.

    • Dear Chris,

      I am so happy to hear that someone was adept enough to get a CT in catch the diagnosis in time and you are ok. Unfortunately this story is all too common. In my time using point of care ultrasound it was become abundantly clear how effective it can be and how many xrays and CTs can be avoided with a 5 minute exam. Unfortunately xrays and stethoscopes just don’t cut it. Thank you for taking the time to comment!

  • Larry
    Great article. I have tried for the last 20 years or so since the first inexpensive handheld POC ultrasound came out to shift my residents over to their use but the hospital and the education committee has balked at ignoring the obvious deficits in the stethoscope technology for fear it would reduce billable procedures I can only assume. Using POC anything is a doorway into bundling and that reduces income to the departments so solely focused on revenues. I can only hope that the CV19 situation opens our eyes to the efficiency factor of high tech that ultimately will lead to better revenues and fewer costs. Sure radiology and cardiology will suffer initially but in the long run, if we find things we have missed we can then send for more services currently not being ordered and lower the time we spend in all aspects of care to balance out the tables.
    Heck, I can even see one day mailing an ultrasound transducer to a patient to have them hold and position it so we can do a survey during telemedicine follow up so patients don’t need to travel and we don’t need to have 6 digit costly offices to staff and support.
    Dr. D

  • Is the POC ultrasound billable as a separate procedure or it is included in the medical exam CPT?

    • Hi Bret,

      Yes it can be billed as separate exams. You just need appropriate documentation and forever image storage which is certainly an issue for many hospitals and EMRs

    • Of course it can. As we mentioned in the article, “In the Covid-19 era, point-of-care ultrasound has proven invaluable. While it also carries significant risk of transmitting infection…” The question remains does the net benefit ultrasound can provide outweigh the infection risk. I would argue it clearly does not with a stethoscope.

  • POC ultrasound could also render mammograms unnecessary if gynecologists were to adopt this technology to perform breast examinations of their patients. Any time the results of my mammogram have been unclear, the next step has always been ultrasound — why not go there first, especially since it is radiation-free?

    • It’s a great point! If the sensitivity and specificity are good, it would be a great option.

  • reality check
    For a long time the stethoscope has been not much more than a fashion accessory, and a status symbol. It’s a common sight in hospitals’ cafeterias seeing people hanging there with a stethoscope around their neck, just to let the others know …. I am a doctor!

    • Exactly right! a fashion statement and a status statement. Like many things in healthcare, it is 10 years past its prime.

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