Amidst the crushing human and economic carnage inflicted by the COVID-19 pandemic, one innocent bystander has been cowering in the dark corner of medicine’s past, clinging to its final breaths of iconicity: the beloved stethoscope.
For over two centuries, there has been no better physician archetype than the quintessential rubber tube donned confidently over a crisp white coat. This recognizable image has been with us in part since 1816, when Dr. René Laennec listened through a paper cylinder flush to a patient’s chest, revealing a treasure trove of muted thumps, crackles and wheezes comprising the cacophony of physical exam findings we rely on today.
Now, 204 years later, as the world suffers through this once-in-a-generation 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 presenting with even a whiff of COVID-19 related illness. In its place has risen a budding dark horse of modern bedside medicine: the portable, increasingly affordable ultrasound.
We are entering the point of care ultrasound (POCUS) era, which does not solely rely on the spectrum of audible noise our aging doctor ears increasingly cannot discern. Gone should be the time when listening to a cellulitis patient’s heart and lungs each day is seen as anything but a futile daily drudgery of medical tradition preservation.
Instead, we should yearn for an inspiring future in its place, with a pocket-sized and radiation-free device that peers into a patient’s body in real-time. POCUS enables us to digitally peel back the epidermis and observe a new ecosystem of internal organs functioning in real-time, an ability our forefathers and stethoscope-monogamous colleagues could only infer through skin changes, audible noises and subjective symptoms. While lack of formal training and cost are certainly barriers to adoption, if medical students with only 18 hours of ultrasound training can more accurately diagnose cardiac pathology with POCUS than experienced cardiologists can with a stethoscope, is it time to admit that our trusty analog listening device has jumped the shark?
Like with any exam, auscultation requires adequate scrutiny and understanding of its limitations. An American Journal of Diagnostic Imaging and Related Sciences published ten criteria for an ideal screening test. Two of the criteria: ‘affordability/availability’ and ‘high accuracy’ are most relevant to the stethoscope vs. POCUS debate. While the stethoscope is certainly more ubiquitous 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 POCUS may provide additional benefit over a stethoscope, perhaps the lung examination is the most telling. When evaluating a patient with shortness of breath, the sensitivity of lung auscultation overall is around 35 percent, meaning nearly 7 out of 10 patients with the disease in question are missed using auscultation alone. In patients with congestive heart failure (CHF), listening for the characteristic “crackles” only picked up 4 out of 10 cases, and only 67 percent of patients in whom crackles are heard actually have congestive heart failure. In contrast, POCUS is almost perfect, accurately detecting 97 percent of cases with only 2 percent false positives. POCUS also outperforms auscultation in diagnosing asthma, COPD, and pleural effusions.
In the COVID-19 era, POCUS has proven invaluable. Multiple studies have confirmed that there are very characteristic lung ultrasound findings for COVID-19 that can be used to triage patients with respiratory symptoms. It is more sensitive than chest X-ray in detecting COVID-19, conserves PPE, and limits health care worker exposure by allowing the physician to assess the patient and perform the imaging simultaneously. In patients with a high suspicion for COVID-19 but a negative nasal swab test, lung POCUS 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 are very important aspects of health care that should be learned and respected. But with the high stakes, time-sensitive decisions we make on a daily basis, art and tradition take a backseat to precision and certainty. Interventional cardiologists like to say that “time is heart” when referring to this time-sensitivity of a cardiac catheterization to open a blocked artery, For the ultrasound-yielding 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 a large pericardial effusion compressing the heart in a patient with dropping blood pressures. Time is life when you can find a large blood clot brewing in the leg before it has broken off and traveled to the lung, causing a life-threatening pulmonary embolism. Given the remarkable diagnostic accuracy POCUS can offer, every patient presenting to a clinic or hospital should have a focused ultrasound to augment their physical exam findings. There is just no excuse not to.
With the advent of small ultrasound probes that connect to a smartphone and cost 20X less than their traditional ultrasound counterparts, we are finally in a position where we can make POCUS as routine as auscultation. We need to pivot our residency training and continuing education to focus on POCUS skills in order to bestow this superpower upon every clinician in every health care setting worldwide, so we can one day soon see our adored stethoscope reach its final resting place, collecting dust inside the medical exam room drawer labeled “wheeze-detector.”
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