A bit of good news for a change: a “Perspective” article in the New England Journal of Medicine describes how point-of-care ultrasound devices are being integrated into medical education. The wonders of modern medical technology are akin to science fiction. We don’t yet have a tricorder like “Bones” McCoy uses on Star Trek, but we are heading in that direction, and the new handheld ultrasound devices are a promising development.
The stethoscope has become iconic, a symbol of medical expertise draped proudly around the neck by doctors and other medical personnel. Before it was invented, doctors could only try to listen to a patient’s heart by direct application of ear to chest. In 1816, Laennec interposed a tube of rolled paper between ear and chest, and the stethoscope was born. It quickly became an essential tool, allowing us to hear the distinctive murmurs produced by different heart valve abnormalities, to take blood pressures, to detect the wheezing of asthma or the collapse of a lung , to hear the bruits caused by atherosclerotic narrowing of blood vessels, to detect intestinal obstructions by listening for borborygmi (I love that onomatopoeic word!).
The stethoscope allows us to hear sounds produced by the body, but sound also allows us to see inside the body. Diagnostic ultrasound has a multitude of uses. With prenatal sonograms, we can determine the sex of a fetus, watch it suck its thumb, and even take its picture for the family album. With echocardiography we can evaluate heart valves, see fluid accumulation in the pericardium, observe the thickness and motion of the heart wall, and even quantify the efficiency of the pumping process. Ultrasound lets us see clots in blood vessels and stones in the gallbladder, evaluate abdominal organs, detect cysts, screen for carotid artery narrowing and abdominal aortic aneurysms, and guide needles into the body for therapeutic and diagnostic purposes.
Modern imaging methods allow us to see abnormalities in the living patient that were once only detectable on autopsy. Because of this, medical autopsies are no longer so useful and their rates have declined drastically although forensic autopsies are still required by law. It’s really amazing what we can see with CT scans, MRIs and ultrasound. I recently had an echocardiogram and my mind was boggled as I looked into my own heart and watched the valves open and close. I developed a new respect for my heart as I watched the organ pumping away, working assiduously to keep me alive, with never a moment’s rest. The visual experience was impressive, but perhaps even more impressive was the way the technician was able to precisely measure the thickness of the ventricular wall and quantify the ejection fraction, measuring the amount of blood that was being pushed out of the ventricle with every heartbeat.
Instead of writing an order for technicians to do these tests, doctors now have the option of using ultrasound technology themselves as part of the physical exam at the bedside or in the office. Several US medical schools are offering ultrasound training as early as the first year, even in orientation programs. Ultrasound is used in classes of anatomy, physiology, and physical diagnosis, and eventually on clinical rotations. Harvard has students performing ultrasounds on each other. Mt. Sinai is issuing hand-held ultrasound units to all internal medicine interns.
Studies have shown that first year medical students using these devices are better at detecting cardiac abnormalities than cardiologists (75% vs. 49%) and better at judging liver size than specialists palpating the liver. In the future, ultrasound may well become a standard part of the physical exam. The stethoscope was an extension of the doctor’s sense of hearing, and ultrasound extends the doctor’s senses in far more versatile ways.
Providing these devices to students may not be an unalloyed good. Proper use requires extensive training. False positives and negatives will occur. Students will rely on technology and neglect other diagnostic skills like palpation and auscultation. Full conventional ultrasound studies will still be needed for confirmation and further detail.
Consider this criticism:
Notwithstanding its value, I am extremely doubtful because its beneficial application requires much time, and gives a good deal of trouble both to the patient and the practitioner.
No, that wasn’t criticism of ultrasound, it was an 1829 comment about the stethoscope. Old dogs (and old docs) are slow to learn new tricks, and any new-fangled technology is bound to meet with some resistance. The real question is whether its use will improve medical practice and patient outcomes. It seems logical that it will, but that premise, like any other, will have to be evaluated by controlled scientific testing. I am optimistic.
Developments in scientific medicine are far more awe-inspiring than anything alternative medicine has to offer. Invisible acupuncture meridians and chiropractic subluxations can’t compete with watching your own heart valves open and close.
Reality is a lot more satisfying than fantasy.
This article was originally published in the Science- Based Medicine Blog.
