The stethoscope has been helping doctors detect abnormalities in their patients for over one hundred years. Throughout much of that time, the device has remained largely the same. A few influential designers, such as Dr. David Littmann of the Harvard Medical School, improved the overall design substantially beginning in the early ’60s. These newer stethoscopes featured tunable diaphragms and latex-free tubing.
The first electronic stethoscopes followed soon after. These devices translate the sounds detected by the diaphragm or bell and converts them into digital signals. Once converted, the on-board electronics amplify the signal, enabling doctors to detect abnormalities that are extremely difficult for practitioners to detect with the analog stethoscope. The most sophisticated of these devices utilize an electromagnetic diaphragm, which allows the device to amplify body sounds with greater fidelity.
Ironically, as smartphones become more accessible, many developers are turning the cheaper classic stethoscope into a smart device. The StethoCloud, invented by Dr. Hon Weng Chong, features a stethoscope that contains a microphone. The device connects to compatible smartphones, where an app then scrutinizes the breathing of potential pneumonia patients. Sophisticated algorithms analyze the patient’s breathing pattern and notify health care professionals if pneumonia is suspected. Pneumonia kills thousands of children each year in impoverished areas of the world because doctors can’t afford to treat every patient they suspect of having the disease. What’s more, traditional diagnosis takes several days, by which time the patient may have already died.
The StethoCloud—winner of Microsoft’s Imagine Cup Grant for 2013—allows doctors to detect the disease earlier, and it works with an inexpensive analog stethoscope. Not all innovations in this area bolster the classic stethoscope’s claim to fame, however. The Steth IO, an iPhone case produced on a sophisticated 3D printer, acts as a stethoscope all on its own. Consisting of a plastic diaphragm and a series of hollow tubes, the device channels sound into the iPhone’s microphone. A dedicated app then digitizes the sound and produces an ECG-like output. The case’s inventor, 15-year-old Suman Mulumudi, claims that the device is nearly as sensitive as a traditional stethoscope. However, detractors point out that stethoscopes of any type can potentially spread disease, and doctors may be loath to remove their iPhone case and wash it between each patient.
A New Contender
Since the 1950s, researchers have been working with ultrasound technology to make it smaller and more sensitive. Ultrasound is an umbrella term that describes sound that is too high in frequency for humans to detect. Ultrasound devices work by sending high frequency sound waves through solid matter. As the waves return to the device, it creates an image. This is also how a bat senses its environment and locates prey while on the wing.
Modern ultrasound devices are capable of producing 3D images, and they are the size of a smartphone. Currently, medical devices utilizing this technology cost several thousand dollars, and so they aren’t a practical replacement for the stethoscope—yet. However, the cost of new technologies tends to decline over time.
Several doctors believe that this technology will replace the stethoscope within 50 years. Other experts point out that the combination of compact ultrasound technology and the stethoscope will allow doctors to hear and see their patients’ hearts, lungs and intestines. Under this paradigm, the stethoscope wouldn’t disappear, it would merely change form. However, the stethoscope as it is has a few key advantages that may keep it relevant for quite a long time.
FIrst off, the stethoscope is orders of magnitude cheaper than other diagnostic technologies such as MRI and ultrasound. A good stethoscope costs around $200. The average MRI scan can cost as much as $1,500. Furthermore, the average analog stethoscope, if properly used, can uncover a myriad of diseases. In fact, some models can even detect abnormalities through clothing.
Dr. Charles Cutler, who heads the American College of Physicians’ Board of Regents, had this to say on the issue of the stethoscope’s longevity: “The stethoscope is as important as it ever has been.” The doctor is quick to point out that more complex technology is not always better. Indeed, the analog stethoscope will remain an invaluable tool for this reason if for no other: it requires no electricity and lasts for decades if properly cared for. It will remain useful in emergency situations, if nothing else. What’s more, as an inexpensive diagnostic tool, it will likely remain popular among students and young doctors for decades to come.