Why Do Doctors Use Stethoscopes

Ah yes, the stethoscope. A universal symbol of medicine. But you must be wondering, what in the world are these pieces of rubber doing next to high-tech equipment like MRI scanners and robotic surgery? Surely these are obsolete relics from the 19th century. Well, the answer lies at the intersection of history, the human body and technology. The stethoscope was invented in 1816 by a French physician called René Lennec. René invented it because he was a gentleman, and he felt uncomfortable putting his ear on women's chests to hear their heart sounds. And no, I'm not making that up. But why would you want to listen to the heart sounds in the first place? A key challenge for a doctor is to find out what's happening inside the human body without resorting to opening it up. As technology has progressed, we've found different ways of peering inside a living person without harming them. Things like x-rays, ultrasound and MRI. But the first x-ray wasn't taken until 1895, and an x-ray can only provide you with a still image. It can't tell you about what's happening inside the body in real time. As a physician in the early 1800s, René knew that listening to the heart sounds can provide a clue to whether the heart valves are working properly. In our hearts, there are four valves that help push blood only in one direction. When the valves shut, they make a sound, and the normal heartbeat has two clearly distinguishable sounds. When the heart valves don't function properly, you can hear this whooshing sound as blood passes through them. For example, this is the sound of a common heart valve condition called aortic stenosis. You can hear this sound even if you put your ear to someone's chest. Of course, modern stethoscopes make this much less awkward, but also amplify the sound. Stethoscopes are not just useful for the heart. You can also listen to the lungs to check if air is passing freely in and out, the intestines to check whether the gut is working after having an operation, and stethoscopes also help you when taking someone's blood pressure. Technology has advanced dramatically since the 1800s. We now have automatic blood pressure machines that require little human input, ultrasound echocardiography that helps us see the heart valves in real time, and CT scanning which can provide detailed images of the lung. This doesn't mean that stethoscopes have become obsolete. These humble pieces of rubber are still an important screening tool. If we hear something odd, then we may follow up with a more sophisticated test like an echocardiogram. In countries where healthcare resources are scarce, basic tools like the stethoscope become even more important because sometimes critical decisions may need to be made without having access to scanning equipment like CT scans. Just like a fancy self-driving electric car still needs wheels, doctors and nurses will continue to use the stethoscope as an important part of the medical toolkit. As always, if you have any questions, let me know in the comments. Thanks for watching and I'll see you in the next one.