How useful is a stethoscope to a surgeon

medicine : Farewell to eavesdropping

Before the doctor places the transducer on the patient's chest, she asks him to “free himself”. Then the cold metal lies on the bare skin, the acoustically amplified sound waves from the chest penetrate through the flexible tube and its two branches to the doctor's ears. What she hears, the rustling, rattling, rubbing, tells her whether the heart valves are doing their job, whether the heart is weak or the alveoli are inflated. The stethoscope allows numerous diagnoses and it is the symbol of the medical profession. For the unequal distribution of roles between doctor and patient, for attentive, intensive care - until today.

But more and more researchers believe that the stethoscope belongs in a museum. Ultrasound images of the heart would soon make the device superfluous, wrote US heart specialists Jagat Narula and Bret Nelson recently in the journal “Global Heart”: “The time is definitely ripe for a change; Just as long-playing records have been replaced by CDs and MP-3 technology, the stethoscope will give way to ultrasound. ”Other studies even show that the stethoscope can endanger patients. Because when the device and patient are in close contact, germs accumulate and are then passed on to the next patient.

In the beginning, the stethoscope just managed to keep the distance. Listening to the heart has long been customary, and Hippocrates already mentioned the technology. As a rule, doctors pressed their ears directly to the patient's chest - until February 17, 1816. On this day, the young Parisian doctor René-Théophile-Hyacinthe Laënnec used a piece of thin cardboard rolled up into a cylinder around the Improve the transmission of sound waves. According to his own statement, he got the idea for his handicraft work while watching children in the park who joyfully held their ears to a tree trunk, at the other end of which their playmate was making rubbing noises with a nail. For reasons of practicality and morality, Laënnec first used the simple pipe with an overweight young lady: It was not appropriate to put the ear directly to her breast, and in this case it would have been less acoustically effective than with a slim person. The stethoscope was born on this February day in Paris.

But at first the doubts prevailed. Colleagues around the world dismissed the invention as a decadent “French gimmick”, as a tool used by medical professionals who are simply too fine to put their ears to the patient's bare chest. Laënnec tried to convince the professional world with a book that provided detailed information about the knowledge gained thanks to "auscultation médiate", about the correspondences between rattling, humming and wheezing in the lungs of tuberculosis sufferers or hissing, rustling, pouring noises in heart sufferers and the, what one already knew about heart and lung diseases from findings from cadaveric openings.

But it was not until the Viennese doctor Josef von Skoda ensured acceptance among German-speaking doctors with his "Treatise on Auscultation and Percussion" from 1839. He divided the sounds into four dimensions: full and empty, dull and light, high and low, "tympanitic" (long lasting and sounding) and "non-tympanic". And he made them part of clinical training at hospitals. It quickly gained in importance, especially for the diagnosis of "pulmonary consumption": metallic, rattling tones accompany breathing as background noises. In Thomas Mann's “Magic Mountain”, published in 1924, the diagnosis was made, which at that time could already be supported by an X-ray. The new method changed little for the patients at first: Before the discovery of antibiotics, the doctors could only recommend lying down cures and diet.

The stethoscope slowly gained popularity and changed at the same time. The self-made cardboard tubes were initially short, pierced wooden cylinders. In 1963 David Littmann patented the tube stethoscope with the two flexible tubes, which today should not be missing on any doctor's photo or series of doctors.

It is precisely this insignia of medical art that a study from Switzerland now explains as a source of danger for patients. “From the point of view of infection control and patient safety, the stethoscope should be seen as part of the doctor's hand and disinfected after every patient contact,” write the Swiss infection expert Didier Pittet and his colleagues in the current issue of the “Mayo Clinic Proceedings”. For their investigation, the researchers had several medical professionals listen to a total of 71 patients, using stethoscopes that had previously been sterilized and fresh disposable gloves. After listening, they examined the hands and stethoscope for bacteria. They found that the device was almost as colonized with germs as the fingertips of the doctors. This also applied to methicillin-resistant Staphylococcus aureus (MRSA), a bacterium that is resistant to common antibiotics and is therefore particularly dangerous for many patients. The doctors conclude that stethoscopes, like hands, must be rubbed with a disinfecting solution before each new patient contact.

But is it even worth the effort? The heart specialists Jagat Narula and Bret Nelson from the Mount Sinai School of Medicine in New York do not believe this: The era of the stethoscope will soon come to an end anyway and the device will be replaced by modern sonography or ultrasound devices that fit in any smock pocket. “Sonography” literally means “sound recording”, and based on the propagation of high-frequency sound (“ultrasound”), the devices provide sectional images of body structures that can be viewed on the monitor. The information has improved so much in their field through echocardiography, the heart ultrasound, that auscultation will soon be superfluous, write the two cardiologists. In addition, the devices are becoming ever smaller and more manageable - with transducers that are “hardly bigger than a deck of cards”. "Medical students will already learn how to use it during their training, they will experience living anatomy and physiology in a way that was previously only possible with simulation," rave the two heart specialists.

With the introduction of the first X-ray examinations, the ear was replaced by the eye as a privileged medical organ of perception, writes the medical sociologist Jens Lachmund in his story of the stethoscope, "The listened-to body". In the meantime, the sovereignty of interpretation through modern imaging, through magnetic resonance imaging, X-ray examinations and ultrasound, has completely shifted to the "technical view". In medicine, the eye has triumphed over the ear. For Narula and Nelson the only question is whether the stethoscope will survive at least as a nostalgic fanatic: "Will some clinicians continue to swear by the analog acoustics of the stethoscope, just as some audiophiles claim that the record player delivers the real sound?" they ask in their article.

"The transducer is the stethoscope of the future," says Joseph Osterwalder from the Cantonal Hospital in St. Gallen. The doctor heads the emergency sonography working group of the German Society for Ultrasound in Medicine (Degum). He thinks that every medical “generalist” today, whether it is a family doctor, internist, intensive care doctor, emergency doctor or anesthetist, should be able to master a basic form of ultrasound, the “focused” sonography. The “Primus” study, which traced the fate of 1,452 patients who came to an emergency room between April 2010 and February 2011 because of unclear complaints, shows what this brings in everyday life. Around three quarters of the patients were examined by ultrasound within the first 24 hours, the others only later. In this situation, the most important domain of ultrasound is all ambiguities in the area of ​​the abdomen and chest, the detection of water retention, blood or swelling, effusions in the pericardium or air in the lung tissue. In 94.4 percent of those examined early, the result had an impact on the therapy; on average, they could be discharged three days earlier than the comparison group. According to Degum, it is best to do the ultrasound in the ambulance. After all, the suspected diagnosis is important when it comes to which clinic is going to.

But Matthias Leschke, heart and lung specialist at the Esslingen Clinic, does not believe that doctors will soon be able to do without the stethoscope. In the department for cardiology, pulmonology and angiology of the clinic there are four of the ultrasound devices in smartphone format - which are not entirely cheap at around 6,000 euros. "They are very helpful in diagnosing a weak heart or an effusion in the space between the lungs," says chief physician Matthias Leschke. Nevertheless, the stethoscope is still useful. "We need it in everyday clinical practice to diagnose shortness of breath, to assess pulmonary congestion in the case of cardiac insufficiency or the progression of pneumonia," he says. Ultrasound is less convincing, especially with tissue in which air is not stored but liquid. Diseased inflated lung tissue such as occurs in chronic bronchitis, the typical "wheezing" in asthma or intestinal noises are a domain of "hearing" medicine. For all of these reasons, Leschke still finds it important to learn how to systematically examine the chest, including listening. "What are you listening to? How do you interpret the findings? These questions must continue to arise in the training of young doctors. "

Osterwalder also does not think that the abolition of the stethoscope is imminent. “It remains important for the first assessment of a patient with chest complaints.” In the long term, ultrasound could perhaps make the stethoscope superfluous. Today, however, in many cases it is more of a substitute for other imaging methods such as x-rays. Should the doctors really say goodbye to the stethoscope, it should happen as slowly as they once welcomed it.

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