A stethoscope, considered a must-have device of healthcare and healthcare providers, is a diagnostic medical device used for auscultation or listening to sounds produced by the lungs, heart, and intestinal tract of humans as well as animals.
The First Stethoscope
A French physician, René Laënnec invented the first Stethoscope. The invention took place in Paris, at the prestigious Necker-Enfants Malades Hospital. It was similar to an ear trumpet and consisted of a tube of wood. Modifications consisting of a flexible tube and binaural were made from 1829 to 1851.
Modifications in the design
Eventually in 1852, George Cammann perfected the design of the stethoscope for standard commercial production. In the 1940s, Rappaport and Sprague designed a new stethoscope consisting of two sides, one used for respiratory system and the other for cardiovascular system. This model became a standard by which other stethoscopes are measured today. After various modifications, in the 1960s David Littmann created a light weight model with better acoustics.
What are the different types of stethoscopes?
Stethoscopes come in different designs, and they differ in materials too. Majority of these devices are made of rubber tubing of Y-shape. This tube allows the device to catch the sound at its one end, and let the sound travel to the ear pieces at the other end. There are many stethoscopes available with a sound-detecting device that is two sided.
Stethoscopes are available in four basic types:
The original stethoscope model, acoustic stethoscope, operates by using a chest piece with hollow tubes that transmit sounds to the listener’s ears. The medium of transmission for the sound is the air inside the hollow tubes. The chest piece has two sides, a diaphragm and a bell. The diaphragm creates high-frequency sounds, while the bell creates low-frequency sounds. This model was designed by Rappaport and Sprague. The only disadvantage of the acoustic stethoscope is that the sound level is extremely low.
Electronic stethoscope, also known as stethophone, amplifies body sounds using electronic transducers. These transducers convert sound waves of the body to electrical signals that are amplified and provide clearer and louder sounds. Thus electronic stethoscopes overcome the drawback of an acoustic stethoscope of low sound levels.
An electronic stethoscope can be a wireless device because the sound is transmitted electrically. Due to this it can even enhance and record the signals, provide noise reduction and display audio and visual outputs. Owing to these features an electronic stethoscope can be used from a distance for remote monitoring and diagnosis.
A recording stethoscope is a special type of electronic stethoscope that connects audio output to a recording device. This allows the audio output to be recorded for evaluation and consultation at a later examination. The recordings can even be shared thus allowing for remote diagnosis as well as fast and efficient consultations.
A fetal stethoscope is also known as a fetoscope. It is shaped like a trumpet and is placed against the abdomen of a pregnant woman to hear the heart beats of the foetus. This stethoscope was invented by French obstetrician, Adolphe Pinard and is therefore also known as “Pinard’s stethoscope’ or the ‘pinard’ too.
You can also find few other stethoscopes likes 3M Littmann Classic 11 S.E Stethoscope,American Diagnostic Corporation stethoscope,3M Littmann Master Classic II Stethoscope and 3M Littmann Cardiology III Stethoscope. These Stethoscope are best and very durable. Doctors and nurses are highly recommended these above mentioned machines.
What are the benefits of Stethoscopes?
The stethoscope redefined diagnosis of disease from external evaluation of symptoms to internal auscultation, without using lethal, invasive instruments to explore internal anatomy.
With the help of a stethoscope you can hear, both normal and abnormal sounds of respiratory organs. You can also use it for hearing of pleural, cardiac, arterial, uterine, venous, intestinal and fetal and sounds. This aids effective diagnosis and evaluation of patients.
Stethoscopes are painless and only require skin contact. Also they are quick and easy to use and require no previous training to handle.
Electronic stethoscopes, as mentioned previously, amplify sounds and can also record the audio output. This simplifies sharing of audio recordings with others, even if remotely located. Evaluation of recordings at a later time as well as portability of the information is possible due to electronic stethoscopes.
What sorts of accessories are available for stethoscope?
One of the most vital accessories for the stethoscope is the ear piece. Usually ear pieces are made of rubber as they are comfortable and improve acoustic function of the stethoscope. The standard earpieces can be replaced with moulded earpieces which provide improved sound transmission and comfort. The other accessories are binaural pieces, flexible tubing, a stem, and a chest piece.
The binaural pieces are generally made of metals, like aluminium or stainless steel, and they run from the ear pieces to the flexible tubing.
The flexible tubing connects the binaural pieces with stem and is made of latex rubber. And the stem comes with ball bearings and spring, both made of steel, inside. The chest piece consists of two sides that can be placed against the patient for sensing sound, a diaphragm (plastic disc) and bell (hollow cup). A stethoscope can alternate from a diaphragm to a cupped bell when turned by shifting the ball bearing of the stem in order to cover the pathway to the diaphragm that is not being used. A tunable diaphragm was introduced in the 1970s which allowed increased excursion of the diaphragm member in a “z”-axis with respect to the plane of the sound collecting area. The diaphragm is made of a rigid disk that is thin and flat and is composed of Bakelite or a suitable plastic. The chest piece, also houses a chill ring apart from the diaphragm and bell. The chill-ring stands between the patient’s body and the chest piece. Now days, stethoscopes also have an anti-chill ring. This ring is fixated on the diaphragm from both sides. This ring improves suction and transmits loud and clear sound waves. and is comfortable for the patients too.
Another accessory on a stethoscope is tags for identification and is an external accessory not present on all stethoscopes.
This concludes a comprehensive article on What is stethoscopes, their types, accessories and benefits.