What Is a Doppler Stethoscope?

The stethoscope is the most commonly used diagnostic tool for internal and external physicians, and it is the symbol of the physician. Modern medicine began with the invention of the stethoscope. Since the stethoscope was used clinically on March 8, 1817, its appearance and sound transmission methods have been continuously improved, but its basic structure has not changed much. It is mainly composed of the pickup part (chest piece), conductive part (hose) and listening (Ear pieces). ^[1]

Chinese name: Stethoscope
Foreign name: Stethoscope

Product properties: Diagnostic aids
Product Category: , medical equipment

Stethoscope product description

It usually consists of auscultation head, sound tube, and ear hook. (Frequency) non-linear amplification of the collected sound. ^[2]

Intended use of stethoscope

Used to collect and amplify sounds from the heart, lungs, arteries, veins and other internal organs. ^[2]

Examples of stethoscope names

Single-use stethoscope, dual-use stethoscope, medical stethoscope, fetal stethoscope, electronic stethoscope. ^[2]

Stethoscope auscultation head size

The larger the contact surface between the auscultation head and the body, the better the sound picked up. However, the surface of the human body is curved. If the chest piece is too large, the hearing head cannot fully contact the human body, and the audio can not only be picked up well, but also leak out from the gap. Therefore, the size of the auscultation head should be based on clinical needs. The diameter of stethoscope chestpieces is almost uniformly between 45-50 mm. The diameter of special chest pieces such as pediatrics is generally 30 mm, and that of newborns is 18 mm. ^[1]

Stethoscope stethoscope material

Materials play an important role in sound effects. Sound is transmitted through air or matter, and eventually turns into heat energy and disappears. The transmission of sound waves has almost no attenuation in heavy metals, and it is prone to attenuation in lighter metals or plastics. Therefore, high-grade stethoscopes must use stainless steel or even titanium and other heavy metals. ^[1]

Stethoscope Conducting part of stethoscope

Transmission lines are also important. The larger the inner diameter of the tube, the shorter the length, and the thicker the tube wall, the better the effect of the stethoscope. The international standard length is 27 inches. The material of the sound transmission tube of modern stethoscopes is generally PVC, which has good sound effects and beautiful appearance, but has poor tensile resistance. After using the stethoscope, she should be hung flat on both sides of the neck. This can be seen in foreign TV series and is the standard method of wearing a high-quality stethoscope. ^[1]

Clinical application of stethoscope listening head

When the heart is auscultated, the membrane-type head can listen to high-frequency sounds well, and the cup-type head is suitable for low-frequency sounds or noise. Modern stethoscopes are double-sided stethoscopes. There are both membrane and cup types on the auscultation head, and the conversion only needs to be rotated by 180 °. Experts recommend that clinical doctors use double-sided stethoscopes. There is another patented technology, called floating membrane technology. The membrane-type auscultation head can be changed into a cup-type head to listen to low-frequency noise in a special way. Both normal and abnormal lung sounds belong to high-frequency sounds, and only a membrane-type ear can be used for lung auscultation. ^[1]

Cold ring on stethoscope listening head

In diagnostics, the teacher taught to hold the stethoscope in his hand for a while before auscultating the patient, so that the cold metal on the stethoscope would not irritate the patient. The use of cold protection rings on modern stethoscopes is more user-friendly, reducing the irritation of patients by cold metals. ^[1]

Stethoscope earplugs

It is very important that the earbuds fit well with the ears. If the earbuds are not suitable, the sound will leak out, and at the same time, external noise can enter the confusion auscultation effect. Professional stethoscopes are generally equipped with closed earplugs with excellent sealing and comfort. ^[1]

Ear stethoscope for stethoscope

The new stethoscope ear springs are made of good toughness steel, which can be adjusted to a suitable tightness, which is more comfortable to wear, and it is also convenient to adjust the orientation of the earplugs. Because the ear canal and the side are not exactly 90 ° perpendicular, but are tilted slightly backward, the earplug should be tilted slightly forward when worn. The orientation of the earplugs of a high-quality stethoscope can be pre-fixed anatomically, which is called an anatomically correct earpiece.

The above technology combined with closed earplugs with high-fidelity effects can allow users to enjoy the unprecedentedly clear auscultation effect and comfortable feeling brought by using a high-quality stethoscope. ^[1]

Stethoscope type

Acoustic stethoscope

Acoustic stethoscopes are the earliest stethoscopes and medical diagnostic tools familiar to most people. This stethoscope is a symbol of the doctor, who wears it around his neck every day. Acoustic stethoscopes are the most commonly used. ^[1]

Electronic stethoscope

The electronic stethoscope uses electronic technology to amplify the sound of the body, and overcomes the high noise noise of the acoustic stethoscope. Electronic stethoscopes need to convert the electrical signals of sound waves to sound, which are then amplified and processed for optimal listening. Compared to acoustic stethoscopes, they are all based on the same physical principles.

Electronic stethoscopes can also be used with computer-aided auscultation programs to analyze recorded heart sound pathologies or innocent heart murmurs. ^[1]

Stethoscope shooting stethoscope

Some electronic stethoscopes have a direct audio output that can be used to connect to an external recording device, such as a laptop or MP3 recorder. By saving these sounds and listening to previously recorded sounds through a stethoscope headset, doctors can do further research, even remote diagnosis. ^[1]

Stethoscope fetus stethoscope

In fact, a fetal stethoscope or fetal mirror is also a type of acoustic stethoscope, but it is beyond the ordinary acoustic stethoscope. A fetal stethoscope can hear the sound of a fetus in the belly of a pregnant woman. It is very beneficial for nursing during pregnancy. ^[1]

Doppler stethoscope

A Doppler stethoscope is an electronic device that measures the Doppler effect of reflected waves from ultrasound waves inside a body organ. Motion is detected as frequency changes due to the Doppler effect and reflected waves. Therefore, Doppler stethoscopes are particularly suitable for handling moving objects, such as a beating heart. ^[1]

Use of stethoscope

How to wear a stethoscope properly

The stethoscope is designed with a patented ergonomic ear canal and ear sinus that conforms to the angle of the ear canal. It fits snugly into the ear canal of the listener without leaving you tired and uncomfortable. Before putting on the ear canal, please pull the ear canal of the stethoscope outwards; the metal ear canal should be tilted forward, put the ear canal into your outer ear canal, and close the ear sinus with your ear canal; the size of each ear canal It's different, you can choose the right size ear sinus. If the wearing method is correct, but the closeness of the ear sinus and ear canal is poor, and the auscultation effect is not good, please pull the ear tube outside to adjust its elasticity. Improper wearing methods can cause poor auscultation when the ear sinus and the ear canal are not in close contact. For example, when the ear tube is worn backward, it will be completely inaudible. ^[1]

Stethoscope clearing debris

If the stethoscope is left in the pocket or not regularly maintained, lint, fiber, or dust from clothing may block the stethoscope ear canal. Regular maintenance and cleaning can avoid this situation. ^[1]

Stethoscope to check tightness

The high-quality sound transmission effect of the stethoscope is related to the closeness between the stethoscope and the patient's body surface, and the stethoscope to the ear canal of the listener. Loose parts of the earpiece, loose Y-tube, and damaged Y-tube will affect the tightness. The better the tightness, the more accurately the sound from the patient's body can be introduced into the listener's ear. So check the status of your stethoscope often. ^[1]

Double-sided stethoscope

When using a double-headed stethoscope, the user needs to switch the clock face or membrane surface mode of the head to use. When using the film side, the clock face will be closed to avoid interference. vice versa. ^[1]

Stethoscope stethoscope effect

The stethoscope effect is common in in-ear headphones, that is, the earphone cable or the unit is subject to external impact or air friction. The vibration generated by the earphone cable is directly transmitted to the ear canal through the earphone cable. Very unpleasant voice.

Rear-mounted headphones can greatly improve the stethoscope effect. Personally, using a cable clip to clip the headset cable to your clothes can almost completely eliminate the stethoscope effect. ^[1]

Stethoscope recordable stethoscope

The core device of the stethoscope mainly includes 4 parts, a pickup, an amplification and filtering circuit, a processing chip and a Bluetooth module.

The main function of the pickup is to collect auscultation sounds, which is equivalent to a "microphone". The amplification and filtering device is a "speaker", which amplifies the auscultation sound. The processing chip is used to reduce the interference of noise and ensure that the ideal sound data is obtained. Finally, the Bluetooth module passes the sound signal to the computer for storage. The auscultation sound data collected by the Bluetooth stethoscope can be transmitted to a computer or can be connected to the hospital's HIS system (hospital information system) to match the patient's medical record. ^[1]