Medical Equipments Reviews

Perhaps there is a symbol of medicine’s most famous addition to the stethoscope. “Hearing aids” This simple allows doctors to hear voices coming from inside the body, especially heart and lung in addition to joints and partially blocked artery. Listening to these sounds with a stethoscope is called auscultation (Mediate auscultation), or usually just auscultation. Many sounds from the chest area can be utilized to diagnose diseases. Before the year 1818, the only existing method for examining the chest is touching with his hands, percussion, and sometimes, auscultation close to his ear pressed to his chest.

In A Treatise on the Diseases of the Chest and on Mediate Auscultation (1818), R. T. H. Laennec explain the purpose of direct ear to his chest: “This action is not always fun, both for physicians and patients; in women, this action is not only presumptuous, but also difficult to apply, and for those who are in hospital, this action sucks . ‘At the time, doctors routinely conduct home visits and treat nearly all patients in his home. Only patients who go to the charity hospital.

Laennec direct auscultation method until 1816 when he was examining a girl with common symptoms of heart disease. Because patients are obese, young, and women, he felt that the usual method of examination is not appropriate. However, he remembered that when one end of a piece of wood carved with a needle, a voice that will arise can be heard clearly if the other end of the timber affixed to the ear.

He immediately rolled up several sheets of paper forming a cylinder and glue one end into the ear and the other into the chest above the heart of the girl. The results have been dramatic and encouraging Laennec perfect appliance. Finally, he creates a hollow wooden cylinder with length 30 cm and inner diameter of about 1 cm and outer diameter of 4 cm. He calls this tool as a stethoscope, which means “look at my chest.” In his book, he reported his research on the stethoscope and the interpretation of natural sound and pathologically from the lungs, heart, and voice.

Stethoscope that is currently used is based on original artwork Lucienne. The main parts of the lid on the modern stethoscope (bell), which may be open or closed by a thin membrane, and earpieces.

Function Stethoscope

Open lid (open bell) function to adjust / match the impedance between skin and air. This section collects the sound from the contact area. Patient’s skin in contact with the lid open function like a diaphragm. Patient’s skin has a natural resonant frequencies which are effective for delivering heart sounds.

Resonant frequency is determined by the diameter of the lid and lid pressure on the skin. The more tightly drawn skin, the higher the resonant frequency. The bigger the diameter of the lid, the lower the resonant frequency of the skin. Desired voice range can be expanded by changing the size of the lid and to vary the pressure of the open lid of the skin (so the tension on the skin are also different). Low-frequency heart murmur will be heard if the stethoscope is not too hard pressed to the skin.

Lid closed (closed bell) is really just a lid that has a diaphragm with a specific resonant frequency, usually high, and inhibits the low-frequency noises. Resonant frequency is controlled by factors similar to factors that regulate the frequency of the open lid pressed to the skin. Stethoscope lid closed primarily used for listening to lung sound frequency higher than the heart sounds.

What is the best form of caps? Because we are dealing with a system that is closed at one end of satay away by the diaphragm pressure-sensitive ear drum-lid should be used in a volume as small as possible. The smaller the volume of gas inside the lid, the greater the pressure change caused by movement of the diaphragm at the other end of the bell.

Volume hoses should also be small, and should sound that is lost due to friction with the wall of the hose a bit. Restrictions by the small volume that shows a short interval of small diameter, whereas restriction by small friction shows large-diameter hose.

Therefore, if the diameter of the hose is too small, many voices will be lost due to friction. If the diameter is too large, the volume of displaced air becomes too much. In both, the efficiency is reduced. Below approximately 100 Hz, the length of the hose does not much affect the efficiency, but the • above this frequency, the efficiency is reduced along with the length of the hose. At 200 Hz, the change interval of length 7.5 cm to 66 cm cause a loss of 15 dB. A decision is agreed intervals with approximately 25 cm long and 0.3 cm in diameter.

Be attached earpiece fit in the ear because of air leakage reduces the audible sound. The lower the frequency, the more significant leak. Leakage also causes noise around us go into the ear. Earpiece is usually designed to follow the direction of the ear canal is bent slightly forward.