About Stethoscopes

Stethoscopes give physicians an auditory glimpse of the workings of their patients' internal organs. Physicians use stethoscopes for auscultation--the ability to listen to the sounds produced by internal organs. Doctors use stethoscopes to listen to breathing, gastrointestinal noises and heartbeats, and to aid in their diagnosis.

History

• In 1816, French doctor Rene' Laennec broke ground on the invention and evolution of the stethoscope. Not satisfied with the traditional method physicians used to listen to their patients' heart and lungs--previously doctors would place their ears against the patient's chest--Laennec invented a stethoscope made of paper; later he upgraded to wood. Laennec's cone only allowed doctors to monitor the heart and lungs with one ear, so in 1829 the problem was addressed. The introduction of the "binaural"--two earpieces--was not well received at first. But by the 1860s, they were standard.

Function

• Listening to your internal organs, doctors can check for things ranging from breathing problems to heartbeat irregularities. Stethoscopes give doctors that ability. The "chestpiece" of the stethoscope acoustically or electronically amplifies the vibrations of organs such as your heart and lungs. The vibrations travel through the hollow tubes of the stethoscope. The vibrations bounce off the doctor's eardrums and are interpreted as sound.

Features

• The three major parts of a stethoscope are the headset, tubing and chestpiece. The headset is composed of the earpieces and the metal ear tubes. The ear pieces direct sound down the user's ear canal and toward the eardrum; the metal ear tubes give the headset support. The tubing is composed of either one or two shafts. Stethoscopes with one shaft break into two shafts at the headset. Dual shaft models also separate at the headset--one shaft goes to the right ear piece and the other goes to the left. The chestpiece of the stethoscope features the "bell," "chill ring" and the "diaphragm." The bell amplifies low frequencies, and the diaphragm amplifies higher ones. The chill ring stands between the patient's chest and the chestpiece. On digital stethoscopes, the chestpiece houses an electronic amplifier.

Types

• The two main types of stethoscopes are acoustic and electronic. On acoustic models, high frequencies are picked up by the diaphragm and low frequencies are amplified by the bell. Acoustic models are extremely efficient, but if there could be any complaint against them it would be their low frequency amplification. Some sound may be muddled.

  Electronic models often feature an equalizer, noise filter and extended range to give doctors clean and crisp sound. The equalizer allows doctors to adjust the sound to various parameters. The noise filters allows doctors to pick up only relevant sounds, and the extended range allows for higher and lower frequencies.

Prevention/Solution

• Maintain a stethoscope by cleaning it with a bit of alcohol or soapy water applied to a cloth, then cleansing it with warm water and a dry cloth. Keep the stethoscope away from extreme temperatures for extended periods. Also, do not submerge it into a liquid of any kind.