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To the Editor:—
I wish to report on the use of increased air pressure to augment sounds in the stethoscope. At first this new principle was tried out on a stethoscope designed to let mothers hear fetal heart tones (as described in the November, 1964, issue of Obstetrics and Gynecology [24:800] ), and recently I have been trying the technique in normal stethoscopes for heart and lung examinations. An inflating bulb is attached by a Y-connector to the stethoscope tubing. The pressure usually used amounts to about 20 mm Hg and is without discomfort to the ears.The most pronounced feature is the reduction of background noises. Even though we are not aware of it, most of the time we are bombarded by noises from the air conditioning cr ventilation openings, the hum of fluorescent lamps and electric clocks, background music, remote conversations, and outside noises. Everyone has at some
Bacon AR. Air Pressure Stethoscope. JAMA. 1965;191(13):1087. doi:10.1001/jama.1965.03080130047022