Assessment of Acoustic and Electronic Stethoscope Performance in the UH-60 Noise Environment

摘要

U.S. Army helicopters used to provide aeromedical transport are extremely noisy (105 dB) and this prevents auscultation with current generation stethoscopes. Four stethoscopes were tested in simulated helicopter noise at 70 to 100 dB to determine the detection threshold of a normal heart and breath sound. They were unable to detect physiological sounds in high noise but they did differ in performance (p < 0.001); the best being the acoustic, followed by the three electronic stethoscopes. An electronic stethoscope modified with the Communications Ear Plug performed better (p < 0.05) at 70 and 80 dB than at higher noise levels, implying that ambient noise was amplified after entering the sensing head. The threshold of noise for the detection of heart and breath sounds was 85 dB and 75-80 dB, respectively, indicating the need for at least a 30 dB improvement in signal to noise ratio. Future research must measure the threshold for detection of abnormal sounds to determine if a greater improvement is required. If the electronic stethoscope is to be developed further, as seems most pragmatic, a suitable sensor will be needed before successful auscultation in rotary-wing aeromedical transport aircraft is possible.