Preliminary Characterization of the Noise-Immune Stethoscope (NIS) in High Ambient Noise Environment Using a Reverberation Sound Chamber

摘要

This report details the preliminary testing of advanced technology development for clinical auscultation in high noise environments. The Noise Immune Stethoscope (NIS) is a hybrid dual function device with electromechanical acoustic and ultrasound Doppler modes. Quantitative evaluation consisted of signal-to-noise ratio (SNR) calculations from 70 to 110 dB ambient noise. The acoustic mode preserved SNR > 0 to 90 dB of ambient noise for heart sounds and 100 dB for breath sounds. The Doppler mode preserved SNR of 20 dB to 110 dB for both heart and breath sounds. Qualitative assessment consisted of representative clinicians evaluating the device at 70, 90, and 110 dB. Clinical usefulness of the signal was determined to be of at least 'fair' rating at 70 dB and 90 dB for the acoustic mode and at 70 dB, 90 dB, and 110 dB in the Doppler mode for both heart and breath sounds. Apical position for heart sounds and midaxillary position for breath sounds was found to be preferential. Given this preliminary testing, the NIS represents a viable answer to the need for clinical auscultation in high noise environments across the spectrum of casualty care.