The Science Journal of the American Association for Respiratory Care

2005 OPEN FORUM Abstracts

A COMPARISON OF STETHOSCOPE BELL VERSUS DIAPHRAGM CHEST PIECES

Jonathan B. Waugh, PhD; Dale W. Callahan, PhD; Wesley M. Granger, PhD; George A. Mathew, MS. University of Alabama at Birmingham, Birmingham, AL.

BACKGROUND: We categorized stethoscope models by intended use and price to
determine if there was a difference based on analysis of power spectral density
(PSD).

METHODS: Thirty-eight different adult models were categorized into five
groups: high cardiology (Hi Cardio), cardiology, patient assessment (P Assess),
basic assessment (BA/BP), and disposable. Not all models had bell chest pieces so
the comparison is based on measurement though the diaphragm chest piece using a
pink noise input from 50-3000 Hertz. Four copies of each model were tested and the
data averaged for comparison by ANOVA. The area under the curve (AUC)
measured from PSD plots of the relative change in decibels (dB) (difference of
stethoscope output signal from reference input signal) for each model versus the
measured frequency range was compared.



RESULTS: The Bonferroni (All-Pairwise) Multiple Comparison Test indicated no
statistical difference (alpha level 0.05) among the four groups with the lowest AUC
averages (the lower the AUC the less signal loss).

CONCLUSION: The results
indicate that differences in audio performance of stethoscopes cannot be based on
marketing classification or price. Only the disposable group was different from one
of the remaining four groups. This does not mean that individual scopes are not
different from others across the different groups.

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