  During the COVID-19 outbreak, the auscultation of heart and lung sounds has
played an important role in the comprehensive diagnosis and real-time
monitoring of confirmed cases. With clinicians wearing protective clothing in
isolation wards, a potato chip tube stethoscope, which is a secure and flexible
substitute for a conventional stethoscope, has been used in the first-line
treatment of COVID-19 by Chinese medical workers. In this study, an optimal
design for this simple cylindrical stethoscope is proposed based on the
fundamental theory of acoustic waveguides. Analyses of the cut-off frequency,
sound power transmission coefficient, and sound wave propagation in the uniform
lossless tube provide theoretical guidance for selecting the geometric
parameters for this simple cylindrical stethoscope. In addition, relevant
suggestions about surface treatments for the inner wall as well as the use of
noise-reduction earplugs are also part of this optimal design.
