RESUMO
Background: The COVID-19 pandemic has continued for more than two years since its outbreak. Due to the clinical auscultation needs of doctors when wearing airtight protective clothing, a cylindrical tube stethoscope was proposed to address this problem. However, the idea has been questioned by some experts. Methods: To address these questions, we performed three-part experiments using cylindrical tube stethoscopes. First, we performed laboratory tests to detect the sound intensity from a cylindrical tube stethoscope. Second, we improved the cylindrical tube stethoscope to achieve better results. Third, we revealed the difference in the auscultation effects of the cylindrical tube stethoscope and a conventional professional 3 M stethoscope. Results: From these experiments, we found that a narrow cylindrical tube with a diameter of 4.2 cm and a length of 20 cm equipped with a silicone gasket better auscultation of heart sounds. A cylindrical tube stethoscope and a 3 M stethoscope were used to perform stethoscope tests on 10 volunteers. The alveolar lung sounds were 44.478 decibels vs 49.529 decibels, the heart sounds were 46.631 decibels vs 41.109 decibels, and the intestinal sounds were 40.132 decibels vs 43.787 decibels, respectively. Conclusion: This improved cylindrical tube stethoscope can meet the auscultation requirements for cardiorespiratory and abdominal diagnosis during infectious disease pandemics.
RESUMO
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 by Chinese medical workers in the first-line treatment of COVID-19. In this study, an optimal design for this simple cylindrical stethoscope is proposed based on the fundamental theory of acoustic waveguides. Analyses of the cutoff 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. A basic investigation into the auscultatory performances of the original tube and the optimal tube with proposed dimensions was conducted both in a semi-anechoic chamber and in a quiet laboratory. Both experimental results and front-line doctors' clinical feedback endorse the proposed theoretical optimization.