Nowak Karolina M, Nowak Lukasz J
Department of Endocrinology, Centre of Postgraduate Medical Education, Warsaw, Poland.
Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland.
Postgrad Med J. 2017 Sep;93(1103):523-527. doi: 10.1136/postgradmedj-2017-134810. Epub 2017 Mar 13.
The force with which the diaphragm chestpiece of a stethoscope is pressed against the body of a patient during an auscultation examination introduces the initial stress and deformation to the diaphragm and the underlying tissues, thus altering the acoustic parameters of the sound transmission path. If the examination is performed by an experienced physician, he will intuitively adjust the amount of the force in order to achieve the optimal sound quality. However, in case of becoming increasingly popular auto-diagnosis and telemedicine auscultation devices with no such feedback mechanisms, the question arises regarding the influence of the possible force mismatch on the parameters of the recorded signal.
The present study describes the results of the experimental investigations on the relation between pressure applied to the chestpiece of a stethoscope and parameters of the transmitted bioacoustic signals. The experiments were carried out using various stethoscopes connected to a force measurement system, which allowed to maintain fixed pressure during auscultation examinations. The signals were recorded during examinations of different volunteers, at various auscultation sites.
The obtained results reveal strong individual and auscultation-site variability.
It is concluded that the underlying tissue deformation is the primary factor that alters the parameters of the recorded signals.
在听诊检查期间，将听诊器的膜型胸件按压在患者身体上的力会给膜片及下方组织带来初始应力和变形，从而改变声音传播路径的声学参数。如果检查由经验丰富的医生进行，他会直观地调整按压力量以获得最佳音质。然而，对于越来越流行的没有此类反馈机制的自动诊断和远程医疗听诊设备而言，可能存在的力不匹配对记录信号参数的影响问题便随之而来。
本研究描述了关于施加在听诊器胸件上的压力与所传输生物声学信号参数之间关系的实验研究结果。实验使用了连接到测力系统的各种听诊器进行，该系统可在听诊检查期间保持固定压力。在不同志愿者的不同听诊部位进行检查时记录信号。
所获结果显示出强烈的个体差异和听诊部位差异。
得出的结论是，下方组织变形是改变记录信号参数的主要因素。
