Comparison of stethoscope bell and diaphragm, and of stethoscope tube length, for clinical blood pressure measurement

Thirty-two healthy subjects (19 male and 13 female) were recruited from May to July 2014, with ages from 24 to 68 years. For each subject, there were two repeat sessions with four measurements for each, giving a total of 8 recordings. There was a time interval of at least 1 min between the four measurements within a session and at least 4 min between the two sessions, allowing recovery cardiovascular hemodynamics. The order of the four measurements within the sessions for each subject was randomised. During cuff deflation, the cuff pressure and Korotkoff sounds were digitally recorded at a sample rate of 2,000 Hz. Cuff pressure was linearly deflated at a standard rate of 2-3 mmHg/s. The deflation rate was controlled by an automatic device.

三十二名健康受试者（其中男性19名，女性13名）于2014年5月至7月期间招募，年龄介于24至68岁之间。每位受试者均进行了两次重复实验，每次实验包含四次测量，共计8次记录。每次实验中四次测量之间的时间间隔至少为1分钟，两次实验之间至少为4分钟，以便心血管动力学得到恢复。每位受试者实验中四次测量的顺序是随机排列的。在袖带放气过程中，袖带压力和Korotkoff声音以2,000赫兹的采样率进行数字记录。袖带压力以每秒2至3毫米汞柱的标准速率线性放气。放气速率由自动设备控制。