Influence of Different Presentations of Oscillometric Data on Automatic Determination of Systolic and Diastolic Pressures

Abstract

Most non-invasive blood pressure measurements are based on either the auscultatory or the oscillometric technique. In this study, we performed an extensive analysis of the signals, i.e., responses of a microphone implanted in the cuff and pressure changes in the cuff, which can be recorded during such measurements. We applied several methods to separate the cuff deflation from the arterial pressure pulses, as well as to separate the microphone data into an audible part (Korotkoff sounds) and a low frequency part. The oscillometric technique is based on some empirically derived criteria applied to the oscillometric index, which is defined as a certain characteristic physical property of pressure pulses. In addition to the pressure pulses, which are a typical physical property used for the oscillometric index, we also used in this study other properties such as a time derivative and an audible part of data measured by a microphone implanted in the cuff (Korotkoff sounds). We performed a case study of 23 healthy subjects to evaluate the influence of different presentations of the oscillometric index on known height-based and slope-based empirical algorithms for the automatic determination of the systolic and diastolic blood pressures.