Study of Physics and Mathematics Principles of Cuff-Based Blood Pressure Measurement Methods

Abstract

The two most important methods used to measure blood pressure, the cuff-based methods of oscillometry and auscultation, are analyzed in this work. The goal is to understand the principles and shortcomings of each method in order to suggest some improvements that can be immediately implemented in the devices used in their application, or in the development of an improved technique. The discussion on the oscillometric method is approached by a study on the Maximum Amplitude Ratio Algorithm, believed to be one of the most common options that automated devices use to estimate blood pressure. The study includes analyzing different options of data representation and how this affects the accuracy of the method. Blood pressure measurement through auscultation is boarded from the perspective of psychoacoustics to understand how the human operator perceives the Korotkoff sounds that define the measurement. A study on the masking of these sounds serves as the foundation for a proposed algorithm to automate the procedure. Finally, physics-based mathematical models of the phenomena involved in each cuff-based measurement are derived based on models found in the literature. The equations obtained are compared to measured data by means of a non-linear least squares regression analysis, to determine which model most effectively represents the observed phenomena.