An experimental and mathematical study of non-invasive blood pressure measurement

In order to reach a deeper understanding of the main errors introduced by non-invasive blood pressure measurements based on Riva-Rocci method, we performed a quantitative study of the pressure profile induced in the arm by an occluding cuff. The work includes both quantitative experiments performed by means of an original pneumatic system and theoretical analyses using three mathematical models. The first trials were performed using a single cuff. The results of these studies demonstrated that pressure profile in the arm is strongly influenced by the value of the tissue elastic parameters, Young´s modulus and Poisson´s ratio. However these parameters could not be identified using the information provided by a single cuff. Consequently, we are now using a more complex method based on two contiguous cuffs, which can be separately inflated and deflated. The first experimental and mathematical results indicate that the elastic properties of the arm can be now characterized, and the proposed approach may contribute to improve the accuracy of non-invasive blood pressure measurement.