Blood pressure estimation based on pulse transit time and compensation of vertical position

A chronically high blood pressure (BP) may lead to arteriosclerosis and consequently is a risk factor for apoplectic stroke and cardiac infarction the main death causes in industrial countries. Hence, blood pressure recently has become one of the most relevant parameters for the assessment of a patients health status. For the purpose of a continuous monitoring of cardiovascular patients, we have investigated a non-invasive and continuous (beat-by-beat) blood pressure estimation model, which is not based on the occlusion of arteries (like i.e. the auscultatory or the oscillometric method), but on the so called pulse transit time (PTT). In two studies, on the one hand we have evaluated the assumed linear relationship between pulse transit time and blood pressure and on the other hand we have examined the correlation between heart-rate and pulse transit time respectively the influence of the measuring arm position on the measured PTT.