An influence of multiple affecting factors on characteristic ratios of oscillometric blood pressure measurement

Abstract

We studied how interactions between the arterial pressure pulse and mechanical characteristics of the arterial wall and occluding cuff can modulate the characteristic ratios used for oscillometric estimation of systolic and diastolic blood pressures (ksyst and kdiast, respectively). Using an integrated artery-cuff pressure/volume model with different arterial pressure pulses as input signals we obtained the oscillation envelopes and calculated characteristic ratios. For the tested range of affecting factors, ksyst varied from 0.41 to 0.81 and k diast from 0.56 to 0.90. This gives evidence that oscillometric estimation may lead to substantial inaccuracies if fixed characteristic ratios are used. Errors can be reduced by considering changes in the pulse pressure amplitude and in the symmetry index of the artery-cuff pressure/volume relationship. © 2011 Springer-Verlag.