REAL-TIME MEASUREMENT OF VENTRICULAR STROKE VOLUME VARIATIONS BY CONTINUOUS ARTERIAL PULSE CONTOUR ANALYSIS

摘要

Ventricular stroke volume variation (SW) is estimated as a function of thestandard deviation of arterial blood pressure value measured over each of atleast two cardiac cycles, preferably over each of the cardiac cycles in acomputation interval covering a full respiratory cycle. In one embodiment,maximum and minimum standard deviation values are determined over thecomputation interval. SW is then estimated proportional to the ratio of thedifference between the maximum and minimum standard deviation values and themean of the standard deviation values. In another embodiment, SW is thenestimated proportional to the ratio of the standard deviation of the standarddeviation values and the mean standard deviation over the entire computationinterval. A pre-processing arrangement for improving reliability of estimatesof more general cardiac or hemodynamic parameters is also disclosed andinvolves smoothing with an approximating function, and sampling and low-passfiltering at an adjustable rate.