Accuracy of some algorithms to determine the oscillometric mean arterial pressure: a theoretical study

To compare different algorithms to determine the oscillometric mean arterial pressure.

Using a computer-based model, the accuracy of five algorithms was studied: maximum amplitude algorithm, 33 and 40% formulas calculating the mean arterial pressure from oscillometrically measured systolic and diastolic pressures, and two oscillation shape-based algorithms. We examined to which extent the tested algorithms were influenced by variations in four affective factors: pulse pressure, arterial pressure pulse shape index, and two shape indices (symmetry and steepness) of the artery-cuff pressure/volume relationship. Different ranges of variation of affecting factors were applied.

The accuracy of the oscillation shape-based algorithms was found to be higher than the accuracy of the oscillation amplitude-based algorithms. The oscillation mean shape index-based determination had an almost 2-3 times narrower error range compared with the maximum amplitude algorithm. Modeling showed that the mean arterial pressure changes resulting from the varying shape of the arterial pressure waveform cannot be measured using the oscillation amplitude-based algorithms, whereas these changes can be determined effectively using the oscillation shape-based algorithms.

The maximum amplitude algorithm has a relatively low accuracy for the estimation of the mean arterial pressure. Its error range is even larger than that of estimates calculated by the 33 or 40% formulas from the oscillometrically measured systolic and diastolic blood pressures. A considerably higher accuracy can be achieved by applying the oscillation shape-based algorithms.