Accuracy of an ultrasound Doppler servo method for noninvasive determination of instantaneous and mean arterial blood pressure.

A new noninvasive method for determining arterial blood pressure is presented. Using a fast servo system, the pressure in the arm cuff is controlled so that the flow is maintained at a low value. Transcutaneous ultrasound Doppler techniques are used to detect flow to the artery. Comparison with invasive pressure measurements demonstrated that the servo method reproduced beat-to-beat variations in arterial blood pressure faithfully. Mean arterial blood pressure was determined from the noninvasive recordings using the same mathematically valid procedure as was used for the invasive recordings. The deviation between the invasive and the noninvasive determinations of this measurement was -0.6 +/- 2.2 mm Hg (mean +/- SD) in 23 subjects.