A new noninvasive method to measure blood pressure - Results of a multicenter trial

Background: Blood pressure (BP) monitoring with arterial waveform display r equires an arterial cannula. We evaluated a new noninvasive device, Vasotra c (Medwave, Arden Hills, MN) that provides BP measurements approximately ev ery 12-15 beats and displays pulse rate and a calibrated arterial waveform for each BP measurement. Methods: Surgical and critically ill patients (n = 80) served as subjects f or the study. BPs, pulse waveforms, and pulse rates measured via a radial a rtery catheter were compared with those obtained by the Vasotrac from the o pposite radial artery. Data were analyzed to determine agreement between th e two systems of measurement. Results: Blood pressure measured noninvasively by the Vasotrac demonstrated excellent correlation (P < 0.01) with BP measured via a radial arterial ca theter (systolic r(2) = 0.93; diastolic r(2) = 0.89; mean r(2) = 0.95). Dif ferences in BP measured by the Vasotrac versus the radial arterial catheter were small. The mean +/- SD bias and precision were as follows: systolic B P 0.02 +/- 5.4 mmHg and 3.9 +/- 3.7 mmHg; diastolic BP -0.39 +/- 3.9 mmHg a nd 2.7 +/- 2.8 mmHg; mean BP -0.21 +/- 3.0 mm Hg and 2.1 +/- 2.2 mmHg compa red with radial artery measurements. The Vasotrac pulse rates were almost i dentical to those measured directly (r(2) = 0.95) The Vasotrac BP waveform resembled those directly obtained radial artery pulsatile waveforms. Conclusions: In surgical and critically ill patients, the Vasotrac measured BP, pulse rate, and displayed radial artery waveform, which was similar to direct radial arterial measurements. It should be a suitable device to mea sure BP frequently in a noninvasive fashion.