BackgroundBlood pressure (BP) monitoring with arterial waveform display requires an arterial cannula. We evaluated a new noninvasive device, Vasotrac (Medwave, Arden Hills, MN) that provides BP measurements approximately every 12–15 beats and displays pulse rate and a calibrated arterial waveform for each BP measurement.MethodsSurgical and critically ill patients (n = 80) served as subjects for the study. BPs, pulse waveforms, and pulse rates measuredviaa radial artery catheter were compared with those obtained by the Vasotrac from the opposite radial artery. Data were analyzed to determine agreement between the two systems of measurement.ResultsBlood pressure measured noninvasively by the Vasotrac demonstrated excellent correlation (P< 0.01) with BP measuredviaa radial arterial catheter (systolic r2= 0.93; diastolic r2= 0.89; mean r2= 0. 95). Differences in BP measured by the Vasotracversusthe radial arterial catheter were small. The mean ± SD bias and precision were as follows: systolic BP 0.02 ± 5.4 mmHg and 3.9 ± 3.7 mmHg; diastolic BP −0.39 ± 3.9 mmHg and 2.7 ± 2.8 mmHg; mean BP −0.21 ± 3.0 mm Hg and 2.1 ± 2.2 mmHg compared with radial artery measurements. The Vasotrac pulse rates were almost identical to those measured directly (r2= 0.95). The Vasotrac BP waveform resembled those directly obtained radial artery pulsatile waveforms.ConclusionsIn 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 measure BP frequently in a noninvasive fashion.