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.