Accuracy of radial artery blood pressure determination with the Vasotrac (TM)

Purpose: To evaluate the accuracy of a new non-invasive method (Vasotrac(TM )) to measure blood pressure (BP) with accompanying arterial wave-form and pulse-rate display when compared with BP and waveform measured invasively. Methods: Healthy volunteers (n=53) served as subjects far the study. Blood, pressures and waveforms obtained via a radial artery catheter (IABP) were compared with non-invasive measurements obtained every 12-15 beats by the n ew system (Vasotrac BP) from the opposite radial artery. In a sub-group of volunteers (n=11), BP was acutely increased and decreased with isoprotereno l, phenylephrine and sodium nitroprusside; Data were analyzed by determinin g correlation and agreement between the two systems of measurement. Wavefor ms obtained by the two systems were qualitatively examined. Results: Non-invasive BP measured every 12-15 beats by the Vasotrac correla ted with IABP (systolic r(2) = 0.89; diastolic r(2) = 0.88; mean r(2) = 0.9 4). The actual values obtained by the two methods agreed closely with > 90% of readings being within 2SDs when plotted by the Bland Altman method. Thi s was also true during vasoactive drug infusion when BP changed acutely and swiftly. During this dynamic period, Vasotrac BP accurately tracked the ch anges in IABP with correlations (systolic r(2)= 0.82; diastolic r(2) = 0.89 ; mean r(2) = 0.95) and close agreement (> 90% of readings were within 2 SD s in the Bland Altman plot). Waveforms displayed by the two systems were qu alitatively very similar. Pulse rates measured by the two systems were iden tical. Conclusions: The Vasotrac system displayed an arterial waveform which was s imilar to that obtained directly and measured BP and pulse rate accurately It should be a convenient device to measure BP continually in a non-invasiv e fashion.