title: A new noninvasive method to measure blood pressure: results of a multicenter trial.
abstract: BACKGROUND
  Blood 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.
  
  
  METHODS
  Surgical and critically ill patients (n = 80) served as subjects for the study. BPs, pulse waveforms, and pulse rates measured via a 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.
  
  
  RESULTS
  Blood pressure measured noninvasively by the Vasotrac demonstrated excellent correlation (P<0.01) with BP measured via a radial arterial catheter (systolic r2 = 0.93; diastolic r2 = 0.89; mean r2 = 0.95). Differences in BP measured by the Vasotrac versus the radial arterial catheter were small. The mean+/-SD bias and precision were as follows: systolic BP 0.02+/-5.4 mm Hg and 3.9+/-3.7 mm Hg; diastolic BP -0.39+/-3.9 mm Hg and 2.7+/-2.8 mm Hg; mean BP -0.21+/-3.0 mm Hg and 2.1+/-2.2 mm Hg 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.
  
  
  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 measure BP frequently in a noninvasive fashion.
authors.affiliation: Department of Anesthesiology, University of Minnesota, Minneapolis 55455, USA. belan001@tc.umn.edu
authors.forename: K
authors.initials: K
authors.lastname: Belani
authors.forename: M
authors.initials: M
authors.lastname: Ozaki
authors.forename: J
authors.initials: J
authors.lastname: Hynson
authors.forename: T
authors.initials: T
authors.lastname: Hartmann
authors.forename: H
authors.initials: H
authors.lastname: Reyford
authors.forename: J M
authors.initials: JM
authors.lastname: Martino
authors.forename: M
authors.initials: M
authors.lastname: Poliac
authors.forename: R
authors.initials: R
authors.lastname: Miller
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D001795:Blood Pressure Determination; D006801:Humans; D008875:Middle Aged; D011674:Pulse; D017534:Radial Artery / Q000502:physiology