Different responses of Finapres and the oscillometric finger blood pressure monitor during intensive vasomotion

Two different techniques for non-invasive beat-to-beat finger arterial bloo d pressure monitoring are compared in six healthy volunteers during local h and heating from 21 to 38 degrees C. The degree of peripheral vasoconstrict ion was established by recording the thumb pulp skin blood flow with a lase r Doppler instrument. For time episodes without vasoconstriction no systema tic difference in the readings of beat-to-beat mean blood pressure of the t wo monitors was found (the oscillometric device UT9201 minus Finapres diffe rence was 0.3 mm Hg, SD 0.3). For the episodes with vasoconstriction the di fference was statistically significant (6.7 mm Hg, SD 2.0). The oscillometr ic device minus Finapres difference and the laser Doppler signal were found to be inversely correlated, the correlation coefficient varying from -0.28 to -0.67. A disagreement between the readings of the instruments during in tensive vasomotion is assumed to be caused mainly by the tendency of the os cillometric method to overestimate the finger mean blood pressure under the condition of peripheral vasoconstriction.