Simultaneous application of differential servo-oscillometry and volume-clamp plethysmography for continuous non-invasive recording of the finger blood pressure response to a hand postural change.

Continuous blood pressure recordings obtained by the volume-clamp method (Finapres 2300 BP monitor, Ohmeda, USA) were compared with measurements made by using the modified oscillometric method (UT9201 beat-to-beat monitor, University of Tartu, Estonia) in normal subjects during a hand postural change. Changes in the local blood pressure were induced in 11 healthy volunteers by passive elevation of the hand by 40 cm and lowering it again after one minute. We did not reveal a statistically significant difference between the group-averaged responses of the oscillometric finger mean blood pressure measurement device and those of Finapres during this test. The difference UT9201 minus Finapres equalled -1.3 +/- 3.1 mm Hg (p = 0.15). Blood pressure responses were similarly tracked by both beat-to-beat finger blood pressure monitors despite the considerable variability in the shape of the subjects' individual responses.