Since blood pressure measurement are influenced by psychic factors, it is desirable that blood pressure be measured in noninvasive physiological conditions especially in the evaluation of autonomic nervous function. Combining a noninvasive continuous blood pressure monitor based on the principle of tonometry (CBM-7000), an ECG monitor (BP-306), and a personal computer, a system for simultaneous manometric and electrocardiographic measurement and analysis was developed. The blood pressure measurements (CBM) obtained with the CBM-7000 were compared with direct measurements (IBP) made through radial artery catheterization to evaluate the clinical applicability of the CBM-7000,When the CBP and IBP data obtained in 2 healthy persons and 1 patient with an autonomic nervous disorder were compared, the CBP waveforms were closely correlated to the IBP data. An excellent correlation (r>0.900) between CBP and IBP data was obtained in all the subjects so that CBP measurements can be considered highly reliable. In order to obtain accurate blood pressure measurements by tonometry, it is necessary to fix the sensor at the center of the radial artery. To meet this requirement it seems to be of critical importance to immobilize the antebrachium and the first finger. Judging from the results of the present study the noninvasive sontinuous blood pressure mesurement system incorporating the CBM-7000 seems to be of sufficient clinical value.
