[Vascular-volume compensation method for noninvasive measurement of instantaneous arterial blood pressure: its usefulness in psychological research].

A new method of measuring blood pressure proposed previously by us (1980) was examined to evaluate its usefulness and applicability for psychological research. In this method, beat-to-beat systolic and diastolic pressures and pressure waveforms of the human finger are measured noninvasively by the use of a volume-servocontrol system, in which vascular volume changes, associated with intraarterial pressure and photo-plethysmographically detected, are compensated by an applied counterpressure (cuff pressure) to maintain a proper value corresponding to the unloaded vascular volume. At this state, the servocontrolled cuff pressure follows the intraarterial pressure instantaneously. Comparative data with direct measurement from the brachial artery were analyzed in a normotensive and a hypertensive subjects, and fairly valid regression coefficients as well as highly significant correlation coefficients were obtained between these two methods in each subject under various conditions. The present system can be used without any discomfort for the measurement of instantaneous arterial pressure for more than one hour, since the blood circulation in the finger is maintained. This system, therefore, was found to be an useful and practical means to study human subjects in various fields of psychology.