Apparatus and method for measurement and control of blood pressure

Abstract

Apparatus and method for measurement and control of blood pressure are disclosed. Blood pressure is indirectly continually monitored without use of a pressure transducer by sensing the pulse transit time to different sites in an artery, which transit time is inversely related to blood pressure, and developing pulses therefrom which are utilized to form arterial pulse waves, the comparison between which provide an indication of measured blood pressure. This indication is used to control blood pressure by controlling automatic release of a suitable drug into the body in amounts and over a time period as needed. The unit for measuring blood pressure includes two sets of electrodes positioned adjacent to but outside an artery at two sites (with the electrodes implanted or outside the body). Each electrode set is connected with an alternating current generator to supply alternating current at a low level to the electrodes and with demodulators to produce pulses due to a change of impedance offered to the supplied alternating current at each site. Each demodulator is connected with a detector to sense pulse arrival, and the detectors are connected with a time-interval measuring circuit. The system for control of blood pressure includes a blood pressure measuring unit that is connected with an electronic processing unit which controls a drug dispensing unit implanted in the body or attached outside the body.