Journal of Applied Physiology, Vol 43, Issue 2 379-381, Copyright © 1977 by American Physiological Society
Semiautomatic blood pressure monitor utilizing an electronic sphygmomanometer
R. Winn, J. R. Hildebrandt and J. Hildebrandt
A semicontinuous but noninvasive blood pressure monitoring system is
described. It consists of a commercial electronic sphygmomanometer which
utilizes a microphone under an occluding arm cuff to detect the Korotkoff
sounds, a pressure transducer, and a simple gating circuit. The gate passes
the cuff pressure signal to a recorder only when a proper Korotkoff sound
is detected. The cuff is rapidly inflated to just above the anticipated
systolic pressure, then deflated at a steady rate of 2-6 Torr/heartbeat.
When diastolic pressure is passed, the cuff is fully deflated momentarily
before repeating the cycle. Systolic and diastolic pressures can be
recorded up to 3 or 4 times/min. Spurious signals are rejected by the
electronics which process the output of the microphone. This allows the use
of the system in experiments on exercising man and in environments where
unwanted signals exist. The system offers greater versatility than
commercial semiautomatic pressure monitors, at less than half the cost.
