Integrated circuit system for digitizing arterial blood pressure and heart rate

Abstract

The measurement of arterial blood pressure during physiological, pharmacological or behavioral manipulations generates a vast amount of data which must be reduced. Hand scoring is both time consuming and inaccurate, while on-line computer analysis may be prohibitively expensive. As an alternative, an inexpensive circuit is described which digitizes, stores, and prints out mean systolic and diastolic blood pressure, as well as heart rate, from up to four analog channels. Channels are sequentially digitized, each for an interval dialed on the front panel (1–999 sec). For each beat, a peak and trough detector enables the systolic and diastolic accumulators, respectively, thus storing two ten bit words from the analog to digital converter. For each systolic occurrence, a count of one is added to the heart rate counter. At the end of the recording interval, an output routine prints the interval number, mean systolic pressure, mean diastolic pressure, and total heart beats. Offset and gain controls allow precise calibration of various transducer and polygraph amplifiers.