Blood pressure measurement

Abstract

Blood pressure measurement apparatus comprises means for variably occluding a body zone by progressive application of external pressure between levels respectively above systolic and below diastolic, means for detecting variations in blood volume in said zone during variable occlusion thereof, and means responsive to the occluding and detecting means to indicate as systolic and diastolic pressures the values of said external pressure respectively when the maximum and minimum detected volume levels are each about half way between zero and the maximum level following the last minimum which does not depart significantly from zero. The blood volume variations are preferably determined by reference to light transmission through the zone, suitably infrared, but other measures are suitable as determined by strain gauge, proton magnetic resonance or microwave absorbtion.

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