Automatic sphygmomanometer for predictively measuring pressure by

Abstract

An automatic sphygmomanometer of this invention is arranged to predict, on the basis of the relationship between cuff pressure and the amplitude of a pulse wave, maximal and minimal blood pressures while the cuff pressure is being increased. This automatic sphygmomanometer is capable of minimizing the discomfort inflicted upon a subject by increasing or reducing the cuff pressure to the neighborhood of a predicted maximal or minimal blood pressure at a relative high rate. Concretely, the pressure in the cuff is increased at a relatively high pressure-increasing rate to a level immediately below the predicted maximal blood pressure and, thereafter, the pressure-increasing rate is reduced to a rate suitable for measurement. The maximal blood pressure is in turn measured. When the minimal blood pressure is to be measured, as soon as the maximal blood pressure has been measured, the cuff pressure is rapidly reduced to a level immediately above the predicted minimal blood pressure and, then, the pressure-reducing rate is reduced. The minimal blood pressure is measured under the condition of this reduced rate. Accordingly, it is possible to minimize the discomfort inflicted upon the subject due to pressure and a lengthy operation. Moreover, this invention eliminates the awkward operation of setting a pressure which is approximately 30 mmHg higher than the expected maximal blood pressure.