METHOD AND APPARATUS FOR DETECTING BLOOD PRESSURE BY BLOOD PRESSURE SOUNDS IN THE PRESENCE OF SIGNIFICANT NOISE

摘要

A method and apparatus is provided for detecting blood pressure sounds produced by the opening snap of an artery in a patient in the presence of significant noise using the phase information contained in two microphone signals. The two microphones (16, 18) are placed on a patient along the axis of an artery with their centers separated by a distance, such that blood pressure sounds picked up by the microphones will be out of phase. Pressure is applied to the artery such that the artery opens and closes during each heart cycle, the opening snap of the artery producing blood pressure sounds. The two microphone signals are filtered, preferably using band pass filters (48, 50) having pass bands corresponding to the frequency of the blood pressure sounds. The filtered microphone signals are sampled and multiplied together or convolved in the frequency domain to generate a microphone signal product, which indicates whether the blood pressure signal is valid.