Patent ID: 6805671
Filing Date: 2004-10-19
Classification: A61B

Abstract:
A method for measuring blood pressure of a patient comprising the steps of:sensing Korotkoff sounds using an array of primary acoustic sensors placed on skin of a patient's limb over an artery occluded by applying pressure thereupon, the primary acoustic sensors being placed in rows and columns forming a planar array, the planar array being placed on the patient's skin such that the rows are oriented approximately perpendicular to the artery and the columns are oriented approximately parallel to the artery, each primary acoustic sensor for producing a first acoustic signal in dependence upon the Korotkoff sounds; sensing noise and vibrations using a secondary acoustic sensor for producing a secondary acoustic signal in dependence upon noise and vibrations; sensing the pressure applied to the occluded artery using a pressure transducer for sensing pressure and for providing a pressure signal in dependence thereupon; providing the first acoustic signal of each primary acoustic sensor, the secondary acoustic signal and the pressure signal to a processor; using the processor beamforming the first acoustic signals based on a focused beamformer for beamforming approximately perpendicular to the artery and a plane wave beamformer for beamforming approximately parallel to the artery in order to produce an output beam time series in dependence thereupon; processing the first acoustic signals for removing interference due to noise and vibrations using the secondary acoustic signal in an adaptive interferer canceller; detecting the Korotkoff sounds based on the beam time series; and, determining at least one of systolic and diastolic pressure by relating the detected Korotkoff sounds to the pressure signal.