| abstract |
This invention is an apparatus for assessing cardiovascular status of a mammal comprising a system (20) for locally applying a pressure to an artery, capable of restricting blood flow through said artery, a wideband external pulse transducer (26), having an output, situated to measure acoustic signals proximate to said artery, and a computing device (32) receiving said output for calculating, based on said output, a peripheral vascular impedance value. The systolic and diastolic pressure are determined by an appearance and disappearance of a high frequency signal upon changes in cuff (10) pressure partially occluding arterial blood flow. The arterial pressure waveform is estimated by measuring the wide band acoustic emissions from a non-occluded artery. The peak and trough of the arterial pressure waveform are calibrated with the determined systolic and diastolic pressures. The systemic vascular resistance is computed by occluding blood flow with a supersystolic pressure, and calculating, based on a natural logarithm of a difference in amplitude between a first major systolic peak and first major systolic trough, and an amplitude of a second major systolic peak, a first order linear equation, which may be normalized for body surface area. The data combined may also be used to analyze cardiac output, arterial compliance, and dp/dt. |