NON-INVASIVE METHOD AND APPARATUS FOR MEASURING PHYSIOLOGIC PARAMETERS

摘要

The present invention provides means and methods for noninvasively identifying the blood pressure characteristics in each of the seven types of vessels in the circulatory system, including the central venous pressure (CVP) through a single monitoring system using fluid depletion plethysmography. Known pressure is applied to a body region in increasing amounts to force blood volume from the body region in step-wise fashion through each vessel type. Blood volume depletion for each vessel type is measured by the increasing electrical impedance of the body part during depletion and is plotted against the increasing pressure data. The resulting series of slope changes within the plotted curve reveals the blood pressure for each vessel type. The data obtained may further be used to determine vessel wall compliance/tension as well as standard measurements such as pulse and large artery systolic and diastolic pressure. Release of the applied pressure may then yield similar data by measuring blood volume replenishment against the decreasingly applied pressure during the same diagnostic operation. The method is not dependent on oscillometric or pulsatile measurement methods. The electrical leads of the impedance/volume sensor and the means for applying pressure to the body part are coextensive to ensure accurate indication of blood volume depletion and replenishment in the body region under pressure and may be incorporated into a single integrated structure.