Method and device for detecting and assessing reactive hyperemia using segmental plethysmography

A method for measuring arterial blood flow in a subject, comprising:

• performing a first segmental cuff plethysmography on a portion of the body of the subject with an inflatable cuff having a cuff pressure, wherein the cuff pressure is increased to a peak cuff pressure and immediately reduced from the peak cuff pressure;
• generating a pressure descent curve and a cuff compliance (dV/dP)cuff curve based on change in cuff pressure and cuff volume;
• generating an arterial compliance (dV/dP)artery curve;
• obtaining values of (dV/dP)artery at any transmural pressure based on said arterial compliance (dV/dP)artery curve;
• taking derivative of said pressure descent curve to obtain a (dP/dt)artery curve;
• multiplying (dP/dt)artery by (dV/dP)artery to obtain an arterial flow curve (dV/dt)artery.

An apparatus for measuring arterial blood flow in a subject, comprising:

• an inflatable cuff;
• a metering pump for inflating the cuff;
• a pressure transducer for measuring the pressure inside the cuff;
• and
• a computer configured to:
• generate a pressure descent curve and a cuff compliance curve by directly measuring volume change in said cuff with said metering pump and pressure change inside the cuff with said pressure transducer;
• calculate an arterial compliance curve during the inflation and deflation process of the cuff;
• and
• generate an arterial compliance (dV/dP)artery curve;
• obtain values of (dV/dP)artery at any transmural pressure based on the arterial compliance (dV/dP)artery curve;
• take derivative of said pressure descent curve to obtain a (dP/dt)artery curve;
• multiply (dP/dt)artery by (dV/dP)artery to obtain an arterial flow (dV/dt)artery curve.