A Catheter Tip Method for Measurement of the Instantaneous Aortic Blood Velocity

Abstract

A method of determining the instantaneous aortic blood velocity from the pressure difference between two points along the axis of the aorta was derived from the Navier-Stokes equation. Experimental support for the derived formula was obtained in a flow model and in a living animal aorta. The flow model was a small piston pump which produced a known sinusoidal fluid velocity. The velocity computed from the formula compared well with the known values. In the living animal the formula yielded a velocity curve which compared favorably with those in the literature. The pressure difference from which the velocity was computed was obtained through a specially designed double lumen catheter attached to a differential pressure transducer. The method is applicable only to pulsatile flow.