A Method for Determining Cardiac Stroke Volume From Arterial Pressure That Is Especially Applicable to Ectopic Beats

摘要

The theoretical development of a method for estimating stroke volume from phasic arterial pressure is presented. The method is designed to be especially applicable to ectopic beats when stroke volume can change significantly from beat to beat. The derived formulae contain only one sensitive free parameter which is the mean vascular resistance, allowing its evaluation from values of mean cardiac output obtained via indicator dilution or Fick techniques. The theoretical development is based upon the abstraction of the cardiovascular system to a sequence of increasingly realistic (and complex) Windkessel theories. The most accurate theory accounts for arterial distensibility being dependent upon instantaneous pressure, finite pulse transmission velocity, and upon change in the pulse shape as it propagates down the arterial tree. Experimental validation of the method is discussed. (Author)