VASOCONSTRICTOR DRUG EFFECTS ON VASCULAR COMPLIANCE BY PULSE CONTOUR ANALYSIS.

The effect of the vasoconstrictors norepinephrine (NE) and angiotensin (AT) on vascular compliance in dogs was studied using pulse contour analysis (PCA). The femoral arterial pressure waveform was recorded. Resistance was determined from measured mean arterial pressure (MAP) and cardiac output (CO), obtained via thermodilution. The beginning of systole, diastole, and the end of diastole were manually marked on ten consecutive beats. A Gauss-Newton parameter-estimation algorithm calculated the Ai (i equals 1,. . . ,6) coefficients for the third-order function representing the femoral artery pressure. MAP, CO A2, A4 and A5 were then used to obtain vascular resistance and proximal and distal compliances. Measurements were made in the control state and during NE infusion and repeated in a recontrol period and during AT infusion. Vascular response to each vasoconstrictor was determined by the paired t-test, with each dog serving as its own control.