Arterial pulse wave velocity: a limited index of systemic vascular resistance during normotensive anesthesia in dogs

We investigated the relationship between systemic vascular resistance (SVR) and arterial pulse wave velocity (PWV) to determine if PWV might provide an index of SVR during anesthesia. A wide range of SVR measurements was obtained pharmacologically in 8 dogs during halothane anesthesia at each of three mean blood pressure (BP) ranges: low (40 to 60 mm Hg), medium (90 to 110 mm Hg), and high (140 to 160 mm Hg). For pooled data the SVR-PWV linear correlation coefficient at the low BP range was 0.44; at the medium BP range it was 0.75; in both cases p was less than 0.001. At the high BP range the correlation coefficient was -0.06 and was not significant. We conclude that only directional trends in SVR during normotensive anesthesia (medium BP range) can be estimated using arterial PWV measurements. Thus, on the basis of this study, PWV measurement cannot be used as a direct substitute for SVR measurement. Further study of SVR-PWV relationships is needed to determine if noninvasively measured PWV might provide a more accurate estimate of SVR.