Effects of passive leg raising on cardiovascular functions as analyzed by fingertip pulse pressure profiles

Abstract

Objective: This study investigated the efficacy, duration, and possible adverse effects of passive leg raising (PLR) by examining the cardiovascular responses over the entire course of PLR. Methods/results:Continuous measurements of cardiovascular parameters using a non-invasive finger blood pressure measurement system during PLR were performed on 8 healthy subjects. Blood pressures significantly increased during PLR when legs were raised at 20°, 30°, and 40° angles. This blood pressure increase was observed to be primarily due to an increase in stroke volume, which remained almost constant until the final 10 min of PLR. No significant differences in cardiovascular parameters between the different PLR angles were observed. The return of the legs to the horizontal position after PLR caused transient changes in cardiovascular parameters, including considerable transient decreases in stroke volume and total peripheral vascular resistance. Relevance of these findings to the cases with deteriorated cardiovascular functions, in which, PLR may cause a severe transient decrease in blood pressure leading to transient cerebral ischemic attack, is discussed.Conclusion: PLR caused increases in blood pressure, primarily because of an increase in stroke volume. A 20° PLR angle was sufficient to produce these effects.