Comparison of mean systemic pressure in patients with acute circulatory failure receiving passive leg raising vs. pneumatic leg compression

Abstract

Background: Driving pressure of venous return (VR) is determined by a pressure gradient between mean systemic pressure (Pms) and central venous pressure (CVP). While passive leg raising (PLR) and pneumatic leg compression PC (PC) can increase VR, no study has explored the effects of these two procedures on Pms and VR-related hemodynamic variables. Methods: Forty patients with acute circulatory failure were enrolled in this analysis. All patients obtained both PLR and PC, and were measured for Pms, CVP, mean arterial pressure (MAP), cardiac output (CO), VR resistance (RVR), and systemic vascular resistance (SVR) at baseline and immediately after procedures. To minimize carry over effect, the patients were divided in 2 groups based on procedure sequence which were 1) patients receiving PLR first then PC (PLR-first), and 2) patients receiving PC first then PLR (PC-first). Both groups waited for a washout period before performing the 2 second procedure. Primary outcome was difference in Pms between PLR and PC procedures. Secondary outcome were differences in CVP, MAP, CO, RVR, and SVR between PLR and PC procedures. Results: No difference was found in baseline characteristics and no carry over effect was observed between the 2 groups of patients. Compared with baseline, both PLR and PC significantly increased Pms, CVP, MAP, and CO. PLR increased Pms (9.0±2.3 vs 4.8±1.7 mmHg, p<0.001), CVP (4.5±1.2 vs. 1.6±0.7 mmHg, p<0.001), MAP (22.5±5.6 vs. 14.4±5.0 mmHg, p<0.001), and CO (1.5±0.5 vs. 0.5±0.2 L/min, p<0.001) more than PC. However, PC, also significantly increased RVR (16 ± 27.2 dyn.s/cm5, p=0.001) and SVR (78.4 ± 7.2 dyn.s/cm5, p<0.001) but no difference in PLR group. Conclusion: Among patients with acute circulatory failure, PLR increased Pms, CVP, MAP, and CO more than PC.