Passive leg raising for predicting fluid responsiveness: importance of the postural change

For predicting fluid responsiveness by passive leg raising (PLR), the lower limbs can be elevated at 45A degrees either from the 45A degrees semi-recumbent position (PLRSEMIREC) or from the supine position (PLRSUPINE). PLRSUPINE could have a lower hemodynamic impact than PLRSEMIREC since it should not recruit the splanchnic venous reservoir. Prospective study A 24-bed medical intensive care unit. A total of 35 patients with circulatory failure who responded to an initial PLRSEMIREC by an increase in cardiac index a parts per thousand yen 10%. PLRSEMIREC, a transfer from the semi-recumbent to the supine position and PLRSUPINE were performed in all patients in a random order before fluid expansion (500 mL saline). PLRSEMIREC, supine transfer and PLRSUPINE significantly increased the pulse-contour derived cardiac index (PiCCOplus) by 22 (17-28)%, 9 (5-15)% and 10 (7-14)% (P < 0.05 vs. PLRSEMIREC for the latter two), respectively. These maneuvers significantly increased the right ventricular end-diastolic area (echocardiography) by 20 (14-29)%, 9 (5-16)% and 10 (5-16)% (P < 0.05 vs. PLRSEMIREC for the latter two) and the central venous pressure by 33 (22-50)%, 15 (10-20)% and 20 (15-29)% (P < 0.05 vs. PLRSEMIREC for the latter two), respectively. Volume expansion significantly increased cardiac index by 27 (21-38)% and all patients were responders to volume expansion. If an increase in cardiac index a parts per thousand yen 10% is considered as a positive response to PLRSUPINE, 15 (43%) patients would have been unduly predicted as non-responders to fluid administration by PLRSUPINE. PLRSEMIREC induces larger increase in cardiac preload than PLRSUPINE and may be preferred for predicting fluid responsiveness.