Central venous pressure measurements improve the accuracy of leg raising-induced change in pulse pressure to predict fluid responsiveness

Passive leg raising (PLR) is a maneuver performed to test the cardiac Frank-Starling mechanism. We assessed the influence of PLR-induced changes in preload on the performance of PLR-induced change in pulse pressure (Delta PLRPP) and cardiac output (Delta PLRCO) for fluid responsiveness prediction. Sedated, nonarrhythmic patients with persistent shock were included in this prospective multicenter study. Cardiac output and pulse pressure were measured at baseline (patient supine), during PLR (lower limbs lifted to 45A degrees) and after 500-ml volume expansion. Patients were classified as responders or not. In the whole population (n = 102), the area under the receiver-operating characteristic curve (AUC) was 0.76 for Delta PLRPP and was higher for Delta PLRCO (0.89)(p < 0.05), but likelihood ratios were close to 1. In patients with a PLR-induced increase in central venous pressure (CVP) of at least 2 mmHg (n = 49), Delta PLRPP and Delta PLRCO disclosed higher AUCs than in the rest of the population (0.91 vs. 0.66 and 0.98 vs. 0.83; p < 0.05); positive/negative likelihood ratios were 9.3/0.14 (8% cutoff level) and 30/0.07 (7% cutoff level), respectively. A PLR-induced change in CVP a parts per thousand yen2 mmHg was required to allow clinical usefulness of PLR-derived indices. In this situation, Delta PLRPP performed well for predicting fluid responsiveness in deeply sedated patients.