Published in:
01-06-2010 | Original
Central venous pressure measurements improve the accuracy of leg raising-induced change in pulse pressure to predict fluid responsiveness
Published in: Intensive Care Medicine | Issue 6/2010
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Purpose
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 (ΔPLRPP) and cardiac output (ΔPLRCO) for fluid responsiveness prediction.
Methods
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 45°) and after 500-ml volume expansion. Patients were classified as responders or not.
Results
In the whole population (n = 102), the area under the receiver-operating characteristic curve (AUC) was 0.76 for ΔPLRPP and was higher for ΔPLRCO (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), ΔPLRPP and ΔPLRCO 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.
Conclusions
A PLR-induced change in CVP ≥2 mmHg was required to allow clinical usefulness of PLR-derived indices. In this situation, ΔPLRPP performed well for predicting fluid responsiveness in deeply sedated patients.