Accuracy of plethysmographic indices as predictors of fluid responsiveness in mechanically ventilated adults: a systematic review and meta-analysis.

Purpose: To systematically review the accuracy of the variation in pulse oxymetry plethysmographic waveform amplitude (∆POP) and the Pleth Variability Index (PVI) as predictors of fluid responsiveness in mechanically ventilated adults.
Methods: MEDLINE, Scopus and the Cochrane Database of Systematic Reviews were screened for clinical studies in which the accuracy of ∆POP/PVI in predicting the hemodynamic response to a subsequent fluid bolus had been investigated. Random-effects meta-analysis was used to summarize the results. Data were stratified according to the amount of fluid bolus (large vs. small) and to the study index (∆POP vs. PVI).
Results: Ten studies in 233 patients were included in this meta-analysis. All patients were in normal sinus rhythm. The pooled area under the receiver operating characteristic curve (AUC) for identification of fluid responders was 0.85 [95 % confidence interval (CI) 0.79-0.92]. Pooled sensitivity and specificity were 0.80 (95 % CI 0.74-0.85) and 0.76 (0.68-0.82), respectively. No heterogeneity was found within studies with the same amount of fluid bolus, nor between studies on ∆POP and those on PVI. The AUC was significantly larger in studies with a large bolus amount than in those with a small bolus [0.92 (95 % CI 0.87-0.96) vs. 0.70 (0.62-0.79); p < 0.0001]. Sensitivity and specificity were also higher in studies with a large bolus [0.84 (95 % CI 0.77-0.90) vs. 0.72 (0.60-0.82) (small bolus), p = 0.08 and 0.86 (95 % CI 0.75-0.93) vs. 0.68 (0.56-0.77) (small bolus), p = 0.02], respectively.
Conclusions: Based on our meta-analysis, we conclude that ∆POP and PVI are equally effective for predicting fluid responsiveness in ventilated adult patients in sinus rhythm. Prediction is more accurate when a large fluid bolus is administered.