Variation of perfusion index to evaluate fluid responsiveness during the preload challenge tests: a systematic review and meta-analysis.

Background: The ability of perfusion index (PI) for predicting fluid responsiveness has been extensively studied with conflicting results. This meta-analysis evaluated the value of variation of PI (ΔPI) for predicting fluid responsiveness in adult patients undergoing preload challenge tests. Methods: PubMed, Embase, and Cochrane Library were searched up to 20th July 2026. Pooled sensitivity, specificity, diagnostic odds ratio (DOR), and area under the summary receiver operator characteristic curve (AUROC) were calculated. Results: Overall, nine studies including 492 preload challenge tests were administered to 419 patients in this review, of whom 52% were fluid responsive. The cutoff values of ΔPI were increased between 1.024% and 33% or decreased between -7% and -40%. Pooled sensitivity and specificity were 0.79 (95% CI: 0.71-0.85) and 0.82 (95% CI: 0.75-0.87), respectively. DOR was 17 (95% CI: 10-30) and AUROC was 0.88 (95% CI: 0.85-0.90), indicating good diagnostic accuracy. Heterogeneity was low ( Conclusions: Our meta-analysis suggests that ΔPI may serve as a promising adjunct non-invasive marker for predicting fluid responsiveness during preload challenge tests, but the current evidence base remains limited, heterogeneous, and at risk of bias.