Context-specific clinical applicability of the end-expiratory occlusion test to predict fluid responsiveness in mechanically ventilated patients: A systematic review and meta-analysis

BACKGROUND The emergence of context-specific clinical evidence from the end-expiratory occlusion test (EEOT) may change the perception of its operative performance to predict fluid responsiveness. OBJECTIVE(S) Assessment of predictive performance of the EEOT in the intensive care unit (ICU) and operating room. DESIGN Systematic review of observational diagnostic test accuracy studies with meta-analysis. DATA SOURCES MEDLINE, Embase and Scopus were used as data sources for relevant publications until February 2024. ELIGIBILITY CRITERIA Prospective clinical studies in which the EEOT was used to predict fluid responsiveness in mechanically ventilated adults, regardless of the clinical care context. The operative performance characteristics must also have been reported. RESULTS Twenty-four studies involving 1073 adult patients (588 receiving intensive care and 485 in the operating room) were systematically reviewed, and 22 studies comprising 1049 volume expansions were meta-analysed. The pooled sensitivity [95% confidence interval (CI)] of the EEOT was 0.87 (0.81 to 0.92), and the pooled specificity was 0.90 (0.85 to 0.94); the median [interquartile range] cardiac index (CI) threshold for a positive test was a 5.0 [3.3 to 5.3] increase. The clinical context, the method used for haemodynamic monitoring, the ratio of the averaging time of the monitoring method to the occlusion time and the levels of positive end-expiratory pressure were identified as significant sources of heterogeneity. However, the occlusion duration, choice of cardiac output marker and tidal volume did not significantly affect its performance. A novel insight is that performance was notably lower in the operating room setting. The likelihood ratios were 14 (positive) and 0.12 (negative) for the ICU, both better than 3.1 and 0.21 for the operating room. The overall quality of the evidence was assessed to be very low, mainly due to high heterogeneity and risk of bias; however, no publication bias was detected. CONCLUSION The EEOT for predicting fluid responsiveness in critical care performs acceptably well overall and is a confirmative test. In the operating room and/or with specific technical settings, its performance and clinical utility are reduced, driving the need for more context-specific and patient-specific fluid responsiveness assessments.