Delirium in Extracorporeal Membrane Oxygenation (ECMO) Patients: A Systematic Review and Meta-Analysis of Prevalence,...

Background: Delirium is a common complication in patients receiving extracorporeal membrane oxygenation (ECMO), but its prevalence and determinants remain uncertain due to variable clinical practices. We conducted a systematic review and meta-analysis to estimate the pooled prevalence of delirium in ECMO-supported patients, evaluate the influence of diagnostic tools and ECMO modality, and synthesize evidence on associated risk factors and outcomes. Methods: We systematically searched PubMed, Embase, and Web of Science up to May 2025 for studies reporting delirium prevalence in adult ECMO patients. Subgroup analyses were stratified by ECMO modality and delirium assessment tool. Meta-regression was performed to explore potential moderators. Publication bias was assessed visually using funnel plots and statistically using Egger's and Begg's tests via the metabias command. Results: Thirteen studies involving 8679 adult ECMO patients were included. The pooled prevalence of delirium was 40.54% (95% CI: 23.01-58.06%), with substantial heterogeneity (I² = 98%; τ² = 0.29; p < 0.01). Subgroup prevalence was 56.83% (95% CI: 41.52-72.14%) for VA-ECMO, 32.84% (95% CI: 3.39-62.29%) for VV-ECMO, and 37.24% (95% CI: 13.71-60.77%) for mixed cohorts; differences were not statistically significant. Delirium prevalence varied by assessment tools, ranging from 57% with NuDESC to 7% with ICD-10 coding. Meta-regression showed a negative but non-significant association between sample size and delirium prevalence (β = -0.000049; p = 0.088). Sensitivity analyses confirmed the robustness of pooled estimates. Conclusions: Delirium affects a substantial proportion of ECMO-supported patients and is linked to considerable clinical and neurocognitive morbidity. The marked heterogeneity in prevalence reflects differences in diagnostic tools and clinical management practices, including sedation strategies. These findings underscore the urgent need for standardized, ECMO-specific delirium assessment protocols and proactive prevention strategies. Well-designed prospective studies with uniform methodologies and long-term follow-up are essential to clarify the trajectory and impact of delirium in this high-risk population.