Predictors of favourable outcome after in-hospital cardiac arrest treated with extracorporeal cardiopulmonary resuscitation: A systematic review and meta-analysis.

Aims: To identify the predictors of survival to discharge in adults resuscitated with extracorporeal cardiopulmonary resuscitation (ECPR) following in-hospital cardiac arrest (IHCA).
Methods: MEDLINE and ISI Web of Science were searched for eligible studies. Pooled Odds Ratio (OR) and Pooled Mean Difference (PMD) for each predictor were calculated. The quality of evidence (QOE) was evaluated according to the GRADE guidelines.
Results: Eleven studies were included totalling 856 patients. Of these, 324 (37.9%) survived to discharge. Good neurological outcome (Cerebral Performance Category 1 or 2) occurred in 222/263 (84.4%) survivors. Survival was associated with significantly higher odds of an initial shockable rhythm (OR 1.65; 95% confidence interval [95%CI] 1.05-2.61; p=0.03), shorter low-flow time (PMD -17.15 [-20.90, -13.40]min; p<0.00001), lower lactate levels both immediately before ECPR start (PMD -4.12 [-6.0,-2.24]mmol/L; p<0.0001) and on ICU admission (PMD -4.13 [-6.38, -1.88]mmol/L; p<0.0003), lower SOFA score (PMD -1.71 [-2.93, -0.50]; p=0.006) and lower creatinine levels within 24h after ICU admission (PMD -0.37 [-0.54, -0.19]mg/dl; p<0.00001). No significant association was found between survival and age, gender, or cardiac vs. non-cardiac aetiology. The overall QOE was low or very low.
Conclusions: In adult IHCA treated with ECPR a shockable initial rhythm, a lower low-flow time, lower blood lactate levels before ECPR start or on ICU admission, and a lower SOFA score or creatinine levels in the first 24h after ICU admission were associated with a higher likelihood of survival. These factors could help identifying patients who are eligible for ECPR.
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