Predictors of mortality in patients successfully weaned from extracorporeal membrane oxygenation

Purpose: Extracorporeal membrane oxygenation (ECMO) has been utilized for critically ill patients, such as those with life-threatening respiratory failure or post-cardiotomy cardiogenic shock. This study compares the predictive value of Acute Physiology, Age, and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), and Organ System Failure (OSF) obtained on the first day of ECMO removal, and the Acute Kidney Injury Network (AKIN) stages obtained at 48 hours post-ECMO removal (AKIN_48-hour) in terms of hospital mortality for critically ill patients. Methods: This study reviewed the medical records of 119 critically ill patients successfully weaned from ECMO at the specialized intensive care unit of a tertiary-care university hospital between July 2006 and October 2010. Demographic, clinical, and laboratory data were collected retrospectively as survival predictors. Results: Overall mortality rate was 26%. The most common condition requiring ECMO support was cardiogenic shock. By using the areas under the receiver operating characteristic (AUROC) curve, the Sequential Organ Failure Assessment (SOFA) score displayed good discriminative power (AUROC 0.805±0.055, p<0.001). Furthermore, multiple logistic regression analysis indicated that daily urine output on the second day of ECMO removal (UO_{24-48 hour}), mean arterial pressure (MAP), and SOFA score on the day of ECMO removal were independent predictors of hospital mortality. Finally, cumulative survival rates at 6-month follow-up differed significantly (p<0.001) for a SOFA score<13 relative to those for a SOFA score≥13. Conclusions: Following successful ECMO weaning, the SOFA score proved a reproducible evaluation tool with good prognostic abilities.