Venoarterial extracorporeal membrane oxygenation in adult patients: predictors of mortality

Background: Extracorporeal membrane oxygenation is a cardiopulmonary supportive therapy. In this study, we reviewed our experience with extracorporeal membrane oxygenation support and tried to identify measurable values which might predict in-hospital mortality. Methods: From January 2004 through December 2008, 50 of 21,298 adult patients received venoarterial extracorporeal membrane oxygenation. We retrospectively analyzed clinical records of these 50 consecutive patients. Details of demographics, preoperative measurements, clinical characteristics at the time of extracorporeal membrane oxygenation implantation, extracorporeal membrane oxygenation-related complications and in-hospital mortality were collected. Logistic regression analyses were performed to investigate predictors of mortality. A p-value ≤ 0.05 was accepted as significant. Results: Thirty-eight patients were weaned from extracorporeal membrane oxygenation and 33 patients survived to discharge. The overall survival rate was 66%. In a multiple logistic regression analysis, blood lactate level before initiation of extracorporeal membrane oxygenation was a risk factor associated with in-hospital mortality (OR 1.27 95% CI 1.042-1.542). To evaluate the utility of the lactate in predicting mortality, a conventional receiver operating characteristic curve was produced. Sensitivity and specificity were optimal at a cut-off point of 12.6mmol/L, with an area under the curve of 0.752. The positive and negative predictive values were 73.3% and 83.9%, respectively. Conclusions: Extracorporeal membrane oxygenation is a justifiable alternative treatment for postoperative refractory cardiac and pulmonary dysfunction which could rescue more than sixty percent of otherwise fatal patients. Patients with pre-extracorporeal membrane oxygenation lactate levels above 12.6mmol/L are at higher risks for in-hospital death. Evidence-based therapy for this group of high risk patients is needed.