The Impact of Renal Failure and Renal Replacement Therapy on Outcome During Extracorporeal Membrane Oxygenation Therapy

Acute kidney injury (AKI) is common in patients treated with veno-arterial (VA-) or veno-venous (VV-) extracorporeal membrane oxygenation (ECMO). In this setting, the use of continuous renal replacement therapy (CRRT) can help to optimize fluid status but may also negatively impact on patients' outcome. In contrast, the relationship between AKI, CRRT, and survival in critically ill adult patients receiving ECMO is not well defined. The institutional ECMO database (n=162) from November 2008 to December 2013, excluding patients with ICU survival <24 hours was reviewed. Demographics, co-morbidities, and concomitant therapies for all patients were collected. AKI was defined according to the Acute Kidney Injury Network (AKIN) criteria. ICU mortality was noted. Data were retrieved for 135 patients (79 with VA-ECMO and 56 with VV-ECMO). Of these, 95 developed AKI, 63 (47%) of whom required CRRT; thus three groups of patients were identified: (a) no AKI; (b) AKI without CRRT (AKI(NOCRRT)); and (c) CRRT with AKI (AKI(CRRT)). AKI(NOCCRT) patients were more likely to have preexisting heart disease, to be more severely ill, and to be treated with VA-ECMO than those without AKI. AKI(CRRT) patients were also more likely to be treated with VA-ECMO, had more organ dysfunction at the time of ECMO insertion, and needed more transfusions and inotropic agents than patients without AKI. ICU mortality was 53% (72/135) and was similar in the three groups, even when different AKI stages or VA/VV-ECMO were analyzed separately. In this study, the use of CRRT was not associated with an increased mortality in an adult population of patients treated with ECMO, even after adjustment for confounders.