Acute Kidney Injury in Patients with Severe Acute Respiratory Distress Syndrome Requiring Extracorporeal Membrane Oxygenation: Incidence, Prognostic Impact, and Risk Factors

Objectives: Although acute kidney injury (AKI) is a frequent complication in patients receiving extracorporeal membrane oxygenation (ECMO), only few studies have been conducted on incidence, clinical impact and risk factors of AKI. We aimed to define the incidence and clinical course of AKI in critically ill adults receiving ECMO support due to acute respiratory distress syndrome (ARDS).

Methods: This is a retrospective analysis of patients undergoing venovenous ECMO treatment in a tertiary care center. We retrospectively evaluated all patients undergoing ECMO treatment at our center between December 2008 and December 2017. Data was obtained by chart review.

Results: During the observation period, 124 patients underwent venovenous ECMO implantation for severe ARDS. Mean age of patients was 53 ± 16 years, 80 patients were male (65%). In the AKI group, 81 patients (65%) were identified, and classified in stage AKI 2 (n = 5) or 3 (n = 76). Seventy-eight patients (63%) required renal replacement therapy (RRT).

Weaning rate from ECMO (28/81 [35%] vs. 26/43 [60%], p = 0.0058) as well as 30-day survival (13/81 [16%] vs. 23/43 [53%], p < 0.0001) was significantly lower for patients with AKI as compared with the non-AKI-group. Infectious complications (78/81 [96%], vs. 34/43 [79%], p = 0.0021) and blood stream infections (40/81 [49%] vs. 13/43 [30%], p = 0.0355) were observed more frequently in the AKI group. Interestingly, bleeding complications (60/81 [74%] vs. 34/43 [79%], p = 0.0209) were occurred less in the AKI group. Univariate regression analysis revealed high lactate, acidosis, elevated liver function parameters (bilirubin, AST, ALT), thrombocytopenia and serum creatinine, anemia, reduced SaO₂, and high qSOFA score before ECMO implantation as predictors of AKI. In addition, fluid balance 6 hours after ECMO initiation and initial ECMO blood flow/ECMO pump speed were risk factors for AKI.

Conclusion: Two-thirds of adult patients receiving ECMO suffered from moderate to severe AKI, with a significantly increased mortality risk. The initial pump speed and flow of ECMO as well as markers of multiorgan failure before ECMO implantation, for example, lactate or bilirubin, were associated with the development of AKI in the further course.