RIFLE classification is predictive of short-term prognosis in critically ill patients with acute renal failure supported by extracorporeal membrane oxygenation

Abstract

Background: Extracorporeal membrane oxygenation (ECMO) has been utilized for critically ill patients, such as those with post-cardiotomy cardiogenic shock or life-threatening respiratory failure. Acute renal failure following ECMO support has an extremely elevated mortality rate. This study examined the outcomes of patients treated with ECMO and characterized the association between mortality and RIFLE (risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function and end-stage renal failure) classification.

Methods: This retrospective study analysed the medical records of 46 critically ill patients-most had post-cardiotomy cardiogenic shock-treated by ECMO. Sixteen patients (34.8%) were treated with both ECMO and continuous renal replacement therapies.

Results: The overall mortality rate was 65.2% (30/46). A progressive and significant increase (chi(2) for trend, P < 0.001) was observed for mortality based on RIFLE classification severity. The Hosmer and Lemeshow goodness-of-fit test demonstrated that the RIFLE category has a good fit. By applying the area under the receiver operating characteristic curve (AUROC), the RIFLE classification tool had good discriminative power (AUROC 0.868 +/- 0.068, P < 0.001). Cumulative survival rates at 6 months follow-up following hospital discharge differed significantly (P < 0.05) for non-ARF vs RIFLE-I and RIFLE-F, and RIFLE-R vs RIFLE-F.

Conclusion: This investigation confirms that the prognosis for critically ill patients supported by ECMO is grave. The RIFLE category is a simple, reproducible and easily applied evaluation tool with good prognostic capability that might generate objective information for patient families and physicians and supplements the clinical judgment of prognosis.