Renal replacement therapy in critically ill patients with acute kidney injury--when to start.

BACKGROUND: Despite the frequent use of renal replacement therapy (RRT) for patients with acute kidney injury (AKI) in the intensive care unit (ICU), there is no accepted consensus on the optimal indications and timing.

METHODS: The aim of this paper is to identify optimal triggers for RRT in critically ill patients with AKI.

RESULTS: We examined data from 2 randomized controlled trials, 2 prospective studies and 13 retrospective trials and found large variation in the different parameters and cut-offs for initiation of RRT. No single biochemical parameter was adequate to define the optimal indication and time to commence RRT. Degree of fluid overload, oliguria and associated non-renal organ failure appeared to be more appropriate parameters for initiation of RRT. We propose a clinical algorithm based on regular assessment of the patient's condition and trends in these parameters. It is intended to aid the process of deciding when to start RRT in critically ill adult patients with AKI.

CONCLUSION: Available evidence suggests that the decision when to start RRT in critically ill patients with AKI should be based on trends in the patient's severity of illness, presence of oliguria and fluid overload and associated non-renal organ failure rather than specific serum creatinine or urea values.