Renal replacement therapy: when to start.

Critically ill patients whose course is complicated by acute kidney injury (AKI) often commence renal replacement therapy (RRT). For these patients, initiation of RRT results in a measurable escalation in both the complexity and associated costs of care. While RRT is commonly used in critical care practice, there is uncertainty about the ideal circumstances for the initiation of RRT. This decision is naturally complex and is influenced by numerous factors, including those that are patient-specific, clinician-specific and those related to local logistics. Survey data have clearly shown marked heterogeneity between clinicians and across jurisdictions for the initiation of RRT. As a consequence, analysis of ideal circumstances under which to initiate RRT is challenging and there is currently no broad consensus to guide clinicians on this issue. In this review, we discuss the theoretical benefits and risks of earlier, as compared to later initiation RRT, the accumulated data, and future directions for investigation.