Clinical review: Timing and dose of continuous renal replacement therapy in acute kidney injury

The optimal management of renal replacement therapy (RRT) in acute kidney injury (AKI) remains uncertain. Although it is well accepted that initiation of RRT in patients with progressive azotemia prior to the development of overt uremic manifestations is associated with improved survival, whether there is benefit to even earlier initiation of therapy is uncertain. Although retrospective and observational studies have suggested improved survival with very early initiation of continuous RRT (CRRT), interpretation of these studies is confounded by their failure to include patients with AKI who recover renal function or die without ever receiving RRT. Several studies have suggested that more intensive delivery of CRRT during AKI is associated with improved survival, although results of trials have been inconsistent. Two large multicenter randomized clinical trials addressing this question are currently underway and should provide more definitive data within the next two years.