Renal replacement therapy in critically ill patients.

OBJECTIVE: To provide updated information (including on treatment) in relation to renal replacement therapy in critically ill patients. DATA SOURCES AND STUDY SELECTION: Literature search of Medline and PubMed till June 2008. DATA EXTRACTION: Original studies, literature review, and book chapters. DATA SYNTHESIS: The prevalence of acute renal failure in critically ill patients remains high and mortality is up to 60%. Both the practice of renal replacement therapy (continuous against intermittent, haemofiltration against haemodialysis) and patient outcomes vary widely between studies. To better understand this heterogeneous group of patients, a unified classification of acute renal failure proposed by the Acute Dialysis Quality Initiative allows better understanding of the epidemiology and outcome of this disease. Similar to patients with chronic renal failure, there exists a direct relationship between the dose of dialysis and survival; 35 mL/kg/h is the accepted norm. However, this traditional practice is being challenged by recent trials. Although the use of citrate as anticoagulant in renal replacement therapy can prolong circuit patency and decrease bleeding risk, its use is limited by the complex set up and metabolic problems. CONCLUSIONS: The RIFLE classification allows an accurate description of the epidemiology and outcome of critically ill patients with acute renal failure. The well-accepted continuous renal replacement therapy dose of 35 mL/kg/h in critically ill patients needs further verification from ongoing clinical trials. The complex set-up and the use of citrate anticoagulant has limited the use of such dialysis, which can nevertheless be overcome with the support of pharmaceutical companies.