Intermittent hemodialysis for renal replacement therapy in intensive care: new evidence for old truths

Acute renal failure requiring dialysis is a frequent complication in critically ill patients with a high morbidity and mortality. Until recently, no evidence-based guidelines on the optimal treatment modality for renal replacement in the ICU could be issued because of a lack of well-performed randomized controlled trials (RCT). Over the last years however, some important new concepts and RCTs have been published on this topic. An important concept is the understanding that 'chronic dialysis strategies' are not suitable for acute renal failure patients in the ICU. From this understanding the necessity of daily dialysis followed, and later on, the need for flexible treatments related to the patients' need, using slow long extended daily dialysis (SLEDD). Several recent papers compared continuous renal replacement therapy and intermittent hemodialysis (IHD) in ICU patients, pointing to a lack of differences in outcome, but there were less practical problems using IHD, even in unstable patients. In conclusion, it can be stated that all patients can be treated with IHD when available, without jeopardizing their outcome. Slow extended daily dialysis emerged as a hybrid renal replacement therapeutic modality and has promising features because it combines the advantages of both continuous renal replacement therapy and IHD, but until now, no studies evaluating whether SLEDD is superior to 'regular IHD' are available.