Different aspects of RRT modality may impact on outcomes, and data that have emerged over the last decade have improved evidence and also rejected commonly accepted dogma. Initial data suggested a better outcome when a higher dose of treatment was applied [5,6]. However, one small and two large prospective randomised controlled trials failed to reproduce these earlier findings. Observational data seems to suggest that continuous RRT (CRRT) modalities are associated with better outcomes. However, relative small, randomized studies and meta-analyses do not demonstrate such a benefit. Observational data suggests that CRRT is associated with improved renal recovery, and also examining the data from the 2 large randomized studies on intensity of RRT suggest that CRRT confers a benefit. Also, despite RRT being available for over 50 years there are no clear consensus guidelines for the initiation of RRT. A recent survey found that up to 89 different combinations of indications are used. Recently, the Acute Kidney Injury Network and the Kidney Disease: Improving Global Outcomes (KDIGO) group, formulated recommendations for this. Recent observational studies indicated that commonly accepted cut offs such as serum urea concentration are probably not that important. Furthermore, timing of initiation may have an effect on outcome. Some studies suggest that early initiation is associated with better outcome, on the other hand others could not demonstrate a benefit and have even demonstrated inferior outcomes.