In the field of continuous renal replacement therapy (CRRT), session length, downtime and dose require detailed research, which will provide information important in relation to prescription, anticoagulation and circuit material choice (membrane type and size, vascular access site and size). In particular, it appears that many of the data currently existing in the literature and accepted regarding CRRT prescription and delivery in critically ill adult patients are not strictly applicable to the paediatric setting. Furthermore, many of the available paediatric studies are small, retrospective or underpowered. In paediatric CRRT, epidemiological investigations and prospective trials to investigate practical aspects of extracorporeal therapies are welcome and urgently needed.