Continuous renal replacement therapy: understanding circuit hemodynamics to improve therapy adequacy

Purpose of review The utilization of continuous renal replacement therapy (CRRT) increases throughout the world. Technological improvements have made its administration easier and safer. However, CRRT remains associated with numerous pitfalls and issues. Recent findings Even if new-generation CRRT devices have built-in safety features, understanding basic concepts remains of primary importance. Summary CRRT circuits’ maximum recommended lifespan (72 h) can often not be achieved. Such early artificial kidney failures are typically related to two processes: circuit clotting and membrane clogging. Although these processes are to some degree inevitable, they are facilitated by poor therapy management. Indeed, the majority of device-triggered alarms are associated with blood pump interruption, which through blood stasis, enhance clotting and clogging. If the underlying issue is not adequately managed, further alarms will rapidly lead to prolonged stasis and complete circuit clotting or clogging making its replacement mandatory. Hence, rapid recognition of issues triggering alarms is of paramount importance. Because most alarms are related to circuit's hemodynamics, a thorough understanding of these concepts is mandatory for the staff in charge of delivering the therapy. This review describes CRRT circuits, measured and calculated pressures and the way their knowledge might improve therapy adequacy.