Can circuit lifetime be a quality indicator in continuous renal replacement therapy in the critically ill?

Purpose: Continuous renal replacement therapy (CRRT) is frequently used in critically ill patients with acute renal failure and sepsis. Frequent circuit changes increase nursing workload, blood loss and costs, and also compromise achievement of the filtration rate goal. Circuit downtime is the most important factor that compromises the cumulative filtration goal.

Methods: We used continuous venovenous hemodiafiltration (Prismaflex, Gambro, Meyzieu Cedex, France) in our 12-bed medical intensive care unit (ICU). Circuit lifetimes, indication to start CRRT anticoagulation protocol, reason for circuit change, and location of the vascular access were prospectively documented for 12 months in consecutive patients. Unfractionated heparin was the first choice for anticoagulation. No anticoagulation was used in patients with severe coagulation abnormalities or hepatic failure; regional citrate-based anticoagulation (CBA) was used in patients with recurrent circuit clotting or with bleeding predisposition. Our aim was to assess the suitability of circuit lifetime as a quality indicator, evaluated by survival analysis.

Results: Median circuit lifetime was significantly longer for CBA (log rank chi2 = 8.08; p = 0.018). This is consistent with the literature. There were no differences in vascular access site, proportion of sepsis, or vasopressor dependency between the three anticoagulation groups.

Conclusions: In addition to monitoring the complication rate, the evaluation of circuit lifetime using survival analysis stratified by anticoagulation strategy is a simple and feasible means of assessing the quality of CRRT in the ICU.