A Practical Citrate Anticoagulation Continuous Venovenous Hemodiafiltration Protocol for Metabolic Control and High Solute Clearance

Obstacles to the widespread use of continuous renal replacement therapy (CRRT) include the need for anticoagulation, customized solutions, and complex protocols that carry an attendant risk for error, raise cost, and increase pharmacy and nursing workload. However, high solute clearance using CRRT with an effluent rate of 35 ml/kg per h has also recently been associated with improved survival in critically ill patients with acute renal failure. No published CRRT protocols using dilute regional citrate anticoagulation have achieved adequate metabolic control, effective anticoagulation, and high solute clearance in a practical, user-friendly, and economical manner. The safety and the efficacy of continuous venovenous hemodiafiltration at effluent rates of 35 ml/kg per h in critically ill acute renal failure patients were evaluated prospectively using a standardized bicarbonate-based dialysate; a systemic calcium infusion; and two separate trisodium citrate replacement solutions, a 0.67% solution and a 0.5% solution. All patients achieved adequate metabolic control, the desired effluent rate of 35 ml/kg per h, and high solute clearance. Use of the 0.67% citrate replacement solution resulted in mild alkalosis, whereas the 0.5% solution maintained appropriate acid-base balance. There was no difference in dialyzer survival between the 0.67 and 0.5% citrate groups (80 versus 82%; P = 0.60, Kaplan-Meier analysis). Dilute regional citrate as part of a CRRT protocol with a standard 25-mmol/L bicarbonate dialysate provides adequate metabolic control, high diffusive and convective clearance, and excellent dialyzer patency in a practical and cost-effective manner.