Comparative study of anticoagulation versus saline flushes in continuous renal replacement therapy

Systemic heparinization during continuous renal replacement therapy (CRRT) is associated with disadvantage of risk of bleeding. This study analyses the efficacy of frequent saline flushes compared with heparin anticoagulation to maintain filter life. From January 2004 to November 2007, 65 critically ill patients with acute renal failure underwent CRRT. Continuous venovenous hemodialfiltration (CVVHDF) was performed using Diapact Braun CRRT machine. 1.7% P.D. fluid was used as dialysate. 0.9% NS with addition of 10% Ca Gluconate, Magnesium Sulphate, Soda bicarbonate and Potassium Chloride added sequentially in separate units were used for replacement, carefully monitoring their levels. Anticoagulation of extracorporeal circuit was achieved with unfractionated heparin (250-500 units alternate hour) in 35 patients targeting aPTT of 45-55 seconds. No anticoagulation was used in 30 patients with baseline APTT 55 seconds and extracorporeal circuit was maintained with saline flushes at 30 min interval. 65 pa­tients including 42 males. Co-morbidities were comparable in both groups. HMARF was signifi­cantly more common in heparin group while Sepsis was comparable in both the groups. CRRT parameters were similar in both groups. Average filter life in heparin group was 26 ± 6.4 hours while it was 24.5 ± 6.36 hours in heparin free group ( P=NS). Patients receiving heparin had 16 bleeding episodes (0.45/patient) while only four bleeding episodes occurred in heparin free group (0.13/patient, P 0.05). Mortality was 71% in heparin group and 67% in heparin free group. Frequent saline flushes is an effective mode of maintainance of extracorporeal circuit in CRRT when aPTT is already on the higher side, with significantly decreased bleeding episodes.