1002

Introduction: During CVVH in liver failure minimal or no anticoagulation is used because of abnormal clotting and increased bleeding risk. But, circuits still clot. Methods: We investigated CVVH circuit life in children with acute liver failure over a 2 year period using prospectively stored electronic clinical data. All children had vascular access via a double lumen catheter placed in the femoral or internal jugular vein. The filter sizes were determined by body weight. Heparin anticoagulation, if used, was titrated to an ACT of 180-220 seconds. Results: 31 children in acute liver failure (ALF) received CVVH (17 male, median age 7.4 yrs, range 0.01-18). Of these 31 patients with ALF, 17 (54.8%) died. The number of filtration episodes was 98. The smallest double lumen venous access catheter used was 6.5 Fr (14%) and the largest 13.5 Fr (11%). The commonest filter used was HFO7 (63%). Each filter was used for (median) 22 hours (range 1-126). 52 filters were changed electively. Of the remaining 46, the circuit blocked in 25 and the access catheter in 13. 62 filtration episodes had prostacyclin anticoagulation, 30 had none. Others had either heparin or prostacyclin or both. The median 'down time' (time off CVVH whilst new circuit being prepared) was 3 hours (Range 0-68). Most children who had circuit failure due to blockage had FFP or RBC within the preceding 2 hours, whereas Cryoprecipitate, FFP, RBC, or platelet transfusions had been received by most prior to access catheter blockage. Neither the duration of CVVH nor the 'down time' had a demonstrable influence on outcome. Conclusions: The CVVH filter circuits fail in children with liver disease despite prolonged clotting. The use of blood products and vascular access catheter related problems seems to reduce filter life despite anticoagulation. The effects of 'downtime' on outcomes need further investigation.