Enoxaparin vs. unfractionated heparin for anticoagulation during continuous veno-venous hemofiltration: a randomized controlled crossover study

Objective: The purpose of this study was to evaluate the efficacy and safety of the low molecular weight heparin enoxaparin as anticoagulant in continuous veno- venous hemofiltration ( CVVH) compared with unfractionated heparin. Design: Prospective randomized controlled crossover study. Setting: Medical and Surgical Intensive Care Unit of a University Hospital. Patients: Forty consecutive adult medical and surgical ICU patients with normal anticoagulation parameters requiring CVVH. Intervention: CVVH was performed with pre- filter fluid replacement at 2500 ml/ h and blood flow rates of 180 ml/ min. Heparin- treated patients received an initial pre- filter bolus of 30 IU/ kg and a maintenance infusion at 7 units/ kg h(-1), titrated to achieve a systemic activated partial thromboplastin time ( aPTT) of 40 - 45 s. Enoxaparin- treated patients received an initial pre- filter bolus of 0.15 mg/ kg and a maintenance infusion starting at 0.05mg/ kg h(-1), which was subsequently adjusted to maintain systemic anti- factor Xa activity ( anti- Xa) at 0.25 - 0.30 IU/ ml. Each patient received both regimens in a crossover design. Maximum treatment duration for each set was 72 h. Results: Patients included had a mean APACHE II score of 22 ( 10 - 35). Thirty- seven patients completed both study arms. Mean filter life span was 21.7 h (+/- 16.9 h) for heparin and 30.6 h (+/- 25.3) for enoxaparin ( p = 0.017, ANOVA for repeated measures). One major bleeding episode occurred during heparin as well as during enoxaparin treatment. Cost analysis showed average daily costs of 270 and 240 e for heparin and enoxaparin, respectively. Conclusion: Enoxaparin can be safely used for anticoagulation during CVVH resulting in higher filter lifespan compared with unfractionated heparin.