There is no universally accepted algorithm for anticoagulation in patients on veno-venous extracorporeal membrane oxygenation. The purpose of this pilot study was to compare a non-titrating weight-based heparin infusion to that of a standard titration algorithm.

We performed a prospective randomized non-blinded study of patients: Arm 1—standard practice of titrating heparin to activated partial thromboplastin times goal of 45-55 seconds, and Arm 2—a non-titrating weight-based (10 units/kg/h) infusion. Primary outcome was need for oxygenator/circuit changes. Secondary outcomes included differences in hemolysis and bleeding episodes. Descriptive statistics were performed for the continuous data, and primary and secondary outcomes were compared using Fisher’s exact test as appropriate.

Six patients were randomized to Arm 1 and four to Arm 2. There was no difference in age, pH, P_aO₂/F_iO₂ratio, peak inspiratory pressure, positive end expiratory pressure, mean airway pressure at time of cannulation, time on extracorporeal membrane oxygenation, or survival to hospital discharge in the two arms. Arm 1 had a statistically higher median activated partial thromboplastin times (48 (43, 52) vs 38 (35, 42), p < 0.008) and lower LDH (808 units/L (727, 1112) vs 940 units/L (809, 1137), p = 0.02) than Arm 2. There was no difference in plasma hemoglobin (4.3 (2.5, 8.7) vs 4.3 (3.0, 7.3), p = 0.65) between the two arms. There was no difference in mean oxygenator/circuit change, transfused packed red blood cell, or documented bleeding complications per patient in each arm (p = 0.56, 0.43, 0.77, respectively).

In this pilot study, a non-titrating, weight-based heparin infusion appears safe and as effective in preventing veno-venous extracorporeal membrane oxygenation circuit thrombotic complications as compared to a titration algorithm. Larger studies are needed to confirm these preliminary findings.