Anti-Factor Xa measurements in acute care surgery patients to examine enoxaparin dose

Abstract

BackgroundThe purpose of this study was to determine if fixed dose enoxaparin prophylaxis provided effective anticoagulation for acute care surgery patients and to examine whether a real-time enoxaparin dose adjustment algorithm optimized anticoagulation. MethodsAcute care surgical patients placed on enoxaparin prophylaxis 30 mg twice daily were recruited prospectively. Peak steady state aFXa levels were drawn with a goal peak aFXa range of 0.2–0.4 IU/ml. A real time dose adjustment algorithm was implemented for patients with out-of-range levels. ResultsFifty five patients were included. 56.4% of patients had low aFXa levels (<0.2 IU/mL). Real-time enoxaparin dose adjustment significantly increased the proportion of patients who achieved in-range peak aFXa levels, compared to standard dosing (74.5% vs 41.8%, p < 0.001). Patients with initial inadequate peak aFXa levels had a higher rate of 90-day post-operative VTE, although not statistically significant (16.1% vs. 8.3%, p = 0.50). ConclusionThe majority of acute care surgery patients receive inadequate VTE prophylaxis with fixed enoxaparin dosing.