Safety and Efficacy of a High-Intensity, Weight-Based, Intravenous Heparin Protocol Revision in Patients who are Obese

Abstract

Purpose Data collected previously within this institution concluded that the initial heparin infusion rate in the high-intensity, weight-based, intravenous (IV) heparin protocol should be adjusted from 18 to 15 units/kg/h (based on actual body weight) in patients who are more than 50% above ideal body weight (IBW). The purpose of this study was evaluation of the safety and efficacy of the revised protocol. Methods A retrospective chart review was conducted from the initiation of the revised protocol on October 28, 2006, through March 15, 2007. All patients receiving high-intensity, weight-based heparin dosing were eligible for inclusion. Outcome measures included percentage of patients achieving therapeutic activated partial thromboplastin time (aPTT), time to first therapeutic aPTT, follow-up aPTT levels, adverse event occurrence, venous thromboembolism recurrence, and influence of concomitant disease states. Results A total of 55 regimens met inclusion criteria. There were no statistically significant differences between patients who were obese (greater than 50% above IBW) and those who were not obese (less than 50% above IBW) with respect to percentage achieving a therapeutic aPTT, time to therapeutic aPTT, or follow-up aPTT values. Patients who were more than 50% above IBW had improved therapeutic anticoagulation parameters postrevision, whereas patients who were 30% to 50% above IBW had worsened therapeutic anticoagulation parameters postrevision. Although the 30% to 50% IBW class had the highest incidence of end-stage renal disease, it appears that the group of patients in this class was overanticoagulated as a whole. Conclusion The institution's revised, high-intensity, weight-based, IV heparin protocol was found safe and effective, validating a potential heparin dosing adjustment for patients who are obese.