Development and implementation of a nurse-driven, sliding-scale nomogram for bivalirudin in the management of heparin-induced thrombocytopenia

Abstract

A simplified dosing nomogram to assist nurses in adjusting the rate of i.v. bivalirudin administration in cases of heparin-induced thrombocytopenia (HIT) is described. To facilitate the availability of bivalirudin [corrected] as an alternative direct thrombin inhibitor (DTI) for patients with HIT at The Ohio State University Wexner Medical Center (OSUWMC), a team of clinical pharmacists developed a nomogram designed to simplify infusion dosage adjustments by nurses. In contrast to bivalirudin nomograms requiring patient-specific, percentage-based dose adjustments, the nomogram developed at OSUWMC specifies fixed adjustments (0.005 or 0.01 mg/kg/hr) according to the current activated partial thromboplastin time (aPTT) value relative to aPTT goals. During pilot testing over three years, the nomogram was used to guide dosage adjustments in 65 adult patients receiving continuous infusions of bivalirudin for suspected or confirmed HIT in intensive care units. Overall, the use of the nomogram resulted in adequate anticoagulation, with 53.7% of all measured aPTT values in the target range; 30.5% of aPTT values were below target, and 15.8% of values were above target. The median time to steady state was 11.0 hours (range, 5.0-31.8 hours), and bleeding rates were consistent with those reported in the literature. Nurse adherence to the nomogram was 100%, and no dosing errors occurred during a total of 487 dosage changes. Based on the pilot study results, the nomogram was refined to improve initial dosing for patients with creatinine clearance values of >30 mL/min; other refinements were made to enhance the safety of bivalirudin therapy for HIT in patients with severe renal impairment. A nurse-driven, sliding-scale nomogram for bivalirudin therapy in patients with HIT provided a simple dosing protocol and resulted in a high rate of adherence by nurses.