Computer-assisted dosing of heparin: Management with a pharmacy-based anticoagulation service

Background: Expert consultation by means of established practice guidelines has been shown to lead to improved accuracy of inpatient anticoagulation therapy, with a reduction in the frequency of hemorrhagic complications. We evaluated a different strategy to improve the accuracy of in-hospital anticoagulation: pharmacybased, computer-assisted dosing of intravenous heparin therapy. Methods: Patients treated with computer-assisted dosing of heparin (N=131) were compared with a randomly selected historical cohort (N=57) in whom heparin therapy was managed by the primary physician. All patients treated by the pharmacy team received a bolus of heparin, 70 U/kg of ideal body weight, except for patients with pulmonary embolism, who received 100 U/kg of ideal body weight. A computer-generated infusion dose was selected (generally 13 to 16 U/kg per hour). The target was an activated partial thromboplastin time (APTT) ratio of 1.8 times the patient's baseline APTT, with a therapeutic range of 1.5 to 2.5 times baseline. Computer-assisted dosage recommendations were generated after each APTT measurement. Results: In the historical control group, 62% of the patients achieved a therapeutic APTT during the first 24 hours; 17% failed to reach a therapeutic level by 48 hours. The median time to reach a therapeutic APTT was 15 hours. Of all 696 APTTs in this group, 42% were below, 43% in, and 15% above the therapeutic range. In the computer-assisted group, 90% achieved a therapeutic APTT within 24 hours ( P P P P Conclusions: Pharmacy-based, computer-assisted dosing of heparin is feasible and results in faster and more accurate anticoagulant dosing. (Arch Intern Med. 1994;154:1005-1011)