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: pharmacy-based, 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 < .001); 97% had a therapeutic APTT by 48 hours (P < .01). The median time to achieve a therapeutic APTT was 7 hours (P < .001). Of all 880 APTTs in this group, 17% were below, 75% in, and 8% above the therapeutic range (P < .001).


CONCLUSIONS
Pharmacy-based, computer-assisted dosing of heparin is feasible and results in faster and more accurate anticoagulant dosing.
Kershaw
B
B
Department of Pharmacy, Beaumont Hospital, Royal Oak, MI.
White
R H
RH
Mungall
D
D
Van Houten
J
J
Brettfeld
S
S
D000368:Aged; D004360:Drug Therapy, Computer-Assisted; D005069:Evaluation Studies as Topic; D005260:Female; D006493:Heparin / Q000008:administration & dosage*; D006744:Hospital Bed Capacity, 100 to 299; D006764:Hospitals, Community; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008824:Michigan; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D010607:Pharmacy Service, Hospital; D011446:Prospective Studies; D012189:Retrospective Studies; D012984:Software
D006493:Heparin