Outcomes of weight-based heparin dosing based on literature guidelines and institution individualization.
OBJECTIVE
To determine whether unfractionated heparin is optimally dosed using published weight-based guidelines.


METHODS
Six-month, prospective study.


METHODS
University hospital.


METHODS
Ninety-six patients in the weight-based unfractionated heparin-dosing group 1 (WBHD1; 37 men; mean age 66.9 +/- 15.1 years; mean weight 80.1 +/- 20.6 kg) and 68 patients in the WBHD2 (25 men; mean age 68.2 +/- 15.6 years; mean weight 82.0 +/- 19.6 kg).


METHODS
The WBHD1 received a 100-U/kg intravenous bolus followed by an 18-U/kg/hour continuous intravenous infusion. After 3 months, the protocol was modified, and the WBHD2 received a 90-U/kg bolus followed by a 16-U/kg/hour continuous infusion for 3 months.


RESULTS
Activated partial thromboplastin times (aPTTs), frequency of bleeding episodes that required blood transfusions, and the number of recurrent thromboembolic events were collected from both groups after 3 months on the study. In the WBHD1, 24 hours after starting heparin, 38.5% of patients had therapeutic aPTTs, and at 48 hours, 54.3% were therapeutic. In the WBHD2, 42.6% and 51.4% of patients had therapeutic aPTTs at 24 and 48 hours, respectively. There was no statistical difference between the WBHD1 and WBHD2 in the percentage of patients with therapeutic aPTTs.


CONCLUSIONS
Weight-based heparin dosing resulted in low percentages of patients with therapeutic aPTTs. The use of weight alone to dose heparin may not be adequate to optimize therapy.
Davydov
L
L
St. John's University School of Pharmacy, Jamaica, New York, USA.
Dietz
P A
PA
Lewis
P
P
Twichell
M L
ML
Bertino
J S
JS
D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D001803:Blood Transfusion; D001835:Body Weight; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced / Q000628:therapy; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D012008:Recurrence; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000188:drug therapy
D000925:Anticoagulants; D006493:Heparin