Monitoring heparin treatment with the APTT: the effect of methodological changes on the APTT.
OBJECTIVE
To assess the effect on the desired activated partial thromboplastin time (APTT) of altered practice in the laboratory control of heparin treatment.


METHODS
Descriptive study of the number of APTTs in the desired range (DR) in 1987 (historical controls) and in 1992/1993. In the latter period, four changes in the implementation of heparin treatment took place: another coagulation analyser was used, laboratory control was intensified with a nomogram as guideline, and the DR was changed form 90-120 to 45-60 s. Furthermore, a standard heparin solution of 417 U/ml was supplied by the hospital pharmacy.


RESULTS
The total amount of APTTs in the desired range increased from 19% in 1987 to 46% in 1992/1993, and the DR was reached in 1987 in 1 day by 14%, and in 1992/1993 by 48% of patients. The mean daily heparin dose was higher in 1992/1993 (34.1 * 1000 U, 95% CI 33.4-34.8) than in 1987 (32.3 * 1000 U, 95% CI 31.5-33.0). The starting dose of heparin of 400 U/kg during the first day, following an initial bolus injection of 70 U/kg, was correct in 44% of patients, too low in 46%, and too high in 10%.


CONCLUSIONS
The new policy in the laboratory control of heparin treatment resulted in an increased number of APTTs in the DR, and a shorter time to reach this.
Krulder
J W
JW
Department of General Internal Medicine, University Hospital Leiden, Netherlands.
van der Meer
F J
FJ
Briët
E
E
Meinders
A E
AE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000097:blood / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006493:Heparin / Q000097:blood / Q000627:therapeutic use*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010314:Partial Thromboplastin Time; D011655:Pulmonary Embolism / Q000188:drug therapy*; D012015:Reference Standards; D012189:Retrospective Studies; D013924:Thrombophlebitis / Q000188:drug therapy*; D013925:Thromboplastin / Q000032:analysis
D000925:Anticoagulants; D006493:Heparin; D013925:Thromboplastin