An institution-specific heparin titration nomogram: development, validation, and assessment of compliance.
OBJECTIVE
To develop, validate, and assess compliance with a heparin titration nomogram.


METHODS
Prospective, open-label trial.


METHODS
University teaching hospital.


METHODS
Patients admitted with heart failure who required therapy with intravenous unfractionated heparin. Intervention. An in vitro concentration-response was determined by measuring activated partial thromboplastin times (aPTTs) on normal pooled plasma containing known concentrations of heparin. The therapeutic aPTT range was determined from the concentration-response by using the therapeutic heparin concentration range of 0.2-0.4 U/ml (protamine neutralization). Patients were consecutively enrolled, and therapy was managed by using the heparin titration nomogram. Paired aPTT-heparin concentrations were obtained, and nomogram validation was performed by comparing the in vitro and the ex vivo concentration-responses with use of linear regression. Nomogram compliance also was assessed.


RESULTS
The therapeutic aPTT ranges based on in vitro and ex vivo data were determined to be 45-72 seconds and 47-61 seconds, respectively. The ranges were significantly different (p<0.001). Overall compliance with the nomogram was 88%.


CONCLUSIONS
These results confirm that, even in a relatively homogeneous disease-state patient population, in vitro data do not accurately predict ex vivo data. If in vitro data are used to develop an institution-specific nomogram, a validation procedure should be used to ensure accuracy. Although 100% compliance to a nomogram may not be attainable, it should be expected. Therefore, a compliance rate of 88% is concerning and suggests a need for increased nursing and physician education.
Sherman
D S
DS
Department of Pharmacy Practice, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA.
Clarke
S H
SH
Lefkowitz
J B
JB
Valuck
R J
RJ
Lindenfeld
J
J
Stringer
K A
KA
D000925:Anticoagulants / Q000008:administration & dosage* / Q000032:analysis / Q000627:therapeutic use*; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006493:Heparin / Q000008:administration & dosage* / Q000032:analysis / Q000627:therapeutic use*; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008508:Medication Errors / Q000517:prevention & control; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results
D000925:Anticoagulants; D006493:Heparin