title: An institution-specific heparin titration nomogram: development, validation, and assessment of compliance.
abstract: 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.
authors.affiliation: Department of Pharmacy Practice, School of Pharmacy, University of Colorado Health Sciences Center, Denver 80262, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Sherman
authors.forename: S H
authors.initials: SH
authors.lastname: Clarke
authors.forename: J B
authors.initials: JB
authors.lastname: Lefkowitz
authors.forename: R J
authors.initials: RJ
authors.lastname: Valuck
authors.forename: J
authors.initials: J
authors.lastname: Lindenfeld
authors.forename: K A
authors.initials: KA
authors.lastname: Stringer
mesh_terms: 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
chemical_list: D000925:Anticoagulants; D006493:Heparin