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An Institution‐Specific Heparin Titration Nomogram: Development, Validation, and Assessment of Compliance
Author(s) -
Sherman Deb S.,
Clarke Susan H.,
Lefkowitz Jerry B.,
Valuck Robert J.,
Lindenfeld JoAnn,
Stringer Kathleen A.
Publication year - 2001
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.21.15.1167.33895
Subject(s) - nomogram , heparin , partial thromboplastin time , medicine , therapeutic index , ex vivo , population , thromboplastin , in vivo , coagulation , surgery , pharmacology , drug , biology , microbiology and biotechnology , environmental health
Study Objective. To develop, validate, and assess compliance with a heparin titration nomogram. Design. Prospective, open‐label trial. Setting. University teaching hospital. Subjects. 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. Measurements and Main 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%. Conclusion. 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.