title: Pharmacy-managed protocol for warfarin use in orthopedic surgery patients.
abstract: A pharmacy-managed protocol for warfarin use in orthopedic surgery patients was studied. In 1990 a protocol designed to accommodate either protocol- or physician-determined dosing of warfarin for orthopedic antithrombotic prophylaxis (OAP) was implemented at a community hospital. A "protocol" group consisting of patients treated entirely under the protocol-determined dosing option was prospectively identified over a two-year period. A "physician" group consisting of patients treated by physicians in the 10 months immediately preceding implementation of the protocol was also identified. The ability of the protocol to achieve laboratory-test and clinical goals was assessed by comparing the two groups. The proportion of patients who received OAP increased from 89% for the physician group to 98% for the protocol group. Mean prothrombin times (PTs) were significantly higher in the protocol group only on postoperative day 2; 66% of all PTs beyond post-operative day 1 in the protocol group were within the targeted range, which reflected an International Normalized Ratio of 1.6-3.2. The frequencies of clinically apparent postoperative thrombotic events and bleeding episodes were low in each group and comparable to literature values. Analysis of protocol-group patients with PTs of > 20 seconds indicated that lower weight, female sex, and blood loss during surgery were associated with an elevated PT. The protocol was revised to provide for a lower initial warfarin dose in elderly women. A pharmacy-managed protocol for dosing warfarin achieved therapeutic goals and promoted nearly universal use of OAP in patients undergoing high-risk orthopedic surgery.
authors.affiliation: Department of Pharmacy Practice, School of Pharmacy, University of Montana, Missoula 59812, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Rivey
authors.forename: R D
authors.initials: RD
authors.lastname: Wood
authors.forename: D R
authors.initials: DR
authors.lastname: Allington
authors.forename: T P
authors.initials: TP
authors.lastname: Stratton
authors.forename: C C
authors.initials: CC
authors.lastname: Erickson
authors.forename: T A
authors.initials: TA
authors.lastname: Stenson
mesh_terms: D001780:Blood Coagulation Tests; D001835:Body Weight; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D008297:Male; D009009:Montana; D009985:Orthopedics; D010595:Pharmacists; D010607:Pharmacy Service, Hospital / Q000592:standards*; D010820:Physicians; D011446:Prospective Studies; D011517:Prothrombin Time; D012737:Sex Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D014859:Warfarin