title: Safety of warfarin dosing in the intensive care unit following the Fontan procedure.
abstract: OBJECTIVE
  To determine the incidence of supratherapeutic international normalized ratio (INR) values in patients initiated on warfarin in the pediatric intensive care unit after the Fontan procedure.
  
  
  METHODS
  Retrospective chart review.
  
  
  METHODS
  Pediatric intensive care unit in a freestanding pediatric teaching hospital.
  
  
  METHODS
  Thirty-two consecutive children with single ventricle physiology with an initial Fontan conversion. All were initiated on warfarin in the postoperative period while in the intensive care unit.
  
  
  METHODS
  Supratherapeutic INR values, interventions in warfarin dosing to address or prevent supratherapeutic INR values, major and minor bleeding episodes, and venous thromboembolic events.
  
  
  RESULTS
  Supratherapeutic INR values after warfarin initiation occurred in 12.5% (n = 4) of patients with an additional 6.3% (n = 2) requiring dose adjustments due to a rapidly increasing INR. Patients with a supratherapeutic INR were started on warfarin earlier compared with other patients (median postoperative day 2 vs. 5, P = .037, respectively). There were no reported thrombi or thromboembolic events and the only clinically significant bleeding event occurred while the INR value was subtherapeutic.
  
  
  CONCLUSIONS
  Patients undergoing the Fontan procedure may be more sensitive to warfarin dosing when initiated closer to the surgical procedure date. Despite this observation, warfarin appears to be a safe medication for use within the early postoperative period after the Fontan procedure when response to therapy is monitored closely. Clinicians should use caution when initiating warfarin before postoperative day 3 in patients undergoing an initial Fontan operation.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Thomas
authors.forename: Kathryn
authors.initials: K
authors.lastname: Taylor
authors.forename: Marcus S
authors.initials: MS
authors.lastname: Schamberger
authors.forename: Alexandre T
authors.initials: AT
authors.lastname: Rotta
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001777:Blood Coagulation / Q000187:drug effects; D002675:Child, Preschool; D054796:Drug Dosage Calculations; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects; D006470:Hemorrhage / Q000139:chemically induced; D006776:Hospitals, Pediatric; D006784:Hospitals, Teaching; D006801:Humans; D015278:Intensive Care Units, Pediatric; D019934:International Normalized Ratio; D008297:Male; D011182:Postoperative Care; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013923:Thromboembolism / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin