title: Pharmacokinetic evaluation of triiodothyronine supplementation in children after modified Fontan procedure.
abstract: BACKGROUND
  Triiodothyronine (T(3)) supplementation may be a useful adjunct in the management of patients after cardiopulmonary bypass. Limited data are available regarding the use and pharmacokinetics of T(3) in children. The present study was performed to evaluate T(3) pharmacokinetics in a cohort of children undergoing the modified Fontan procedure.
  
  
  RESULTS
  A total of 28 patients were enrolled in this randomized, prospective study. The patients were divided into 4 groups: 1 group received a placebo and 3 groups received intravenous T(3) at dosages of 0.4, 0.6, and 0.8 microg/kg, respectively. All 28 patients survived their operative procedures. Two patients developed low cardiac output, and 3 patients had pleural effusions. The median length of hospital stay was 7 days. The mean free T(3) level was 316+/-67 pg/dL after then administration of a placebo. Patients who received T(3) had mean peak free T(3) levels of 972+/-88, 1351+/-299, and 1869+/-281 pg/dL for the dosages of 0.4, 0.6, and 0.8 microg/kg, respectively. The calculated half-life of T(3) was 7 hours.
  
  
  CONCLUSIONS
  The half-life of intravenous T(3) in children is approximately one-third of that reported for adults. These results provide a framework for studying the efficacy of T(3) supplementation in children undergoing open-heart surgery.
authors.affiliation: Nemours Cardiac Center, Alfred I. Dupont Hospital for Children, Wilmington, DE 19899, USA. rmainwar@nemours.org
authors.forename: R D
authors.initials: RD
authors.lastname: Mainwaring
authors.forename: E
authors.initials: E
authors.lastname: Capparelli
authors.forename: K
authors.initials: K
authors.lastname: Schell
authors.forename: M
authors.initials: M
authors.lastname: Acosta
authors.forename: J C
authors.initials: JC
authors.lastname: Nelson
mesh_terms: D002302:Cardiac Output; D002675:Child, Preschool; D018729:Fontan Procedure; D006207:Half-Life; D006330:Heart Defects, Congenital / Q000601:surgery; D006801:Humans; D007275:Injections, Intravenous; D007902:Length of Stay; D010996:Pleural Effusion / Q000209:etiology; D011183:Postoperative Complications; D011446:Prospective Studies; D013954:Thyroglobulin / Q000097:blood; D013972:Thyrotropin / Q000097:blood; D014284:Triiodothyronine / Q000008:administration & dosage / Q000493:pharmacokinetics*
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013954:Thyroglobulin