Objective: To determine the impact of a thyroid hormone infusion (T4) on the vasopressor requirements in children with cessation of neurologic function (i.e., brain death) during evaluation for organ recovery Design: Retrospective cohort study. Setting: The 1998-2002 database of a regional organ recovery program. Patients: Children <=18 yrs with cessation of neurologic function during evaluation for organ recovery (n = 171) were included. The treated group (n = 91) received a weight-based bolus and continuous infusion of T4 according to the organ procurement agency protocol. All other children (n = 80) were considered untreated. Interventions: T4 was administered at the clinician's discretion. All children (treated and untreated) had identical goals for fluids, blood pressure, and organ function criteria. Vasopressor score ([dopamine x 1] + [dobutamine x 1] + [epinephrine x 100] + [norepinephrine x 100] + [phenylephrine x 100]) at the time of the program's involvement (T0) and at organ recovery (TOR) were recorded. The Wilcoxon rank sum and Student's two-sample t-test were used to compare the average vasopressor score at T0 vs. TOR. The Wilcoxon signed rank test was used to analyze the difference in median vasopressor score at T0 vs. TOR. Multivariable linear regression was used to assess the impact of T4 on the ability to wean vasopressor support while accounting for the effects of several potential confounders. Measurements and Main Results: One hundred seventy-one subjects were included in the final analysis. T4 administration was associated with an unadjusted decrease in the vasopressor score of 32 (95% confidence interval, 12-53; p = .002). After adjusting for steroid administration, fluid balance, and baseline vasopressor score, T4 administration was associated with a decrease in vasopressor score of 24 (95% confidence interval, 6-43; p = .011). Conclusions: T4 reduced vasopressor needs in children with cessation of neurologic function and hemodynamic instability. A prospective study of T4 in critically ill and hemodynamically unstable children appears warranted. (C) 2004 Lippincott Williams & Wilkins, Inc.