Objective: To investigate the efficacy of a remifentanil infusion for pediatric cardiac catheterization. Design: Prospective. Setting: University hospital. Participants: Children undergoing cardiac catheterization (n = 55). Interventions: All patients (age range, 2 months to 12 years) were premedicated with an oral mixture of hydroxyzine and midazolam 60 minutes before the procedure. A remifentanil infusion was initiated at 0.1 mug/kg/min before the start of cardiac catheterization. Noninvasive systolic blood pressure, heart rate, oxygen saturation (SPO2), respiratory rate, and sedation score were recorded before the remifentanil infusion and every 15 minutes thereafter throughout the procedure. Episodes of apnea, vomiting, pruritus, and muscle rigidity and recovery time were noted. Measurements and Main Results: There were no significant changes in systolic blood pressure, heart rate, SPO2, or respiratory rate during the procedure. The sedation scale scores at 30, 45, 60, 75, and 90 minutes of remifentanil infusion were significantly lower than the scores recorded at baseline and 15 minutes. In 23 patients, the remifentanil infusion maintained a satisfactory level of sedation, but 32 patients required additional drugs (18 received midazolam, and 14 received midazolam plus ketamine). Recovery was rapid after the remifentanil infusion was discontinued, with a mean time of 2.04 +/- 2.32 minutes to reach a recovery score of greater than or equal to5. Three patients experienced apnea after bolus doses of remifentanil, 1 patient vomited, and I patient complained of pruritus. Conclusion: In pediatric cases in which other intravenous analgesics and sedatives are contraindicated, remifentanil infusion appears to be a suitable alternative based on its associated rapid recovery and stable hemodynamics. Copyright (C) 2001 by W.B. Saunders Company.