Infant sedation for MR imaging and CT: Oral versus intravenous pentobarbital

PURPOSE: To compare the effectiveness and safety of oral ( PO) versus intravenous (IV) pentobarbital sedation for magnetic resonance (MR) imaging and computed tomography (CT) in infants younger than 12 months. MATERIALS AND METHODS: The institutional review board approved the review of medical records and determined informed consent to be unnecessary. All parents gave informed consent for patient sedation. Prior to MR imaging or CT, infants younger than 12 months were sedated with PO pentobarbital ( 4 - 8 mg per kilogram body weight) or IV pentobarbital ( 2 - 6 mg/kg), depending on the presence of an IV catheter or need for IV contrast medium. A computer database used to record sedation data was reviewed for data from January 1997 to September 2003. PO and IV sedation groups were compared for mean age, weight, dose, time to sedation, time to discharge, and duration of sedation with a two-sample Student t test. Multivariate analysis of covariance was used to determine whether differences in sedation time, time to discharge, and duration of sedation between groups were independent of age, weight, sex, American Society of Anesthesiologists physical status classification, dose, and type of procedure. Sedation effectiveness ( outcome) was determined as the percentage of sedation failures in each group. Safety was determined separately for other adverse events as a total and for respiratory adverse events. RESULTS: A total of 2164 infants received 2419 ( 1264 PO, 1155 IV) doses of pentobarbital for sedation. Weight and sex were comparable between groups. Time to sedation was significantly longer with PO than with IV pentobarbital ( 18 minutes +/- 11 vs 7 minutes +/- 7; P <.01), but time to discharge was similar, at approximately 108 minutes +/- 35. Total adverse events rate during sedation was not significantly different (0.8% [PO] vs 1.3% [IV]), but incidence of abnormal oxygen saturation (5% decrease from baseline, > 1 minute duration) differed significantly (0.2% [PO] vs 0.9% [IV]; P =.02). Sedation effectiveness was comparable ( failure rate, 0.5% [PO] vs 0.3% [IV]; P =.76). CONCLUSION: PO pentobarbital has comparable effectiveness and a lower rate of respiratory complications compared with IV pentobarbital in infants younger than 12 months; its use should be considered, regardless of presence of an IV catheter.