SEDATION OF DIFFICULT-TO-SEDATE CHILDREN UNDERGOING MR-IMAGING - VALUE OF THIORIDAZINE AS AN ADJUNCT TO CHLORAL HYDRATE

OBJECTIVE. The purpose of this prospective study was to evaluate the s afety and efficacy of thioridazine as an adjunct to chloral hydrate se dation when children undergoing MR imaging are difficult to sedate. SU BJECTS AND METHODS. All 87 children in the study either could not be s edated with chloral hydrate alone or were mentally retarded. Thioridaz ine (2-4 mg/kg) was administered orally 2 hr before and chloral hydrat e (50-100 mg/kg) was administered orally 30 min before the 104 MR exam inations. All children were monitored by continuous pulse oximetry. Al l images were individually evaluated by pediatric radiologists and wer e graded acceptable if they contained only minimal motion artifact or no motion artifact. Studies were considered successful only when 95% o r more of the images were acceptable. RESULTS. MR imaging was successf ul in 93 (89%) of 104 examinations. The success rate for children ente red into the study because of prior failure of chloral hydrate sedatio n was not significantly different from the success rate for children w ith mental retardation. A tendency for increasing failure rate with ag e was not significant. No serious complications occurred during the st udy. The most common adverse reaction, transient reduced oxygen satura tion, was seen in five children. Other adverse effects encountered wer e vomiting in four children, hyperactivity in two children, transient tachycardia in one child, and prolonged sedation in one child. No chil d required hospitalization because of an adverse reaction to sedation. CONCLUSION. The study indicates that thioridazine is a safe and effec tive adjunct to chloral hydrate when a child undergoing MR imaging is difficult to sedate.