Another Rapid Sedation Option for Pediatric CT Scanning

abstract & commentary

Source: Pomeranz ES, et al. Rectal methohexital sedation for computed tomography imaging of stable pediatric emergency department patients. Pediatrics 2000;105:1110-1114.

When children in the emergency department (ED) require immobilization for imaging procedures, it is notoriously difficult for them to remain motionless. Numerous pharmacologic agents have been employed for sedation, but most require intravenous (IV) or intramuscular (IM) injection, display delayed onset of action by oral or nasal routes, or achieve inadequate immobilization. To evaluate a more acceptable modality for pediatric sedation, Pomeranz and colleagues at the University of Michigan studied 100 children, ages 3 to 60 months, who were seen at three academic pediatric EDs in Ann Arbor. Indications for scanning were closed head injury (63%), mental status change, ventriculoperitoneal shunt malfunction, acute ataxia, sinusitis, or inappropriate head circumference.

Methohexital (MXT) 25 mg/kg was administered per rectum with a syringe and 8-Fr feeding tube 15 minutes prior to scanning. In addition to continuous pulse oximetry and ECG monitoring, a nurse observed the procedure and took vital signs every five minutes. Onset, adequacy, and duration of sedation were assessed by the nurse and physician in attendance in all 100 cases.

Average age was 24 months, with an average time to full sedation of 8.2 minutes (range: 6.98-9.42 min). Average time between drug administration and full recovery was 79.3 minutes (range: 71.00-85.74 min). Ninety-two of 99 patients (95%) were adequately sedated for scanning, while three required mild restraint and four (5%) were judged failures. CT images were adequate in 98%. Forty-five of 49 parents (90%) surveyed reported satisfaction with MTX and would accept it again if required for their child. Ten children (10%) had side effects—hiccoughs, hypersalivation, cough, and brief oxygen desaturation (which responded to chin repositioning). None required intubation.

Pomeranz et al conclude that rectal MXT, an ultrashort-acting barbiturate, is a rapid, effective, and safe agent for pediatric sedation in stable patients too young or anxious to satisfy CT scanning requirements. The authors state, however, that they are not the first group to study rectal MXT in children. Thirty-five years ago, Orallo evaluated this agent in 316 children undergoing general anesthesia, achieving 85% satisfactory seda-tion.1 In 1987, another group demonstrated an 82.5% success rate for rectal MXT among 40 children requiring CT or MRI imaging.2 Manulli and Davies found rectal MXT provided adequate sedation in 87% of cases compared to 83% with chloral hydrate, in 190 pediatric outpatients (average age 25 months) under-going CT or MRI procedures.3

Comment by Michael Felz, MD

I researched rectal MXT via our Drug Information Center and colleagues in Pediatric Anesthesia and the ED. Our institution, like large academic centers elsewhere, tends to employ oral chloral hydrate (80-100 mg/kg) for outpatient pediatric sedation. Onset of action averages 20 minutes or longer, duration of sedation is usually 60-90 minutes, and adequacy of immobility for scanning is 70-90%, although sometimes immobility is unpredictable. Two other agents—midazolam, by oral, nasal, or IV routes, and ketamine IM—do not display MXT’s spectrum of simplicity, rapidity, immobilization, and painless administration. Given the noteworthy onset of action—a mere eight minutes for rectal MXT—depth and duration of sedation comparable or superior to other agents, and safety profile documented in this paper and in previous sizeable studies, I consider rectal MXT a viable alternative to chloral hydrate for children undergoing nonpainful procedures. This seems especially applicable when rapid sedation is desirable, IV access is avoidable, and parental satisfaction is a goal.


1. Orallo MO, Eather KF. Sodium methohexital as a rectal agent in pediatric anesthesia. Anesth Analg 1965;1:97-103.

2. Griswold JD, Liu LMP. Rectal methohexital in children undergoing computerized cranial tomography and magnetic resonance imaging scans. [abstr] Anesthesiolog 1987;67:3a.

3. Manulli MA, Davies L. Rectal methohexital for sedation of children during imaging procedures. AJR Am J Roentgenol 1993;160:577-580.