Cardiovascular effects of rectal methohexital in children

J Clin Anesth. 1992 Mar-Apr;4(2):116-9. doi: 10.1016/0952-8180(92)90026-w.

Abstract

Study objective: To define the cardiovascular effects of rectal methohexital in children with normal cardiac function.

Design: Cardiovascular evaluation of each patient was performed before and after medication. Each patient's predrug results were used as control measurements for comparison with measurements made after methohexital administration.

Setting: Inpatient operating room induction area in a privately endowed philanthropic children's hospital.

Patients: Forty-seven children age 35 +/- 22 months (mean +/- SD) scheduled for elective orthopedic or plastic surgery, free of cardiac or pulmonary disease, and receiving no medication with central nervous system activity.

Interventions: Control measurements of heart rate (HR), blood pressure (BP), and echocardiographic evaluations were obtained on the day before scheduled surgery. Repeat measurements were performed after the onset of methohexital-induced sleep. The time span of the measurements was designed to include the period of peak plasma methohexital concentration. In the preoperative holding area, 30 mg/kg of a 10% methohexital solution was administered rectally. If sleep did not occur in 15 minutes, an additional 15 mg/kg was given.

Measurements and main results: HR increased markedly after rectal methohexital [126 +/- 23 beats per minute (bpm) to 144 +/- 21 bpm, p less than 0.001], and stroke volume (SV) decreased (24 +/- 9 ml to 21 +/- 8 ml, p less than 0.01). There were no significant changes in BP or cardiac index. The shortening fraction and ejection fraction remained within the normal range for this age-group.

Conclusions: Rectal methohexital induces sleep in healthy pediatric patients with minimal cardiovascular side effects. The primary effects are increased HR and decreased SV.

MeSH terms

  • Anesthesia, Rectal*
  • Child
  • Child, Preschool
  • Echocardiography
  • Electrocardiography
  • Hemodynamics / drug effects*
  • Humans
  • Infant
  • Methohexital / administration & dosage
  • Methohexital / pharmacology*

Substances

  • Methohexital