Thiopental requirements for induction of anesthesia in neonates and in infants one to six months of age.

The authors determined the thiopental dose needed for satisfactory induction in ten neonates, 0-14 days of age, and 20 infants, 1-6 months of age. A single iv bolus of thiopental was given. Thirty seconds after injection the anesthesia mask was applied and the response was observed during the following 30 s while the patient breathed oxygen. Induction was considered satisfactory if there were no gross movements or coughing. The dose required for satisfactory induction in 50% of patients, ED50 (+/- SE), was 3.4 +/- 0.2 mg/kg in neonates and 6.3 +/- 0.7 mg/kg in infants (P less than 0.001). It is concluded that the thiopental dose needed for satisfactory induction is less in neonates than in infants.