Propofol: effective dose and induction characteristics in unpremedicated children.

The induction dose, induction characteristics, and cardiovascular and respiratory effects of propofol were studied in 90 unpremedicated children 3-12 yr old. Propofol in a dose of 1-3 mg.kg-1 was injected in an antecubital vein over 10-30 s. Successful induction was defined by loss of eyelash reflex occurring within 50 s of the conclusion of propofol injection and followed by subsequent acceptance of face mask without excessive movement. The effective dose of propofol resulting in loss of eyelash reflex in 50% (ED50) and 95% (ED95) of children were 1.3 (1.1-1.4) and 2.0 (1.7-2.6) mg.kg-1 (95% confidence interval). The corresponding ED50 and ED95 for a successful induction that included acceptance of face mask were 1.5 (1.3-1.7) and 2.3 (2.1-3.0), respectively. There was a 6.6% incidence of mild to moderate pain on injection and a 12.7% incidence of involuntary movement. Apnea (cessation of breathing greater than 20 s) was seen in 21% of patients. Blood pressure decreased by more than 20% of baseline value in 48% of patients who received halothane (1-3%) after the bolus injection of propofol. It is concluded that propofol is an effective induction agent in children. A dose of 2.5-3.0 mg.kg-1 is recommended to ensure a smooth transition to an inhalational maintenance technique. The use of antecubital veins is associated with a low incidence of pain on injection.