The pharmacology of sevoflurane in infants and children.

BACKGROUND: Sevoflurane is a new volatile anesthetic with physical properties that should make it suitable for anesthesia (MAC of sevoflurane on oxygen alone and in 60% nitrous oxide, (MAC) of sevoflurane in oxygen alone and in 60% nitrous oxide, the hemodynamic, induction and emergence responses to sevoflurane and the metabolism to inorganic fluoride were studied in 90 ASA physical status 1 or 2 neonates, infants, and children.
METHODS: MAC of sevoflurane in oxygen was determined in six groups of subjects stratified according to age: full-term neonates, infants 1-6 and > 6-12 months and children > 1-3, > 3-5 and > 5-12 yr. MAC in 60% nitrous oxide was determined in a separate group of children 1-3 yr of age. After an inhalational induction, the trachea was intubated (except for neonates in whom an awake intubation was performed). MAC for each age group was determined using the Up-and-Down technique of Dixon.
RESULTS: MAC of sevoflurane in neonates, 3.3 +/- 0.2% and in infants 1-6 months of age, 3.2 +/- 0.1%, were similar; MAC in older infants 6-12 months and children 1-12 yr was constant at approximately 2.5%; MAC of sevoflurane in 60% nitrous oxide in children 1-3 yr of age was 2.0 +/- 0.2%. Systolic arterial pressure decreased significantly at 1 MAC before skin incision compared with awake values in all subjects except children 1-3 yr with 60% nitrous oxide and children 5-12 yr in oxygen, and then returned toward awake values after skin incision. Heart rate was unchanged at approximately 1 MAC sevoflurane before incision compared with awake values in all subjects except children > 3-5 and > 5-12 yr in whom heart rate increased before incision. Induction of anesthesia, particularly with respect to airway irritability, and emergence from sevoflurane anesthesia were not remarkable. The plasma concentration of inorganic fluoride reached maximum values (8.8-16.7 microM) 30 min after discontinuation of anesthesia.
CONCLUSIONS: We conclude that sevoflurane appears to be a suitable anesthetic agent for use in neonates, infants and children undergoing < or = 1 h of anesthesia.