END-TIDAL SEVOFLURANE CONCENTRATION FOR TRACHEAL INTUBATION AND MINIMUM ALVEOLAR CONCENTRATION IN PEDIATRIC-PATIENTS

Background: Sevoflurane is a new inhalational anesthetic agent having low solubility in blood and a relatively nonpungent odor. As such it s hould be useful as an inhalation induction in pediatric patients. The objectives of the study were to determine both the minimum alveolar co ncentration (MAC) and the concentration required for tracheal intubati on (MAC(EI)) of sevoflurane in pediatric patients. Methods: The study group consisted of 36 ASA physical status 1 elective surgical patients , aged 1-9 yr. MAC(EI) determination: After establishing and maintaini ng the end-tidal concentration for 15 min, tracheal intubation was att empted with an uncuffed tracheal tube without neuromuscular relaxants or other adjuvants. Each concentration at which tracheal intubation wa s attempted was predetermined according to the up-and-down method (wit h 0.5% as a step size). MAC determination: The patients examined were the same as those for MAC, determination except that for the exclusion of those to whom neuromuscular relaxants or other adjuvants drugs wer e administered. End-tidal sevoflurane concentration was determined acc ording to the up-and-down method (with 0.5% as a step size) and held c onstant for at least 15 min before a skin incision. Result: MAC(EI) of sevoflurane was 2.69% (95% fiducial limits: 2.23% and 3.37%); MAC of sevoflurane was 2.03% (95% fiducial limits: 1.51% and 2.53%); and the MAC(EI)/MAC ratio was 1.33. Conclusion: Sevoflurane appears to be suit able for use in pediatric patients as an induction agent, permitting t racheal intubation without neuromuscular relaxants.