End-tidal sevoflurane concentrations for laryngeal mask airway insertion and for tracheal intubation in children.
BACKGROUND
Sevoflurane, a new inhalational anesthetic agent characterized by a low blood-gas partition coefficient and nonpungent odor, appears suitable as an induction agent for children. The laryngeal mask airway is a new device for maintaining airway patency during anesthesia. This study was conducted to determine the sevoflurane concentrations required for insertion of a laryngeal mask (MACLMI) and for tracheal intubation (MACTI) in children.


METHODS
Forty-two patients, aged 1-9 yr, scheduled for surgery during general anesthesia were randomly assigned into two groups: MACLMI (n = 21) and MACTI (n = 21). After the predetermined end-tidal concentration had been established and maintained for 20 min, laryngeal mask insertion or tracheal intubation was attempted without neuromuscular relaxants or other adjuvants. Each concentration at which laryngeal mask insertion or tracheal intubation was attempted was predetermined by the up-and-down method (with 0.5% as a step size).


RESULTS
Sevoflurane MACLMI was 2.00 +/- 0.28%. Sevoflurane MACTI was 2.83 +/- 0.34%, significantly greater than MACLMI.


CONCLUSIONS
Laryngeal mask insertion can be performed at a lesser sevoflurane concentration than that required for tracheal intubation.
Taguchi
M
M
Department of Anesthesia, Mito Saiseikai General Hospital, Ibaraki, Japan.
Watanabe
S
S
Asakura
N
N
Inomata
S
S
D000758:Anesthesia / Q000379:methods; D000777:Anesthetics / Q000493:pharmacokinetics / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004987:Ethers / Q000493:pharmacokinetics* / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007223:Infant; D007442:Intubation, Intratracheal / Q000379:methods*; D017214:Laryngeal Masks; D008297:Male; D008738:Methyl Ethers; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012044:Regression Analysis; D000077149:Sevoflurane; D013990:Tidal Volume
D000777:Anesthetics; D004987:Ethers; D008738:Methyl Ethers; D000077149:Sevoflurane