A comparison of the end-tidal sevoflurane concentration for removal of the laryngeal mask airway and laryngeal tube in anesthetized children.
BACKGROUND
In this study we quantified and compared the optimal sevoflurane concentration required to prevent coughing or moving during or after removal of the laryngeal mask airway (LMA) and the laryngeal tube (LT) in anesthetized children.


METHODS
Forty unpremedicated children, aged 8 mo to 12 yr, were randomly allocated to receive the LMA or LT. General anesthesia was induced via mask with sevoflurane and the LMA or LT was inserted. Anesthesia was maintained with sevoflurane and oxygen. At the end of surgery, a predetermined end-tidal sevoflurane concentration was maintained for at least 10 min and the LMA or LT was removed. Using Dixon's up-down method, the concentration for LMA and LT removal was determined by adjusting the dose by a 0.2% increment. Success was defined by the absence of coughing, teeth clenching, gross purposeful movement, breath holding, laryngospasm, and desaturation.


RESULTS
The end-tidal concentration of sevoflurane to achieve successful LMA removal in 50% of children was 1.90%, in 95% of children was 2.15%. For the LT, the concentrations were 1.83% and 2.00%. The 50% effective dose values did not differ significantly between groups.


CONCLUSIONS
LMA and LT removal in 95% of anesthetized children (aged 8 mo to 12 yr) can be safely accomplished without coughing, moving, or any other airway complications at 0.86 and 0.80 minimum alveolar anesthetic concentration, respectively, and a similar concentration should be used for removal of the LT or LMA in children.
Lee
Jeong-Rim
JR
Department of Anesthesiology, Seoul National University College of Medicine, Seoul, Korea.
Lee
Young-Sun
YS
Kim
Chong Sung
CS
Kim
Seong Deok
SD
Kim
Hee-Soo
HS
D000769:Anesthesia, Inhalation / Q000379:methods*; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007442:Intubation, Intratracheal; D017214:Laryngeal Masks; D008738:Methyl Ethers / Q000493:pharmacokinetics*; D012449:Safety; D000077149:Sevoflurane; D013990:Tidal Volume
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane