[Bispectral index (BIS) in infants anesthetized with sevoflurane in nitrous oxide and oxygen].
BACKGROUND
The bispectral index (BIS) has been shown to be useful in monitoring a degree of hypnosis in anesthetized adults. Although several studies have been performed to evaluate BIS in pediatric patients, it is unclear whether BIS monitor can be applied to infants. This study was designed to evaluate if the BIS monitor can be used in infants as a measure to monitor a degree of hypnosis.


METHODS
Forty-three infants were divided into two age groups according to their age: group A (3-6 months; n = 31) and B (7-12 months; n = 12). And the patients in the younger group were randomly allocated to one of two groups, A (+) (premedicated with oral midazolam 0.5 mg.kg-1; n = 19) and A (-) (without premedication; n = 12). BIS values and other parameters were recorded at a steady state of end-tidal sevoflurane concentration (2.5, 2, and 1.5%) and immediately before extubation.


RESULTS
At each concentration of sevoflurane and extubation, the BIS values were lower in group A (+) than in group B (P < 0.05). In infants < or = 6 months of age, premedication did not affect the BIS values.


CONCLUSIONS
There were significant differences of BIS values between < or = 6 months and > or = 7 months old infants. BIS values should be interpreted cautiously in infants younger than 6 months.
Department of Anesthesiology, Osaka Medical Center, Research Institute for Maternal and Child Health, Izumi 594-1101.
Yoshitaka
Y
Kawaraguchi
Kazuo
K
Fukumitsu
Keiko
K
Kinouchi
Osamu
O
Hirao
Yoshikazu
Y
Miyamoto
Akihiro
A
Taniguchi
D000367:Age Factors; D000769:Anesthesia, Inhalation; D003243:Consciousness; D004569:Electroencephalography; D006801:Humans; D006990:Hypnosis; D007223:Infant; D008738:Methyl Ethers; D016343:Monitoring, Intraoperative / Q000379:methods*; D009609:Nitrous Oxide; D010100:Oxygen; D000077149:Sevoflurane
D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide; D010100:Oxygen