Risk factors for the occurrence of electroencephalogram abnormalities during induction of anesthesia with sevoflurane in nonepileptic patients.
BACKGROUND
The aim of this prospective study was to determine the risk factors of epileptiform discharge during induction with sevoflurane in healthy adult patients.


METHODS
Forty adult patients with American Society of Anesthesiologists physical status I were randomly allocated to one of four groups. Group A: Patients breathed 8% sevoflurane in oxygen (8 l/min) via a prefilled circuit. End-tidal sevoflurane was maintained at 4%. Tracheal intubation was performed at the third minute after cisatracurium injection. Group B: The anesthesia protocol was similar, but a vital capacity technique was performed. Group C: Patients were anesthetized as in group A but were hyperventilated. Group D: Patients were anesthetized as in group A, but end-tidal sevoflurane was maintained at 2%. An electroencephalogram was recorded before and during induction up to 11 min after the start of induction. Statistical analysis was performed with Statview 5.0 (SAS Institute Inc., Cary, NC) for multivariate analysis.


RESULTS
Twelve patients experienced epileptiform discharges. Risk factors were female sex (odds ratio, 12.60; 95% confidence interval, 1.46-135), delay to the occurrence of beta waves (odds ratio, 0.92; 95% confidence interval, 0.86-0.99), and end-tidal sevoflurane (odds ratio, 8.78; 95% confidence interval, 1.12-69). Epileptiform discharges were not associated with significant hemodynamic or Bispectral Index variations.


CONCLUSIONS
Induction with sevoflurane may result in epileptiform electroencephalographic activity. Only electroencephalographic monitoring allows the diagnosis. Risk factors are mainly female sex, short delay to onset of anesthesia, and high alveolar sevoflurane concentration. Induction with high sevoflurane concentration is controversial mainly in women.
Julliac
Benjamin
B
Département d'anesthésie réanimation 4, France. benjamin.julliac@chu-bordeaux.fr
Guehl
Dominique
D
Chopin
Fabrice
F
Arne
Pierre
P
Burbaud
Pierre
P
Sztark
François
F
Cros
Anne-Marie
AM
D000328:Adult; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D002245:Carbon Dioxide / Q000097:blood; D003071:Cognition / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008738:Methyl Ethers / Q000009:adverse effects*; D012307:Risk Factors; D000077149:Sevoflurane; D012727:Sex Characteristics
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane