Vital capacity induction with 8% sevoflurane and N2o causes cerebral hyperemia.
OBJECTIVE
Little is known about the influence of high-dose sevoflurane on cerebral volume. We evaluated induction time and cerebral blood volume with 8% sevoflurane using the "vital capacity induction" technique.


METHODS
Thirty-four patients were randomly allocated into three groups. Group P received 2.0 mg x kg(-1) of propofol i.v. and inhalation of 67% N2o/O2, whereas group S5 and group S8 received inhalation of primed 5% and 8% sevoflurane in 67% N2O/O2, respectively. Induction time was measured as the time from the start of inhalation, or from the end of injection, until loss of eyelash reflex. Near-infrared spectroscopy and bispectral index (BIS) were monitored continuously until 3 min after tracheal intubation.


RESULTS
Induction time was less in group S8 (17.3 +/- 6.4s, mean +/- SD) than in groups P (25.7 +/- 8.2s) and S5 (33.0 +/- 16.8s). There was a significant increase in cerebral blood volume after intubation in group S8, as suggested by higher cerebral oxyhemoglobin and total hemoglobin levels. There were no differences in BIS scores among the groups during the study period.


CONCLUSIONS
Vital capacity inhalation of 8% sevoflurane produces a faster loss of eyelash reflex than does 5% sevoflurane or propofol, but increases cerebral blood volume.
Iwasaki
Kanako
K
Department of Anesthesia, Kanto Rosai Hospital, 2035 Kizukisumiyoshi-cho, Nakahara-ku, Kawasaki 211-8501, Japan.
Nomoto
Yukiko
Y
Ishiwata
Miwako
M
Yokota
Tetsuya
T
Ogawa
Ryo
R
D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology*; D004569:Electroencephalography; D006339:Heart Rate / Q000187:drug effects; D006454:Hemoglobins / Q000187:drug effects; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced* / Q000503:physiopathology*; D008738:Methyl Ethers / Q000009:adverse effects*; D008875:Middle Aged; D009609:Nitrous Oxide / Q000009:adverse effects*; D000077149:Sevoflurane; D013997:Time Factors; D014797:Vital Capacity / Q000502:physiology*
D018685:Anesthetics, Inhalation; D006454:Hemoglobins; D008738:Methyl Ethers; D000077149:Sevoflurane; D009609:Nitrous Oxide