Cerebrovascular carbon dioxide reactivity in children anaesthetized with sevoflurane.
BACKGROUND
To determine the effects of sevoflurane on cerebrovascular carbon dioxide reactivity (CCO2R), middle cerebral artery blood flow velocity (CBFV) was measured at different levels of PE'CO2 by transcranial Doppler sonography in 16 ASA I or II children, aged 18 months to 7 yr undergoing elective urological surgery.


METHODS
Anaesthesia comprised 1.0 MAC sevoflurane and air in 30% oxygen delivered through an Ayre's T piece by intermittent positive-pressure ventilation, and a caudal epidural block with 0.25% bupivacaine 1.0 ml kg(-1) without epinephrine. PE'CO2 was randomly adjusted to 25, 35, 45 and 55 mm Hg (3.3, 4.6, 5.9 and 7.2 kPa) with an exogenous source of CO2, while maintaining ventilation variables constant.


RESULTS
CBFV increased as PE'CO2 increased from 25 to 35, and to 45 mm Hg (P<0.001), but did not increase significantly with an increase in PE'CO2 from 45 to 55 mm Hg. Mean heart rate and arterial pressure remained constant.


CONCLUSIONS
CCO2R is preserved in healthy children anaesthetized with 1.0 MAC sevoflurane.
Rowney
D A
DA
Department of Anaesthesia, The Hospital for Sick Children, University of Toronto, Ontario, Canada,.
Fairgrieve
R
R
Bissonnette
B
B
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D008738:Methyl Ethers / Q000494:pharmacology*; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D010313:Partial Pressure; D012044:Regression Analysis; D000077149:Sevoflurane; D017585:Ultrasonography, Doppler, Transcranial
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane