Cerebral blood flow velocity increases when propofol is changed to desflurane, but not when isoflurane is changed to desflurane in children.
BACKGROUND
Children may exhibit delayed emergence following maintenance of anesthesia with propofol or isoflurane. Desflurane is often used towards the end of procedures to facilitate emergence. This study evaluated the effect on middle cerebral artery blood flow velocity (Vmca) in anesthetized children when propofol or isoflurane was substituted with desflurane.


METHODS
Forty-two healthy children aged 1-6 years were enrolled. A standardized anesthetic induction was used. Anesthesia was maintained with remifentanil (0.5 microg.kg(-1) bolus followed by an infusion of 0.2 microg.kg(-1).min(-1)) and a randomly selected sequence of propofol/desflurane/propofol, desflurane/propofol/desflurane, isoflurane/desflurane/isoflurane or desflurane/isoflurane/desflurane. Propofol was administered to maintain a steady-state serum concentration of 3 microg.ml(-1). Desflurane and isoflurane were administered at age-corrected 1 MAC. Hemodynamic stability was maintained. Transcranial Doppler sonography was used to measure Vmca. Hemodynamic variables as well as Vmca were measured 30 min after skin incision and repeated 30 min after each change in anesthetic maintenance agent.


RESULTS
The mean age and weight was 2.3 +/- 1.3 years and 13.0 +/- 3.7 kg, respectively. The Vmca (mean) increased by 35% from 37.7 +/- 10.5 cm s(-1) to 57.8 +/- 14.6 cm s(-1) (P < 0.0001) when propofol was changed to desflurane but was unaffected when desflurane replaced isoflurane.


CONCLUSIONS
When propofol is changed to desflurane, cerebral blood flow velocity increases significantly in normal children. This cerebral vasodilatory effect may have important implications in the neurosurgical setting.
Smith
J H
JH
Department of Anesthesia, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada.
Karsli
C
C
Lagacé
A
A
Luginbuehl
I
I
Barlow
R
R
Bissonnette
B
B
D000762:Anesthesia Recovery Period; D000767:Anesthesia, Epidural; D000768:Anesthesia, General; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D000077335:Desflurane; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D007530:Isoflurane / Q000031:analogs & derivatives*; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D015742:Propofol; D011446:Prospective Studies; D017585:Ultrasonography, Doppler, Transcranial
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D000077335:Desflurane; D007530:Isoflurane; D002045:Bupivacaine; D015742:Propofol