Propofol is associated with impaired brain metabolism during hypothermic circulatory arrest: an experimental microdialysis study.
BACKGROUND
Propofol is a widely used anesthetic in cardiac surgery. It has been shown to increase cerebrovascular resistance resulting in decreased cerebral blood flow. Efficient brain perfusion and tissue oxygenation during cardiopulmonary bypass (CPB) is essential in surgery requiring hypothermic circulatory arrest (HCA). The effects of propofol on brain metabolism are reported in a surviving porcine model of HCA.


METHODS
Twenty female juvenile pigs undergoing 75 minutes of HCA at a brain temperature of 18 degrees C were assigned to either propofol- or isoflurane anesthesia combined with alpha-stat perfusion strategy during CPB cooling and rewarming. Brain microdialysis analysis was used for determination of brain metabolism, and tissue oxygen partial pressure and intracranial pressures were also followed-up until 8 hours postoperatively.


RESULTS
Brain concentrations of glutamate and glycerol were significantly higher in the propofol group throughout the experiment (P < .01 and P < .01, respectively). The lactate/pyruvate ratio was significantly higher in the propofol group at 6-, 7-, and 8-hour intervals (P < .05, P < .01, and P < .05, respectively). The intracranial pressure was significantly higher at the 8-hour postoperative interval (P < .05) in the propofol group. A trend toward higher brain oxygen concentrations was observed in the isoflurane group.


CONCLUSIONS
Anesthesia with propofol as compared with isoflurane is associated with impaired brain metabolism during experimental HCA.
Dahlbacka
Sebastian
S
Department of Surgery, Clinical Research Center, Oulu University Hospital, University of Oulu, Oulu, Finland. sdahlbac@paju.oulu.fi
Mäkelä
Jussi
J
Kaakinen
Timo
T
Alaoja
Hanna
H
Heikkinen
Janne
J
Laurila
Päivi
P
Kiviluoma
Kai
K
Salomäki
Timo
T
Tuominen
Hannu
H
Ohtonen
Pasi
P
Lepola
Pasi
P
Biancari
Fausto
F
Juvonen
Tatu
T
D018686:Anesthetics, Intravenous / Q000009:adverse effects; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism*; D001928:Brain Diseases, Metabolic / Q000139:chemically induced* / Q000175:diagnosis / Q000378:metabolism*; D050792:Circulatory Arrest, Deep Hypothermia Induced; D005260:Female; D017551:Microdialysis; D015742:Propofol / Q000009:adverse effects*; D013552:Swine
D018686:Anesthetics, Intravenous; D015742:Propofol