Local cerebral blood flow, local cerebral glucose utilization, and flow-metabolism coupling during sevoflurane versus isoflurane anesthesia in rats.
BACKGROUND
Compared to isoflurane, knowledge of local cerebral glucose utilization (LCGU) and local cerebral blood flow (LCBF) during sevoflurane anesthesia is limited.


METHODS
LCGU, LCBF, and their overall means were measured in Sprague-Dawley rats (8 groups, n=6 each) during sevoflurane and isoflurane anesthesia, 1 and 2 MAC, and in conscious control animals (2 groups, n=6 each) using the autoradiographic 2-[14C]deoxy-D-glucose and 4-iodo-N-methyl-[14C]antipyrine methods.


RESULTS
During anesthesia, mean cerebral glucose utilization was decreased: control, 56+/-5 micronmol x 100 g(-1) x min(-1); 1 MAC isoflurane, 32+/-4 micromol x 100 g(-1) x min(-1) (-43%); 1 MAC sevoflurane, 37+/-5 micromol x 100 g(-1) x min(-1) (-34%); 2 MAC isoflurane, 23+/-3 micromol x 100 g(-1) x min(-1) (-58%); 2 MAC sevoflurane, 23+/-5 micromol x 100 g(-1) x min(-1) (-59%). Local analysis showed a reduction in LCGU in the majority of the 40 brain regions analyzed. Mean cerebral blood flow was increased as follows: control 93+/-8 ml x 100 g(-1) x min(-1); 1 MAC isofurane, 119+/-19 ml x 100 g(-1) x min(-1) (+28%); 1 MAC sevoflurane, 104+/-15 ml x 100 g(-1) x min(-1) (+12%); 2 MAC isoflurane, 149+/-17 ml x 100 g(-1) x min(-1) (+60%); 2 MAC sevoflurane, 118+/-21 ml x 100 g(-1) min(-1) (+27%). LCBF was increased in most brain structures investigated. Correlation coefficients obtained for the relationship between LCGU and LCBF were as follows: control 0.93; 1 MAC isoflurane, 0.89; 2 MAC isoflurane, 0.71; 1 MAC sevoflurane, 0.83; 2 MAC sevoflurane, 0.59).


CONCLUSIONS
Mean and local cerebral blood flows were lower during sevoflurane than during isoflurane anesthesia. This difference cannot be explained by differing changes in glucose utilization because glucose utilization was decreased to the same extent in both groups.
Lenz
C
C
Department of Anesthesiology, Faculty of Clinical Medicine, University of Heidelberg, Mannheim, Germany. jr1@ix.urz.uni-heidelberg.de
Rebel
A
A
van Ackern
K
K
Kuschinsky
W
W
Waschke
K F
KF
D000758:Anesthesia; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives; D001345:Autoradiography; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002250:Carbon Radioisotopes; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003847:Deoxyglucose; D005947:Glucose / Q000378:metabolism*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D002250:Carbon Radioisotopes; D008738:Methyl Ethers; D000077149:Sevoflurane; D003847:Deoxyglucose; D007530:Isoflurane; D005947:Glucose; D000983:Antipyrine; C008135:iodoantipyrine