Regional brain blood flow and cerebral cortical O2 consumption during sevoflurane anesthesia in healthy isocapnic swine.

Regional distribution of brain blood flow was examined in seven previously catheterized healthy isocapnic swine while awake (control), and during 1.0 and 1.5 minimum alveolar concentration (MAC--2.66 and 3.99% end-tidal, respectively) sevoflurane anesthesia using radionuclide-labeled 15-micron diameter microspheres that were injected into the left atrium. In six additional pigs, the superior sagittal sinus was also catheterized so that cerebral cortical O2 consumption could be ascertained during these conditions. Control values of blood flow in the cerebral cortical gray matter, white matter, and caudate nuclei were 117 +/- 9, 38 +/- 2 and 105 +/- 8 ml X min-1 X 100 g-1, respectively. At 1.0 MAC sevoflurane, blood flow in these regions decreased to 66, 76, and 75% of respective control values, and these values were not different from those recorded at 1.5 MAC anesthesia. Cerebral cortical O2 consumption decreased by 50 and 52% at 1.0 and 1.5 MAC sevoflurane anesthesia, but the hemoglobin-O2 saturation in the cerebral cortical venous drainage (57 +/- 3% and 69 +/- 3% at 1.0 and 1.5 MAC) consistently exceeded control value (42 +/- 1%), suggesting that cortical O2 supply during both levels of sevoflurane anesthesia remained adequate. In cerebellum, blood flow decreased from 86 +/- 5 (control) to 68 +/- 4 ml X min-1 X 100 g-1 with 1.0 MAC sevoflurane, but returned toward control value at 1.5 MAC anesthesia. The thalamohypothalamic perfusion decreased to 59 and 75% of the control value with 1.0 and 1.5 MAC sevoflurane anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)