Department of Neuroanaesthesiology, Aarhus University Hospitals, Noerrebrogade 44, 8000 Aarhus C, Denmark.
Acta Anaesthesiol Scand. 2010 May;54(5):603-9. doi: 10.1111/j.1399-6576.2010.02208.x. Epub 2010 Jan 18.
The precise mechanism by which sevoflurane exerts its effects in the human brain remains unknown. In the present study, we quantified the effects of sevoflurane on regional cerebral glucose metabolism (rGMR) in the human brain measured with positron emission tomography.
Eight volunteers underwent two dynamic 18F-fluorodeoxyglucose positron emission tomography (PET) scans. One scan assessed conscious-baseline metabolism and the other scan assessed metabolism during 1 minimum alveolar concentration (MAC) sevoflurane anaesthesia. Cardiovascular and respiratory parameters were monitored and bispectral index responses were registered. Statistical parametric maps and conventional regions of interest analysis were used to determine rGMR differences.
All subjects were unconsciousness at 1.0 MAC sevoflurane. Cardiovascular and respiratory parameters were constant over time. In the awake state, rGMR ranged from 0.24 to 0.35 mumol/g/min in the selected regions. Compared with the conscious state, total GMR decreased 56% in sevoflurane anaesthesia. In white and grey matter, GMR was averaged 42% and 58% of normal, respectively. Sevoflurane reduced the absolute rGMR in all selected areas by 48-71% of the baseline (P< or = 0.01), with the most significant reductions in the lingual gyrus (71%), occipital lobe in general (68%) and thalamus (63%). No increases in rGMR were observed.
Sevoflurane caused a global whole-brain metabolic reduction of GMR in all regions of the human brain, with the most marked metabolic suppression in the lingual gyrus, thalamus and occipital lobe.
七氟醚在人脑内发挥作用的确切机制尚不清楚。本研究采用正电子发射断层扫描（PET）定量检测七氟醚对人脑局部脑葡萄糖代谢（rGMR）的影响。
8 名志愿者接受了 2 次 18F-氟脱氧葡萄糖正电子发射断层扫描（PET）动态扫描。一次扫描评估清醒基础代谢，另一次扫描评估 1 最低肺泡有效浓度（MAC）七氟醚麻醉时的代谢。监测心血管和呼吸参数并记录脑电双频指数（bispectral index）反应。采用统计参数图和常规感兴趣区分析来确定 rGMR 差异。
所有志愿者在 1.0 MAC 七氟醚麻醉时均无意识。心血管和呼吸参数随时间保持不变。在清醒状态下，所选区域的 rGMR 范围为 0.24-0.35 μmol/g/min。与清醒状态相比，七氟醚麻醉时总 GMR 降低 56%。在白质和灰质中，GMR 分别为正常的 42%和 58%。七氟醚使所有选定区域的 rGMR 绝对降低了 48%-71%（P<或=0.01），其中舌回（71%）、枕叶（68%）和丘脑（63%）降幅最大。未观察到 rGMR 增加。
七氟醚导致人脑所有区域的 GMR 出现全脑代谢降低，其中舌回、丘脑和枕叶的代谢抑制最为明显。
