Laitio Ruut M, Kaisti Kaike K, Låangsjö Jaakko W, Aalto Sargo, Salmi Elina, Maksimow Anu, Aantaa Riku, Oikonen Vesa, Sipilä Hannu, Parkkola Riitta, Scheinin Harry
Turku PET Centre, Department of Anesthesiology and Intensive Care, Turku University Hospital, Finland.
Anesthesiology. 2007 Jun;106(6):1128-33. doi: 10.1097/01.anes.0000267596.57497.92.
Animal studies have demonstrated a strong neuroprotective property of xenon. Its usefulness in patients with cerebral pathology could be compromised by deleterious effects on regional cerebral blood flow (rCBF).
15O-labeled water was used to determine rCBF in nine healthy male subjects at baseline and during 1 minimum alveolar concentration (MAC) of xenon (63%). Anesthesia was based solely on xenon. Absolute changes in rCBF were quantified using region-of-interest analysis and voxel-based analysis.
Mean arterial blood pressure and arterial partial pressure for carbon dioxide remained unchanged. The mean (+/-SD) xenon concentration during anesthesia was 65.2+/-2.3%. Xenon anesthesia decreased absolute rCBF by 34.7+/-9.8% in the cerebellum (P<0.001), by 22.8+/-10.4% in the thalamus (P=0.001), and by 16.2+/-6.2% in the parietal cortex (P<0.001). On average, xenon anesthesia decreased absolute rCBF by 11.2+/-8.6% in the gray matter (P=0.008). A 22.1+/-13.6% increase in rCBF was detected in the white matter (P=0.001). Whole-brain voxel-based analysis revealed widespread cortical reductions and increases in rCBF in the precentral and postcentral gyri.
One MAC of xenon decreased rCBF in several areas studied. The greatest decreases were detected in the cerebellum, the thalamus and the cortical areas. Increases in rCBF were observed in the white matter and in the pre- and postcentral gyri. These results are in clear contradiction with ketamine, another N-methyl-D-aspartate antagonist and neuroprotectant, which induces a general increase in cerebral blood flow at anesthetic concentrations.
动物研究已证明氙具有强大的神经保护特性。其对脑部病变患者的有效性可能会因对局部脑血流量（rCBF）的有害影响而受到损害。
使用15O标记水在9名健康男性受试者的基线期以及在1个最低肺泡浓度（MAC）的氙气（63%）期间测定rCBF。麻醉仅基于氙气。使用感兴趣区域分析和基于体素的分析对rCBF的绝对变化进行量化。
平均动脉血压和二氧化碳动脉分压保持不变。麻醉期间氙气的平均（±标准差）浓度为65.2±2.3%。氙气麻醉使小脑的绝对rCBF降低34.7±9.8%（P<0.001），丘脑降低22.8±10.4%（P = 0.001），顶叶皮质降低16.2±6.2%（P<0.001）。平均而言，氙气麻醉使灰质的绝对rCBF降低11.2±8.6%（P = 0.008）。在白质中检测到rCBF增加22.1±13.6%（P = 0.001）。基于全脑体素的分析显示中央前回和中央后回的皮质广泛减少且rCBF增加。
1个MAC的氙气降低了所研究的几个区域的rCBF。在小脑、丘脑和皮质区域检测到最大程度的降低。在白质以及中央前回和中央后回中观察到rCBF增加。这些结果与氯胺酮（另一种N-甲基-D-天冬氨酸拮抗剂和神经保护剂）明显矛盾，氯胺酮在麻醉浓度下会导致脑血流量普遍增加。
