Mills P, Sessler D I, Moseley M, Chew W, Pereira B, James T L, Litt L
Anesthesiology. 1987 Aug;67(2):169-73. doi: 10.1097/00000542-198708000-00003.
19F nuclear magnetic resonance spectroscopy was performed at 2.0 Tesla to evaluate the washout of isoflurane from the adult rabbit brain after 90 min of anesthesia. This investigation reconciles previous in vivo NMR studies of others, which observed a slow anesthetic washout, with invasive non-NMR studies that found a rapid washout, as predicted by perfusion-limited models of anesthetic uptake and elimination. Two NMR surface coil experiments were performed: in the first, a 1-cm surface coil was placed directly over the exposed dura to be certain that the washout was observed only from the brain; in the second, a 3-cm coil was placed noninvasively over the intact scalp to emulate previous NMR experiments. As in previous NMR experiments, a slow washout of isoflurane was observed with the large coil. The NMR signal that is observed with the large coil cannot be attributed solely to brain tissue. Fat surrounding the brain contributes significantly to the fluorine NMR spectra that are observed with the 3-cm coil, and its contributions lengthen the apparent washout time. A rapid washout of isoflurane from the rabbit brain was observed with the small coil, whose signal unambiguously arises only from brain tissue. The observed rapid washout is consistent with previous invasive biochemical measurements of anesthetic washout from the brain.
在2.0特斯拉的磁场强度下进行了19F核磁共振光谱分析，以评估成年兔麻醉90分钟后异氟烷从脑中的清除情况。本研究调和了之前其他人的体内核磁共振研究结果（这些研究观察到麻醉剂清除缓慢）与侵入性非核磁共振研究结果（这些研究发现清除迅速，这与麻醉剂摄取和消除的灌注限制模型预测一致）之间的矛盾。进行了两个核磁共振表面线圈实验：第一个实验中，将一个1厘米的表面线圈直接放置在暴露的硬脑膜上方，以确保仅观察到来自脑的清除情况；第二个实验中，将一个3厘米的线圈无创地放置在完整头皮上方，以模拟之前的核磁共振实验。与之前的核磁共振实验一样，使用大线圈观察到异氟烷清除缓慢。使用大线圈观察到的核磁共振信号不能仅归因于脑组织。脑周围的脂肪对使用3厘米线圈观察到的氟核磁共振光谱有显著贡献，其贡献延长了表观清除时间。使用小线圈观察到异氟烷从兔脑中迅速清除，其信号明确仅来自脑组织。观察到的快速清除与之前对脑内麻醉剂清除的侵入性生化测量结果一致。
