PET分析丙泊酚对人脑葡萄糖能量代谢的影响

Imaging study on the effect of propofol on cerebral metabolism with positron emission tomography

目的 应用正电子发射计算机体层显像(PET)技术,观察丙泊酚对人脑不同区域内葡萄糖能量代谢(CMGlu)的影响,探讨丙泊酚在人脑可能的作用部位。方法 健康志愿者 7 名,每位志愿者分别在清醒、丙泊酚 1 .5μg/ml(镇静)和 3 0μg/ml(意识消失)靶浓度状态下注射18氟脱氧葡萄糖(18F -FDG)显像剂,平衡后进行PET扫描。以清醒状态作为对照,通过靶控输注(TCI)丙泊酚使志愿者达到镇静和意识消失状态。结果 (1)与清醒状态比较,镇静状态下脑电双频指数(BIS)明显降低(P<0. 05),平均动脉压(MAP)、呼吸频率(RR)和心率(HR)等指标无显著性改变;而意识消失状态下,MAP、BIS降低,呼吸抑制,呼气末二氧化碳分压( PET CO2 )升高,均有显著性差异(P<0. 05)。(2)与清醒状态比较,镇静状态下全脑的CMGlu下降(18. 0±4. 0)%。CMGlu的下降在大脑皮质最为明显(P<0. 05)。CMGlu在丘脑、小脑、海马和桥脑等区域也有不同程度的降低,但与清醒状态比较,无显著性差异。意识消失状态下,全脑 CMGlu 与清醒状态比较显著下降了(34. 1±7 .0)%(P<0 .05),在丘脑、大脑皮质、小脑和海马等区域 CMGlu明显低于清醒状态(P<0 .05),其中丘脑降幅最大为(51. 5±5 .0)%。结论 丙泊酚麻醉可明显降低全脑能量代谢,低剂量的丙泊酚首先影响皮层区的能量代谢,?

Objective To examine the changes in regional cerebral glucose metabolisn produced by propofol with application of positron emission tomography(PET) technic, and investigate the specific brain structures effected by propofol.Methods Seven volunteers underwent PET scan for three times.One scan assessed awake-baseline metabolism(T1).The second scan assessed metabolism during sedative propofol(TCI 1.5μg/ml,T2).The third scan assessed metabolism at loss of consciousness(propofol TCI of 3.0μg/ml,T3).Results (1)Compared with T1,BIS was significantly decreased at T2.BIS and MAP,RR and P_ ETCO_2 were all depressed at T3 compared with those at T1.(2)Whole brain glucose metabolism(CMGlu) decreased by (18.0±4.0)% at T2 compared with that at T1,which was most obvious in cortical regions,and had no significant difference among the other regions.Total CMGlu decreased by (34.1±7.0)% in whole brain at T3 compared with that at T1,which was all significant in the thalamus,cortical,hippocampal and cerebellum.The largest decrease of CMGlu(51.5±5.0)% was seen in the thalamus.Conclusion CMGlu is decreased in whole brain during propofol anesthesia.Low doses of propofol seem to affect cortical areas preferentially.Higher doses of propofol not only affect the cortical but also the subcortical structures,the thalamus and hippocampus in particular.These areas appear to be specific targets for propofol.