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目的探讨蛛网膜下腔出血(SAH)后脑血管痉挛的脑代谢变化规律及其与脑血管痉挛程度的相关性。方法 16只成年新西兰白兔随机分为:枕大池2次注生理盐水组(NS组)8只,枕大池2次注血组(SAH组)8只。两组均采用微透析仪于注血(或生理盐水)前、后第1,3,5,7天检测脑细胞外液的葡萄糖、乳酸、丙酮酸、谷氨酸及天冬氨酸的浓度,并计算乳酸与丙酮酸(L/P)比值。经颅多普(TCD)测定两组兔基底动脉血流速度;DSA测定两组兔基底动脉直径。结果与注血前相比,SAH组注血后各指标均有不同程度变化。基底动脉直径显著缩小及血流速度明显增快均于第3天开始(P<0.05),并于第5天达高峰;且轻度和中度脑血管痉挛血流速度与管径呈负相关(γ轻=0.673,P<0.01;γ中=0.613,P<0.01)。乳酸和L/P比值均于第1天明显升高(P<0.05),第5天达高峰;且与基底动脉直径变化呈负相关(γ乳酸=0.624,P<0.01;γL/P=0.713,P<0.01)。谷氨酸第1天显著升高(P<0.05),后急剧下降。结论 TCD可通过检测血流速度变化判断兔脑血管痉挛情况,但痉挛程度的判断存在局限性。脑细胞外液乳酸和L/P比值变化可预测兔脑血管痉挛的发生并判断其痉挛程度。
Objective To investigate the changes of cerebral metabolism after cerebral vasospasm following subarachnoid hemorrhage (SAH) and its correlation with the degree of cerebral vasospasm. Methods Twenty - six adult New Zealand white rabbits were randomly divided into two groups: control group (n = 8), saline group (n = 7) and saline group (n = 8). The microdialysis apparatus was used to detect the concentration of glucose, lactate, pyruvate, glutamic acid and aspartic acid in brain extracellular fluid on the 1st, 3rd, 5th and 7th day before and after the injection of blood (or normal saline) , And calculate the lactic acid and pyruvate (L / P) ratio. Transcranial Doppler (TCD) was used to measure basilar artery blood flow velocity in both groups. DSA was used to measure the diameter of basilar artery in rabbits in both groups. Results Compared with pre-injection, all indexes of SAH group changed to different degrees after injection. The basilar artery diameter was significantly reduced and the blood flow velocity was significantly increased both on the third day (P <0.05) and reached the peak on the fifth day. The blood flow velocity of the mild and moderate cerebral vasospasm was negatively correlated with the diameter (γ light = 0.673, P <0.01; γ = 0.613, P <0.01). Lactic acid and L / P ratio increased significantly on the first day (P <0.05) and peaked on the fifth day, and was negatively correlated with the change of basilar artery diameter (γ-lactate = 0.624, P <0.01; γL / P = , P <0.01). Glutamate significantly increased on the first day (P <0.05), then decreased sharply. Conclusions TCD can judge the cerebral vasospasm in rabbits by detecting the change of blood flow velocity, but the judgment of the spasticity is limited. Changes in brain extracellular fluid lactic acid and L / P ratio can predict the occurrence of cerebral vasospasm in rabbits and determine the degree of spasticity.