The Clinical Study Of Early Brain Injury And Permeability Changes Of Blood Brain Barrier After Subarachnoid Hemorrhage

Early Brain Injury (EBI) after Subarachnoid Hemorrhage (SAH) is referred to the direct brain injury after SAH within 72 hours which involves all kinds of physiological and pathological events before delayed cerebral vascular spasm(3 days-3weeks) including increased intracranial pressure, reduced cerebral blood flow, BBB(blood brain barrier) disruption, brain edema, acute vascular spasm, microcirculation dysfunction and brain cell death.BBB (blood brain barrier) is formed by brain capillary endothelial cells, astrocytes, pericytes and vascular basement membrane. Due to the tight junction between brain capillary endothelial cells, the permeability between cells is tiny. Normally, except few lipid soluble molecules and other small molecules, most molecules are difficult to pass BBB. After the destruction of BBB, permeability between cells changes obviously. Most big molecules such as Albumin (Alb) could pass BBB. Of course, under normal condition, these molecules cannot pass BBB.This study is aimed to explore the evaluation criteria to judge whether early brain injury is existed or not and to evaluate the degree of early brain injury according to the collected data, then try to find out reliable criteria to judge the degree of early brain injury,finally explore the relationship between NSE and prognosis of patients. After early brain injury, NSE (neuron specific enolase) in these damaged cells will release into the blood, concentration of NSE in blood will increase. Serum NSE concentration of patients with conscious disturbance(25.16±14.02 ng/ml)is significantly higher than that of patients without conscious disturbance(13.58±5.76 ng/ml),the difference between them has statistical significance; when NSE concentration is different, prognosis in different groups has statistical difference., serum NSE concentration more than 15.35ng/ml is a risk factor of poor prognosis, which is similar to the value(less than 16ng/ml) used commonly in clinical research. It is approved that nerve inflammation is existed after SAH, among these inflammatory factors, only IL-6 (Interleukin-6) is confirmed that prognosis is different when CSF IL-6 concentration is different. The increasing of CSF IL-6 concentration is a risk factor of death in prognosis. Then this study is aimed to explore the relationship between changes of BBB permeability and prognosis in patients after SAH. After SAH, BBB has been destroyed, Albumin will enter cerebrospinal fluid, so it could be a criterion to judge whether BBB has been destroyed or not and the destruction degree. When comparing the difference between CSF Alb concentration of patients with conscious disturbance(1257.07±1648.16 mg/L) and CSF Alb concentration of patients without conscious disturbance(680.50±675.12 mg/L),we find that P=0.074>0.05,which means the difference between them does not have statistical significance. Using single factor analysis of variance (post hoc:LSD) test method, we choose any two groups in three groups, the value of P is always more than 0.05. So we can conclude that there is no practical criterion to evaluate the destruction degree of blood brain barrier at present.