The Research Of The Value Of Measuring Optic Nerve Sheath Diameter By High Frequency Ultrasound In Evaluating Intracranial Pressure

Objective: The purpose of this thesis is to measure the Optic Nerve Sheath Diameter(ONSD)of the normal adults in physical examination center and the patients in ICU of emergency surgery who need lumbar puncture to measure intracranial pressure.Furthermore,to explore the reference range of ONSD in normal adults and its influencing factors,analyze the relationship between ONSD and ICP,and clarify the best threshold of ONSD when ICP is increased.Methods:(1).A total of 193 normal adults who underwent physical examination in the physical examination center of shaanxi provincial people's hospital from September 2017 to February 2018 were selected as subjects.The subjects were selected strictly according to the exclusion and inclusion criteria,and were included as the control group of this study.The ONSD of each subject was measured by high frequency ultrasound from the cross section and sagittal plane.At the same time,the age,gender,head circumference,waist circumference,body mass index(BMI)and anteroposterior axis of eyeball were recorded.The reference value range and possible influencing factors of ONSD in normal adults were analyzed.(2).A total of 63 patients who needed lumbar puncture due to craniocerebral diseases were collected in the emergency ICU of Shaanxi Provincial People's hospital from March 2018 to July 2018,and their ICP values before lumbar puncture and after cerebrospinal fluid drainage were measured,totaling 171 person times.The subjects were selected in strict accordance with the exclusion and inclusion criteria,and were included as the experimental group of this study.Using the high frequency ultrasound to measure the ONSD of each subject before and after the operation of lumbar puncture.The ultrasound examination was carried out within 15 minutes before the operation and within 15 minutes after the operation,meanwhile,the age,gender,head circumference,waist circumference,body mass index(BMI),anteroposterior axis of eyeball,the ICP before cerebrospinal fluid discharge and the ICP after cerebrospinal fluid discharge were recorded.The experimental group was divided into two groups: ICP normal group and ICP increased group.To analyze the relationship between ONSD and age,gender,head circumference,waist circumference,body mass index,eyeball axis length,ICP,and further to determine the best threshold of ONSD when it means ICP increased.Results:(1).There were 193 cases in the control group,and the average ONSD of normal adults was 3.55±0.48 mm,and the 95% confidence interval is 3.47~3.62 mm,the minimum value is 2.49 mm,and the maximum value is 5.15 mm.The correlation analysis showed that ONSD was correlated with gender,BMI and head circumference,but not with age,waist circumference and anteroposterior axis of eyeball.(2).The experimental group consisted of 63 patients with 171 person-times,and were divided into the normal ICP group and the increased ICP group,and the ONSD values of the two groups were about4.239±0.50 mm and 4.73±0.61 mm respectively.The ONSD of ICP increased group was significantly higher than that of ICP normal group(P=0.000)and control group(P=0.000),and the ONSD of ICP normal group was significantly higher than that of control group(P=0.001).The correlation analysis showed that ONSD was correlated with BMI and ICP,but not with age,waistline,head circumference and eyeball axis length,and also the correlation analysis showed that ONSD was correlated with ICP,but not with age,BMI,waist circumference,head circumference and eyeball axis length.When ICP increased to a certain extent,ONSD value was only affected by ICP.The ROC curve was used to determine the best threshold value of ONSD in the diagnosis of ICP increase.The results showed that the best threshold value of ONSD in the diagnosis of ICP increase was4.3mm,that is,when ONSD was more than 4.3mm,ICP increase could be diagnosed.At this time,the sensitivity was 77.8%,and the specificity was 69.9%.Conclusion: Using high frequency ultrasound to measure ONSD is a reliable,convenient,safe and simple noninvasive method to evaluate ICP.It has high accuracy and high clinical value.the average ONSD of normal adults was 3.55±0.48 mm,and the 95%confidence interval is 3.47~3.62 mm.The optimal threshold value for ICP diagnosis was4.3mm,which was significantly lower than that of foreign standards,therefore,the use of high-frequency ultrasound to measure ONSD to assess ICP needs to consider ethnic differences.