无创测定临界关闭压变化率对高血压患者脑血管储备能力的评估价值

Noninvasive Estimating Values of Changed Percentage of Critical Closing Pressures for Evaluating Cerebrovascular Reserve Capacity in Hypertension

目的无创测定临界关闭压变化率,并评价其对高血压者脑血管储备能力的评估价值。方法招募符合入组标准的原发性高血压患者25例和健康志愿者35例为研究对象。用经颅超声多普勒仪、无创血压监测仪持续记录高血压组及对照组的大脑中动脉的血流流速和桡动脉血压,用潮气末CO2监测仪持续监测呼出气体的PCO2。高碳酸血症通过吸入混合气体(5%CO2、21%O2和74%N2)获得。用傅立叶变换法分别测得两组吸入混合气体前后的临界关闭压(CCP)。分别计算两组吸入混合气体后流速增加率和CCP变化率。结果两组试验对象的大脑中动脉平均流速、CCP在吸入混合气体前比较差异均无显著性意义(t=1·008,P=0·318;t=0·059,P=0·437)。吸入混合气体后,高血压组的流速增加率低于对照组的流速增加率,差异有显著性意义(t=-4·325,P=0·000),但两组的CCP减少率比较差异无显著性意义(t=0·459,P=0·648)。结论传统的流速变化率对脑血管储备能力的评价要优于CCP变化率,进一步评价脑血管储备能力仍宜测定流速变化率。

Objective Noninvasive estimating the values of the changed percentage of critical closing pressures for evaluating the cerebrovascular reserve capacity （CRC） in the patients of essential hypertension. Methods 25 patients of essential hypertension accorded with basic admission criterion were admitted, and 35 control subjects were recruited from a group of healthy volunteers. Transcranial Doppler velocities of middle cerebral artery and noinvasive blood pressure in radial artery were continuous recorded in subjects. End -tidal CO2 was also measured by a monitor. Hypercapnia was gained by conducting subjects breath a gas mixture of 5% CO2,21% 02,74% nitrogen. The critical closing pressures（CCP） of two groups were calculated by Fourier transform method. The changed percentage of velocities and the changed percentage of CCP were caculated, respectively. Results Both of mean velocities and CCPs had not significant differences between two groups in baseline phase （ t = 1. 008, P = 0. 318 ; t = 0. 059, P = 0. 437）. The changed percentage of velocities in hypertension group was lower than that of control group （ t = - 4. 325, P = 0. 000）, but this trial did not have sufficient statistical power to detect differences in the changed percentage of CCPs of two groups （ t = 0. 459, P = 0. 648） Conclusion The changed percentage of velocities is superior than the changed percentage of CCPs in the evaluation of CRC, and the latter is not recommended in the future.