无创性脑电阻抗测定在脑出血患者脑水肿监测中的应用

Application of noninvasive cerebral electrical impedance measurement on brain edema in patients with intracerebral hemorrhage

目的应用无创性脑电阻抗测定探讨急性脑出血患者脑水肿的变化规律及意义。方法分别检测200名健康志愿者和78例脑出血患者的脑电阻抗扰动系数及其动态变化,通过多媒体图像分析系统计算头颅 CT 上血肿和血肿周围水肿的体积,并进行相关分析。结果①健康志愿者左、右大脑半球扰动系数分别为(7.98±0.95)和(8.02±0.71),基本对称(P>0.05)。性别、年龄及3～6 h 连续检测前后对其无明显影响(P>0.05)。②脑出血患者的总体检测阳性率为73.1%。血肿位于基底节区时阳性率最高(83.3%),病灶体积大于20 ml 者阳性率(80.0%～88.9%)明显高于体积小于20 ml 者(48.1%)。③脑出血患者血肿侧扰动系数由低于血肿对侧至逐渐升高并超过血肿对侧,这个"交叉"时间平均为起病后(19.67±11.52)h,在该时间点后血肿周围水肿体积较前明显增大(P<0.05),同时扰动系数亦明显升高(P<0.01)。④起病24 h 内的血肿侧扰动系数变化与血肿体积及血肿周围组织水肿体积无相关关系(P>0.05);而病后3 d 的血肿侧扰动系数变化与血肿周围组织水肿体积具有显著正相关关系(r=0.5977,P<0.01)。结论脑电阻抗测定可较敏感地反映脑出血患者脑水肿的变化,扰动系数越高,则提示脑水肿越重。病灶位于基底节区时检测阳性率最高。该方法为临床上进行动态、床旁连续无创性脑水肿监测提供了新的有意义的手段。

Objective To explore the change of brain edema in patients with intracerebral hemorrhage （ICH） by noninvasive cerebral electrical impedance （CEI） measurement. Methods An invariable secure current at a frequency 50 kHz and a intensity of 0, 1 mA was given into a person＇ s brain, and the CEI of the two hemispheres was converted into perturbative index （PI）. PI of 200 healthy volunteers and 78 patients with ICH was measured by noninvasive Brain-Edema Monitor. The results of PI were compared with the volumes of hematoma and surrounding edema, which calculated by image analyzing system according to CT scan. Results ①In the normal group, PI in the left and right hemisphere was respectively 7.98 ± 0.95 and 8. 02 ± 0.71, and there was no significant difference between the either sides （ P 〉 0. 05 ）. Age, sex and different measuring times did not obviously affect the PI values （ P 〉 0. 05 ）. ②The total positive ratio of PI in ICH was 73.1%. PI was the most sensitive when the position located in the basal ganglia （83.3%）or the volumes of lesions were more than 20 ml （80.0%-88.9%）, but was low when the volumes less than 20 ml or the position near the midline. ③In the patients with ICH, PI of the hematoma side initially was lower and finally higher than contralateral one. The average transitional time was （ 19. 67 ± 11.52） h. The ipsilateral PI after the transitional time was much higher than that before the transitional time in the same patients（ P 〈 0. 01 ）. The volumes of peri-hematoma edema were also significantly larger after the transitional time than before（ P 〈 0. 05 ）. ④There was a positive correlation between the ipsilateral PI and the volume of peri-hematoma edema in the patients 3 days after onset （ r = 0. 5977, P 〈 0. 01 ）. But there was no such significant correlation within 24 h. Conclusions CEI may be a sensitive parameter for noninvasive monitoring the change of brain edema in patients with ICH. The higher the PI, the more severe the edema can result. The sensitivity of PI is the highest when the position of hematoma locates in the basal ganglia.CEI is a new technology for judging the patients＇ condition of brain edema noninvasively.