国产电极片可代替原装电极片用于体表生物电阻抗法细胞外液测量

The China-made electrodes can be used for the measurement of extracellular water but not for intracellular water by bioimpedance

目的探讨是否可以使用国产电极片代替原装电极片用于生物电阻抗法测量细胞外液(extracellular water,ECW)和细胞内液(intracellular water,ICW)。方法选择12例健康志愿者和23例维持性血液透析(maintenance hemodialysis,MHD)患者。受试者平卧5min后,使用Xitron体表生物电阻抗频谱分析仪测量不同频率下的电阻和电抗。先使用原装电极片测量一次,然后再用国产电极片测量1次。健康志愿者接受1次测量;MHD患者于血液透析前后分别进行一次测量。使用Xitron公司提供的软件计算ECW和ICW,用配对t检验及Bland-Altman作图分别比较两种测量方法获得的ECW和ICW的差异,以P<0.05为差异有统计学意义,如果两种方法的差值的绝对值小于0.5L,则认为可用国产电极片代替原装电极片。结果原装电极片测量ECW(ECW-C)为(15.41±4.53)L,国产电极片ECW(ECW-Y)为(15.18±4.46)L;原装电极片测量ICW(ICW-C)为(17.87±6.03)L,国产电极片ICW(ICW-Y)为(19.93±6.09)L。配对t检验和Bland-Altman图上ECW-Y与ECW-C的差值为(-0.23±0.43)L;ICW-Y与ICW-C差值为(2.06±3.05)L。结论国产电极片可以代替原装电极片用于ECW测量,但不能用于ICW测量。

Objective To investigate if the original electrodes can be replaced by China-made electrodes for the measurement of extracellular water （ECW） and intracellular water （ICW） by bioimpedance. Methods Twelve healthy subjects and 23 patients on maintenance hemodialysis （MHD） were included in this study. Examinees were asked to keep in a supine position for at least 5 minutes. Xitron surface bioimpedance analyzer was used to measure resistance and reactance under different frequencies. ECW and ICW were calculated using the software provided by Xitron. The examination for an examinee included ECW and ICW measurements using the electrodes in the original instrument package and the electrodes made in china. The examination was performed once for healthy subjects, and performed once before dialysis session and once after the session for MHD patients. Results were compared using paired t test and Bland-Altman plot. A P value less than 0.05 was considered to be statistically significant. The absolute value of a mean difference and its standard deviation less than 0.5L was considered to be acceptable. Results ECW measured by origi- nal electrodes was （15.41 ± 4.53）L, while by China-made electrodes was （15.18 ±4.46）L; ICW measured by origi- nal electrodes was （17.87± 6.03）L, while by China-made electrodes was （19.93± 6.09）L. The mean difference was （-0.23 ± 0.43）L for ECW, and was （2.06 ± 3.05）L for ICW. Conclusion The China-made electrodes can replace the original electrodes for ECW but not for ICW measurement.