评价血液透析患者容量状态的新参量:峰值阻抗

目的本研究初步总结血液透析患者在血液透析前后阻抗-频率曲线变化的规律,提出评价血液透析患者容量状况的新参量。方法本研究随机抽取20例健康人(对照组)与20例血液透析患者(透析组),在100Hz到50kHz频率范围内对其全身阻抗进行扫频测量,描绘并比较两组的阻抗曲线。结果阻抗曲线与ECFC模型相吻合,透析组透析前后阻抗曲线变化明显,透析后阻抗曲线更接近对照组阻抗曲线。透析组患者透析前后峰值阻抗分别为(415±106)Ω和(566±74)Ω,峰值频率分别为(5.16±1.49)kHz和(3.94±0.91)kHz,差异均有统计学意义(P0.01);透析前峰值频率、峰值阻抗分别与对照组健康人的峰值频率[(4.03±0.50)kHz]、峰值阻抗[(502±38)Ω]相比差异有统计学意义(P0.01),而透析后峰值频率、阻抗与对照组峰值频率、阻抗相比差异无统计学意义(P0.05)。透析组患者透析前后的峰值阻抗差与体质量差呈显著相关(r=0.574,P0.01);在控制变量年龄和身高体质量比进行偏相关分析后,透析前后的体质量差和峰值阻抗差仍呈显著正相关(r=0.631,P0.01)。结论生物阻抗曲线可以较好地反映血液透析患者的容量状况;峰值阻抗可作为评价血液透析患者容量状况的新参量。

A new parameter for the evaluation of volume status in hemodialysis patients: The peak value of impedance

Objective In this study we summarized the changes of bioimpedance-frequency curve before and after hemodialysis with the multifrequency bioimpedance spectroscopy, and recommended a new parameter for the evaluation of volume status in hemodialysis patients. Method Twenty healthy volunteers and 20 stable mainte- nance hemodialysis patients were included in this study. Whole-body bioimpedance was measured by using the spec-troscopy with the frequency range between 100Hz and 50k Hz. The bioimpedance-frequency curves from hemodialysis patients were compared with those from healthy volunteers. Results The significance ofbioimpedance-frequeney curve was in accordance with that of the ECFC model. The impedance curve was significantly different between the patients before and after hemodialysis. The curve after hemodialysis was similar to that of healthy volunteers. The peak impedance value and peak frequency value were significantly different between pre- and post-hemodialysis, and between pre-hemodialysis and control group, but were indifferent between post-hemodialysis and control group. Peak impedance value was positively correlated with age, the ratio of weight to stature, and the change of weight before and after hemodialysis （r=0.631,p〈0.01）. Conclusion The peak impedance value is applicable for the evaluation of dry weight in hemodialysis patients.