多频生物电阻抗法评价血液透析患者体液分布

目的利用多频生物电阻抗测量法了解维持性血液透析（HD）患者体液分布情况。方法选择透析龄大于3个月的维持性HD患者119名,应用多频生物电阻抗频谱分析法分别于透析前、后测定细胞外液（ECW）、细胞内液（ICW）,并分别计算占体重的百分比（ECW%、ICW%）。选择性别、年龄和体重相匹配个体82例作为正常对照。结果男性和女性维持性HD患者ECW%较同性别正常对照组明显增高（男P〈0.01,女P〈0.05）,透析后较透析前显著降低（P〈0.01）;ICW%与同性别正常对照组无显著性差异（P〉0.05）,且透析前、后无明显变化;男女患者ECW/ICW比值透析前均显著高于同性别正常对照组（P〈0.01）,透析后虽较透析前显著降低（P〈0.01）,但仍高于同性别正常对照组（P〈0.05）。HD患者透析过程ECW下降值与实际超滤量呈显著正相关（男r=0.572,P〈0.01;女r=0.556,P〈0.01）。同性别透析高血压组的ECW%透析前后均高于正常血压组和正常对照组（P〈0.05）;正常血压组透后ECW%与对照组无明显差异。高血压组和正常血压组ICW%在透析前、透析后与正常对照均无差别。结论①透析前HD患者存在体液分布异常,主要表现为ECW%显著增加;②HD脱水主要来自细胞外液,对细胞内液无明显影响;③利用多频生物电阻抗测量透后ECW%可能是评价HD患者干体重的有效指标。

Assessment of fluid distribution in patients on maintenance hemodialysis by bio-impedance spectrum analysis

Objective To evaluate the fluid distribution in patients on maintenance hemodialysis by the whole-body bio-impedance spectroscopy. Methods A total of 119 patients with stable bemodialysis for more than 3 months were enrolled in this study. Pre-and post-dialysis intracellular water (ICW) and extracellular water (ECW) were measured by whole-body multi-frequency bio-impedance spectroscopy (Bodystat, UK), and stan-dardized by body weight to produce ICW% and ECW%. Eighty-two normal individuals of matched sex, age and body weight were used as controls. Results Patients on maintenance hemodialysis had significantly higher ECW% and ECW/ICW ratio compared with normal controls (P<0.01 ). ECW% and ECW/ICW ratio decreased significantly after hemodialysis, but were still higher than those of controls. By contrast, pre- and post-dialysis ICW% values in HD patients were similar to those of controls. Lower ECW after dialysis was positively correlated with ultrafiltration volume (r=0.572, P<0.01 for males; r=0.556, P<0.01 for females). Patients with hypertension had higher pie-and post-dialysis ECW% values than those without hypertension. In patients with normal blood pressure, post-dialysis ECW% was similar to that of controls. Conclusions Hemodialysis pa-tients have higher pre-dialysis ECW%. Fluid ultrafiltration is mainly derived from extracellular water during hemodialysis. Post-dialysis ECW% may be a useful parameter for the evaluation of dry weight in HD patients.