目的 观察透析过程中在线监测相对血容量（ RBV）变化对预测和防止透析中低血压及调整透析 患者干体重的作用。方法 监测12例血液透析患者透析过程中RBV、血压、心率的变化，并用超声心动同步测定下腔静脉宽度（IVCD）及心脏参数。结果 透析结束时RBV变化范围在78.9%～102.6%，在有和无症状性低血压的透析过程最低血容量（mRBV）有显著差别［（84.41±3.85) v (87.38±4.66)%， P=0.01］， RBV与超滤量及心率变化均呈线性相关（r值分别为0.293，-0.359； P<0.01）； IVCD变化率与RBV变化呈线性相关（r=0.311， P<0.05）；透析结束时 RBV降低小于5%的患者经下调干体重高血压好转。结论 尽管血液透析过程中RBV变化存在较大的个体间和个体内差异，RBV与透析中低血压的发生密切相关，故血容量监测对预测和防止低血压具有一定作用，此外对判断干体重的高估也有辅助作用。

Objective To investigate the role of relative blood volume(RBV) monitoring on prediction and prevention of intradialysis hypotension and modulating dry weight of hemodialysis patients. Methods In 12 patients on chronic hemodialysis, RBV, blood pressure, heart rate and inferior caval vein diameter(CDIV) were measured during hemodialysis sessions. Results RBV at the end of treatments the range from 78.9% to 102.6%, Lower minimal RBV was found in treatments with symptomatic hypotension compared with those without symptoms［(84.41±3.85)v (87.38±4.66)%, P=0.01］. We found significant correlation between RBV and ultrafiltration volume(UV)or heart rate(r=0.293、-0.359 respectively, P<0.01). There was significant correlation between the change of RBV and CDIV(r=0.311, P<0.05). The dry weight of a patient with drug-resistant hypertension who had less than a 5% decrease in intradialysis blood volume was intentionally decreased, the blood pressure was controlled consequently. Conclusions Although RBV changes during hemodialysis showed a considerable intra- and inter-individual variability, lower RBV was significantly related with hypotensive episodes. Blood volume monitoring is helpful in the prevention of hemodialysis-related hypotension, it is also useful in the detection of fluid overload. 