Evaluation of body water change for patients suffering from dialysis difficulties by the bioelectrical impedance method

The body water change in hemodialysis patients was evaluated by the bioelectrical impedance method using a body composition analyzer (BCA). Sixty-four hemodialysis patients were selected from our clinic. Method: TBW (total body water) which was calculated from UFV (ultrafiltration volume) and BCA was compared before and after hemodialysis. Then the patients were divided into two groups according to the treatment of hypotension during hemodialysis; The control group consisted of 29 patients who did not have any hypotension treatment for 13 hemodialysis treatments before BCA measurement. The other is the hypotension group with 35 patients who needed more than 5 hypotension treatments during 13 hemodialysis treatments before BCA mesurement. TBW change was also compared between these two groups. Results: UFV was not identical to the difference in TBW after hemodialysis. Because of the discrepancy, we hypothesized that the analysis should be done using the data after hemodialysis. As UFV and the difference in normalized TBW after hemodialysis were almost identical (r=0.94), the following evaluation was performed using our established normalized value. Although, in the control, normalized ICW/ECW did not change before and after hemodialysis (r=0.77), a change before and after hemodialysis was observed in the hypotension group. Reduction rates of both normalized ECW and ICW were correlated with Δn-TBW in both the control and hypotension group. In the hypotension group, as ECW decreased, ICW was further increased. The concentration of hematocrit (Ht) and serum albumin (AIb) after hemodialysis in the hypotension group significantly differed from that in the control. Those results indicate that dehydration in vessels was dominant in the hypotension group, whose body water can easily move from ECW to ICW during hemodialysis.