Time-averaged concentration of dialysate sodium relates with sodium load and interdialytic weight gain during sodium-profiling hemodialysis

Background: Factors determining sodium level during sodium-profiling hemodialysis rarely have been studied. We hypothesized that the time-averaged concentration of dialysate sodium (TACNa) is related to intradialytic sodium load and interdialytic complications. Methods: Eleven patients underwent 6-week periods of (1) conventional hemodialysis with a dialysate sodium concentration of 138 mmol/L (TAC138) and (2) sodium-profiling hemodialysis with a dialysate sodium concentration of 150 to 138 mmol/L (TACNa, 140 mmol/L [TAC140]) and (3) 155 to 130 mmol/L (TACNa, 147 mmol/L [TAC147]). Serum sodium level, weight gain, 24-hour blood pressure, and intradialytic and interdialytic discomfort were compared. Results: Serum sodium levels increased during the TAC140 and TAC147 periods (P < 0.05 compared with predialysis serum sodium). Intradialytic change in sodium level correlated positively with TACNa (r = 0.945; P < 0.001). Regression analysis indicates that positive sodium load occurred with TACNa more than 137.8 mmol/L. Interdialytic weight gain increased in proportion to TACNa (P < 0.05 compared with each other period), with a positive correlation (r = 0.823; P < 0.001). TACNa causing interdialytic weight gain less than 3 kg was estimated to be less than 143.5 mmol/L. Intradialytic hypotension decreased, but interdialytic discomforts increased during the TAC147 period (P < 0.05 compared with TAC138 and TAC140). Mean 24-hour blood pressures and pressure loads increased during the TAC147 period (P < 0.05 compared with TAC138 and TAC140). Mean diastolic blood pressure correlated positively with TACNa (r = 0.354; P < 0.05). Conclusion: TACNa is a factor determining sodium load and interdialytic complications during sodium-profiling hemodialysis. Defining the optimal TACNa for individual centers based on their protocols will be helpful to avoid sodium load and excessive weight gain. © 2002 by the National Kidney Foundation, Inc.