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 (TAC(Na)) 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 (TAC(138)) and (2) sodium-profiling hemodialysis with a dialysate sodium concentration of 150 to 138 mmol/L (TAC(Na), 140 mmol/L [TAC(140)]) and (3) 155 to 130 mmol/L (TAC(Na), 147 mmol/L [TAC(147)]). Serum sodium level, weight gain, 24-hour blood pressure, and intradialytic and interdialytic discomfort were compared.

RESULTS

Serum sodium levels increased during the TAC(140) and TAC(147) periods (P < 0.05 compared with predialysis serum sodium). Intradialytic change in sodium level correlated positively with TAC(Na) (r = 0.945; P < 0.001). Regression analysis indicates that positive sodium load occurred with TAC(Na) more than 137.8 mmol/L. Interdialytic weight gain increased in proportion to TAC(Na) (P < 0.05 compared with each other period), with a positive correlation (r = 0.823; P < 0.001). TAC(Na) 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 TAC(147) period (P < 0.05 compared with TAC(138) and TAC(140)). Mean 24-hour blood pressures and pressure loads increased during the TAC(147) period (P < 0.05 compared with TAC(138) and TAC(140)). Mean diastolic blood pressure correlated positively with TAC(Na) (r = 0.354; P < 0.05).

CONCLUSION

TAC(Na) is a factor determining sodium load and interdialytic complications during sodium-profiling hemodialysis. Defining the optimal TAC(Na) for individual centers based on their protocols will be helpful to avoid sodium load and excessive weight gain.