Effect Of Blood Pressure And Dialysis Parameters By Dialysate Sodium Concentration On Sodium Gradient In Hemodialysis Patients

Objective: In chronic hemodialysis (HD) patients, sodium (Na+) balance largely depends on interdialytic dietary salt intake and intradialytic Na+ removal. To preserve a neutral Na+ balance, interdialytic Na+ gain should be removed during HD. We investigate to determine the ranges of the sodium gradient (SG) between the dialysate sodium concentration (DNa) and serum sodium concentration (SNa) in hemodialysis (HD) patients and to examine the relationships between HD parameters over a one year period. Design and Method: Fifty-five clinically stable HD patients, who had been on HD >2 years were enrolled. Monthly HD ultrafiltration (UF) amount, systolic blood pressure (SBP), frequency of intradialytic hypotension (IDH) and laboratory data were collected and 12-month means were subjected to analysis. The SG was calculated by subtracting SNa from prescribed DNa. Results: The mean number of anti-hypertensive drugs being taken was 1.6 ± 1.2. In the 55 patients, SNa values ranged from 130 to 142 mEq/L and the mean CV of SNa was 1.5 ± 0.5%. Mean SG values were 1.5 ± 3.3 mEq/L (range -5.6∼9.1). Significant positive correlations were observed between DNa and SG. In addition, significant positive correlations were noted between mean UF amounts. On the other hand, no relationship was observed between SG was positively related to DNa and the frequency of IDH. A higher SG was associated with larger UF amounts and SBP reduction during HD. The percentages of patients with a SG > 3 mEq/L increased as DNa increased. On the other hand, SG was not found to be associated with SNa or pre-HD SBP. Conclusions: DNa appears to cause a significant increase in SG, and this seems to be related to HD parameters, such as, UF amount and IDH. Numbers of anti-hypertensive drugs tended to be less in patients with a SG of > 3 mEq/L, which might have been due in part to the adjustment of DNa according to BP status.