Abstract
The effects of high sodium hemodialysis (HD) on blood pressure, hematocrit, plasma osmolality and vasoactive substances were studied in 10 chronic HD patients and compared with those of standard HD.
High sodium HD was carried out for the first 2 hours with a high sodium dialysate (Na 155mEq/l) consisting of a constant injection of high salt solution into the standard dialysate, and then standard dialysate (Na 140mEq/l) was used for the last 2 to 3 hours.
Blood pressure was measured at one hour intervals for 24 hours using an ambulatory blood pressure monitor.
Although there was no significant difference in pre- and post-dialysis body weight and removed fluid volume between high sodium HD and standard HD, significantly higher blood pressure was observed during high sodium HD and the hypertensive tendency persisted after HD.
As compared with the standard HD, the high sodium HD showed a significantly higher concentration of plasma sodium at 2 hour- and post-dialysis tests (p<0.01 for both) and a significantly higher plasma osmolality at 2 hour-dialysis test (p<0.05). The hematocrit, however, was significantly lower at pre- and 2 hour-dialysis tests (p<0.001 for both).
While atrial natriuretic peptide (ANP) significantly decreased during both forms of HD, plasma renin activity (PRA) did not change significantly with either HD. Plasma aldosterone concentration (PAC) significantly decreased with high sodium dialysate, but not with standard dialysate.
Plasma noradrenaline (NA) and adrenaline (A) were significantly decreased at 2 hour-dialysis test and increased to the pre-dialysis levels after HD. There was no significant difference between the high sodium HD and the standard HD in the plasma levels of ANP, PRA, PAC, NA, and A at the pre-, 2 hour- or post-dialysis tests.
These results suggest that intracellular and extracellular fluid moved into the vascular space more quickly and compensated for the reduction of circulatory plasma volume on high sodium HD.
