The role of sequential ultrafiltration and varying dialysate sodium on vascular stability during hemodialysis

Hypotension is a very common problem during HD. We studied vascular stability during sequential UF with constant and variable dialysate Na. Ten chronic patients underwent HD using two protocols. Protocol A was sequential UF (50% weight loss in the first hour, 30% in the second, and 20% in the third hour) with a dialysate Na of 140 mEq/L. Protocol B was sequential UF as in protocol A with varying dialysate Na (150 mEq/L in the first hr, 142 in the second, and 137 in the third). BP and pulse were monitored every 30 min. Hct, BUN, creatinine, osmolality, and serum albumin were checked every hour. The plasma volume decreased by 5.3% in protocol A as compared with 1.2% in protocol B, as shown by the Hct values. The decrease in serum osmolality during the first and second hours was more marked in protocol A than in protocol B (p < 0.05), but post-dialysis values were similar. The clinical parameters (UF, BP, pulse rate) and serum Na showed no difference. The intradialytic mannitol infusion was 10 ml/HD and 0, whereas saline was 80 ml/HD and 10 for A and B, respectively. These data suggest: (1) Sequential UF with varying dialysate Na could benefit patients who are hemodynamically unstable. (2) The need for mannitol and saline may be more readily alleviated with protocol B than with protocol A. (3) The beneficial effect of varying dialysate Na with sequential UF may be due to improved plasma refilling and decreased early intradialytic osmolar changes.