High sodium bicarbonate and acetate hemodialysis: Double-blind crossover comparison of hemodynamic and ventilatory effects

The superiority of bicarbonate dialysis (Bi HD) over acetate dialysis (Ac HD) using a high sodium dialysate has not been established to our knowledge. We compared Bi HD to Ac HD over 6 weeks each in ten stable patients using a double-blind crossover design and a dialysate sodium concentration of 140 mEq/liter. The dialyzer, delivery system, and dialysate constituents were identical except for the substitution of Bi or Ac. Interdialytic weight gain, pre- and post-HD blood pressures, and heart rates were also comparable in the two protocols. Beginning of the week pre-HD serum Bi was greater during Bi HD than Ac HD (19.1 ± 0.9 vs. 15.1 ± 0.8 mEq/liter, P < 0.001); post HD Bi values were also higher during Bi HD. Similarly, pre-HD pH was also greater with Bi HD (7.40 ± 0.012 vs. 7.35 ± 0.001 U, P < 0.01). The number of adverse symptoms and signs were similar during each protocol (2.0 ± 0.65 for Bi HD vs. 2.5 ± 0.5 for Ac HD episodes/patient/6 weeks, NS). However, fewer therapeutic interventions were required during the Bi HD protocol (1.5 ± 0.43 vs. 3.1 ± 0.6 treatments/patient/6 weeks, P < 0.02). The ventilatory effects of the two dialysate were evaluated at the end of the 6-week course in seven of ten patients and revealed comparable declines in carbon dioxide excretion, minute ventilation, and arterial oxygen tension. In summary, these results demonstrate strikingly similar hemodynamic and ventilatory responses with the two dialysate when a higher osmolality dialysate is used. However, Bi HD was associated with a significant reduction in the number of therapeutic interventions required, and also resulted in a greater pre-HD pH and bicarbonate concentration.