Will there be acetate in dialysis solutions for the foreseeable future

: The biological effects in vitro and in vivo of acetate as the main dialysate buffer have been well documented since the introduction of bicarbonate dialysis in the late 1970s. Bicarbonate dialysis solutions have become the standard but still contain 3-5 mmol/L of acetate for chemical stability. This is an important controversy given the recent introduction in numerous hemodialysis techniques of totally acetate-free solutions in an attempt to improve the hemodynamic efficiency and prevent inflammatory and cardiovascular damage. The issue is particularly relevant with the use of on-line techniques, in which, by summing the quota diffused from the dialysate and the quota infused directly into the blood, elevated quantities of acetate can be transferred to the patient's blood. In spite of the relatively small concentration of acetate in the bicarbonate dialysate, the acetate mass transfer is underestimated, leading to various and serious side effects especially in malnourished patients and/ or patients with a low muscle mass or with hepatocellular dysfunction. These patients do not have the capacity to effectively and rapidly metabolize the acetate, leading inevitably to acetate intoxication and accumulation. As the acetate cannot be transformed, it will follow alternative metabolic pathways, with worsening of the acidosis, and will induce the production of nitric oxide with negative hemodynamic effects such as vasodilation. The hemodynamic consequences are myocardial disease with contractile dysfunction and hemodynamic instability. Other problems triggered by acetate include cytokine production with higher microinflammation, dyslipidemia, arterial hypotension, and myocardial dysfunction with a rise in troponin. The use of acetate is hard to defend. Bicarbonate dialysate with a low acetate concentration can be used in patients with a good acetate tolerance. In such patients acidosis adjustment can be continued in the post-dialysis period. Some broad scientific documentation on the benefits of convective-diffusive treatments, almost all of which performed with non-acetate-free techniques, seems to contradict the negative effects of acetate but several studies have shown better hemodynamic stability during dialysis sessions with totally acetate- free dialysate. In conclusion, the future of hemodialysis is likely to be without acetate because acetate-free solutions are easy to produce and their cost will diminish.