ASSESSMENT OF ACETATE-FREE CONTINUOUS VENOVENOUS HEMOFILTRATION IN ACUTE-RENAL-FAILURE

Among the limitations of continuous renal replacement therapy (CRRT) i n patients with severe acute renal failure (ARF) and cardiovascular in stability is the use of acetate in the substitution fluid. Acetate is required to maintain acidity of the polyelectrolytic solution to avoid calcium carbonate precipitation in the presence of bicarbonate. In ad dition, in patients with cardiovascular instability, acetate metabolis m is impaired and further compromises hemodynamics. A new CRRT techniq ue is proposed in which bicarbonate is used as a buffer, but the aceta te requirements are cancelled: acetate free veno-venous hemofiltration (AF-CVVH). This technique allows control of acid-base disturbances in dependent of urea removal. This preliminary report describes the feasi bility of the technique based on separate infusion of water and electr olytes administered prefiltration, and isotonic sodium bicarbonate adm inistered post filtration. The setting of the technique, adapted to th e PRISMA device (Hospal, Lyon, France), was based on a model predictin g the bicarbonate infusion rate for a target plasma bicarbonate level. The AF-CVVH was compared with conventional, continuous veno-venous he mofiltration (CWH) in a crossover study that showed AF-CVVH allowed fa stest control of acidosis, avoiding 70 to 80 mmol/ d of acetate transf er to the patient. Urea removal was similar with both techniques. It w as concluded that AF-CVVH, when compared with CVVH, has the main advan tage of separately controlling urea retention and metabolic acidosis i n patients with severe ARF and cardiovascular instability.