Bicarbonate hemodialysis of patients with acute renal failure and severe sepsis

During hemodialysis (HD), septic patients with acute renal failure (ARF) often exhibit severe hemodynamic instability, with a fall in BP that requires a large-volume infusion or even cessation of dialysis. To investigate the hypothesis that acetate transfer plays a role in the BP decrease, we compared acetate (Ac) and bicarbonate (Bi) HD in ten septic ARF patients. Patients were dialyzed daily for 4 h with a single-pass system and 1.1 m2 cuprophan dialyzers, alternately using Ac and Bi as the dialysate buffer. Heart rate and systemic arterial resistance did not change significantly during use of either buffer, and changes in pulmonary wedge pressure were similar. However, decreases in cardiac output and mean arterial pressure were more pronounced during Ac-HD than during Bi-HD. Rapid correction of metabolic acidosis and a larger decrease of plasma potassium concentration occurred during Bi-HD. These results suggest that Bi-HD was better tolerated than Ac-HD because of changes in myocardial contractility that may be related to different effects on acid-base status and plasma potassium concentrations.