Extreme metabolic alkalosis treated with normal bicarbonate hemodialysis

Metabolic alkalosis (MA), defined as a primary increment in plasma bicarbonate concentration, is a common complication in hospitalized patients and is associated with high morbidity and mortality in severe cases. One of the major routes of compensation for MA (ie, the secretion of an alkaline urine) is lost in renal failure patients. We report three cases involving four episodes of extreme MA with an arterial pH value greater than 7.60, serum bicarbonate concentration greater than 55 mmol/L, and stupor or seizure. Profound vomiting or massive gastric drainage combined with concurrent oliguric renal failure was the underlying mechanism for severe MA. Hydration and normal central venous pressure failed to improve the MA. The extreme MA was reversed quickly and safely by conventional hemodialysis with normal bicarbonate dialysate of 25 to 28 mmol/L. To our knowledge, this is the first reported successful use of normal bicarbonate dialysate in the treatment of severe MA. We also found that either H(2) blockers or proton-pump inhibitors have a prophylactic effect on the formation of MA.