Prevention of carbon dioxide (CO₂) narcosis during hemodialysis in elderly hypercapnic patients by lowering bicarbonate (HCO₃⁻) concentration of dialysate

Abstract

Carbon dioxide (CO₂) narcosis developed in chronically hypercapnic patients during hemodialysis using dialysate with a bicarbonate (HCO₃⁻) concentration of 25-30 mEq/L. The elderly hemodialysis patients had presented with hypoventilation because of atrophy in the respiratory muscles due to malnutrition. The hypercapnic respiratory failure during hemodialysis was prevented by lowering the HCO₃⁻ concentration to 22 mEq/L. During hemodialysis, the supply of HCO₃⁻ from dialysate to the blood desensitizes respiratory chemoreceptors for pulmonary ventilation. The elevation of blood HCO₃⁻ concentration also raises PaCO₂ by the reaction between HCO₃⁻ and H⁺. Dialysate HCO₃⁻ concentration should be modified for patients with ventilatory failure to prevent excessive CO₂ retention.