Extracorporeal Selective Chloride Removal By Electrodialysis: An Innovative Treatment For Respiratory and Metabolic Acidosis
KeywordsRenal Replacement Therapy Metabolic Acidosis Plasma Osmolality Respiratory Acidosis Extracorporeal Circuit
Acidosis is a frequent disorder among critically ill patients. When patient compensatory responses fail to restore a normal pH, administration of sodium bicarbonate (NaHCO3) or renal replacement therapy may be required. Intravenous NaHCO3 increases plasma Strong Ion Difference ([SID] = [Na+] + [K+] - [Cl-]) and HCO3- concentration by raising Na+ concentration. Although effective, this treatment is not devoid of complications, such as hypernatremia, hyperosmolarity and fluid overloading. Selective chloride (Cl-) removal, by increasing SID in an alternative way, may allow a rapid correction of acidosis without altering plasma osmolality and Na+ concentration.
In an experimental animal model of severe respiratory and metabolic acidosis, we aimed to assess the efficacy of an electrodialytic system, able to selectively remove anions from plasma ultrafiltrate, to normalize pH.
Seven sedated and paralyzed healthy swine were connected to a veno-venous extracorporeal circuit including a dialyzer and an electrodialysis unit. Animals underwent 2 randomly-ordered experimental sequences of respiratory and metabolic acidosis, obtained by reducing the respiratory rate or by continuous infusion of lactic acid, respectively, targeting an arterial pH of 7.15 ± 0.02. the electrodialysis treatment was then started to restore baseline pH. Hemodynamics, acid-base equilibrium, and laboratory parameters were recorded.
Selective extracorporeal removal of Cl- by electrodialysis is a feasible, rapid and effective in-vivo treatment to completely reverse severe respiratory or metabolic acidosis.
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