Section 3: Anesthesia Management
Part D: Perioperative Therapy
Chapter 45: Fluid and Electrolyte Physiology

CHLORIDE PHYSIOLOGY

Chloride is the predominant anion in the extracellular fluid volume. Hyperchloremic, metabolic acidosis results from excess intake, and/or inadequate excretion due to renal dysfunction. When administering infusions to such patients, bicarbonate, acetate, citrate, or phosphate salts should be substituted for chloride salts.

Excess loss of chloride in gastric secretions or urine causes hypochloremic alkalosis. Chloride depletion tends to limit bicarbonate excretion, and this may be due to reduced delivery of chloride to the collecting tubules where chloride is needed for bicarbonate secretion via bicarbonate-chloride exchange. Additionally, sodium reabsorption is enhanced in chloride-depleted states, as it is generally associated with extracellular fluid volume depletion. When less chloride is available for reabsorption, a greater fraction of the sodium must be reabsorbed with bicarbonate via increased proton secretion. 49  Sodium or potassium chloride should be administered if intravascular volume depletion or hypokalemia is present. If these are not a problem, 0.1 N HCl should be administered via a central catheter. The dose of chloride is