Hyperchloremic metabolic acidosis
Basic, Physiology - Renal/Urine/Electrolytes
Hyperchloremic metabolic acidosis is defined as metabolic dysfunction characterized by acidemia (pH < 7.35), a normal anion gap, and an elevated serum chloride. In anesthesia practice, it is often the result of fluid resuscitation with normal saline (NS) ( 1 , 2 ) .
Several clinical trials (both randomized controlled and observational) have linked normal saline administration to hyperchloremic metabolic acidosis and inferior outcomes, though the effect on clinically-relevant outcomes remains controversial. In renal failure patients undergoing renal transplant, NS has been found to worsen hyperkalemia and metabolic acidosis(6). In a large, unblinded, cluster randomized, intention-to-treat study of critically ill patients, balanced crystalloids (LR and PlasmaLyte-A) were associated with decreased rates of composite all-cause mortality, renal replacement therapy, or persistent renal dysfunction when compared to NS(7). In non-critically ill patients, another non-blinded randomized control study of balanced crystalloid vs NS showed no differences in mortality, but when NS was used, patients were more likely to experience major adverse kidney events(7).