Hyperchloremic acidosis in the critically ill: one of the strong-ion acidoses?
Decreases in plasma bicarbonate are associated with hyperchloremic acidosis and lactic acidosis. According to the Stewart approach to acid-base physiology, the strong-ion difference regulates plasma bicarbonate, with chloride and lactate being the only strong anions routinely measured in clinical chemistry. We hypothesized that the plasma strong-ion difference, both with and without lactate, would have a stronger association with plasma bicarbonate than plasma chloride alone would have with bicarbonate. We used plasma acid-base data from 300 critically ill patients. The correlation with bicarbonate became progressively weaker (P < 0.001): all measured strong ions, r = 0.60; measured strong ions without lactate, r = 0.42; chloride alone, r = -0.27. In a subgroup of 26 patients with traditional hyperchloremic acidosis (base excess < -2 mmol/L and anion gap <17 mmol/L), the measured strong-ion difference (without lactate) had a stronger correlation (P < 0.001) with bicarbonate than chloride had: r = 0.85 versus r = -0.60. We conclude that hyperchloremic acidosis and lactic acidosis are strong-ion acidoses. Hyperchloremia should be viewed relative to the plasma strong cations. A practical conclusion is that both managing and preventing acid-base disorders with IV fluid therapy involves manipulating each of the plasma strong ions, particularly sodium and chloride.
Story
David A
DA
Department of Anaesthesia, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia. David.Story@austin.org.au
Morimatsu
Hiroshi
H
Bellomo
Rinaldo
R
D000136:Acid-Base Equilibrium; D000138:Acidosis / Q000097:blood*; D001639:Bicarbonates / Q000097:blood; D002712:Chlorides / Q000097:blood*; D016638:Critical Illness; D006801:Humans
D001639:Bicarbonates; D002712:Chlorides