Metabolic alkalosis in infants: role of water depletion and changes in composition of stool. Review of a physiological problem.

Abstract

SummarySimple calculations of the effect of volume depletion on the concentration of titratable base of blood show this effect to be largely adequate to account for commonly observed degrees of metabolic alkalosis in patients with mild or extreme dehydration due to obstructive vomiting. This suggests that hydrochloric acid depletion per se may not be a major determinant of the blood acid‐base status in such conditions. Clearly, part of the base equivalents missing in the extracellular fluid may be sought in the cell water; but currently available evidence concerning gastrointestinal transport of acid and base invites a conception of gastrointestinal acid‐base homeostasis–and the hypothesis that in obstructive vomiting changes in the composition of stool may appreciably modify the effect of gastric hydrochloric acid depletion. In studies of intracellular buffering and net base balance in gastric alkalosis, it must be realized that the primary extracellular disturbance may be largely contractional and that stool losses (or luminal pooling) of base may be an important variable.