What happens to serum potassium levels as the pH is corrected in an acidotic patient?

In an acidotic patient, serum potassium levels are typically elevated due to a shift of potassium ions from the intracellular to the extracellular space in response to acidosis. When the acidosis is corrected, usually through the administration of bicarbonate or other interventions, the pH moves toward normal. As pH improves, potassium ions re-enter the cells, leading to a decrease in serum potassium levels.

This phenomenon occurs because the correction of acidosis normalizes the hydrogen ion concentration in the extracellular fluid. As hydrogen ions move back into cells to restore the acid-base balance, potassium ions move out to maintain charge neutrality, resulting in lower serum potassium concentrations. Consequently, monitoring serum potassium levels becomes essential during the management and correction of acidosis in critically ill patients.