What situation(s) can result in metabolic alkalosis? Select all that apply.

A. Cardiopulmonary arrest: Cardiopulmonary arrest leads to inadequate tissue perfusion and oxygenation, resulting in anaerobic metabolism and lactic acid accumulation. This produces metabolic acidosis rather than alkalosis. The primary disturbance is an increase in hydrogen ion concentration due to impaired circulation.

B. Hypokalemia: Hypokalemia promotes metabolic alkalosis through hydrogen–potassium exchange mechanisms. When potassium levels are low, hydrogen ions shift intracellularly to maintain electroneutrality, reducing serum hydrogen ion concentration. Additionally, renal mechanisms increase bicarbonate reabsorption in the setting of potassium depletion.

C. Nasogastric suctioning: Nasogastric suctioning removes gastric secretions that contain hydrochloric acid. Loss of hydrogen ions leads to a relative increase in serum bicarbonate, resulting in metabolic alkalosis. Prolonged gastric fluid loss significantly alters acid–base balance.

D. Diarrhea: Diarrhea typically causes metabolic acidosis due to excessive loss of bicarbonate-rich intestinal secretions. The resulting decrease in serum bicarbonate lowers blood pH. Therefore, it is more commonly associated with an acidotic state rather than alkalosis.

E. Renal failure: Renal failure often results in metabolic acidosis because the kidneys are unable to excrete hydrogen ions or regenerate bicarbonate effectively. Accumulation of metabolic acids lowers systemic pH, making alkalosis unlikely in this condition.