Marked hypochloremic metabolic alkalosis with severe compensatory hypoventilation

In metabolic alkalosis, a compensatory decrease in alveolar ventilation with hypercapnia has been noted only rarely. We recently managed a patient with gastric outlet obstruction from a duodenal ulcer who survived after arriving in the emergency room comatose with severe hypochloremic metabolic alkalosis, compensatory hypoventilation, and hypercapnia. We know of no report in the English literature of a patient with gastric outlet obstruction having a respiratory acidosis or hypochloremia as severe as that in our patient. Proper understanding of the pathophysiology of primary metabolic alkalosis due to gastric losses is necessary to correct the acid-base abnormalities quickly and to restore normal alveolar ventilation.