Primary alveolar hypoventilation treated by nocturnal administration of O2.

A case of idiopathic alveolar hypoventilation is described. Although lung function was normal, the alveolar-arterial O2 tension difference was abnormally large for reasons which were unclear. Despite this, the patient's pulmonary hypertension and polycythemia were out of proportion to the relatively mild hypoxemia that he demonstrated while awake. Sleep was associated with severe hypoxemia, and administration of O2 during sleep produced CO2 retention. The patient did well on no treatment for 5 years, until respiratory infection precipitated severe hypoxemia and pulmonary hypertension. He was treated with O2, at first continuously then nocturnally (12 hours per day), with reversal of polycythemia and pulmonary hypertension. He was then treated with nocturnal O2 as an outpatient for 7 months and maintained his improvement. Nocturnal administration of O2 may be an effective treatment of some forms of primary hypoventilation.