[Value of sleep polygraph examination in the etiological diagnosis of apparently inexplicable respiratory insufficiency].

This study describes the case of a 58 year old man who presented with an episode of acute respiratory failure and right heart decompensation. After recovery from the acute illness, hypoxaemia, hypercapnia and pulmonary arterial hypertension remained, the causes of which were not known. There was no airway obstruction, only a moderate restrictive ventilatory defect, a little weight increase and a unilateral diaphragmatic paralysis. Obstructive sleep apnoea was finally suspected and confirmed by sleep recording. The obstructive sleep apnoea probably explained the respiratory insufficiency and the pulmonary hypertension. Loss of weight was associated with the disappearance of hypercapnia and pulmonary hypertension. As a result of this study, the value of sleep recording is emphasized. When respiratory failure or pulmonary hypertension seem unexplained, think of obstructive sleep apnoea.