[Orthopnea: not always of cardiac origin].

Respiratory insufficiency developed in a man aged 68 after cardiac surgery and in a man aged 60 with COPD and a history of cigarette smoking after an attack of 'flu', while in a woman aged 70 with non insulin-dependent diabetes mellitus it had been present for years. All three had bilateral diaphragmatic paralysis. The diagnosis is based on the triad orthopnoea, paradoxical abdominal movements during respiration in the recumbent position and a decrease of the vital capacity in the horizontal as compared with the sitting position. The patients' physical condition could be improved with the aid of (noninvasive) ventilatory support.