Platypnea in the intensive care unit. A newly described cause.

Platypnea in a patient with COPD developed during the subacute onset of an ileus. Arterial blood gas studies failed to document orthodeoxia. Routine treatment for COPD failed to resolve the patient's positional dyspnea, but the dyspnea rapidly resolved following resolution of the ileus. The authors postulate that impaired abdominal muscle contraction in the upright position secondary to the ileus was responsible for the development of platypnea.