Re-opened foramen ovale--a rare cause of postoperative dyspnea following pneumonectomy.

Dyspnea and hypoxemia are common postoperative problems following pneumonectomy. Platypnea, the increased dyspnea in the erect position relieved by assuming a prone position, has been reported as a result of right to left inter-atrial shunt. We report here on our experience with a patient who had severe platypnea with remarkable positional arterial desaturation following right pneumonectomy. After establishing the diagnosis with contrast-enhanced transesophageal echocardiography of the preoperatively undetected interatrial right-left shunt, cardiac surgery led to clinical improvement and resumption of platypnea. Given the rarity of the diagnosis, we think interatrial shunt, based on an open foramen ovale, should be taken into consideration when platypnea occurs in patients as a postoperative complication following lung surgery. Transesophageal echocardiography may be helpful in detecting patients with "anatomical closed but functional open" foramen ovale or genuine inter-atrial septal defect prior to lung surgery.