Objectives.– The playpnea-orthodeoxy syndrome (POS) is described in literature and characterized by dyspnea, hypoxemia and desaturation in the upright position. It is caused by mechanical obstruction of the inferior vena cava (IVC), by mediastinal shift, after pneumonectomy.

Materials and methods.– We report on a 32-year-old patient who underwent a right pneumonectomy for recurrent severe pulmonary infection after destruction of the lung by tuberculosis. Six months later, the patient suffered from dyspnea and orthostatic vertigo. The perfusion scintigraphy of the lung excluded a shunt. Right heart catheterization excluded pulmonary hypertension and showed negative diastolic pressures in the cardiac cavities and a positive central venous pressure in the IVC. A cardiac MRI (cine MR, velocity encoded MR) showed a right-sided mediastinal shift with compression of the IVC and stenosis of the innominate vein, resulting in a significant postural decrease of venous return. Surgical mediastinal recentration by intrathoracic positioning of an inflatable breast prosthesis was planned.

Results.– Intraoperative transesophageal echocardiography (TEE) confirmed collapse of the inferior vena cava (0.5 cm internal diameter) at the intrathoracic level with elevated flow velocities (75.1 cm/s), measured with pulsed wave Doppler at the cavo-artial junction. After positioning of the intrathoracic prosthesis, IVC diameter and flow velocities were measured during inflation of the prosthesis. Based on these measurements, the prosthesis was finally inflated to a total volume of 620 ml, resulting in an internal diameter of the IVC of 1.3 cm and flow velocities of 14.1 cm/s.

Conclusion.– The use of intraoperative TEE allowed for the confirmation of the anatomical and functional findings of preoperative cardiac MRI in this rare complication of pneumonectomy. Furthermore, we successfully used intraoperative TEE to evaluate and guide mediastinal repositioning.