RESUMO
A bronchopulmonary vein fistula (BVF) establishes a communication between a pulmonary vein and the alveolar space presumably secondary to alveolar rupture from increase in alveolar pressure. This rare fistula allows air to move continuously from the lungs to a pulmonary vein and into the left side of the heart causing systemic air embolization which is often fatal. We describe an adult patient undergoing a second mitral valve replacement surgery in whom intra-operative transesophageal echocardiography proved crucial in diagnosing BVF by showing persistent and increased streaming of air bubbles into the left heart from the left superior pulmonary vein during each positive pressure ventilation cycle with consequent inability to de-air the heart. This allowed initiation of appropriate management. The patient eventually had a fatal outcome from multiple organ infarcts.