[A case of pulmonary artery injury which might have been caused by a pulmonary artery catheter during the mitral valve replacement].

We experienced a pulmonary artery injury which might have been caused by a pulmonary artery catheter (PAC). A 66-year-old woman after mitral valve replacement, developped massive tracheal bleeding during weaning from the cardiopulmonary bypass. Transesophageal echocardiography revealed the air bell in the right pulmonary artery synchronized with ventilation. We speculated pulmonary artery injury and performed pulmonary artery angiography; however, it could not clarify the bleeding point. Surgical approach found the air leak from the erasure of the bronchus intermedius and the lobectomy led to lifesaving. A pulmonary artery injury caused by PAC is very rare, but life-threatening. In this case, she had some risk factors (i. e. 60 years or older, female, short statue, and mitral valve disease); however, it was hard to predict the pulmonary injury from these factors.