[Case of bronchial obstruction by thrombosis after cardiopulmonary bypass].

A 78-year-old man underwent total arch replacement for an aortic arch aneurysm under cardiopulmonary bypass. After protamine sulfate administration, his peak inspiratory pressure suddenly rose, and his arterial oxygen saturation dropped. We checked his bronchus with a bronchoscope and found that his left main bronchus was blocked by a large thrombus. We tried to remove the thromus with suction via the bronchoscope channel, but it was too large to pick out. We had no way to perform this removal, and we called a respiratory specialist who performed the removal. The size, shape and time of onset suggested that the thrombus had been formed by residual blood left after administration of protamine. This case indicated that residual blood in the bronchus should be cheeked carefully after cardiopulmonary bypass.