Intraoperative hypoxemia is a common yet potentially life-threatening complication during general anesthesia, resulting from alterations in pulmonary physiology as well as mechanical or clinical factors. Mucus plug–related atelectasis often remains asymptomatic but may cause severe oxygenation impairment and hemodynamic instability if not promptly recognized and treated. We report a case of intraoperative left lung collapse caused by a mucus plug during open-heart surgery in a patient with aortic and mitral valve insufficiency. This case emphasizes the importance of considering mucus plug–induced airway obstruction in the differential diagnosis of intraoperative hypoxemia. Early recognition is essential to prevent catastrophic complications.
Keywords: Hypoxemia, intraoperative atelectasis, left main bronchus obstruction, mucus plug, open heart surgery