Unexpected intraoperative desaturation and lobar atelectasis due to left bronchial occlusion by concealed ascending aortic aneurysm

An 81-year-old male scheduled for debridement of a perianal abscess sustained acute upper airway obstruction with atelectasis of the left lower lobe during induction of anesthesia. Results of a fiberoptic bronchoscopy revealed dorsal bulging and obstruction of the left bronchus. Under the context of tortuous aorta and calcified left border of the heart silhouette, aortic aneurysm was suspected; the diagnosis was confirmed by a computed tomography scan. Aortic aneurysm without specific symptoms cannot be screened by a single preoperative chest X-ray. The anesthesiologist should promptly request further radiographic studies to rule out potential aortic pathology if in doubt.