# Postoperative Hypoxemia Caused by Atelectasis Due to an Unrecognized Tracheal Bronchus After Endoscopic Sinus Surgery: A Case Report

## TL;DR

A rare airway anomaly called tracheal bronchus caused postoperative hypoxemia in a patient with a history of heart defect repair.

## Contribution

This is the first reported case of tracheal bronchus-induced hypoxemia occurring after a patient was transferred to the general ward.

## Key findings

- A tracheal bronchus was found to be occluded by aspirated blood, leading to right upper lobe atelectasis.
- Bronchoscopic suction and lung recruitment improved the patient's oxygenation.
- The case emphasizes the need to consider tracheal bronchus obstruction in postoperative hypoxemia differential diagnosis.

## Abstract

Tracheal bronchus is a rare airway anomaly prevalent in individuals with congenital heart disease (CHD). It is typically asymptomatic and diagnosed incidentally due to hypoxemia during general anesthesia in the operating room, where emergency procedures can be performed promptly. To the best of our knowledge, cases in which a tracheal bronchus induced severe hypoxemia after a patient’s transfer to the general ward have not been reported. Herein, we present a case in which a 46-year-old man with tuberous sclerosis and a history of ventricular septal defect (VSD) repair developed postoperative hypoxemia at the general ward after endoscopic sinus surgery. Bronchoscopy after reintubation revealed a tracheal bronchus originating approximately 2 cm above the carina that was occluded by aspirated blood, causing right upper lobe atelectasis. Bronchoscopic suction followed by lung recruitment improved oxygenation. This case highlights the importance of considering lobar atelectasis due to tracheal bronchial obstruction in the differential diagnosis of postoperative hypoxemia, particularly in patients with CHD.