Unintentional endobronchial intubation represents a serious complication during general anesthesia, occurring when the endotracheal tube is incorrectly positioned into a main bronchus rather than remaining in the trachea. This misplacement results in ventilation of only one lung, leading to hypoxia, hypercapnia, and potential lung injury from overdistension on the intubated side and collapse on the contralateral side.
The incidence of unintentional main stem intubation reaches approximately 3% in certain clinical settings, with rightward placement being more common due to the more vertical angle of the right main bronchus. Risk factors include patient positioning changes after intubation, anatomical variations, neck flexion, and intubator experience. Shorter-necked or obese patients face elevated risk due to altered anatomical landmarks and reduced endotracheal tube depth margins.
Early identification is essential to prevent prolonged hypoxemia. Clinical indicators include asymmetric chest movement, diminished or absent breath sounds on the side opposite the intubated bronchus, and unexpected hypoxemia. Capnography may reveal sudden changes in end-tidal CO₂. Chest radiography or bronchoscopy can confirm placement, though both may require time that is not always available in emergency situations.
Management involves gentle endotracheal tube withdrawal under continuous clinical monitoring and capnographic guidance. Lung-protective ventilation strategies minimize injury during the repositioning process. Prevention requires structured training protocols and the use of devices such as depth-marked endotracheal tubes, video laryngoscopy systems, and routine auscultation immediately following intubation to confirm bilateral breath sounds.
Pediatric consequences are particularly severe due to smaller airways and higher oxygen demands. Complete endobronchial obstruction risks and rapid hypoxic deterioration necessitate heightened vigilance and appropriate tube sizing for all pediatric patients. Simulation-based training has been shown to significantly improve clinician competency in identifying and managing this complication.
In critical care settings, preprocedural checklists and multidisciplinary team communication enhance airway management outcomes. While unintentional main stem intubation is preventable with proper technique and monitoring, it remains potentially life-threatening when unrecognized. Protocol adherence, appropriate technology, and clinical vigilance remain the most effective safeguards.