Unintentional endobronchial, or “main stem,” intubation is a complication that can occur during the administration of general anesthesia, particularly in emergency situations. This condition involves the incorrect insertion of the endotracheal tube (ETT) into one of the main bronchi beyond the trachea, resulting in ventilation of only one lung. The consequences of this misplacement include hypoxia, hypercapnia, and potential lung injury due to overdistension of the ventilated lung and collapse of the non-ventilated lung (1).
The incidence of main stem intubation varies but may be as high as 3% in certain clinical settings. The right main bronchus is more likely to be intubated due to its more vertical orientation compared to the left main bronchus. Several factors contribute to the risk of unintentional endobronchial intubation, including patient positioning, anatomical variations and the level of experience of the intubator. For example, patients with shorter necks or those who are obese are at higher risk due to altered anatomical landmarks (2).
Early recognition of endobronchial intubation is critical to prevent serious complications. Clinical signs include asymmetric chest movement, diminished or absent breath sounds on the side opposite the intubated bronchus, and unexpected hypoxemia. Capnography may show a sudden drop in end-tidal CO2 levels, indicating inadequate ventilation. Confirmation of tube placement by chest radiography or fiberoptic bronchoscopy is considered the gold standard, although these tools are not always readily available (3).
Management of main stem intubation includes prompt repositioning of the ETT. The tube should be gently withdrawn while carefully monitoring the patient’s clinical signs and using capnography to confirm improved bilateral ventilation. The use of lung protective ventilation strategies can help reduce lung injury during repositioning. Repeated training and the use of protocols for correct tube placement are essential preventive measures. Devices such as depth-marked ETTs and advanced airway management techniques, including video laryngoscopy, may also reduce the incidence of this complication (4).
The consequences of unintentional endobronchial intubation are particularly severe in pediatric patients due to their smaller airway diameters and higher oxygen consumption rates. Pediatric airways are more prone to complete obstruction and even brief periods of hypoxia can lead to rapid deterioration. Therefore, increased vigilance and the use of appropriately sized tubes with careful monitoring are paramount in this population. Studies have shown that simulation-based training for anesthesiology residents significantly improves the ability to correctly identify and manage this complication, thereby improving patient safety (5).
In the critical care setting, the challenges associated with difficult airway management are compounded by the urgency and complexity of the patient’s condition. The use of preprocedural checklists and the involvement of multidisciplinary teams can improve outcomes. Research suggests that structured airway management protocols, including pre-intubation checklists and the use of capnography, can reduce the incidence of airway-related complications, including main stem intubation (6).
In conclusion, unintentional endobronchial intubation is a preventable but potentially life-threatening complication that requires prompt recognition and management. Implementation of preventive strategies such as proper training, use of technological devices, and adherence to protocols is essential to minimize its occurrence. Ongoing education and simulation training for healthcare providers is critical to improving the skills necessary to accurately place ETTs, ultimately improving patient safety and outcomes.
References
- Welter S, Essaleh W. Management of tracheobronchial injuries. J Thorac Dis. 2020;12(10):6143-6151. doi:10.21037/jtd-2019-as-05
- Higgs A, McGrath BA, Goddard C, et al. Guidelines for the management of tracheal intubation in critically ill adults. Br J Anaesth. 2018;120(2):323-352. doi:10.1016/j.bja.2017.10.021
- Ahmed Z, Mohyuddin Z. Management of flail chest injury: internal fixation versus endotracheal intubation and ventilation. J Thorac Cardiovasc Surg. 1995;110(6):1676-1680. doi:10.1016/S0022-5223(95)70030-7
- Pinheiro JM, Munshi UK. Factors contributing to endobronchial intubation in neonates. Pediatr Crit Care Med. 2015;16(1):54-58. doi:10.1097/PCC.0000000000000270
- Cook TM, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth. 2012;109 Suppl 1:i68-i85. doi:10.1093/bja/aes393
- Heyne G, Ewens S, Kirsten H, et al. Risk factors and outcomes of unrecognised endobronchial intubation in major trauma patients. Emerg Med J. 2022;39(7):534-539. doi:10.1136/emermed-2021-211786