The enduring myth of why a distally placed endotracheal tube always goes into the right mainstem bronchus

> Misunderstanding is generally simpler than true understanding, and hence has more potential for popularity. —Raheel Farooq (writer) In an Australian study, the most common mishap with endotracheal tube (ETT) placement was inadvertent endobronchial intubation (ETT placed too deep), more so than oesophageal intubation, accounting for nearly half of all the ETT-related incident reports.1 In the prehospital setting in a German study, emergency physicians inadvertently intubated the right mainstem bronchus in 6.7% of their intubations.2 In patients intubated by an emergency physician or anaesthesiologist in a German emergency department, the incidence of right mainstem intubation was 7%.3 In that study, the ETT tip was within 2 cm of the carina in another 13% of patients.3 When an ETT tip is that close to the carina, events such as head flexion can move the ETT up to 3.1 cm (mean 1.9 cm) toward the carina from the neutral position.4 Furthermore, rostral displacement of the carina because of Trendelenburg positioning (to treat hypotension, to cannulate a central vein or during surgery) or pneumoperitoneum for laparoscopy can result in right mainstem bronchial intubation. The margin of safety is correspondingly small in small patients. Mainstem intubation could trigger bronchospasm, cause hypoxaemia due to a massive shunt and atelectasis, and the increased inspiratory pressure may result in barotrauma and even haemodynamic disturbances. In complex cases (eg, major trauma), it can complicate diagnosis and management of life-threatening injuries. Endobronchial intubation accounts for 2% of adverse respiratory claims in adults and 4% in children in the American Society of Anesthesiologists’ Closed Claims Database.5 Inadvertent mainstem intubation is therefore an important discussion topic with learners rotating through anaesthesia, emergency medicine, critical care and surgery. Spanning over 3 decades of our careers, we must have asked hundreds of residents and students in and from …