Bolus obstruction to the airway (by food) usually occurs at the level of the larynx and is often fatal. It tends to occur in the elderly or infirm with a history of poor dentition, neurological deficit, psychiatric illness including dementia, influence of depressant drugs or reduced conscious state. In this case food has passed beyond the vocal cords to enter the trachea and lodged in the left main bronchus causing complete lung collapse.