In the period between 1940 and 1955 the indications for tracheotomy were extended. For centuries tracheotomies were performed to treat obstructive diseases of the upper airway (hypopharynx, larynx, trachea). With the end of the second World War tracheotomy was indicated more and more for the therapy of lower airway disturbances.
Medical empiricism is thought to be responsible for the gradual shift in the indications during that period from upper to lower airway disturbances. Knowledge about the underlying principles of respiratory physiology was, however, already present at the end of the 19th century, but the shift in the indications did not occur until relatively recently. For many victims of World War II the discovery of the beneficial effect of a tracheotomy in a variety of traumatic disorders may have come too late.