[Endotracheal intubation--its evolution].

A historical review of the development of endotracheal intubation is made. Clinical and some X-ray features, allowing to prognosticate the difficult intubation are searched for. Classifications are suggested of the possible reasons for difficulties. It is emphasized that at present there are no reliable criteria for prognosticating difficult tracheal intubation. The possible techniques which might help to overcome the difficulties are indicated. Endotracheal intubation is a particularly responsible element of general anesthesia and even highly experienced anesthesiologists may be faced with difficulties. It is a stress moment both for the patient and for the anesthesiologist. The signs through which the anesthesiologist may determine the position of the tube and rule out eventual esophageal intubation are systematized. Percentages are given on the relative incidence of difficult intubations and fiber optic intubations [correction of fibrointubations] in the different aspects of operative surgery.