 For centuries , tracheotomy was considered the only reliable method for intubation of the trachea . However , because only a minority of patients survived the operation , physicians undertook tracheotomy only as a last resort , on patients who were nearly dead . It was not until the late 19th century however that advances in understanding of anatomy and physiology , as well an appreciation of the germ theory of disease , had improved the outcome of this operation to the point that it could be considered an acceptable treatment option . Also at that time , advances in endoscopic instrumentation had improved to such a degree that direct laryngoscopy had become a viable means to secure the airway by the non @-@ surgical orotracheal route . By the mid @-@ 20th century , the tracheotomy as well as endoscopy and non @-@ surgical tracheal intubation had evolved from rarely employed procedures to becoming essential components of the practices of anesthesiology , critical care medicine , emergency medicine , and laryngology . 
