44P> INJURY TO THE TRACHEA. 



disturbance, which may become so great as finally to produce 

 suffocation. In other cases a loud sound is heard both during in- 

 spiration and expiration. Very slight changes in the trachea are 

 sufficient to produce it. Sometimes the noise may be increased 

 or diminished by pressing on a particular part of the trachea. Laying 

 the ear on the wind-pipe, the position of the stenosis may be more 

 exactly fixed, but this method does not always prevent mistakes. 

 During the next few days the emphysema usually spreads over the 

 body, especially when coughing exists, but disappears later, generally 

 without bad results. 



The course of the injury depends on its extent and the resulting 

 bleeding. The animal may be completely restored to usefulness, 

 or difficulty in breathing may remain (asthma tracheale). The 

 dyspnoea depends partly on the degree of stenosis, partly on the 

 character of work performed. In spite of marked deformity, dyspnoea 

 may be absent, whilst apparently unimportant changes sometimes 

 produce greatly disturbed respiration ; indeed, Schwanefeld's case 

 shows that they may cause death. These diversities are explained 

 by the fact that the respiratory difficulty is determined, not by the 

 external deformity of the trachea, but by the degree of stenosis. 

 The gravity of such cases is gauged by the state of the respiration 

 during severe work. In stenosis of the upper portions of the trachea, 

 tracheotomy usually affords relief, but is not available when the 

 lower portions in the neck or thoracic cavity are affected. Such 

 conditions, however, are often aggravated by lapse of time. 



Treatment. Where great dyspnoea immediately follows injury 

 of the trachea, tracheotomy, using a tampon-cannula, not only removes 

 the threatened danger of suffocation, but also prevents the entrance 

 of blood into the trachea. A tampon-cannula may be extemporised 

 by carefully wrapping the stem of a Barthelemy's tracheal tube with 

 cloth, but care must be taken that the bandage material, tow, wadding, 

 or piece of sponge used for this purpose does not fall into the trachea. 

 Severe emphysema, although seldom endangering life, may some- 

 times necessitate tracheotomy. 



In stenosis the position and extent of the stricture must deter- 

 mine whether tracheotomy is applicable, or likely to be successful. 

 It is generally serviceable when carried out below the stricture. 

 Richolson, by removing a dislocated portion of cartilage, permanently 

 relieved the dyspnoea. Similar cases are rare. 



The interesting communication of Lafosse and Sticker show 

 that " tubage " of the trachea is possible and may be successful. 

 Lafosse divided the trachea below the stricture caused by tracheotomy, 



