Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 273

 When a tracheostomy is performed with the horse anesthetized, the cutaneous and tracheal incisions are sometimes found to be mismatched when the horse stands, because when the horse is recumbent and in dorsal recumbency, with its neck extended, the trachea shifts in relation to the overlying skin.

 Incising the annular ligament more than 180° of the circumference of the trachea may result in an obstructing cicatrix when the tracheal incision heals, and the procedure risks transection of a carotid artery or adjacent nerve, such as the vagosympathetic nerve, which lies dorsal to the carotid artery, or the recurrent laryngeal nerve, which lies ventral to the carotid artery.

 The site of tracheostomy may develop a stricturing cicatrix if the mucosa on the dorsum of the trachea is incised inadvertently when the tracheostomy is created.This complication is most likely to occur when tracheostomy is performed on a small equid.A tracheostomy tube can be accidentally inserted into the inadvertently‐created mucosal incision on the dorsum of the trachea and advanced submucosally, creating a large submucosal pocket.

 When using a Dyson self‐retaining, tracheostomy tube, one of the tongues may be inserted inadvertently into the peri‐tracheal tissue, rather than into the tracheal lumen. This results in insufficient movement of air through the tube into the tracheal lumen and increases the likelihood of infection at the site of tracheostomy.

 Subcutaneous and peri‐tracheal infection.Placing gauze sponges, to which an antimicrobial ointment has been applied, between the faceplate of the tracheostomy tube and the cutaneous incision decreases the likelihood of infection at the wound. Gauze sponges also absorb exudate, preventing excoriation of skin from accumulation of exudate.

 Subcutaneous emphysema often surrounds the site of tracheostomy. This can extend proximally, to involve the head, and caudally, to involve the trunk.Compressing the faceplate of the tracheostomy tube to the wound with elastic adhesive tape decreases the likelihood of subcutaneous emphysema developing at the wound. (see Figure 4.17)Severe subcutaneous emphysema is likely to develop if the tracheostomy tube is insufficient in cross‐sectional area to relieve high negative intrathoracic pressure. Exaggerated inspiratory effort pulls air through the cutaneous incision.

 Pneumothorax can result from migration of subcutaneous air into the mediastinal space and then into the pleural cavities.Inserting a tracheostomy tube insufficient in cross‐sectional area to prevent high intrathoracic pressure may contribute to development of pneumothorax.

 Completely transecting a tracheal ring leads to enfolding of the ring into the tracheal lumen, because the tracheal rings are incomplete dorsally.

 Leaving the cuff of a cuffed tracheostomy tube inflated for more than three hours may lead to mucosal damage, which in turn, may lead to a stricturing cicatrix.