Acute tracheal trauma in sheep caused by percutaneous tracheostomy

The aim of our study was to compare dilation forceps tracheostomy and sequential dilator tracheostomy in anaesthetized live adult sheep with respect to the characteristics of the stoma formed and the associated injury. We performed percutaneous tracheostomy on adult sheep randomly allocated to receive either dilation forceps or sequential dilators. Sheep were sacrificed immediately after insertion of the percutaneous tracheostomy and the tracheas dissected. Specimens were examined for site, shape and size of stoma, mucosal lacerations, and posterior wall trauma. Ten sheep had dilation forceps tracheostomy and ten had sequential dilator tracheostomy. All of the specimens were found to have cephalo-caudal mucosal tears, usually crossing tracheal rings. The dilation forceps technique was found to have a larger stoma (28.8 mm vs 24.0 mm, P=0.023). The incidence of posterior needle trauma and mucosal lacerations were common (35% and 50% respectively), but they were not statistically different between the two groups. The role of the mucosal tears in the development of tracheal stenosis is reviewed in the discussion.