The influence of tracheal vascularization on the optimum location, shape and size of the tracheostomy in prolonged intubation.

Tracheal complications due to prolonged intensive therapy were studied. By means of angiography and dye injection of blood vessels in human cadavers, and by means of surgery in dogs, the arterial systems of the trachea in both species have been analysed with regard to problems arising during prolonged intubation in the Intensive Care Unit. In experiments the main arterial networks of the trachea have been exposed, their extent assessed and the anastomoses between them determined. From analysis of the results, the most advantageous location, shape and size of the tracheostomy is proposed. A transisthmic, round and oval-shaped tracheostomy respectively, taking no more than the medial two quarters of the tracheal diameter, was found to be most suitable. Three main arterial systems, segmentally arranged blood vessels, and rich vertical and horizontal anastomoses effectively prevent necrosis of the major tracheal segments. If only one of the three arterial systems functions, the trachea survives. When designing a tracheostomy, its role in the technical procedure of prolonged intubation should have priority. The blood supply of the trachea is of secondary importance.