What are the indications for a tracheostomy in horses?

A tracheostomy is a procedure that creates a communication between the interior of the trachea and the exterior to allow air passage.
The indications for this intervention include obstructions of the upper respiratory tract, endotracheal intubation for procedures under general anesthesia, or to allow physiological rest of the upper respiratory tract.
The tracheostomy is only performed in emergency situations when the horse has collapsed and is showing signs of severe respiratory distress.