The Combitube is a twin lumen device designed for use in emergency situations and difficult airways. It can be inserted without the need for visualization into the oropharynx, and usually enters the esophagus. It has a low volume inflatable distal cuff and a much larger proximal cuff designed to occlude the oro- and nasopharynx.
If the tube has entered the trachea, ventilation is achieved through the distal lumen as with a standard ETT. More commonly the device enters the esophagus and ventilation is achieved through multiple proximal apertures situated above the distal cuff. In the latter case the proximal and distal cuffs have to be inflated to prevent air from escaping through the esophagus or back out of the oro- and nasopharynx.