The esophageal-tracheal double lumen tube (Combitube) and the King laryngeal tube are twin-lumen tubes that have fundamental similarities: A large proximal balloon cuff seals the hypopharynx A ventilating, proximal lumen terminates at side ports overlying the laryngeal inlet A distal lumen and its smaller balloon cuff terminate in and seal the upper esophagus (in > 90% of insertions) Supraglottic airways are useful for providing rescue ventilation to unconscious patients or patients without a gag reflex and are also used in some elective settings.