Final answer:
Endotracheal intubation is the type of airway adjunct that can be used in unconscious patients with no gag reflex. It involves placing a tube into the trachea to maintain an open airway to the lungs.
Step-by-step explanation:
The type of airway adjunct that may be used in unconscious patients with no gag reflex is endotracheal intubation. This procedure involves placing a tube into the trachea to maintain an open airway to the lungs and prevent the tongue from blocking the airway. The tube is removed once the patient's breathing muscles regain control of respiration. This is the safest procedure to ensure that the patient can breathe properly and avoid complications.