The first step in the ABC protocol is to ensure that the airway is clear. The nurse should check for any obstructions such as food, vomit, or foreign objects. Techniques like the head-tilt-chin-lift or jaw-thrust maneuver can be used to open the airway. If the patient is unconscious, it is essential to insert an airway adjunct like an oropharyngeal or nasopharyngeal airway to maintain patency.
