Essential airway skills include manual clearing, manual maneuvers, suctioning, and which of the following?

The correct answer is the oropharyngeal airway. This device is a crucial tool in maintaining and securing an open airway in patients who are unresponsive and have no gag reflex. The oropharyngeal airway works by preventing the tongue from obstructing the airway, which is a common issue in unconscious individuals. It allows for easier ventilation and is a vital skill to perform in emergency settings, particularly in trauma cases where airway management can be life-saving.

In contrast, nasal cannula insertion is primarily used for providing supplemental oxygen rather than ensuring an open airway. Mouth-to-mouth resuscitation, while a method of delivering breaths in specific scenarios, is less commonly used in modern practice due to the availability of bag-mask devices, and it does not directly involve maintaining an airway. Chest compressions, although essential in cases of cardiac arrest, do not address the airway directly and are acknowledged as part of the broader approach to resuscitation rather than specific airway management. Thus, the oropharyngeal airway stands out as the most relevant choice when discussing essential airway skills in trauma care.