Which of the following conditions should be treated FIRST?

The most critical condition that should be treated first is an obstructed airway. An obstructed airway poses an immediate threat to life because it prevents oxygen from reaching the lungs and subsequently the bloodstream. Without adequate oxygenation, brain cells may start to die within minutes, leading to irreversible damage or death.

When an airway obstruction occurs, the body cannot perform essential functions, making it imperative to clear the obstruction and restore airflow as quickly as possible. This is especially true in emergency situations, as the body's tolerance for hypoxia (lack of oxygen) is very low.

In the context of other conditions listed, while a closed cerebral injury, shock from hemorrhage, and a sucking chest wound are serious and require urgent care, the immediate management of an obstructed airway is prioritized. Failure to address an airway obstruction can lead to the patient's immediate death, whereas other conditions may allow for a brief period of time before they result in critical consequences.