What should be the first action taken if a casualty presents with airway obstruction?

In the scenario where a casualty presents with airway obstruction, the appropriate first action is to perform a Heimlich maneuver (also known as abdominal thrusts) if the obstruction is due to a foreign object and the person is conscious and unable to speak or breathe effectively. This maneuver is specifically designed to expel objects blocking the airway by creating an artificial cough, which can dislodge the obstruction.

Immediate actions are critical in situations of airway obstruction because the inability to breathe can lead to rapid deterioration of the casualty's condition. While checking for lung sounds, administering supplemental oxygen, and calling for additional help are important considerations in the overall management of a casualty, they do not directly address the immediate threat posed by an obstructed airway. The Heimlich maneuver targets the specific issue of obstruction, making it the priority action to restore the airway and ensure that the casualty can breathe.