To start mouth-to-mouth resuscitation on a casualty, which action should you perform first?

Starting mouth-to-mouth resuscitation involves several important steps, and the first action you should perform is to clear the airway. This step is crucial because, before you can effectively deliver breaths, you need to ensure that there is no obstruction preventing air from entering the lungs. An obstructed airway can occur due to various reasons, such as the tongue falling back into the throat or foreign objects blocking the passage.

Once the airway is clear, it becomes possible to provide effective rescue breaths. This foundational action sets the stage for successful resuscitation efforts and increases the chance of restoring normal breathing in the casualty. Clearing the airway might include techniques such as the head-tilt-chin-lift maneuver or the jaw-thrust maneuver, both designed to open the airway effectively.

In contrast, pinching the nostrils, tilting the head back, or monitoring the pulse may be required actions in the overall process, but they should follow the critical step of ensuring the airway is clear first. Therefore, understanding the hierarchy of these actions is vital for effective emergency response.