What technique is used to ensure a casualty does not inhale air in the case of a chest injury?

Using a vented chest seal is crucial in managing chest injuries, particularly when there is a risk of a pneumothorax. This type of injury can lead to air entering the pleural space, which can cause lung collapse and significant respiratory distress. A vented chest seal is specifically designed to allow air to escape from the chest cavity while preventing further air from being inhaled.

When applied correctly, the vented design permits trapped air to exit during expiration, which helps relieve pressure on the lung and allows for normal breathing mechanics to be restored to some extent. This is essential in a combat or emergency situation where rapid intervention is needed to stabilize the casualty.

Other options, while relevant to different aspects of injury management, do not address the specific concern of preventing air from entering the pleural space in the case of a chest injury. For instance, applying an airtight dressing is beneficial for sealing a wound but may not allow pressure to escape, potentially worsening the situation. Conducting a needle decompression is a procedure used to relieve tension pneumothorax but is not a preventive measure and is more invasive. Placing a casualty in the recovery position is primarily aimed at maintaining an open airway rather than addressing issues specific to chest injuries. Thus, the use