What is the most appropriate action if someone is experiencing a severe nosebleed?

The most appropriate action during a severe nosebleed is to apply pressure and lean forward. This method effectively helps manage the nosebleed while preventing blood from flowing down the throat, which can lead to choking or other complications.

Leaning forward allows gravity to aid the situation by keeping the blood from entering the throat or stomach. It also helps the person breathe easier if blood starts to trickle. By applying firm pressure to the nostrils, it promotes the clotting process, which is essential in stopping the bleeding. This technique is a widely recommended practice in first aid for handling nosebleeds, as it addresses both the cessation of bleeding and safety for the individual.

The other options, such as tilting the head back, laying the person down, or encouraging them to swallow, may exacerbate the situation by allowing blood to flow toward the throat, potentially causing gagging or other hazards.