An extremely unpleasant way to die, a sucking chest wound is caused by a penetrating injury to the chest which causes the lung (or lungs if you're particularly unlucky) to collapse and prevents proper respiration.

Someone suffering from a sucking chest wound will gasp for breath, have difficulty breathing out, and may have a bluish or grayish colour to his face. The damaged area may or may not make a sucking noise (hence the name) and bubble frothy blood from the wound.

First aid for a sucking chest wound

Note: This is assuming you're not within five minutes of a phone, ambulance, or trained medical professional.

1) Remove any clothing from the chest area.

2) Seal the wound with either your hand or an airtight non-porous material (cellophane or aluminum foil would do. Karma Debt tells me a credit card or drivers license would suffice and it's much more likely you'll have these on hand in an emergency).

3) While holding the airtight material over the wound wipe the blood from the surrounding skin. Apply tape to all sides of the material but leave one corner of the covering unsealed.

This step allows trapped air to escape when exhaling and prevents air entry into the wound when inhaling.

4) If the casualty exhibits any signs of shock then treat as necessary. Do not give the casualty anything to eat or drink.

5) Get the casualty to a hospital ASAP!