Drowning is defined as Asphyxia (lack of Oxygen reaching the body tissues) due to immersion in water.
There are three types of drowning:
Water enters the lungs (may only be a small amount) which interferes with the transfer of oxygen into the blood. There are approximately 500 drownings in Britain each year. 40% are in the sea and 36% are in rivers, canals and lakes. About 25% are alcohol related.
Muscle spasms in the area around the voice box block the airway, often due to immersion in cold water. This is known as apnoea. No water enters the lungs. Around 10% of drownings are dry drownings.
If a tiny amount of water enters the lungs, this can cause irritation, and the fluid produced in the lungs as a result can accumilate to cause drowning up to 72 hours after immersion in water. Casualties who ave suffered near drowning must always be seen by a doctor as soon as possible, even if they appear to be fine.
Near-drowned casualties may also suffer a condition called Post-immersion Collapse. During prolonged immersion in water, the pressure exerted on the body forces fluid out of the blood into the kidneys. Once back on land, the body re-expands but the drop in blood pressure means circulation is inadequate and signs of shock may appear.
Keep casualty horizontal to counteract possible shock and allow fluids to drain from the mouth.
Follow DRABC procedure and treat accordingly. Remember that the casualty is likely to be cold, possibly hypothermic, so treat accordingly: see information on hypothermia. Do not give up, it may still be possible for the casualty to be revived. In particular, if the casualty has been immersed in ice cold water for up to 60 minutes or if they are a child there is a chance of survival.
You must be prepared to resusitate even if the casualty has vomited or has froth around the mouth, as is often the case in near drowning. If the casualty is breathing, they should be treated for shock. All near-drowning casualties MUST receive prompt medical because of the possibility of secondary drowning.