Kelowna First Aid Courses CPR Course 2508786690 Penticton Vernon BC Red Cross

The recovery position or more technically known as the lateral recumbent position is a first aid technique recommended for assisting people who are unconscious, or nearly so, but are still breathing. It is frequently taught as part of classes in CPR (cardiopulmonary resuscitation) or first aid.
When an unconscious person is lying face upwards, there are two main risk factors which can lead to suffocation:
Fluids, possibly blood but particularly vomit, can collect in the back of the throat, causing the person to drown. When a person is lying face up, the esophagus tilts down slightly from the stomach toward the throat. This, combined with loss of muscular control, can lead to the stomach contents flowing into the throat, called passive regurgitation. As well as obstructing the airway, fluid which collects in the back of the throat can also then flow down into the lungs; stomach acid can attack the inner lining of the lungs and cause a condition known as aspiration pneumonia.
Many fatalities occur where the original injury or illness which caused unconsciousness is not itself inherently fatal, but where the unconscious person suffocates for one of these reasons. This is a common cause of death following unconsciousness due to excessive consumption of alcohol.
To a limited extent, it is possible to protect against risks to the airway by tilting the head back and lifting the jaw. However, an unconscious person will not remain in this position unless held constantly, and crucially it does not safeguard against risks due to fluids. If the person is placed in the recovery position, the action of gravity will allow any fluids to drain. Also the chest is raised above the ground, which helps to make breathing easier.

Reference:
http://en.wikipedia.org/wiki/Main_Page