As its name impies, forced or unnatural breathing. Basically, it's any measure that causes air to flow in and out of a person's lungs when natural breathing is inadequate or absent, as in drowning, electric shock, choking, gas or smoke inhalation, or poisoning. Artificial respiration is an essential part of any basic first aid curriculum.
Respiration can be taken over by any type of mechanical respirator. More usually, however, artificial respiration is provided by individuals in an emergency situation when no mechanical aids are available. In this case, rescuers perform either mouth-to-mouth or mouth-to-nose artificial respiration.
First, remove any foreign material or object from the victim's mouth with your hand.
Place the victim on his or her back, with their head tilted backward and their chin pointing upward so that their tongue does not block the throat.
Place your mouth tightly over the victim's mouth with the nostrils held shut, or over the nose with the mouth held shut. For a small child or infant, you can place your mouth firmly over child's mouth and nose.
Take a deep breath and blow into the victim's appropriate orifice(s). You should feel the air move into the victim's chest. If not, check their head position to be sure it's correct. If changing the head position does not solve the problem, there may be an object lodged in the victim's throat where you can't see it, so turn the victim on their side and rap them smartly between the shoulder blades to dislodge the object.
Once the air passes into the victim's lungs and his or her chest expands, stop blowing, turn your head away, and listen for an exhalation. Then repeat.
If the victim is an adult, blowing should be vigorous, at the rate of about 12 breaths per minute. A child's breaths should be shallower, about 20 per minute, and an infant's breaths should come in short puffs. The procedure should be continued until natural breathing resumes or until professional help arrives
As the heart often stops beating when breathing is interrupted, cardiopulmonary resuscitation (CPR) is typically administered simultaneously. This involves compressing the chest above the heart at 60 or more thrusts per minute, with 2 breaths being administered after every 15 chest thrusts.
Artificial respiration is not difficult to learn, and may help save a life. But don't try to do it based on my description; take a first aid course to learn how. St. John Ambulance Brigade offers a good one.