Oxygen is essential for life; the body obtains it by respiration. Respiration may stop through mishaps like electric shock, inhaling or swallowing poisons, drowning and choking. The heart may continue to beat for a few minutes. If breathing does not pick up, then the heart, deprived of oxygen, will stop also. In some cases, such as acute heart attacks, the heart can stop first and respiration will then also stop almost immediately.

First Aid to be taken

Step 1 : Lie the patient on his back.
Step 2 : Using your forefinger, rapidly scoop round inside the mouth to clear away any possible obstruction. if, however, a denture is in its correct position, leave it there.
Step 3 : Tilt the patient's head back as far as it will go, so that the nostrils point directly upwards. This is best done by pressing the palm of one hand with the fingers pointing towards the nose on the centre of the forehead. This generally stops the tongue from falling to the back of the throat and lets the mouth fall open so that the airways are clear. On rare occasions you may have to pull the mouth open with finger and thumb of the other. At the same time push the jaw upwards, keeping fingers and thumb away from the lower lip.
Step 4 : Take in a deep breath. Pinch the lower half of the patient's nose shut. This prevents the air, which you will breathe into him, from escaping through the nostrils.
Step 5 : Open your mouth wide. Seal your lips round the patient's mouth.
Step 6 : Breathe out firmly but steadily so that air from your mouth and chest goes into the patient. His chest will rise.
Step 7 : Take away your mouth and turn your head sideways while drawing in another breath. your sideways view should confirm that the patient's chest has risen and is now falling against as his lungs empty. Your ear may hear the air coming out and you may feel it on your cheek.
Step 8 : As soon as his chest has ceased falling, give him another breath, and continue to repeat the cycle of steps 5, 6 and 7.
Step 9 : Continue artificial respiration until experts (doctors, ambulance, qualified first aiders) take over the responsibility for the patient. Do your best to shout for help or send by-standers to summon help and an ambulance urgently.