Food, vomit, and the tongue itself can obstruct the airway to the lungs and cause choking. The signs of choking are difficulty breathing and speaking, and sometimes coughing. If the obstruction cannot be removed, the person will turn blue and clutch at the throat, after a minute or so, he or she will become unconscious. Choking while remaining conscious is a frightening experience, but usually the obstruction clears itself before serious harm is done.
The logical first step is to try to clear the mouth and throat of blood, vomit, foreign objects such as dentures, and so on. If this does not work, or if the choking person stops coughing and begins to turn blue, bend the body over slightly (or get the person to lie on his or her side) and sharply thump the back between the shoulder blades three or four times using the heel of your hand. If the casualty is a child hold him or her upside down or face-down over your knee and strike with less force. If the obstruction is not dislodged, repeat after a few seconds. This ‘shock treatment’ usually works even when obstruction is caused by spasm of the muscles lining the windpipe.
If the obstruction remains, try once again to remove it with fingers or tweezers. If this fails, carry out the Heimlich or ‘abdominal thrust’ manoeuvre.
Grasp the casualty from behind, tucking one of your fists underneath the breastbone and grasping it with your other hand. Pull sharply inwards, thrusting in and up beneath the breast bone. This produces a sudden increase of pressure in the chest cavity, which should expel the obstruction. Repeat up to three times if necessary. If the obstruction persists, or if the person becomes unconscious, commence artificial respiration, or put the person in the recovery position (see Breathing and Unconsciousness), and dial 911.
With a child, use just two fingers under the breastbone rather than your whole fist, and pull upwards and inwards more gently. The Heimlich manoeuvre is not without risk itself. After using it, the casualty should be examined in hospital to make sure no internal damage has been done.