Choking is usually caused by a piece of food that has lodged in the throat. Children sometimes choke on small toys or other objects that they put in their mouths. Someone who is choking is unable to speak or breathe and will asphyxiate within four to six minutes unless the obstruction in their airway is dislodged.
First, ask the casualty to cough hard, if he or she can, because coughing usually works. If coughing is weak or non-existent slap the person, who should be bent forward slightly, on the back using the palm of the hand. (A toddler should be held upside-down by the feet and then slapped on the back.) If after four slaps the casualty is still choking, you should try up to four abdominal thrusts (Heimlich manoeuvre). The principle of this technique is to deliver a sudden thrust to the upper abdomen. The force is transferred upwards and compresses the lungs, and, hopefully, causes the object producing the choking to be ‘blown out’.