Sets in when blood flow through vital organs becomes inadequate due to loss of body fluids (see Bleeding, Internal bleeding, Fractures, Burns and scalds), Heart attack, or a sudden drop in blood pressure in response to an allergen or infection (anaphylactic shock). Symptoms include pallor, cold clammy skin, anxiety, nausea, thirst, and faintness. Breathing becomes rapid and shallow, and the pulse ‘thready’ (weak and fast). In some people insect Bites and stings cause a shock reaction, accompanied by swelling of the throat and difficult breathing.

When a person is in shock, every second counts. Dial 911 immediately.

Check breathing and pulse and quickly assess any injuries to see if there is preventable blood loss. If possible, lie the casualty on his or her back and raise the legs slightly (unless injury prevents this) to improve blood flow to the heart, lungs, and brain. Keep the head tilted to one side, with the chin up, to keep the airway open

If the person becomes unconscious or vomits, put him or her into the recovery position (see Unconsciousness) and, if possible, raise the feet. Loosen any tight clothing and cover with a blanket or coat. Do not move the person; do not give anything to drink; and do not apply direct heat.