When referred to in medical emergency, shock is taken to signify a life-threatening condition caused by the failure of the circulatory system to pump blood around the body. Internal and external bleeding can cause this, as can a heart attack, anaphylactic shock and excessive loss of body fluids such as occurs in diarrhea or severe burns. The body tries to maximize the use of remaining body fluids by withdrawing them from the surface and extremities of the body to the centre of the body.
This can progressively produce the following symptoms:
1. The casualty's skin becomes cold, grey and clammy as the body attempts to divert blood supplies to the vital organs.
2. The pulse becomes rapid as the heart works harder to circulate the reduced volume of blood.
3. The pulse becomes weaker and may become irregular as the blood volume and pressure fall.
4. The casualty becomes weak and giddy as oxygen fails to reach the muscles and brain.
5. The casualty's breathing becomes rapid and shallow, and he may appear to be attempting to yawn or gulp in air ('air hunger').
6. The casualty may complain of nausea and actually vomit.
7. The casualty may experience thirst as the brain senses that the body needs to make up a shortfall in fluid.
8. The casualty may become restless and agitated as the oxygen supply to the brain deteriorates.
9. The casualty will lose consciousness, and the pulse at the wrist may become un- palpable.
10. The heart will stop.
It is vital to identify and treat the causes of shock immediately. Always summon medical help at the earliest possible opportunity, but it may be possible to slow the progression of shock by taking prompt action to stop bleeding from an open wound.