Reasons of shock are multifarious and mainly classified into several kinds as follows:

•  Excessive bleeding (internal hemorrhage or external hemorrhage), dehydration (emesis, diarrhea, etc), blood loss (extensive burn) and others.

•  Infectious shock caused by serious infection such as pneumonia, cholecystitis, bacillary dysentery, blood poisoning and peritonitis.

•  Cardiogenic shock caused by acute myocarditis and others.

•  Anaphyiactic shock caused by human body happening anaphylaxis owing to some medicine or biological products.

•  Neurogenic shock caused by trauma bringing about acute pain or anaesthesia suddenness which arouses reducing of blood circulation owing to nerve action.

On account of shock, each organ of human body will appear oxygen deficiency condition. As oxygen consumption of heart is large, the coronary artery which nourishes heart must own sufficient blood flow supply so that demand of heart for nutritive substance and oxygen can be assured. When human shocks, blood flow of coronary artery will reduce obviously, cardiac muscle will lack oxygen and other nutritive substance will be in short of supply too, making heart damaged and heart failure occur or even die. When human shocks, its blood flow of blood vessel of lung will reduce and lungs will lack oxygen which also causes lung damage such as pulmonary atelectasis, pulmonary edema and pneumorrhagia, making lung lacks oxygen more serious and causing death owing to respiratory failure. Although kidney of human is not large but blood vessel and capillary blood vessel inside kidney are very abundant and blood flow is quite a lot accordingly. When human shocks, kidney blood flow will reduce and then cause oliguria and kidney oxygen deficiency, therefore, acute kidney failure will occur or even the kidney necrosis will occur if too serious. Compared with other visceral organs, the brain demands higher oxygen quantity so that once be short of blood for 10 minutes the patients will get into coma because of hydrocephalus and will create irreversible damages till to be a human vegetable without consciousness but only basic physiological function. When shocking, the liver and gstrointestinal tract will appear damages of different extent owing to deficiency of blood flow.

Shocking patients in early stage are in his right senses and just fidget about and appear as pale complexion, oral lips and nail take on little cyanosis, in a cold sweat and heartbeat quickens. Along with state of illness developing, the patients become slow in thought and action and their blood pressure descend. Along with further development, the patients will get into narcosis so that anuria, skin, mucous membrane and visceral hemorrhage will occur and acute failure of visceral organs such as heart, kidney and liver will occur as well.

As a kind of pathological form process which is serious and diversified, shock must be given emergency treatment in time and observed nearly and carefully. If shock develops into the late stage, it is difficult to reverse the state of illness. The general principle of treatment is to carry on intravenous transfusion and medicine administration at the first opportunity. The transfusion content should be chosen as whole blood, blood plasma or low molecular dextrose according to concrete conditions and pressure increasing medicine should be chosen as blood vessels expansion medicine, for instance, sodium nitroprusside, atropine and others. Shock of different types should be treated differently and adjusted according to state of illness.

No matter what kind of shock is, the patients should absorb sufficient oxygen. Oxygen therapy can maintain normal or normal-approaching arterial oxygen, being propitious to visceral organs for gaining maximum oxygen supply, enhancing ischemic state and alleviating a series of damages caused by hypoxia.

When patients accept oxygen therapy first aid, please be sure to keep quiet and adopt appropriate posture and generally speaking the horizontal position is advisable. If you are a patient of cardiogenic shock who can't lie completely owing to dyspnea, you can adopt half horizontal position. Supply patients with pure oxygen by nasal tube or face mask at oxygen flow of 2 ～ 4L/min and oxygen concentration can re ach 30% above, enabling blood oxygen partial pressure of patients to be close to normal value of healthy people. Once shock occurs, the patients must be sent to hospital in time to get timely salvage and appropriate treatment. On the way of sending to hospital, we should create conditions to carry on oxygen therapy to alleviate damages of visceral organs caused by hypoxia, laying the foundation for further treatment.