Shock according to the pathophysiological changes, usually divided into four types: 1, hypovolemic shock, this condition is usually a variety of reasons for the formation of intravascular volume deficiency, such as blood loss or loss of fluid. This type of shock is mainly caused by the loss of tension or resistance of the peripheral blood vessels, resulting in a sudden and severe reduction in the amount of blood returned to the heart, and the retention of blood in the capillaries or veins, thus causing the effective perfusion of the vascular microcirculation. Inadequate perfusion of the microcirculation. The main causes are infectious shock, anaphylactic shock, neurogenic shock, etc. 3, cardiogenic shock, formed due to abnormal heart function, such as acute myocardial infarction, heart failure or malignant arrhythmia. 4, obstructive shock, usually clinically manifested as a result of non-cardiac causes of blood flow obstruction, resulting in the left ventricle diastolic can not be fully filled, reducing the heart’s blood displacement, such as pulmonary embolism, pulmonary embolism, venous flow. The clinical manifestation of obstructive shock is usually due to the blockage of blood flow outside the heart, which causes the diastolic filling of the left ventricle to be inadequate and reduces the heart’s blood displacement, such as pulmonary embolism, pulmonary hypertension, aortic constriction or acute cardiac compression, etc.