The typical symptom of shock is mainly inadequate perfusion of tissues and organs. Because of the decrease in effective blood volume, the blood supply decreases, leading to a lack of blood and oxygen supply to the tissues and organs, and thus certain dysfunctions. Altered consciousness can be seen in the early stages, and the patient may appear irritable, delirious, apathetic, or even comatose. This situation indicates that the central system has suffered from insufficient blood perfusion. If there is a decrease in urine output after adequate rehydration, if the urine output is <0.5 ml/kg/h, i.e., less than 30 ml of urine per hour in a 60 kg body weight person, this also represents inadequate perfusion of the organs. If the skin is cold and clammy, cyanotic or florid, and the capillary filling time is >2s, it also means that the blood supply to the tissues and organs is insufficient. The so-called capillary filling sign can use the thumb to press the skin on the surface of the sternum, and then release it again after 5s, if the redness is not restored for more than 2s, it is called capillary filling time more than 2s.