The whole process of the effect of anesthetics can be divided into three stages: anesthesia induction period, anesthesia maintenance period and anesthesia recovery period. 1. Induction of anesthesia: this period can make people from the awake state over to anesthesia, usually using anesthetic sedatives, so that the body produces a temporary loss of consciousness, loss of pain sensation, muscle relaxation state. 2. Anesthesia maintenance period: this period can also be referred to as the surgical period, this period will enable the body to maintain a certain range of anesthesia depth, in order to ensure that the vital signs are stable. 3. Anesthesia recovery period: stop using anesthesia drugs after the operation, at this time the patient will gradually wake up, consciousness, pain, muscle tone will slowly return to the preoperative state.