The purpose of adding a small amount of epinephrine to local anesthetics is: 1. to make the local blood vessels constrict, delay the absorption of local anesthetics, reduce the amount of local anesthetics, and prevent local anesthetic poisoning. 2. to prolong the action time of nerve block, and can improve the deep nerve block. 3. to prevent a sudden increase in the concentration of local anesthetics in the blood vessels, and reduce the toxic reaction of local anesthetics. 4. to reduce the incidence of systemic adverse reactions incidence, such as dizziness, tinnitus, tongue feeling numb, bitter, etc., to prevent local anesthetic poisoning. The dosing method of local anesthetic and epinephrine is 1:200,000 with physiological saline.