According to the World Health Organization’s grading scheme, pain can be divided into five levels, respectively, 0-4: level 0 is no pain; level 1 is mild pain, manifested as vague pain, intermittent pain, this pain can generally be tolerated without medication; level 2 pain is moderate pain, more often manifested as persistent dull pain, the pain is relatively more pronounced, it will affect the normal rest, you need to consider oral Level 3 pain is severe pain, manifested as persistent cramps, which must be controlled by painkillers; Level 4 pain is persistent severe pain, the pain is very intense, will affect the patient’s blood pressure, heart rate and other vital signs.