Acetaminophen used in multimodal and preemptive therapy is associated with a reduction of opiates side effects and improved postoperative outcomes. (1B)

Coxib administration may be considered if there are no contraindications. (1B)

In the treatment of moderate-to-severe pain, unresponsive to other medications and in which regional anesthesia techniques are not indicated, the use of major opiate is indicated. (1B)

Initial infusion of opioids using intravenous patientcontrolled analgesia should be avoided in opioid naïve patients. (1B)

Sedation levels, respiratory status, and the possible development of adverse events in patients on systemic treatment with opioids must be regularly assessed. (1C)

If indicated, infusion of opiates using intravenous patient-controlled analgesia should be preferred to spinal patient-controlled analgesia in postoperative pain management whenever the intravenous route is viable. (1B)

Oral administration of analgesic drugs should be preferred over intravenous route whenever feasible, and drugs absorption may be reasonably warranted. (1B)

The intramuscular route should be avoided in postoperative pain management. (1B)

Epidural and regional anesthesia is recommended in emergency general surgery, whenever feasible and if not delaying the emergency procedures. (2B)

There is a lack of evidence to assess residual effects of ketamine in the population with OSA（Evidence level:Very Low；Recommendation grade:No Recommendation）.