Postoperative recovery is an important part of the patient's experience, regardless of the type of surgery. The recovery and prognosis of postoperative anesthesia have gradually become important indicators for judging the efficacy and quality of anesthesia. The recovery period of general anesthesia is an important transition period from anesthesia to wakefulness, and a good recovery period is an important guarantee for the recovery of postoperative organs and functions after surgery. However, the delay in awakening after general anesthesia remains one of the biggest challenges facing anesthesiologists. Postoperative resuscitation is the result of the removal of anesthetics from the brain. The time of resuscitation depends on patient factors, effects of anesthetic factors, duration of surgery, and painful stimulation.

The delay of recovery after anesthesia was mainly caused by the use of anesthetic drugs during the perioperative period. The drugs commonly used during the perioperative period are opioid analgesics, sedatives and muscle relaxants. Studies have shown that intravenous opioids are more difficult to control than neuromuscular relaxants. Opioids can extend the recovery time after anesthesia by direct sedation of opioid receptors. It also reduces the sensitivity of brainstem chemoreceptors to carbon dioxide, leading to dose-dependent respiratory depression and hypercapnia, which affects the removal of volatile substances and carbon dioxide, and ultimately leads to coma. In addition, the active metabolites of some opioids can prolong the duration of action, especially in the case of impaired renal function, which can lead to delayed awakening.

As an opioid antagonist, nalmefene can inhibit or reverse the respiratory inhibition, sedation and hypotension effects of opioid drugs. Moreover, it has no opioid excitatory activity, does not produce respiratory inhibition, hallucinogenic effect or pupil dilation. No pharmacological effects were observed without the administration of opioid agonists. In terms of inducing wakefulness during anesthesia, nalmefene can effectively reverse the sedative effect caused by opioids. There have been reports at home and abroad that nalmefene can be used to improve the effect of post-anesthesia resuscitation and reduce agitation during the waking period, but there is still a lack of large sample and well-designed randomized controlled studies to provide important data on how to improve the quality of anesthetized resuscitation. In order to speed up the awakening after anesthesia, promote the patients' consciousness and respiratory recovery, and improve the quality of awakening patients after anesthesia, the patients should control postoperative pain immediatly, improve the comfort of patients in the PACU, reduce the residence time of patients, speed up the circulation of operated patients, reduce the costs of PACU, and reduce the staff workload in the PACU. This study will conduct a rigorous randomized controlled studies, large sample, and the research indicators for patients from the PACU roll-out to ordinary ward, using Aldrete score , in order to obtain a series of data of nalmefene used for anesthesia recovery , and to lay the foundation of related research of nalmefene and similar drugs in clinical application in the future.