Epidural and spinal agents for postoperative analgesia.

The discovery of opioid receptors and the subsequent development of the technique of epidural and intrathecal opioid administration are undoubtedly two of the most significant advances in pain management in recent decades. The use of spinal opioids is widespread and increasing. The technique is used widely to treat intraoperative, postoperative, traumatic, obstetric, chronic, and cancer pain. Newer developments include the increasing use of combined local anesthetics and opioids or nonopioids and also PCEA, particularly in the obstetric population. Meta-analysis of controlled trials has demonstrated improved pulmonary outcome in patients receiving epidural postoperative analgesia. Although rare, respiratory depression continues to be a major problem of the technique. None of the currently available opioids is completely safe; however, extensive international experience has shown that patients receiving spinal opioids for postoperative analgesia can be safely nursed on regular wards, provided that trained personnel and appropriate guidelines are available. The importance of a good acute pain service to provide the safe and effective use of spinal opioids cannot be overemphasized.