Chin Med J (Taipei) 1998;61:S26.

Updates on Postoperative Analgesia

Kwok-Hon Chan

Department of Anesthesiology, Veterans General Hospital-Taipei, Taiwan

Abstract

Postoperative pain is unique as a form of acute pain which is generally perceived as the consequence from various degree of tissue injury. Relief from pain is an intuitive goal and is of unquestionable humanitarian value. Untreated pain causes enormous physiologic derangements, including hemodynamic instability, increased myocardial workload, metabolic alteration, respiratory impairment, immunological suppression and delay in postoperative recovery. In the context of postoperative pain, the tissue injury with inflammatory reaction of the wound area can initiate a barrage of ongoing nociceptive impulse which are continuously transmitted to the spinal neurons and to the higher cortical center. Therefore it is impossible to provide good quality of pain relief if these nociceptive stimulation can not be completely blocked by means of various methods which should be given continuously up to several days after the surgery. Common effective techniques for postoperative analgesia include intravenous patient-controlled analgesia, epidural analgesia and regional blockade, all of which have been successfully applied in various clinical settings.

According to the concept of pre-emptive analgesia, pain control should be initiated well before the surgical stimulation and be continued to a certain period after the surgery until the wounds are gradually healing. The combination of multiple drugs are needed to suppress the central sensitization or "wind-up" phenomenon in the nociceptive pathway. For high risk patients undergoing major surgery, the combined use of balanced general anesthesia with epidural analgesia is highly recommended because it can not only provide high quality of pain control, but also maintain relatively stable hemodynamic variables. This strategic approach can help facilitate the process in rehabilitation in an attempt to prevent major morbidity and hopefully to improve the outcome of these patients.

[Chin Med J (Taipei) 1998;61:S26.]