[Repercussion of postoperative pain, benefits attending to treatment]

Physiological responses to postoperative acute pain may impede organ functions (cardiovascular, pulmonary, coagulation, endocrine, gastrointestinal, central nervous system, etc). Pain alleviation improves patient's comfort, but also may minimise perioperative stress response, physiological responses and postoperative organ dysfunction, assist postoperative nursing and physiotherapy, enhance clinical outcome, and potentially shorten the hospital stay. Potent postoperative analgesia, especially by epidural route, may be associated with reduction in incidence and severity of many perioperative dysfunctions. Peridural analgesia using local anaesthetics is the best technique for decreasing postoperative stress after lower abdominal or lower limb surgery. Analgesia using either epidural or high doses of morphine may improve some cardiac variables such as tachycardia and ischaemia, but does not change the incidence of severe cardiac complications. For patients undergoing vascular or orthopaedic surgery, epidural analgesia can improve clinical outcome by preventing the development of arterial or venous thromboembolic complications. However, in comparative studies, the control groups did not receive adequate prophylactic treatment for thromboembolic complications. Epidural analgesia can hasten the return of gastrointestinal motility and shorten the hospital stay. Postoperative mental dysfunction is decreased using intravenous PCA morphine in the elderly. Epidural analgesia with local anaesthetics improves postoperative respiratory function but, for unknown reasons, these benefits are not associated with a decrease in respiratory complications. On balance, the mode of acute pain relief decreases adverse physiological responses and many intermediate outcome variables; however, there is inconclusive evidence that it affects clinical outcome. Major advances in postoperative recovery can be achieved by early aggressive perioperative care, including potent analgesia, early mobilisation and oral nutrition. As a result, the hospital stay may be shortened.