European surgical research. Europäische chirurgische Forschung. Recherches chirurgicales européennes
-
Patient-controlled analgesia (PCA) is one of the newer techniques for pain management. It was developed in reaction to the large number of unsatisfied postoperative patients suffering from moderate to severe pain despite the availability of potent analgesic drugs. With PCA, patients are allowed to self-administer small analgesic doses into a running intravenous infusion, intramuscularly, subcutaneously or even into the spinal space. ⋯ Although patients generally prefer self-control, pain relief is not necessarily better than with well-conducted conventional techniques. In addition to routine clinical pain management, PCA has proven its importance in research, e.g. for pain measurement, to determine predictors of postoperative pain, to evaluate drug interactions and the concept of pre-emptive analgesia, or for pharmacokinetic designs. PCA has been extremely important in order to change the mind of physicians and nursing staff with respect to individual pain management strategies.
-
Despite a growing trend in acute pain management, many deficiencies still account for the high incidence of moderate to severe postoperative pain to date. Patients nowadays continue to receive inadequate doses of analgesics, but additionally the identification and treatment of those patients with pain still remains a significant health care problem. ⋯ Nonopioid analgesics such as nonsteroidal anti-inflammatory drugs and newer nonopioid drugs such as alpha2-adrenergic agonists, calcium channel antagonists and various combinations of the above are possible. However, the solution to the problem of inadequate pain relief lies not so much in the development of new drugs and new techniques, but in the effective strategy of delivering these to patients through the introduction of acute pain management services on surgical wards.
-
Surgical trauma induces nociceptive sensitization leading to amplification and prolongation of postoperative pain. In experimental studies, preinjury (e.g. pre-emptive) neural blockade using local anaesthetics or opioids has been shown to prevent or to reduce postinjury sensitization of the central nervous system, while similar techniques applied after the injury had less or no effect. Several clinical studies have evaluated possible pre-emptive analgesic effects by administering prior to surgery a variety of analgesic drugs both systemically or epidurally. ⋯ In general, the results from these studies have been disappointing, although some clinical studies have confirmed the impressive results from animal studies. The present paper discusses deficiencies in study design of clinical trials, since the question regarding the effectiveness of pre-emptive analgesic regimens lies not so much in the timing of analgesic administration (e.g. preinjury vs. postinjury treatment), but in the effective prevention of altered central sensitization. Recent evidence suggests that administration of analgesics in order to effectively pre-empt postoperative pain should start before surgery and furthermore, this treatment should be extended into the early postoperative period.
-
Opioids remain at the center of most postoperative pain control therapies. The choice between full agonist opioids should be determined by the time for a given dose to produce its maximum effect (i.e., latency to peak effect), and the duration of action. There is little to choose between different opioids administered by patient-controlled analgesia. ⋯ Morphine may be the opioid of choice for epidural administration. The combination of epidural opioids and local anesthetics provides synergistic analgesia and appears to provide superior analgesia with activity. Several nonopioid receptor agonists are under investigation as neuraxial analgesics.