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  • Image not available.Pain can be classified according to pathophysiology (eg, nociceptive or neuropathic pain), etiology (eg, postoperative or cancer pain), or the affected area (eg, headache or low back pain).
  • Image not available.Nociceptive pain is caused by activation or sensitization of peripheral nociceptors, specialized receptors that transduce noxious stimuli. Neuropathic pain is the result of injury or acquired abnormalities of peripheral or central neural structures.
  • Image not available.Acute pain can be defined as pain that is caused by noxious stimulation due to injury, a disease process, or the abnormal function of muscle or viscera. It is nearly always nociceptive.
  • Image not available.Chronic pain is defined as pain that persists beyond the usual course of an acute disease or after a reasonable time for healing to occur; this period can vary from 1 to 6 months. Chronic pain may be nociceptive, neuropathic, or mixed.
  • Image not available.Modulation of pain occurs peripherally at the nociceptor, in the spinal cord, or in supraspinal structures. This modulation can either inhibit (suppress) or facilitate (aggravate) pain.
  • Image not available.Moderate to severe acute pain, regardless of site, can affect nearly every organ function and may adversely influence postoperative morbidity and mortality.
  • Image not available.Neural blockade with local anesthetics can be useful in delineating pain mechanisms, but more importantly, it plays a major role in the management of patients with acute or chronic pain. The role of the sympathetic system and its pathways can be evaluated.
  • Image not available.Antidepressants are generally most useful in patients with neuropathic pain, eg, from postherpetic neuralgia and diabetic neuropathy. These agents demonstrate an analgesic effect that occurs at a dose lower than needed for their antidepressant action.
  • Image not available.Anticonvulsants have been found to be extremely useful in patients with neuropathic pain, particularly trigeminal neuralgia and diabetic neuropathy.
  • Image not available.Spinal cord stimulation is most effective for neuropathic pain. Proposed mechanisms include activation of descending modulating systems and inhibition of sympathetic outflow. Accepted indications include sympathetically mediated pain, spinal cord lesions with localized segmental pain, phantom limb pain, ischemic lower extremity pain due to peripheral vascular disease, and adhesive arachnoiditis.
  • Image not available.Studies show that patient-controlled analgesia (PCA) is a cost-effective technique that produces superior analgesia with very high patient satisfaction. Total drug consumption is less, compared with intramuscular injections. The routine use of a basal (“background”) infusion is controversial.
  • Image not available.The administration of local anesthetic–opioid mixtures neuraxially (particularly epidurally) is an excellent technique for managing postoperative pain following abdominal, pelvic, thoracic, or orthopedic procedures on the lower extremities. Patients often have better preservation of pulmonary function, are able to ambulate early, and benefit from early physical therapy. Patients may be at lower risk for postoperative venous thrombosis.
  • Image not available.The most serious side effect of epidural or intrathecal opioids is dose-dependent, delayed respiratory depression. Most cases of serious respiratory depression occur in patients receiving concomitant parenteral opioids or sedatives. Elderly patients and those with sleep apnea appear to be particularly vulnerable and require reduced dosing.
  • Image not available.Physical dependence occurs in all patients on large doses of opioids for extended periods. A withdrawal phenomenon can be precipitated by the administration of opioid antagonists.
  • Image not available.Multiple ...

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