Articles: analgesia.
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Regional anesthesia · Mar 1993
Review1992 Bonica Lecture. Advances in chronic pain management since gate control.
Two pain treatment systems that developed soon after the publication of the gate theory are probably a direct result of its publication: neuraxial opiate administration and electrical stimulation of the spinal cord and peripheral nerves and receptors. Although the use of these modalities has become widespread in managing chronic pain, there is disagreement about their long-term efficacy. This presentation will attempt to review the data regarding the mechanisms of action of these modalities and their efficacy in treating chronic pain of malignant and nonmalignant origin. ⋯ Long-term spinal opiate administration has been shown to be more effective than systemic opiates in some patients with cancer pain, but often must be combined with local anesthetics to provide satisfactory pain relief. Loss of effect over time is a significant problem. Since the identification of spinal opiate receptors and the introduction of spinally administered narcotics, a number of other receptors that are important in both sensitization and suppression of pain projection systems have been characterized. Agonists and antagonists to many of these receptors are being developed, and a few are available for clinical trials. Long-term electrical stimulation of the spinal cord produces substantial analgesia below the stimulated spinal segments in some patients with chronic pain. Although initial results are usually encouraging, long-term efficacy may be disappointing. It is postulated that analgesia associated with spinal stimulation is associated with both stimulation of large fiber ascending tracts and blockade of spinothalamic pathways. Transcutaneous electrical nerve stimulation (TENS) has come into widespread use in managing chronic pain and has had limited trials in cancer pain patients. It is well accepted by patients and physicians, but clinical studies of long-term efficacy have yielded variable results. The analgesic action is probably the result of both large afferent fiber activation and blockade of peripheral nociceptors.
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Frequently fluid may be aspirated from epidural catheters during epidural anesthesia/analgesia. This fluid may be either cerebrospinal fluid or local anesthetic. Several methods for differentiation of the two fluids have been recommended. ⋯ When the glucose-positive aspirates were subjected to immunoelectrophoresis, 6 of 7 aspirates revealed a prealbumin band. In conclusion, the glucose test for cerebrospinal fluid may be misleading. The source of this glucose may be normal cerebrospinal fluid drainage into the epidural space.
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Three cases of extradural abscess with delayed presentation after extradural analgesia have been reported previously. The present report describes a patient with alcohol abuse who was treated for 5 days with extradural injections of bupivacaine for pain from multiple rib fractures. The first symptoms of an extradural abscess developed approximately 11 days after removal of the extradural catheter, and definite diagnosis was delayed a further 7 days.
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Comparative Study
Analgesia and sedation during percutaneous radiofrequency electrocoagulation for trigeminal neuralgia.
Patient comfort during percutaneous radiofrequency electrocoagulation for trigeminal neuralgia provides better working conditions for the surgeon and makes the patient more willing to return if a second procedure is necessary. This study evaluates five different regimens for analgesia and sedation including the standard of fentanyl and droperidol (Group A) and four other regimens, each containing midazolam. In a sixth group, droperidol was assessed for its antiemetic effects. ⋯ In another group of 96 patients, 1.25 mg of droperidol was given in addition to the medications described for Groups D and E. There was a statistically significant improvement in comfort in Groups C, D, and E and added amnesia in Groups D and E. Vomiting occurred in none of the patients medicated with droperidol and in 5 of 143 patients who did not receive droperidol.(ABSTRACT TRUNCATED AT 250 WORDS)
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Sixty adult patients following general surgical operation were treated with patient-controlled analgesia using morphine. Patients were allocated into three groups to receive: no background infusion, a 1 mg.h-1 or a 2 mg.h-1 background infusion. The other controls on the patient-controlled analgesia machine were set to allow a maximum dose of morphine of 6 mg.h-1 to each group. ⋯ Patients who received a background infusion of 2 mg.h-1 had an increased incidence of nausea (p < 0.05). A background infusion of 1 mg.h-1, with a 1 mg bolus dose and a 12 min lockout interval provided acceptable pain relief without excessive nausea. In all three groups the ratio of analgesic requests to successful deliveries correlated with the degree of pain reported by visual analogue score (p = 0.0001).