Articles: hyperalgesia.
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Randomized Controlled Trial Clinical Trial
Quantitative sensory examination of epidural anaesthesia and analgesia in man: effects of pre- and post-traumatic morphine on hyperalgesia.
The objectives of the study were: (1) comparison of hypoalgesic effects of pre- and post-traumatic epidural morphine (EM) on primary and secondary hyperalgesia, and (2) comparison of EM hypoalgesia in normal and injured skin. Burn injuries (25 x 50 mm rectangular thermode, 47 degrees C, 7 min) were produced on the calves of healthy volunteers, at 2 different days at least 1 week apart. In randomized order, the subjects received 4 mg of EM administered via the L2-L3 intervertebral space on one day and no treatment on the other day. ⋯ Following NAL, the areas of secondary hyperalgesia expanded beyond control size. It is suggested that the major effect of EM on secondary hyperalgesia is inhibition of C fibre-mediated activity which maintains the altered response properties of central neurons responsible for secondary hyperalgesia. Possible mechanisms of action of NAL in enhancement of hyperalgesia are discussed.
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Anesthesia and analgesia · Feb 1994
Randomized Controlled Trial Comparative Study Clinical TrialPreemptive effect of fentanyl and ketamine on postoperative pain and wound hyperalgesia.
The aim of this study was to test the hypothesis that the induction and maintenance of anesthesia with the use of fentanyl or ketamine reduces postoperative pain and wound hyperalgesia beyond the period when these effects can be explained by the direct analgesic action of these drugs. Twenty-seven patients scheduled for elective hysterectomy were investigated in a double-blind, randomized study. Patients were divided into three groups. ⋯ The intensity of spontaneous incisional pain and movement-associated pain was measured with a visual analog self-rating method. The surgical wound hyperalgesia was assessed by measuring pain threshold to pressure on the wound by using an algometer, and also by measuring the intensity of pain to suprathreshold pressure on the wound with the visual analog self-rating method. Forty-eight hours after surgery, the pain threshold was 0.90 +/- 0.06 kg in controls, 1.69 +/- 0.19 kg (P < 0.001) in the fentanyl group, and 1.49 +/- 0.15 kg (P < 0.01) in the ketamine group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Case Reports Randomized Controlled Trial Clinical Trial
Response of chronic neuropathic pain syndromes to ketamine: a preliminary study.
Hyperactivity of N-methyl-D-aspartate (NMDA) receptors may be one of the factors in the genesis of neuropathic pain. Ketamine is an NMDA-blocking agent widely used in human medicine. Ketamine (at 250 mcg/kg i.v. slow push) was administered to 6 patients for control of chronic neuropathic pain syndromes in double-blind placebo-controlled fashion. ⋯ Continuous subcutaneous infusion of ketamine administered to 1 patient with PNS-related neuropathic pain caused no additional improvement in pain control but caused intolerable cognitive and memory side effects. In contrast, side effects during single-dose injections were mild and well tolerated. Ketamine affected the evoked pain and associated after-sensation in chronic neuropathic pain syndromes more than the ongoing constant pain.
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Randomized Controlled Trial Clinical Trial
Secondary hyperalgesia is not affected by wound infiltration with bupivacaine.
The purpose of this study was to determine the effects of wound infiltration with bupivacaine on incisional pain and the zone of secondary hyperalgesia. Twenty-eight healthy parturients were studied in a double-blind randomized trial. At the time of Caesarean section one wound edge was infiltrated with saline 0.9% and the other with bupivacaine 0.25%. ⋯ The zone of secondary pain was similar overall for both sides of the wound. It is concluded that the bupivacaine-infiltrated side of the wound was less painful than the saline-injected side 24 hr postoperatively. The zone of pain measured around the wound edges was unaffected by bupivacaine or saline.