Pain
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The postoperative analgesic effect of opiate premedication and local anaesthetic blocks was studied in 929 patients having orthopaedic surgery. The median time to first request for postoperative analgesia was less than 2 h when neither opiate premedication nor block was used; opiate premedication increased the time significantly to more than 5 h; local anaesthetic block produced a further significant increase to 8 h and opiate premedication used with local anaesthetic block extended the median time further to more than 9 h. ⋯ Age had no significant effect. Prolonging the time before more pain relief is required may be worthwhile for both patients and staff.
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The similarities between phantom limb pain and preoperative limb pain have been noted, and this raises the possibility of modulating the pain by a preoperative blockade. The aim of this study was to investigate if it was possible to reduce postoperative phantom limb pain by giving lumbar epidural blockade (LEB) with bupivacaine and morphine for 72 h prior to the operation. 25 patients were interviewed about their limb pain before limb amputation, and about their phantom limb pain 7 days, 6 months and 1 year after limb loss. 11 patients, of mean age 77 years (52-93), received an LEB, so that they were pain-free for 3 days prior to operation. The control group, 14 patients of mean age 73.4 years (63.86), all had preoperative limb pain. ⋯ After 6 months all patients in the LEB group were pain-free, whilst 5 patients in the control group had pain (P less than 0.05). After 1 year, all the patients in the LEB group were still pain-free, and 3 patients in the control group had phantom limb pain (P less than 0.20). Preoperative lumbar epidural blockade with bupivacaine and morphine reduces the incidence of phantom limb pain in the first year after operation.
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Randomized Controlled Trial Clinical Trial
The efficacy of hypnosis- and relaxation-induced analgesia on two dimensions of pain for cold pressor and electrical tooth pulp stimulation.
This study evaluated the efficacy of hypnosis- and relaxation-induced suggestions for analgesia for reducing the strength and unpleasantness dimensions of pain evoked by noxious tooth pulp stimulation and by cold pressor stimulation. The Tellegen Absorption Questionnaire was used to assess hypnotic susceptibility for 28 subjects in order to match treatment groups according to sex and susceptibility scores. Tooth pulp stimulation consisted of a 1 sec train of 1 msec pulses at a frequency of 100 Hz, applied at 20 sec intervals to the central incisor. ⋯ Tooth pulp and cold pressor stimulation represent qualitatively different stimuli with respect to both the type of nerves activated and the mode of stimulus application. Discrete, randomly presented levels of noxious electrical stimulation to the teeth activate predominantly small fibers and produce brief pain sensations that vary unpredictably in intensity. In contrast, continuous cold stimulation to the forearm activates a variety of nociceptive and non-nociceptive fibers and produces progressive cold and pain sensations with a predictable increase in intensity from cold sensations to paresthesia and severe pain.
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Randomized Controlled Trial Clinical Trial
Regional sympathetic blockade in primary fibromyalgia.
Twenty-eight patients with primary fibromyalgia participated in the study. Eight patients received a stellate ganglion blockade with bupivacaine, and 14 days later an intravenous regional sympathetic blockade with guanethidine. The remaining patients served as controls and were randomly allocated to receive either a sham (placebo) injection with physiologic saline superficial to the stellate ganglion (n = 10) or bupivacaine intramuscularly (n = 10). ⋯ The guanethidine blockade reduced the number of TePs, but had no effect on rest pain. The reduction in pain and TePs produced by a sympathetic blockade may be due to an improvement in microcirculation. Sympathetic activity may, in some patients, contribute to the pathogenesis of primary fibromyalgia.
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These experiments quantitatively analyzed effects of electrical midbrain stimulation on a nociceptive hind limb flexion reflex in rats anesthetized with sodium pentobarbital. We recorded the force of isometric hind limb flexion withdrawal, and related flexor electromyographic (EMG) activity, elicited by noxious heat (42-54 degrees C, 10 sec) applied to the ventral hind paw. Several hind limb flexors including biceps femoris were active during the reflex. ⋯ Naloxone had little effect, while methysergide and phentolamine reduced PAG- and LRF-evoked reflex suppression in about one-half of the cases. Scopolamine largely reduced PAG- and LRF-evoked reflex suppression (in 8/9 and 4/6 rats, respectively). These results indicate that the flexion reflex is under parametrically but not pharmacologically distinct inhibitory midbrain controls.