Pain
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Randomized Controlled Trial Clinical Trial
Magnesium Bier's block for treatment of chronic limb pain: a randomised, double-blind, cross-over study.
Magnesium is a physiological antagonist of both calcium and the NMDA receptor. Patients with chronic pain of a limb (>1 month's duration) were treated with two Bier's blocks (250 mmHg, 10 m) in a randomised, double-blind, cross-over design. They received once 20% magnesium sulphate (500 mg) + lignocaine 1% (75 mg), and once physiological saline + lignocaine 1% (75 mg). ⋯ For patients with chronic limb pain, the addition of magnesium to a Bier's block with lignocaine improves and prolongs pain relief and reduces the number of treatment failures. The optimal dose of lignocaine to prevent magnesium-induced aching of the treated limb needs to be established. Bier's block with magnesium-lignocaine may provide a possible treatment alternative in these patients.
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Randomized Controlled Trial Comparative Study Clinical Trial
Postsurgical pain outcome assessment.
Reliable and valid measures of pain are essential for conducting clinical trials of pain treatments. Perhaps the most important aspect of a pain measure's validity is its sensitivity, or ability to detect changes in pain over time and due to treatment. Several factors may affect a measure's sensitivity, including the complexity of the rating task for the measure, the number of pain intensity levels assessed by the measure, the dimension of pain assessed (e.g. pain intensity vs. pain relief), and the number of individual ratings (e.g. single rating vs. composite score) used to create the measure. ⋯ However, contrary to our prediction, a composite measure of outcome made up of all three measures was not consistently superior to the individual measures for detecting treatment effects. Finally, we found that pain relief ratings were related to, but also distinct from, change in pain intensity as measured by changes in pain intensity ratings from baseline to each postmedication assessment point. These findings have important implications for the assessment of pain in clinical trials.
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Randomized Controlled Trial Clinical Trial
Blinding effectiveness and association of pretreatment expectations with pain improvement in a double-blind randomized controlled trial.
Patient, provider, and clinical investigator expectations concerning treatments are believed to play important roles in patient response. This study examined the association of patient and research nurse/physician pretreatment expectations of pain relief with actual pain relief, the accuracy of patient and research nurse guesses about patient medication assignment, and changes in research nurse and patient pain relief expectations over the course of a randomized double-blind trial of amitriptyline versus an active placebo for patients with chronic pain and spinal cord injuries (SCI). Patient expectations of pain relief with amitriptyline were associated significantly with actual pain decrease for patients in the amitriptyline, but not placebo, condition. ⋯ The research nurse's, but not the patients', expectations of pain relief with amitriptyline decreased significantly over the course of the study. These findings have implications for future randomized controlled trials. Fully double-blind conditions are very difficult to achieve, and it is informative to assess patient and research clinician expectations and guesses regarding medication assignment.
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The non-communicating children's pain checklist (NCCPC) has displayed preliminary validity and reliability for measuring pain in children with severe cognitive impairments (Dev Med Child Neurol 42 (2000) 609). This study provides evidence of the psychometric properties of a revised NCCPC (NCCPC-R) with a larger cohort of children. Caregivers of 71 children with severe cognitive impairments (aged 3-18) conducted observations of their children using the NCCPC-R during a time of pain and a time without pain. ⋯ Analyses of children's individual scores indicated up to 95% of their scores were consistent. Receiver operating characteristic curves suggest a score of 7 or greater on the NCCPC-R as indicative of pain in children with cognitive impairments, with 84% sensitivity and up to 77% specificity. These results provide evidence of NCCPC-R having excellent psychometric properties.
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We developed a mouse model of neuropathic cancer pain by inoculating Meth A sarcoma cells to the immediate proximity of the sciatic nerve in BALB/c mice. The tumor grows predictably with time and gradually compresses the nerve, thereby causing nerve injury. Time courses of thermal hyperalgesia and mechanical sensitivity to von Frey hairs were determined and signs of spontaneous pain were evaluated. ⋯ In the CCI mice, severe damage to myelinated fibers, especially large fibers, was observed and unmyelinated fibers were damaged to a lesser degree. These results suggest that gradual compression of a nerve by a malignant tumor results in nerve damage with a profile considerably different from that of chronic constriction injury produced by loose ligation of the nerve. Our new tumor model may be useful in studies of neuropathic cancer pain due to nerve compression by malignant tumors.