Pain
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Review Comparative Study
Ketamine and postoperative pain--a quantitative systematic review of randomised trials.
Ketamine, an N-methyl-D-aspartate receptor antagonist, is known to be analgesic and to induce psychomimetic effects. Benefits and risks of ketamine for the control of postoperative pain are not well understood. We systematically searched for randomised comparisons of ketamine with inactive controls in surgical patients, reporting on pain outcomes, opioid sparing, and adverse effects. ⋯ The highest risk of hallucinations was in awake or sedated patients receiving ketamine without benzodiazepine; compared with controls, the odds ratio (OR) was 2.32 (95%CI, 1.09-4.92), number-needed-to-harm (NNH) 21. In patients undergoing general anaesthesia, the incidence of hallucinations was low and independent of benzodiazepine premedication; OR 1.49 (95%CI 0.18-12.6), NNH 286. Despite many published randomised trials, the role of ketamine, as a component of perioperative analgesia, remains unclear.
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A hallmark symptom of irritable bowel syndrome (IBS) is a lower pain threshold during rectal distension, but the mechanism underlying this disorder remains unclear. Examining the relationship between physiological and perceptual responses to rectal distension can provide insight into the underlying peripheral or central dysfunction in IBS. Therefore, we carried out a study of the rectal sensations of urge to defecate, pain and unpleasantness in relation to the varying states of the rectum. ⋯ Abnormalities in IBS patients included: (1) higher incidence of distensions where unpleasantness is greater than pain intensity, (2) significantly longer persistence of ratings after stimulus termination during phasic distensions eliciting either moderate urge or moderate pain, (3) significantly smaller ratings fluctuations during tonic distensions, and (4) significantly higher MPQ scores for painful tonic distensions. Our study demonstrates that IBS patients have abnormal temporal and intensity properties of rectal sensation. These can be accounted for by either altered peripheral neuromuscular processing and/or processing of ascending rectal input in the central nervous system.
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Comparative Study
The development and preliminary validation of a brief measure of chronic pain impact for use in the general population.
From a biopsychosocial perspective, assessing chronic pain's psychological impact should involve at minimum the measurement of pain severity, functional interference, and pain-related emotional burden. This article details the development of a brief instrument, the 15-item Profile of Chronic Pain: Screen (PCP:S), designed to address these three key elements in a national (US) sample of over 2400 individuals recruited via random digit dialing. Retest reliability, internal consistency, and preliminary validity were excellent. ⋯ A series of confirmatory factor analyses on several distinct samples revealed a stable, 3-factor solution reflecting pain severity, interference, and emotional burden. Finally, national norms were developed by gender and three age groups. In view of its strong psychometric properties, the PCP:S has the potential to serve as a brief, cost-effective assessment tool for identifying individuals whose chronic pain merits more detailed psychosocial evaluation.
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Comparative Study
Parent-child interactions among children with juvenile fibromyalgia, arthritis, and healthy controls.
Parent-child interactions during pain-inducing exercise tasks among children (11-17 years old) with fibromyalgia, juvenile rheumatoid arthritis, and pain-free controls were examined and the contribution of parent-child interactions to disability was tested. Fifteen children in each of the three diagnostic groups and their parents completed 5-min exercise tasks and completed questionnaire measures of disability (Functional Disability Inventory) and coping (Pain Coping Questionnaire). There were few group differences in parent-child interactions. ⋯ Across the groups, more pain and less time on task during the exercises were related to Functional Disability Inventory scores and more school absences. Parent-child interaction patterns influence children's adaptation to pain during experimental tasks. Parents' discouragement of coping in response to their children's negative statements related to the pain or the pain-evoking task are counter productive to children's ability to maintain activity in a mildly painful situation.
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Comparative Study Clinical Trial
Gender differences in pain modulation evoked by repeated injections of glutamate into the human trapezius muscle.
Gender differences in pain habituation, temporal summation, and pressure hyperalgesia evoked by repeated injections of glutamate into the dominant trapezius muscle were investigated. The glutamate-evoked muscle pain intensity and pressure pain threshold (PPT) were assessed. The PPTs were measured bilaterally in the trapezius muscles (local pain area) and posterolateral neck muscles (referred pain area) after glutamate injection in healthy and age-matched males and females (each n=14). ⋯ No PPTs changes were observed either in the contralateral trapezius muscle or bilaterally in the referred pain areas in either sex. These results suggest that a less efficient pain habituation and a greater susceptibility to the development of temporal summation of muscle pain in females, but not in males, might be one of the contributing factors to the higher incidence of neck shoulder pain in females. In addition, the reduction of PPTs in the local pain area evoked by intramuscular glutamate injection may represent an early process of peripheral pressure hyperalgesia, which is most likely gender independent.