Pain
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We studied if ethnicity influences patient-controlled analgesia (PCA) for the treatment of post-operative pain. Using a retrospective record review, we examined data from all patients treated with PCA for post-operative pain from January to June 1993. We excluded patients who did not have surgery prior to the prescription of PCA or were not prescribed PCA in the immediate post-operative period. ⋯ While there were no differences in the amount of narcotic self-administered, there were significant differences in the amount of narcotic prescribed among Asians, Blacks, Hispanics, and Whites (F--7,352, P < 0.01). The ethnic differences in prescribed analgesic persisted after controlling for age, gender, pre-operative use of narcotics, pain site, and insurance status. Patient's ethnicity has a greater impact on the amount of narcotic prescribed by the physician than on the amount of narcotic self-administered by the patient.
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Heat pain threshold is commonly considered to be an 'absolute' value, which is not dependent on the area stimulated. In contrast, suprathreshold heat pain sensation has been shown to be highly dependent on the area stimulated, with considerable spatial summation demonstrated both within and between dermatomes. The present study sought to reevaluate two major issues: (a) Whether nociceptive thresholds are, indeed, independent of stimulation area. (b) Whether the spatial summation of suprathreshold heat pain sensation is independent of threshold changes. ⋯ Furthermore, when using a stimulus configuration in which stimulation area was increased without changing nociceptive threshold, no spatial summation of perceived pain intensity was seen. Our results suggest that the spatial summation of perceived heat pain intensity can be attributed to reduced heat pain threshold. Furthermore, our findings stress the importance of determining pain thresholds in studies examining the psychophysics of suprathreshold noxious stimuli.
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One of the physiological changes accompanying neuropathic pain from nerve injury is the spontaneous firing of primary afferent fibers. At least some of this activity is thought to arise from the dorsal root ganglion. We have investigated whether this activity is resident in the cell bodies of dorsal root ganglion neurons and if it is retained in vitro. ⋯ Spontaneous resting potential fluctuations (up to 10 m V peak-to-peak) occurred in both control and CCI neurons, and triggered the spontaneous, random action potentials in neurons from CCI rats. Spontaneously firing neurons exhibited more negative action potential threshold (-34.8 mV) when compared to quiescent neurons from ganglia either after CCI (-18.7 mV) or controls (-20.5 mV). These findings show that spontaneous action potential activity after CCI is a property residing in the cell bodies of dorsal root ganglion neurons and is amenable to more detailed analysis using such an in vitro system, allowing better understanding of the cellular changes underlying neuropathic pain from nerve injury.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of tenoxicam and bromazepan in the treatment of fibromyalgia: a randomized, double-blind, placebo-controlled trial.
Fibromyalgia is a painful syndrome of non-articular origin, predominantly involving muscles, and the commonest cause of chronic widespread musculoskeletal pain. The diversity of therapeutic programs for patients with fibromyalgia reflects both the lack of a known pathophysiology for this disorder and the low efficacy of the current therapies. We studied the efficacy of tenoxicam and bromazepan in the treatment of patients with fibromyalgia. ⋯ At the end of the trial, 17%, 10%, 12%, and 29% of the P, T, B, and TB patients, respectively, had clinical improvement. A statistically significant difference was found only between the T and TB groups. Our data indicate that treatment with tenoxicam + bromazepan can be effective for some patients with fibromyalgia, but the differences with the placebo group were neither clinically nor statistically significant.
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Accuracy and errors in judges' attempts to differentiate facial expressions that displayed genuine pain, no pain or were dissimulated (i.e., masked and exaggerated) were examined. Judges were informed that misrepresentations in the facial expressions were present and were asked to rate their confidence in classifying these expressions. Detailed, objective coding of the patients' facial reactions (e.g., brow lowering, mouth opening) were related to judges' decisions. ⋯ Judges consistently used rules of thumb based on specific facial cues when making judgments. Certain cues were effectively discriminative. Systematic training in the use of specific cues or the use of articulated decision rules may be helpful in improving judges' accuracy.