Pain
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Although adequate assessment of pain and anxiety during burn wound care serves important clinical and scientific goals (e.g., determination of medication dosage and evaluation of treatment effects), few data are actually available. Studies which compare self-reported pain with observational ratings frequently suffer from small sample sizes or questionable data analysis techniques. This paper presents a study in which 126 burn wound dressing changes were independently rated by patient and nurse(s). ⋯ It is argued that it is not useful to discuss the present and earlier studies only in terms of correctness or incorrectness of observational ratings. Recommendations for future studies include the study of pain-related behaviors, coping mechanisms and effects of treatments. Considering the vast differences in prescription regimes among centers, a multicenter trial would be particularly interesting.
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Forty patients with cancer pain receiving intermittent narcotics were admitted to a prospective study designed to assess the cognitive effects of narcotics. Twenty patients had undergone no change in narcotic dose or type greater than or equal to 7 days (stable dose, SD, group), and 20 patients had undergone an increase of greater than or equal to 30% in dose less than or equal to 3 days before (increased dose, ID, group). Age, primary tumor, type, dose and route of narcotic were not different between the SD and ID group. ⋯ Mean percentual change in FT 10 sec, FT 30 sec, A, RM, and VM after the narcotic dose were 97 +/- 9%, 100 +/- 14%, 100 +/- 13%, 100 +/- 15%, 98 +/- 19%, in the SD group, vs. 77 +/- 14% (P less than 0.001), 83 +/- 13% (P less than 0.001), 124 +/- 21% (P less than 0.001), 60 +/- 21% (P less than 0.001) and 68 +/- 21% (P less than 0.001) in the ID group, respectively. Our results suggest that patients who undergo a significant increase in the dose of intermittent narcotics experience significant cognitive impairment, that disappears after 1 week of the increase. More research is needed to better characterize the cognitive toxicity of intermittent narcotics, and to determine the cognitive effects of long acting narcotics, continuous infusions, or of the addition of amphetamines.
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We report the results of a single session, non-blinded, trial of topical application of 10% lidocaine in gel form to the painful skin of 11 patients with well established post-herpetic neuralgia (PHN). Pain decreased as measured by 100 mm VAS pain scale and 100 mm VAS pain relief scale in both trigeminal and thoracic PHN patients.
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Changes in thermal sensibility for warmth, cold, heat pain and cold pain during nerve compression block of impulse conduction in myelinated fibres were studied in 20 healthy subjects. When mainly unmyelinated fibres were conducting, after 30-36 min of nerve compression, the pain threshold, induced by cold stimulation, was shifted towards higher temperatures (from 19.1 degrees C to 22.8 degrees C, mean values). Furthermore, the sensation of cold pain became more unpleasant and had a hot burning rather than a cold quality. ⋯ Whereas dramatic changes in the sensation of cold pain were observed during the course of nerve compression, no alteration in heat pain threshold was seen. This implies that heat pain threshold in hairy skin is due to activation of C nociceptor fibres without any significant contribution from myelinated nociceptor fibres. Furthermore, no gating from heat-sensitive myelinated fibre input was evident on heat pain threshold.
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A modified formalin test in mice was investigated. The pain response curve induced by 0.5% formalin was biphasic, having 2 peaks, from 0 to 5 min (first phase) and from 15 to 20 min (second phase). A low concentration of formalin was used, allowing the effects of weak analgesics to be detected. ⋯ The second phase was inhibited by compound 48/80 pretreatment, indomethacin and bradykinin inhibitor. Therefore, it is suggested that substance P and bradykinin participate in the manifestation of the first phase response, and histamine, serotonin, prostaglandin and bradykinin are involved in the second phase. These results indicate that the first and second phase responses induced by formalin have distinct characteristic properties, and it is a very useful method for examining pain, nociception and its modulation by pharmacological or other means.