Anesthesiology
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Descending influences from the rostral medial medulla (RMM) contribute to secondary hyperalgesia in persistent inflammatory, neuropathic, and visceral pain models. The current study examined if descending inhibition or facilitation from the RMM modulates primary and secondary hyperalgesia after incision in the rat hind limb. ⋯ Primary and secondary hyperalgesia after an incision were not modulated by descending influence from the RMM. The lack of contribution of descending facilitatory influences from the RMM to secondary hyperalgesia after gastrocnemius incision supports the notion that incision-induced pain involves dissimilar mechanisms compared with inflammatory and neuropathic pain.
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The authors determined the influence of cuff volume and anatomic location on pharyngeal, esophageal, and tracheal mucosal pressures for the esophageal tracheal combitube. ⋯ We conclude that mucosal pressures for the esophageal tracheal combitube increase with cuff volume, are highest where the cuff is adjacent to rigid anatomic structures, and potentially exceed mucosal perfusion pressure even when cuff volumes are limited to achieving an oropharyngeal seal of 30 cm H2O.
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Task analysis may be useful for assessing how anesthesiologists alter their behavior in response to different clinical situations. In this study, the authors examined the intraobserver and interobserver reliability of an established task analysis methodology. ⋯ A task analysis technique used in anesthesia research for several decades showed good intrarater reliability. Off-line analysis of videotapes is a viable alternative to real-time data collection. Acceptable interrater reliability requires the use of strict task definitions, sophisticated software, and rigorous observer training. New techniques must be developed to more accurately capture multitasking. Substantial effort is required to conduct task analyses that will have sufficient reliability for purposes of research or clinical evaluation.
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This study tests the hypothesis that loss of spinal activity of gamma-aminobutyric acid (GABA) contributes to the allodynia and hyperalgesia observed after peripheral nerve injury. ⋯ Pharmacologic inhibition of intrinsic GABA tone in normal rats resulted in tactile allodynia and thermal hyperalgesia, consistent with the hypothesis being tested. Exogenous administration of GABA agonists reversed spinal nerve ligation-induced allodynia and hyperalgesia, also consistent with this hypothesis. Isoguvacine produced specific antihyperalgesic and antiallodynic effects, whereas assessment of the effects of baclofen was complicated by motor dysfunction. Spinal GABAA agonists may provide a specific therapy for neuropathic pain.
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Production of retrograde amnesia by anesthetics would indicate that these drugs can disrupt mechanisms that stabilize memory. Such disruption would allow suppression of memory of previous untoward events. The authors examined whether isoflurane provides retrograde amnesia for classic (Pavlovian) fear conditioning. ⋯ Isoflurane provided intense dose-dependent anterograde but not retrograde amnesia for classic fear conditioning. Isoflurane appears to disrupt memory processes that occur at or within a few minutes of the conditioning procedure.