Anesthesiology
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Randomized Controlled Trial Comparative Study
Analgesic efficacy of peripheral kappa-opioid receptor agonist CR665 compared to oxycodone in a multi-modal, multi-tissue experimental human pain model: selective effect on visceral pain.
Peripherally selective opioids may be beneficial in visceral pain management due to absence of centrally mediated side effects. The objectives of this study were: (1) to assess the effects of a peripherally selective tetrapeptide kappa-opioid receptor agonist, CR665, on experimental pain from multi-modal stimulation of skin, muscle, and viscera, and (2) contrast these effects with those of oxycodone (centrally acting opioid). ⋯ CR665 had a selective effect on visceral pain. Oxycodone exhibited a generalized effect, elevating thresholds for cutaneous, deep somatic, and visceral pain stimulation.
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Randomized Controlled Trial Comparative Study
Preserved memory function during bispectral index-guided anesthesia with sevoflurane for major orthopedic surgery.
Memory function under anesthesia is undesired but may arise from light hypnosis as well as stress-enhanced learning during surgery. The bispectral index (BIS, Aspect Medical Systems, Norwood, MA) is a monitor of hypnotic state that can help to avoid light hypnosis (i.e., BIS above 60). This study tested the hypothesis that BIS-guided anesthesia maintaining BIS 50-60 reduces the likelihood of memory function under anesthesia. ⋯ BIS titration to BIS 50-60 does not necessarily curb memory function under anesthesia when BIS values higher than 60 occur. Preoperative analgesia attenuated the likelihood of memory function under anesthesia.
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BACKGROUNDPostoperative pain Is an independent predictor of postoperative delirium. Whether postoperative delirium limits patient-controlled analgesia (PCA) use has not been determined. ⋯ Postoperative delirium did not limit PCA use. Despite more opioid use, visual analog scale scores were higher in patients with delirium. Future studies on delirium should consider the role of pain and pain management as potential etiologic factors.
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Obtaining accurate end-tidal carbon dioxide pressure measurements via nasal cannula poses difficulties in postanesthesia patients who are mouth breathers, including those who are obese and those with obstructive sleep apnea (OSA); a nasal cannula with an oral guide may improve measurement accuracy in these patients. The authors evaluated the accuracy of a mainstream capnometer with an oral guide nasal cannula and a sidestream capnometer with a nasal cannula that did or did not incorporate an oral guide in spontaneously breathing non-obese patients and obese patients with and without OSA during recovery from general anesthesia. ⋯ Mainstream capnometry performed best, and an oral guide improved the performance of sidestream capnometry. Accuracy in non-obese and obese patients, with and without OSA, was similar.
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Traditional methods for approaching the lumbar plexus from the posterior rely on finding the intersection of lines that are drawn based on surface landmarks. These methods may be inaccurate in many cases. The aim of this study was to determine the accuracy of these traditional approaches and determine if modifications could increase their accuracy. ⋯ Improvement of both the proximity and the margin of error is possible by using diagonal landmark vectors. Relying on the position of the posterior superior iliac spine eliminates the sex and sided differences and individual body size, which can be problematic if firm metric distances are used in determining the entry point.