Anesthesiology
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Randomized Controlled Trial
Morphine versus mexiletine for treatment of postamputation pain: a randomized, placebo-controlled, crossover trial.
Stump and phantom pains are debilitating sequelae of amputations that are often resistant to treatment. The efficacy of pharmacologic therapies, including opioids and sodium channel blockers, for postamputation pain is uncertain. ⋯ Therapy with morphine, but not mexiletine, resulted in a decrease in intensity of postamputation pain but was associated with a higher rate of side effects and no improvement in self-reported levels of overall functional activity and pain-related interference in daily activities.
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Randomized Controlled Trial
Low-dose propofol-induced amnesia is not due to a failure of encoding: left inferior prefrontal cortex is still active.
Propofol may produce amnesia by affecting encoding. The hypothesis that propofol weakens encoding was tested by measuring regional cerebral blood flow during verbal encoding. ⋯ If the amnesic effect of propofol were solely due to effects on encoding, activation in the LIPFC should be minimal. Because LIPFC activation was not totally eliminated by propofol, the amnesic action of propofol must be present in other brain regions and/or affect other memory processes.
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The authors hypothesized that inhalational anesthetics induced cell damage by causing abnormal calcium release from the endoplasmic reticulum via excessive activation of inositol 1,4,5-trisphosphate (IP3) receptors, with isoflurane having greater potency than sevoflurane or desflurane. ⋯ Inhalational anesthetics may induce cell damage by causing abnormal calcium release from the endoplasmic reticulum via excessive activation of IP3 receptors. Isoflurane has greater potency than sevoflurane or desflurane to cause calcium release from the endoplasmic reticulum and to induce cell damage.
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Regional anesthesia and analgesia attenuate or prevent perioperative factors that favor minimal residual disease after removal of the primary carcinoma. Therefore, the authors evaluated prostate cancer recurrence in patients who received either general anesthesia with epidural anesthesia/analgesia or general anesthesia with postoperative opioid analgesia. ⋯ Open prostatectomy surgery with general anesthesia, substituting epidural analgesia for postoperative opioids, was associated with substantially less risk of biochemical cancer recurrence. Prospective randomized trials to evaluate this association seem warranted.
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Intraoperative remifentanil infusions have been associated with postoperative opioid-induced hyperalgesia and tolerance. Using a previously identified subpopulation of spinal neurons that displays an augmentation in N-methyl-D-aspartate (NMDA) receptor current after chronic morphine, investigations were undertaken to determine whether remifentanil induces acute increases in NMDA responses that are concentration dependent and receptor subtype dependent. ⋯ Clinically relevant concentrations of remifentanil induce rapid, persistent increases in NMDA responses that mirror the development of remifentanil-induced hyperalgesia and tolerance. NMDA enhancement by remifentanil is dependent on the activation of both mu- and delta-opioid receptors and is inducible solely by delta-opioid receptor activation. Therefore, selective delta-opioid inhibition may attenuate acute paradoxical increases in pain and tolerance to opioids.