Anesthesiology
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Although experimental evidence indicates that preemptive intrathecal treatment with local anesthetics reduces postinjury neuronal hyperexcitability, clinical evidence indicates that preemptive treatments do not consistently reduce postoperative pain. The current study used experimental models of postinjury nociception, in which rats received subcutaneous or intraarticular injections of the irritant formalin, to evaluate the effects of peripheral inflammation, or the use of agents supplemental to anesthesia, as possible confounding influences on the effectiveness of preinjury and postinjury intrathecal local anesthetic treatments. ⋯ The current results attest to the important effects of ongoing inputs from inflamed tissue, and the use of supplemental treatments, as important confounding factors that may influence the effectiveness of preemptive spinal anesthesia for postoperative pain.
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Randomized Controlled Trial Clinical Trial
Parental presence during induction of anesthesia. A randomized controlled trial.
To determine whether parental presence during induction of anesthesia is an effective preoperative behavioral intervention, a randomized controlled trial with children undergoing outpatient surgery was conducted. ⋯ Children who were older than 4 yr or those with a parent with a low trait anxiety or who had a low baseline level of activity/temperament benefited from parental presence during induction.
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Randomized Controlled Trial Clinical Trial
Enzymatic versus pharmacologic antagonism of profound mivacurium- induced neuromuscular blockade.
Mivacurium, a nondepolarizing muscle relaxant, is hydrolyzed by butyrylcholinesterase. The use of butyrylcholinesterase for antagonism of profound mivacurium-induced blockade has not been studied in humans. In part 1 of this two-part study, the authors examined the relationship between the posttetanic count (PTC) and recovery from profound mivacurium-induced blockade. In part 2, an attempt was made to antagonize a quantified level of profound mivacurium-induced blockade using either butyrylcholinesterase, edrophonium, or neostigmine. ⋯ There appears to be no clinical advantage in attempting to antagonize profound mivacurium-induced neuromuscular blockade.
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Postoperative pain relief may be improved by reducing sensitization of nociceptive pathways caused by surgical trauma. Such a reduction may depend on the timing and efficacy of analgesia and the duration of the nociceptive block versus the duration of the nociceptive input. We examined whether a prolonged nerve block administered before a superficial burn injury could reduce local inflammation and late hyperalgesia after recovery from the block. ⋯ These data suggest that a prolonged, preemptive nerve block reduced late hyperalgesia after thermal injury, whereas the erythema and blister formation were not significantly affected.
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Glycine and gamma-aminobutyric acid (GABA) are inhibitory neurotransmitters that appear to be important in sensory processing in the spinal dorsal horn. Intrathecal administration of strychnine (strychnine-sensitive glycine receptor antagonist) or bicuculline (GABAA antagonist) was reported to induce allodynia. Although the strychnine-induced allodynia was shown to be mediated through the N-methyl-D-aspartate (NMDA)-type glutamate receptor, it is not clear whether the bicuculline-evoked-allodynia is mediated through the glutamate receptor system or how different the allodynia induced by strychnine and bicuculline are. ⋯ These results demonstrate that both strychnine- and bicuculline-evoked allodynia were mediated through pathways that include the glutamate receptor and nitric oxide systems but in a different manner. the current study suggests that GABA and glycine may modulate responses to an innocuous tactile stimulus as inhibitory neurotransmitters at presynaptic and postsynaptic sites in the spinal cord, respectively.