Anesthesiology
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During spinal and epidural anesthesia, local anesthetics reach concentrations in cerebrospinal fluid and spinal cord tissues at which their actions may extend beyond the classic blockade of sodium channels. This study examines the effects of several clinical and experimental local anesthetics on the binding and actions of a peptide neurotransmitter, substance P, known to be important in nociceptive transmission in the dorsal horn. ⋯ Because millimolar concentrations of local anesthetics are within the range measured in spinal cord during intrathecal and epidural procedures, these results are consistent with a direct action of local anesthetics on tachykinin-mediated neurotransmission during regional anesthesia.
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Perturbation of neuronal calcium homeostasis may alter neurotransmission in the brain, a phenomenon postulated to characterize the anesthetic state. Because of the central role of plasma membrane Ca(2+)-ATPase (PMCA) in maintaining Ca2+ homeostasis, the authors examined the effect of several inhalational anesthetics on PMCA function in synaptic plasma membranes (SPM) prepared from rat brain. ⋯ Plasma membranes Ca(2+)-ATPase is significantly inhibited, in a dose-related manner, by clinically relevant partial pressures of halothane, isoflurane, xenon, and nitrous oxide. Furthermore, these anesthetics inhibit PMCA activity in accordance with their known potencies, and an additive effect was observed. How inhalational anesthetics inhibit the PMCA pump is not known at this time. It is noteworthy that the only shared characteristic of this group of agents of widely different structure is anesthetic action. The relevance of this dual commonality, anesthetic action and PMCA inhibition, to actual production of the anesthetic state remains to be determined.
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Randomized Controlled Trial Clinical Trial
The dose-response relationship of ondansetron in preventing postoperative emesis in pediatric patients undergoing ambulatory surgery.
Postoperative nausea and vomiting is a distressing anesthetic complication that may delay discharge after ambulatory surgery. Effective prophylaxis for postoperative nausea and vomiting can be achieved in adults with lower doses of ondansetron, a 5-hydroxytryptamine subtype 3 receptor antagonist, compared with chemotherapy-induced emesis. However, the doses of ondansetron used in preventing postoperative nausea and vomiting in children are based on data from chemotherapy-induced emesis. The dose-related efficacy of intravenous ondansetron in the prophylaxis of postoperative emesis in the pediatric outpatient population was determined. ⋯ Intravenous ondansetron in a dose of 50 micrograms/kg is as effective as larger doses for the prophylaxis of emesis in children undergoing surgical procedures known to be associated with an increased risk for postoperative nausea and vomiting.
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Randomized Controlled Trial Comparative Study Clinical Trial
Using alcohol as a standard to assess the degree of impairment induced by sedative and analgesic drugs used in ambulatory surgery.
There is a need for a standard by which to compare the degree of subjective and behavioral impairment caused by anesthetic drugs, because anesthesiologists may not be able to gauge how extreme or important a statistically significant change in psychomotor functioning is. This study examined the psychomotor and subjective effects of alcohol at blood concentrations equal or greater than 0.10% as a standard with which to compare those effects caused by sedative and analgesic agents commonly used in ambulatory surgery. ⋯ This study provides evidence that degree of impairment caused by sedative and analgesic drugs used in ambulatory surgery is similar to that obtained with a dose of alcohol that produces a blood alcohol concentration of 0.11%. We suggest that anesthesiologists can use alcohol as a standard by which to assess degree of impairment produced by drugs used for sedation/analgesia.