Anesthesiology
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The use of opioids to treat pain is often limited by side effects mediated through the central nervous system. The current study used a recombinant herpes simplex virus type 1 to increase expression of the mu-opioid receptor (muOR) in primary afferent neurons. The goal of this strategy was to enhance peripheral opioid analgesia. ⋯ This gene therapy approach may provide an innovative strategy to enhance peripheral opioid analgesia for the treatment of pain in humans, thereby minimizing centrally mediated opioid side effects such as sedation and addiction.
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Vascular dysfunction induced by hyperglycemia has not been studied in cerebral parenchymal circulation. The current study was designed to examine whether high glucose impairs dilation of cerebral parenchymal arterioles via nitric oxide synthase, and whether propofol recovers this vasodilation by reducing superoxide levels in the brain. ⋯ Clinically relevant concentrations of propofol ameliorate neuronal nitric oxide synthase-dependent dilation impaired by high glucose in the cerebral parenchymal arterioles via the effect on superoxide levels. Propofol may be protective against cerebral microvascular malfunction resulting from oxidative stress by acute hyperglycemia.
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Randomized Controlled Trial Multicenter Study
A randomized, double-masked, multicenter comparison of the safety of continuous intrathecal labor analgesia using a 28-gauge catheter versus continuous epidural labor analgesia.
Continuous intrathecal labor analgesia produces rapid analgesia or anesthesia and allows substantial flexibility in medication choice. The US Food and Drug Administration, in 1992, removed intrathecal microcatheters (27-32 gauge) from clinical use after reports of neurologic injury in nonobstetric patients. This study examined the safety and efficacy of a 28-gauge intrathecal catheter for labor analgesia in a prospective, randomized, multicenter trial. ⋯ Providing intrathecal labor analgesia with sufentanil and bupivacaine via a 28-gauge catheter has an incidence of neurologic complication less than 1%, and produces better initial pain relief and higher maternal satisfaction, but is associated with more technical difficulties and catheter failures compared with epidural analgesia.
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Dexmedetomidine reduces cerebral blood flow (CBF) in humans and animals. In animal investigations, cerebral metabolic rate (CMR) was unchanged. Therefore, the authors hypothesized that dexmedetomidine would cause a decrease in the CBF/CMR ratio with even further reduction by superimposed hyperventilation. This reduction might be deleterious in patients with neurologic injuries. ⋯ The predicted decrease in CBFV/CMRe ratio was not observed because of an unanticipated reduction of CMRe and a decrease in the slope of the Paco2-CBFV relation. CBFV and Bispectral Index increases during arousal for hyperventilation at 1.2 ng/ml suggest that CMR-CBF coupling is preserved during dexmedetomidine administration. Further evaluation of dexmedetomidine in patients with neurologic injuries seems justified.