British journal of anaesthesia
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Randomized Controlled Trial Comparative Study
Thoracic epidural analgesia in post-thoracotomy patients: comparison of three different concentrations of levobupivacaine and sufentanil.
Relative effects of dosage, volume and concentration of local anaesthetics used for postoperative thoracic epidural analgesia are still under debate. In this randomized, prospective, double-blinded study, we evaluated the incidence of side-effects such as changes in arterial pressure, postoperative nausea, vomiting, and pruritus in patients admitted for thoracic surgery during continuous thoracic epidural infusion using levobupivacaine and sufentanil mixture in three different volumes. ⋯ The same dose of a mixture of levobupivacaine and sufentanil administered in three different volumes and concentrations during continuous thoracic epidural infusion for thoracotomy provided an equal incidence of adverse haemodynamic effects, nausea, vomiting, or pruritus.
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Review Meta Analysis Comparative Study
Ultrasound guidance compared with electrical neurostimulation for peripheral nerve block: a systematic review and meta-analysis of randomized controlled trials.
Despite the growing interest in the use of ultrasound (US) imaging to guide performance of regional anaesthetic procedures such as peripheral nerve blocks, controversy still exists as to whether US is superior to previously developed nerve localization techniques such as the use of a peripheral nerve stimulator (PNS). We sought to clarify this issue by performing a systematic review and meta-analysis of all randomized controlled trials that have compared these two methods of nerve localization. ⋯ US improves efficacy of peripheral nerve block compared with techniques that utilize PNS for nerve localization. Larger studies are needed to determine whether or not the use of US can decrease the number of complications such as nerve injury or systemic local anaesthetic toxicity.
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Randomized Controlled Trial
Advance of age decreases the minimum alveolar concentrations of isoflurane and sevoflurane for maintaining bispectral index below 50.
We investigated age-related differences in the minimum alveolar concentration (MAC) of isoflurane and sevoflurane for maintaining bispectral index (BIS) below 50 (MAC(BIS50)). ⋯ Advance in age significantly decreased the concentrations of isoflurane and sevoflurane required to maintain BIS below 50. BIS correctly reflected age-associated decrease of end-tidal concentrations of isoflurane and sevoflurane required for maintaining adequate depth of anaesthesia during resting state.
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Inhaled anaesthetics (IAs) produce multiple dose-dependent behavioural effects including amnesia, hypnosis, and immobility in response to painful stimuli that are mediated by distinct anatomical, cellular, and molecular mechanisms. Amnesia is produced at lower anaesthetic concentrations compared with hypnosis or immobility. Nicotinic acetylcholine receptors (nAChRs) modulate hippocampal neural network correlates of memory and are highly sensitive to IAs. Activation of hippocampal nAChRs stimulates the release of norepinephrine (NE), a neurotransmitter implicated in modulating hippocampal synaptic plasticity. We tested the hypothesis that IAs disrupt hippocampal synaptic mechanisms critical to memory by determining the effects of isoflurane on NE release from hippocampal nerve terminals. ⋯ Inhibition of hippocampal nAChR-dependent NE release by subanaesthetic concentrations of isoflurane supports a role in IA-induced amnesia.
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Recent studies suggest that implicit memory (especially perceptual implicit memory) persists during adequate general anaesthesia in adults. Studies in children, however, have failed to demonstrate implicit memory during general anaesthesia, possibly because of differences in methodological design. We therefore designed a prospective study with the aim of evaluating implicit memory in children undergoing general anaesthesia, using a perceptual memory test based on the mere exposure effect, previously tested in a control group. ⋯ The use of a perceptual implicit memory test based on the mere exposure procedure in children failed to reveal any evidence of implicit memory under general anaesthesia.