British journal of anaesthesia
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Randomized Controlled Trial Comparative Study
Teaching airway management to novices: a simulator manikin study comparing the 'sniffing position' and 'win with the chin' analogies.
The 'sniffing position' is widely promoted for teaching airway positioning before intubation, but whether this analogy results in novices placing the head and neck appropriately has not been evaluated. We compared performance following the sniffing position instructions with an alternate analogy, 'win with the chin'. We also compared performance following simple anatomic instructions and no instructions. ⋯ The 'win with the chin' analogy resulted in adequate airway positioning significantly more often than the 'sniffing position' or control. It also maintained atlanto-occipital extension compared with anatomic instructions. Overall, 'win with the chin' was a superior teaching analogy and could replace the 'sniffing position' analogy.
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In experimental trials, ketamine has been shown to reduce hyperalgesia, prevent opioid tolerance, and lower morphine consumption. Clinical trials have found contradictory results. We performed a review of randomized, double-blinded clinical trials of ketamine added to opioid in i.v. patient-controlled analgesia (PCA) for postoperative pain in order to clarify this controversy. ⋯ The benefit of adding ketamine to morphine in i.v. PCA for orthopaedic or abdominal surgery remains unclear. Owing to huge heterogeneity of studies and small sample sizes, larger double-blinded randomized studies showing greater degree of homogeneity are required to confirm these findings.
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Controlled Clinical Trial
Effect of body mass index on the ED50 volume of bupivacaine 0.5% for supraclavicular brachial plexus block.
The aim of this study was to determine whether the ED(50) dose of bupivacaine 0.5% for supraclavicular brachial plexus block increases with increasing body mass index (BMI). ⋯ Our study demonstrates that the ED(50) of bupivacaine 0.5% does not increase with an increase in BMI. We found evidence of a possible inverse relationship between ED(50) and BMI.
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The steep (40 degrees ) Trendelenburg position optimizes surgical exposure during robotic prostatectomy. The goal of the current study was to investigate the combined effect of this position and CO(2) pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during these procedures. ⋯ The combination of the prolonged steep Trendelenburg position and CO(2) pneumoperitoneum was well tolerated. Haemodynamic and pulmonary variables remained within safe limits. Regional cerebral oxygenation was well preserved and CPP remained within the limits between which cerebral blood flow is usually considered to be maintained by cerebral autoregulation.
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Propofol is an i.v. anaesthetic commonly used during general anaesthesia and intensive care. It is known that the second transmembrane segment of the beta subunit in the GABA(A) receptor is an important target for the effects of propofol; however, this has not been investigated in human receptors. The aim of this study was to investigate the effect of propofol on human beta2 and beta3 GABA(A) subunits with point mutations corresponding to the N265M mutation in the rat beta2 and beta3 subunits. ⋯ We demonstrate that N289M or N290M mutation in human GABA(A) beta2 and beta3 subunits increases sensitivity to GABA, which is in contrast to the corresponding rat N265M mutation. Furthermore, the N289M and N289M mutations reduce both the potentiation of GABA-induced currents and the direct effect of propofol on channels incorporating either of the mutated subunits, which confirms earlier findings concerning the corresponding mutation in rat receptors and knock-in mice.