British journal of anaesthesia
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General anaesthetics have marked effects on synaptic transmission, but their neuronal and circuit-level effects remain unclear. The volatile anaesthetic isoflurane differentially inhibits synaptic vesicle exocytosis in specific neuronal subtypes, but whether other common anaesthetics also have neurone-subtype-specific actions is unknown. ⋯ Anaesthetic-agent-selective effects on presynaptic Ca2+ entry have functional implications for hippocampal circuit function during i.v. or volatile anaesthetic-mediated anaesthesia. Hippocampal interneurones have distinct subtype-specific sensitivities to volatile anaesthetic actions on presynaptic Ca2+, which are similar between isoflurane and sevoflurane.
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Current or recent infection with SARS-CoV-2 increases the risk of perioperative morbidity and mortality. Consensus guidelines recommend delaying elective major surgery after acute SARS-CoV-2 infection for 7 or 8 weeks. However, because of the growing backlog of untreated surgical disease and the potential risks of delaying surgery, surgical services may be under pressure to reduce this period. Here, we discuss the risks and benefits of delaying surgery for patients with current or recent SARS-CoV-2 infection in the context of the evolving COVID-19 pandemic, the limited evidence supporting delays to surgery, and the need for more research in this area.
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Optimal respiratory support in early COVID-19 pneumonia is controversial and remains unclear. Using computational modelling, we examined whether lung injury might be exacerbated in early COVID-19 by assessing the impact of conventional oxygen therapy (COT), high-flow nasal oxygen therapy (HFNOT), continuous positive airway pressure (CPAP), and noninvasive ventilation (NIV). ⋯ The failure of noninvasive ventilatory support to reduce respiratory effort may exacerbate pulmonary injury in patients with early COVID-19 pneumonia. HFNOT reduces lung strain and achieves similar oxygenation to CPAP/NIV. Invasive mechanical ventilation may be less injurious than noninvasive support in patients with high respiratory effort.