Anaesthesia
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General anaesthesia is associated with changes in connectivity between different regions of the brain, the assessment of which has the potential to provide a novel marker of anaesthetic effect. We propose an index that quantifies the strength and direction of information flow in electroencephalographic signals collected across the scalp, assess its performance in discriminating 'wakefulness' from 'anaesthesia', and compare it with estimated bispectral index and the auditory middle latency response. We used a step-wise slow induction of anaesthesia in 10 patients to assess graded changes in electroencephalographic directional connectivity at propofol effect-site concentrations of 2 μg.ml-1 , 3 μg.ml-1 and 4 μg.ml-1. ⋯ This then remained relatively constant as effect-site concentration increased, consistent with a step change in directed coherence with anaesthesia. This contrasted with the gradual change with increasing anaesthetic dose observed for estimated bispectral index and middle latency response. Directed coherence performed best in discriminating wakefulness from anaesthesia with an accuracy of 95%, indicating the potential of this new method (on its own or combined with others) for monitoring adequacy of anaesthesia.
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The primary objective of this quality improvement project was to measure and reduce the number of oxycodone immediate-release tablets dispensed to overnight stay surgical patients at discharge. The secondary objective was to reduce the proportion of inappropriate oxycodone immediate-release prescriptions at discharge. Interrupted time series analysis was performed in four surgical wards of St Vincent's Public Hospital, Sydney. ⋯ At the end of the first month of a fifth intervention, comprising audit-feedback plus individual academic detailing, the average number of oxycodone tablets decreased by 77 (95%CI 39-115) tablets/100 surgical cases, and the postintervention linear trend was a monthly reduction of 3.2 (coefficient -3.2 (95%CI -4.5 to -1.8); p = 0.001) tablets/100 surgical admissions. Baseline audit showed 27% of oxycodone prescriptions to be inappropriate. Following our intervention, this dropped to 17% (p = 0.048), and then to 10% (p = 0.002) after 3 years.