Anaesthesia
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We performed a prospective, randomised study to evaluate the echogenicity of 11 regional block needles when inserted into a gel phantom at 45° in the ultrasound plane. Two hundred anaesthetists viewed in random sequence recordings of each needle as it was advanced into the phantom. ⋯ The mean (95% CI) echogenicity score was 1.7 (1.4-2.0) units higher for three needles marketed as 'hyperechoic' compared with standard needles marketed by the same companies, p < 0.001. The odds ratios (95% CI) that an anaesthetist would categorise a needle as hyperechoic were: 5.3 (3.6-8.0) if the needle was marketed as hyperechoic, p < 0.001; and 1.7 (1.1-2.6) if regional anaesthetic experience was ≥ 1 year compared with < 1 year, p = 0.025.
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Three quarters of all critical incidents and a third of all peri-operative cardiac arrests in paediatric anaesthesia are caused by adverse respiratory events. We screened for risk factors from children's and their families' histories, and assessed the usefulness of common markers of allergic sensitisation of the airway as surrogates for airway inflammation and increased risk for adverse respiratory events. One hundred children aged up to 16 years with two or more risk factors undergoing elective surgery were included in the study. ⋯ There was a significant difference (p = 0.001) between the presence of adverse respiratory events in patients with more than four (p = 0.006), compared with less than four (p = 0.001), risk factors. We conclude that while risk factors taken from the child's (or family) history proved good predictors of adverse respiratory events, immunological markers of allergic sensitisation demonstrated low predictive values. Pre-operative identification of children at high risk for an adverse respiratory event should rely on clinical, rather than immunological, assessment.
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Preconditioning has been shown to reduce myocardial damage caused by ischaemia-reperfusion injury peri-operatively. Volatile anaesthetic agents have the potential to provide myocardial protection by anaesthetic preconditioning and, in addition, they also mediate renal and cerebral protection. A number of proof-of-concept trials have confirmed that the experimental evidence can be translated into clinical practice with regard to postoperative markers of myocardial injury; however, this effect has not been ubiquitous. ⋯ Data from recent meta-analyses in cardiac anaesthesia are also not conclusive regarding intra-operative volatile anaesthesia. These inconclusive clinical results have led to great variability currently in the type of anaesthetic agent used during cardiac surgery. This review summarises experimentally proposed mechanisms of anaesthetic preconditioning, and assesses randomised controlled clinical trials in cardiac anaesthesia that have been aimed at translating experimental results into the clinical setting.