British journal of anaesthesia
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The conduct and reporting of studies with a noninferiority hypothesis is challenging because of the complexity involved in their design and interpretation. However, studies with a noninferiority design have increased in popularity. ⋯ Apart from needing a critical appraisal, this draws attention to improve our understanding of noninferiority study framework and its unique features. Given the increasing focus on using various analgesic adjuncts and multiple approaches to fascial plane blocks to avoid more definitive and standard approaches, it is imperative that particular attention is paid to appropriate execution and reporting of noninferiority studies.
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Editorial Randomized Controlled Trial
Should renin-angiotensin system inhibitors be held prior to major surgery?
Many patients undergoing surgical procedures have a history of hypertension, diabetes mellitus, heart failure, or a combination. Often, these conditions involve the chronic use of a renin-angiotensin system inhibitor, including angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). Observational studies have suggested that continuing ACEIs/ARBs before major noncardiac surgery can increase the risk of intraoperative hypotension, which might drive postoperative complications such as acute kidney injury, myocardial injury, or stroke. ⋯ Patients randomised to the 'Stop' group experienced more postoperative hypertension. In a post hoc analysis, patients randomised to the 'Continue' group with low preoperative NT-proBNP concentrations (<100 pg ml-1) experienced less myocardial injury after surgery than the 'Stop' group, whereas no significant difference was observed in patients with elevated preoperative NT-proBNP concentrations. The SPACE trial provides important and new reassuring data on the safety of continuing ACEIs/ARBs before major surgery, challenging previous beliefs.
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To coincide with the annual scientific meeting of Regional Anaesthesia UK in London 2024, where there is a joint scientific session with the British Journal of Anaesthesia, a special regional anaesthesia edition of the journal has been produced. This editorial offers some highlights from the manuscripts contained within the special edition.
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Histological and micro-ultrasound evidence rebuffs deep-rooted views on the nature of nerve block, nerve damage, and injection pressure monitoring. We propose that the ideal position of the needle tip for nerve block is between the innermost circumneural fascial layer and outer epineurium, with local anaesthetic passing circumferentially through adipose tissue. ⋯ Pressure monitoring cannot differentiate between intrafascicular and extrafascicular injection. High injection pressure only indicates intraneural extrafascicular spread, not intrafascicular spread, because it is not possible to inject into the stiff endoneurium in most human nerves.
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A recent study by Suissa and colleagues explored the clinical relevance of a medical image segmentation metric (Dice metric) commonly used in the field of artificial intelligence (AI). They showed that pixel-wise agreement for physician identification of structures on ultrasound images is variable, and a relatively low Dice metric (0.34) correlated to a substantial agreement on subjective clinical assessment. We highlight the need to bring structure and clinical perspective to the evaluation of medical AI, which clinicians are best placed to direct.