British journal of anaesthesia
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Perioperative hypotension is common and associated with poor outcomes, including acute kidney injury (AKI). The mechanistic link between perioperative hypotension and AKI is at least partly a consequence of the susceptibility of the kidney, and particularly the renal medulla, to ischaemia and hypoxia. Several critical gaps in our knowledge lead to uncertainty about when and how to intervene to prevent AKI attributable to perioperative hypotension. ⋯ Third, there is little information regarding the relative risks and benefits of various clinically available therapies (e.g. vasoconstrictors, i.v. fluids, or both) to treat and prevent perioperative hypotension, particularly with regard to renal medullary perfusion and oxygenation. Fourth, there are currently no validated, clinically feasible methods for real-time clinical monitoring of renal perfusion or oxygenation. Thus, future developments in perioperative kidney-protective strategies must rely on the development of methods to better monitor renal perfusion and oxygenation in the perioperative period, and thereby guide timing, intensity, type, and duration of interventions.
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Perioperative hypotension has been repeatedly associated with organ injury and worse outcome, yet many interventions to reduce morbidity by attempting to avoid or reverse hypotension have floundered. In part, this reflects uncertainty as to what threshold of hypotension is relevant in the perioperative setting. Shifting population-based definitions for hypertension, plus uncertainty regarding individualised norms before surgery, both present major challenges in constructing useful clinical guidelines that may help improve clinical outcomes. ⋯ Consideration of the mosaic framework is critical for a more complete understanding of the perioperative response to acute sterile and infectious inflammation. The largely arbitrary treatment of perioperative blood pressure remains rudimentary in the context of multiple complex adaptive hypertensive endotypes, defined by distinct functional or pathobiological mechanisms, including the regulation of reactive oxygen species, autonomic dysfunction, and inflammation. Developing coherent strategies for the management of perioperative hypotension requires smarter, mechanistically solid interventions delivered by RCTs where observer bias is minimised.
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How conscious experience becomes disconnected from the environment, or disappears, across arousal states is unknown. We sought to identify the neural correlates of sensory disconnection and unconsciousness using a novel serial awakening paradigm. ⋯ NCT03284307.
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Patients with COVID-19 can require critical care for prolonged periods. Patients with persistent critical Illness can have complex recovery trajectories, but this has not been studied for patients with COVID-19. We examined the prevalence, risk factors, and long-term outcomes of critically ill patients with COVID-19 and persistent critical illness. ⋯ Almost half of all patients with COVID-19 admitted to critical care developed persistent critical illness, with high resource use in critical care and beyond. However, persistent critical illness was not associated with significantly worse long-term outcomes compared with patients who were critically ill for shorter periods.
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Clinical practice guidelines are increasingly important to guide clinical care. However, they can vary widely in quality, and many recommendations are based on low-level evidence. The COVID-19 pandemic highlighted the need for new flexible formats for rigorously developed guidelines. Future guideline development should be standardised, graded, registered, and updated to ensure that they are 'living' works in progress.