British journal of anaesthesia
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Although RCTs represent the gold standard in clinical research, most clinical questions cannot be answered using this technique, because of ethical considerations, time, and cost. The goal of observational research in clinical medicine is to gain insight into the relationship between a clinical exposure and patient outcome, in the absence of evidence from RCTs. Observational research offers additional benefit when compared with data from RCTs: the conclusions are often more generalisable to a heterogenous population, which may be of greater value to everyday clinical practice. In Part 2 of this methods series, we will introduce the reader to several advanced methods for supporting the case for causality between an exposure and outcome, including: mediation analysis, natural experiments, and joint effects methods.
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Cognitive dysfunction after surgery includes delirium and postoperative cognitive dysfunction. Important risk factors for these include increased age and pre-existing cognitive dysfunction. This study describes preoperative cognitive dysfunction and its associated factors in patients aged ≥60 yr awaiting elective noncardiac surgery in a developing country. ⋯ Undiagnosed pre-existing cognitive dysfunction was common in older patients awaiting surgery at a regional academic hospital in South Africa. Patients at risk for cognitive dysfunction should be identified through brief preoperative screening.
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Anaesthetic agents are likely to alter circulating cytokine concentrations. Because preceding studies have not been able to exclude the contribution of surgical trauma, perioperative stress, or both to circulating cytokine concentrations, the effects of anaesthesia remain unclear. The aim of this study was to quantify serum cytokines in healthy volunteers administered i.v. anaesthetic agents in the absence of surgical trauma and perioperative stress. ⋯ In healthy volunteers not undergoing surgery, different i.v. anaesthesia regimens were associated with differential effects on circulating cytokines.