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This editorial highlights the findings of the Balanced Anaesthesia Delirium study, a 515-patient substudy of the 6644 patient Balanced Anaesthesia trial, which found that targeting deep anaesthesia in patients undergoing major noncardiac surgery was not associated with significantly increased postoperative death or major morbidity. The substudy found that using bispectral index (BIS) guidance with the intention of deliberately achieving deep volatile agent-based anaesthesia (target BIS reading 35 vs 50) significantly increased delirium incidence (28% vs 19%), although not subsyndromal delirium incidence (45% vs 49%). We discuss the implications of these findings for anaesthetic practice, and address whether the BIS should be used as a guide to deliver precision anaesthesia for delirium prevention. We posit that subpopulation-based differences within this multicentre substudy could have affected delirium occurrence, since the findings appeared to rest on outcomes in patients from East Asia. We conclude that questions of whether and for whom deep anaesthesia is deliriogenic remain unanswered. [ABSTRACT FROM AUTHOR]

Background Despite concern that cardiac surgery may adversely affect cognition, little evidence is available from population-based studies using presurgery data. With the use of the Health and Retirement Study, we compared memory change after participant-reported cardiac catheterization or cardiac surgery. Methods Participants were community-dwelling adults aged 65 years and older who self-reported cardiac catheterization or "heart surgery" at any biennial Health and Retirement Study interview between 2000 and 2014. Participants may have undergone the index procedure any time in the preceding 2 years. We modeled preprocedure to postprocedure change in composite memory score, derived from objective memory testing, using linear mixed effects models. We modeled postprocedure subjective memory decline with logistic regression. To quantify clinical relevance, we used the predicted memory change to estimate impact on ability to manage medications and finances independently. Results Of 3,105 participants, 1,921 (62%) underwent catheterization and 1,184 (38%) underwent operation. In adjusted analyses, surgery participants had little difference in preprocedure to postprocedure memory change compared with participants undergoing cardiac catheterization (−0.021 memory units; 95% confidence interval: −0.046 to 0.005 memory units, p = 0.12). If the relationship were causal, the point estimate for memory decline would confer an absolute 0.26% or 0.19% decrease in ability to manage finances or medications, respectively, corresponding to 4.6 additional months of cognitive aging. Cardiac surgery was not associated with subjective memory decline (adjusted odds ratio 0.93, 95% confidence interval: 0.74 to 1.18). Conclusions In this large, population-based cohort, memory declines after heart surgery and cardiac catheterization were similar. These findings suggest intermediate-term population-level adverse cognitive effects of cardiac surgery, if any, are likely subtle. [ABSTRACT FROM AUTHOR]

Postoperative cognitive dysfunction (POCD) is a concern after anaesthesia and surgery, but preoperative discussion of neurocognitive risks with older patients rarely occurs. Anecdotal experiences of POCD are common in the popular media and may inform patient perspectives. However, the degree of alignment between lay and scientific perspectives on POCD is not known. We performed inductive qualitative thematic analysis on website user comments publicly submitted under an article entitled, 'The hidden long-term risks of surgery: "It gives people's brains a hard time"', published by the UK-based news source The Guardian in April 2022. We analysed 84 comments from 67 unique users. Themes that emerged from user comments included the importance of functional impact ('Couldn't work ... even reading was a struggle'), attribution to a range of causes but particularly the use of general, rather than consciousness-preserving, anaesthesia techniques ('side effects aren't fully understood'), and inadequate preparation and response by healthcare providers ('I would have benefited by being warned'). There is misalignment between professional and lay understandings of POCD. Lay people emphasise subjective and functional impact of symptoms, and express beliefs about the role of anaesthetics in causing POCD. Some patients and caregivers affected by POCD report feeling abandoned by medical providers. In 2018, new nomenclature for postoperative neurocognitive disorders was published, which better aligns with lay perspectives by including subjective complaints and functional decline. Further studies based on newer definitions and public messaging may improve concordance between different understandings of this postoperative syndrome. [ABSTRACT FROM AUTHOR]

Abstract: Quantitative histomorphometry is the current gold standard for objective measurement of nerve architecture and its components. Many methods still in use rely heavily upon manual techniques that are prohibitively time consuming, predisposing to operator fatigue, sampling error, and overall limited reproducibility. More recently, investigators have attempted to combine the speed of automated morphometry with the accuracy of manual and semi-automated methods. Systematic refinements in binary imaging analysis techniques combined with an algorithmic approach allow for more exhaustive characterization of nerve parameters in the surgically relevant injury paradigms of regeneration following crush, transection, and nerve gap injuries. The binary imaging method introduced here uses multiple bitplanes to achieve reproducible, high throughput quantitative assessment of peripheral nerve. Number of myelinated axons, myelinated fiber diameter, myelin thickness, fiber distributions, myelinated fiber density, and neural debris can be quantitatively evaluated with stratification of raw data by nerve component. Results of this semi-automated method are validated by comparing values against those obtained with manual techniques. The use of this approach results in more rapid, accurate, and complete assessment of myelinated axons than manual techniques. [Copyright &y& Elsevier]