Treatment threshold for intra-operative hypotension in clinical practice-a prospective cohort study in older patients in the UK

Intra-operative hypotension frequently complicates anaesthesia in older patients and is implicated in peri-operative organ hypoperfusion and injury. The prevalence and corresponding treatment thresholds of hypotension are incompletely described in the UK. This study aimed to identify prevalence of intra-operative hypotension and its treatment thresholds in UK practice. Patients aged ≥ 65 years were studied prospectively from 196 UK hospitals within a 48-hour timeframe. The primary outcome was the incidence of hypotension (mean arterial pressure 20%; systolic blood pressure 20% reduction in systolic blood pressure from baseline and 77.5% systolic blood pressure <100 mmHg. The mean (SD) blood pressure triggering vasopressor therapy was mean arterial pressure 64.2 (11.6) mmHg and the mean (SD) stated intended treatment threshold from the survey was mean arterial pressure 60.6 (9.7) mmHg. A composite adverse outcome of myocardial injury, kidney injury, stroke or death affected 345 patients (7.3%). In this representative sample of UK peri-operative practice, the majority of older patients experienced intra-operative hypotension and treatment was delivered below suggested thresholds. This highlights both potential for intra-operative organ injury and substantial opportunity for improving treatment of intra-operative hypotension

A combinatorial approach to knot recognition

This is a report on our ongoing research on a combinatorial approach to knot recognition, using coloring of knots by certain algebraic objects called quandles. The aim of the paper is to summarize the mathematical theory of knot coloring in a compact, accessible manner, and to show how to use it for computational purposes. In particular, we address how to determine colorability of a knot, and propose to use SAT solving to search for colorings. The computational complexity of the problem, both in theory and in our implementation, is discussed. In the last part, we explain how coloring can be utilized in knot recognition

A high proportion of the world population of the spoon-billed sandpiper occurs at Tiaozini, China, during the post-breeding Moult

The Critically Endangered Spoon-billed Sandpiper Calidris pygmaea breeds in arctic and subarctic Russia and migrates to winter on coastal mudflats in south-east Asia. Its world population is probably about 700 individuals. We report Lincoln-Petersen closed-population estimates of the number of Spoon-billed Sandpipers at Tiaozini, a coastal site in Jiangsu Province, China, based upon resightings and scan surveys of individually-marked leg-flagged birds. Surveys were conducted in September-October, when adult Spoon-billed Sandpipers are moulting their primary feathers and long-distance movements are unlikely. We estimated that 220 birds were present at Tiaozini in 2017 and 224 in 2018. Nearly all of them were adults (one-year old or older), so about 40% of the world population of this age class was estimated to be present. Hence, protection of the mudflats and roost sites at Tiaozini is of global importance for the conservation of the Spoon-billed Sandpiper.Non

Extrastriate projections in human visual system: Evidence from fMRI-informed tractography

The human optic radiation (OR) is the main pathway for conveying visual input to occipital cortex, but it is unclear whether it projects beyond primary visual cortex (V1). In this study, we used functional MRI mapping to delineate early visual areas in 30 healthy volunteers and determined the termination area of the OR as reconstructed with diffusion tractography. Direct thalamo-cortical projections to areas V2 and V3 were found in all hemispheres tested, with a distinct anatomical arrangement of superior–inferior fiber placement for dorsal and ventral projections, respectively, and a medio-lateral nesting arrangement for projections to V1, V2 and V3. Finally, segment-specific microstructure was examined, revealing sub-fascicular information. This is to date the first in vivo demonstration of direct extrastriate projections of the OR in humans

Inflation with Non-minimal Gravitational Couplings and Supergravity

We explore in the supergravity context the possibility that a Higgs scalar may drive inflation via a non-minimal coupling to gravity characterised by a large dimensionless coupling constant. We find that this scenario is not compatible with the MSSM, but that adding a singlet field (NMSSM, or a variant thereof) can very naturally give rise to slow-roll inflation. The inflaton is necessarily contained in the doublet Higgs sector and occurs in the D-flat direction of the two Higgs doublets.Comment: 13 pages, 1 figur

Quality and impact of appraisal for revalidation: the perceptions of London’s responsible officers and their appraisers

BACKGROUND: To evaluate NHS England London region's approach to the revalidation appraisal of responsible officers in London, exploring perceptions of the quality and impact of the appraisal process. Revalidation is the process which aims to ensure doctors in the UK are up-to-date and fit to practice medicine thus improving the quality of patient care. Revalidation recommendations are largely premised on the documentation included in annual appraisals, which includes the professional development a doctor has undertaken and supporting information about their practice. METHODS: A pan-London qualitative study exploring the views of responsible officers and their appraisers about the revalidation appraisal process. The study aimed to gain an in-depth understanding of the experiences and perceptions of the participants. Responsible officers were purposefully sampled to represent the broadest range of designated bodies. Data analysis generated themes pertaining to quality and impact of appraisal for revalidation with the potential to feed into and shape the evolving system under investigation. RESULTS: The central importance of highly skilled appraisers was highlighted. Both groups reported educational opportunities embedded within the appraisal process. Independent appraisers, not matched by clinical speciality or place of work, were considered to take a more objective view of a responsible officer's practice by providing an 'outsider perspective'. However, covering the breadth of roles, in sufficient depth, was challenging. Participants reported a bias favouring the appraisal of the responsible officer role above others including clinical work. Appraisal and revalidation was perceived to have the potential to improve the healthcare standards and support both personal development and institutional quality improvement. CONCLUSIONS: Responsible officers play a central role in the revalidation process. Getting responsible officer appraisal right is central to supporting those individuals to in turn support doctors and healthcare organisations in continuous quality improvement. The complexity and importance of the role of responsible officer may make achieving an appraisal of all roles of such individuals problematic. This evaluation suggests responsible officer appraisal was perceived as educational and effective

On Inflation with Non-minimal Coupling

A simple realization of inflation consists of adding the following operators to the Einstein-Hilbert action: (partial phi)^2, lambda phi^4, and xi phi^2 R, with xi a large non-minimal coupling. Recently there has been much discussion as to whether such theories make sense quantum mechanically and if the inflaton phi can also be the Standard Model Higgs. In this note we answer these questions. Firstly, for a single scalar phi, we show that the quantum field theory is well behaved in the pure gravity and kinetic sectors, since the quantum generated corrections are small. However, the theory likely breaks down at ~ m_pl / xi due to scattering provided by the self-interacting potential lambda phi^4. Secondly, we show that the theory changes for multiple scalars phi with non-minimal coupling xi phi dot phi R, since this introduces qualitatively new interactions which manifestly generate large quantum corrections even in the gravity and kinetic sectors, spoiling the theory for energies > m_pl / xi. Since the Higgs doublet of the Standard Model includes the Higgs boson and 3 Goldstone bosons, it falls into the latter category and therefore its validity is manifestly spoiled. We show that these conclusions hold in both the Jordan and Einstein frames and describe an intuitive analogy in the form of the pion Lagrangian. We also examine the recent claim that curvature-squared inflation models fail quantum mechanically. Our work appears to go beyond the recent discussions.Comment: 14 pages, 2 figures. Version 2: Clarified findings and improved wording. Elaborated important sections and removed an unnecessary section. Added references. Version 3: Updated towards JHEP version. Version 4: Final JHEP versio

Treatment threshold for intra‐operative hypotension in clinical practice—a prospective cohort study in older patients in the UK

Intra-operative hypotension frequently complicates anaesthesia in older patients and is implicated in peri-operative organ hypoperfusion and injury. The prevalence and corresponding treatment thresholds of hypotension are incompletely described in the UK. This study aimed to identify prevalence of intra-operative hypotension and its treatment thresholds in UK practice. Patients aged ≥ 65 years were studied prospectively from 196 UK hospitals within a 48-hour timeframe. The primary outcome was the incidence of hypotension (mean arterial pressure 20%; systolic blood pressure 20% reduction in systolic blood pressure from baseline and 77.5% systolic blood pressure <100 mmHg. The mean (SD) blood pressure triggering vasopressor therapy was mean arterial pressure 64.2 (11.6) mmHg and the mean (SD) stated intended treatment threshold from the survey was mean arterial pressure 60.6 (9.7) mmHg. A composite adverse outcome of myocardial injury, kidney injury, stroke or death affected 345 patients (7.3%). In this representative sample of UK peri-operative practice, the majority of older patients experienced intra-operative hypotension and treatment was delivered below suggested thresholds. This highlights both potential for intra-operative organ injury and substantial opportunity for improving treatment of intra-operative hypotension