bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac efficiency and Starling's Law of the Heart
Authors: Han June‐Chiew , Taberner Andrew J. , Loiselle Denis S. , Tran Kenneth
Published: August 2022

The formulation by Starling of The Law of the Heart states that ‘the [mechanical] energy of contraction, however measured, is a function of the length of the muscle fibre’. Starling later also stated that ‘the oxygen consumption of the isolated heart … is determined by its diastolic volume, and therefore by the initial length of its muscular fibres’. This phrasing has motivated us to extend Starling's Law of the Heart to include consideration of the efficiency of contraction. In this study, we assessed both mechanical efficiency and crossbridge efficiency by studying the heat output of isolated rat ventricular trabeculae performing force–length work‐loops over ranges of preload and afterload. The combination of preload and afterload allowed us, using our modelling frameworks for the end‐systolic zone and the heat–force zone, to simulate cases by recreating physiologically feasible loading conditions. We found that across all cases examined, both work output and change of enthalpy increased with initial muscle length; hence it can only be that the former increases more than the latter to yield increased mechanical efficiency. In contrast, crossbridge efficiency increased with initial muscle length in cases where the extent of muscle shortening varied greatly with preload. We conclude that the efficiency of cardiac contraction increases with increasing initial muscle length and preload. An implication of our conclusion is that the length‐dependent activation mechanism underlying the cellular basis of Starling's Law of the Heart is an energetically favourable process that increases the efficiency of cardiac contraction.

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Key points

Ernest Starling in 1914 formulated the Law of the Heart to describe the mechanical property of cardiac muscle whereby force of contraction increases with muscle length.

He subsequently, in 1927, showed that the oxygen consumption of the heart is also a function of the length of the muscle fibre, but left the field unclear as to whether cardiac efficiency follows the same dependence.

A century later, the field has gained an improved understanding of the factors, including the distinct effects of preload and afterload, that affect cardiac efficiency. This understanding presents an opportunity for us to investigate the elusive length‐dependence of cardiac efficiency.

We found that, by simulating physiologically feasible loading conditions using a mechano‐energetics framework, cardiac efficiency increased with initial muscle length.

A broader physiological importance of our findings is that the underlying cellular basis of Starling's Law of the Heart is an energetically favourable process that yields increased efficiency.
El cerebro del meditador de atención plena: de la prospección a la tarea
Authors: Pelaez Lopez Maria Antonia , Lozano Zuluaga Juan José , Narváez Andrade María José , Becerra Hernández Lina Vanessa
Published: August 2022

La meditación de atención plena es una técnica originaria de la cultura budista, la cual busca “cosechar la conciencia interior”, centrando la atención en el aquí y en el ahora, aceptando los pensamientos y dejándolos fluir.  A través de diferentes estudios se ha evidenciado sus beneficios a nivel del sistema nervioso central, cuyos mecanismos aún no están dilucidados. En la presente revisión se recopila información de estudios que han utilizado resonancia magnética nuclear, morfometría basada en voxel, resonancia magnética funcional y electroencefalograma para valorar los mismos. Dentro de los cambios imagenológicos reportados se encontraron cambios corticales importantes, incluyendo cambios que abarcan engrosamiento de corteza prefrontal, ínsula e incremento en volúmenes hipocampales, además de cambios en el estriado, la corteza cingulada posterior y el precúneo; estructuras involucradas en el control de las emociones, en la memoria, la atención y el aprendizaje. En cuanto a lo evidenciado con el electroencefalograma, al estudiar los cambios funcionales de la actividad eléctrica del cerebro los resultados han sido poco concluyentes, sin embargo, las ondas alpha y theta destacaron sobre el resto, mostrando una mayor amplitud en los practicantes de meditación de atención plena.
El riesgo de recién nacidos expuestos a eventos de morbilidad materna extrema en un centro de alto riesgo obstétrico (Colombia)
Authors: Puello Ávila Antonio Carlos , Rodríguez Ortiz Jorge Augusto , Giraldo Méndez Néstor , Castro Herrera Lina Maria
Published: August 2022

RESUMEN

Introducción: Una atención oportuna y de calidad en una mujer con una complicación obstétrica severa puede prevenir un desenlace fatal. Se estima que dos de cada tres defunciones neonatales son evitables con medidas eficaces en la atención del parto. El objetivo fue determinar el riesgo de exposición de los hijos de madres con eventos de morbilidad materna extrema. Materiales y métodos: Estudio de análisis secundario de datos. La población de estudio incluyó los 2197 registros de nacidos vivos y 103 registros de notificación de morbilidad materna extrema. Resultados: La prevalencia de morbilidad materna extrema fue 5,3%. Los neonatos con un peso entre 3500-4000 gr  y > 4000 gr  tenían menor riesgo con relación a exposición a morbilidad materna extrema en comparación con el peso < 2500 gr. Así mismo, el riesgo de exposición fue menor en los partos a término en comparación con los pretérmino. Conclusiones: Existe asociación entre morbilidad materna y resultados perinatales adversos; con un riesgo significativamente mayor de parto prematuro, bajo peso al nacer, y más tasas de cesárea. Palabras claves: Morbilidad materna severa; Neonatos; mortalidad perinatal; Embarazo; Riesgo  (fuente DeCS).
A Reactor Train System for Efficient Solar Thermochemical Fuel Production
Authors: Patankar Aniket S. , Wu Xiao-Yu , Choi Wonjae , Tuller Harry L. , Ghoniem Ahmed F.
Published: August 2022

Thermochemical redox cycles are a promising route to producing solar fuels. In this work, a novel reactor train system (RTS) is proposed for the efficient conversion of solar thermal energy into hydrogen. This system is capable of recovering thermal energy from redox materials, which is necessary for achieving high efficiency but has been difficult to realize in practice. The RTS overcomes technical challenges of high-temperature thermochemical reactors like solid conveying and sealing, while enabling continuous fuel production and efficient oxygen removal during metal oxide reduction. The RTS is comprised of several identical reactors arranged in a closed loop and cycling between reduction and oxidation steps. In between these steps, the reactors undergo solid heat recovery in a counterflow radiative heat exchanger. The RTS can achieve heat recovery effectiveness of 80% for a train producing 100 kg-H2/day with a 60 min cycle time. The RTS can take advantage of thermal energy storage to operate round-the-clock. Further, it implements waste heat recovery to capture the exothermic heat of water-splitting. If all auxiliary energy demands can be satisfied with such waste heat, the RTS base configuration achieves 30% heat-to-hydrogen conversion efficiency, which is more than four times that of current state-of-the-art thermochemical systems.
Efficiency Improvement of Photovoltaic Solar Modules by Cooling Using an Underground Heat Exchanger
Authors: Valiente-Blanco Ignacio , Lopez-Pascual Diego , Diaz-Villar Pablo , Mallol-Poyato Ricardo , Barragan Alberto , Ocaña Manuel , Granello Guido , Diez-Jimenez Efren
Published: August 2022

Overheating of solar cells under normal operational conditions highly reduces their energy harvesting efficiency and produces additional problems related to thermal cycling and performance degradation of the modules. In this paper, a novel cooling system for solar photovoltaics, using the underground as a heat sink, is proposed, theoretically described and experimentally validated. A prototype of the technology (including a single-axis sun tracking mechanism) has been designed, manufactured, and rigorously tested in outdoor conditions during summer 2021 in Spain, under different environmental conditions. The excess heat is removed from the backside of the solar module by a close-loop and single-phase cooling system and then dissipated in the underground, which is at a constant temperature of about 16 °C at relatively low depths at the location where tests were performed. A single U-shaped copper tube, 18 mm in diameter, immersed in a 15.5-m-deep borehole naturally filled with water, is used as an underground heat exchanger. As a consequence of the reduction of the cooled module temperature, its net power generation is significantly increased. A promising improvement of the net power generation of the cooled solar module up to 12.4% has been measured for a coolant flowrate of 1.84 l/min per square meter of solar module, proving the technical feasibility of the approach. In addition, a dependency of the power gain with the pump efficiency, the global radiation, and ambient temperature has been observed.
Effects of Chevron Micro-Textures on Tribological and Lubricating Performance of Cylinder Block/Valve Plate Interface in Axial Piston Pumps
Authors: Chen Luanxia , Shang Lizhi , Liu Zhanqiang , Mukherjee Swarnava , Cai Yukui , Wang Bing
Published: August 2022

The cylinder block/valve plate interface is one of the major power loss sources and main failure points in axial piston pumps and motors. Surface micro-texture has been proven to be an effective approach to reduce friction and wear in many tribological applications. In the present paper, the effect of micro-texture on the tribological and lubricating performance of the important cylinder block/valve plate interface is studied experimentally and numerically. The experimental investigation was conducted on a disk-on-disk tribometer with similar geometry, operating speed, material, and working fluid to the cylinder block/valve plate interface in the axial piston pump. The tribological test results confirmed the chevron micro-texture's potential to reduce frictional loss in such lubricating interface. Furthermore, a novel numerical method coupling the dynamic loading, squeeze motion, analytical pressure deformation, mixed friction, and cavitation was proposed to study the lubricating performance of micro-textured valve plate/cylinder block interface. This model was then validated comparing to the tribometer experimental results and was used to study the effect of depths, widths, and distances of chevron micro-textures on the lubrication performance of cylinder block/valve plate interface. The results found that the depth of the chevron micro-textures affected whether the cavitation occurred inside the micro-texture, the width of the chevron micro-texture affected the size of the cavitation area that occurred in the micro-textures, and the chevron micro-texture distance affected the size of the convergence zone where positive pressure generated.
Nonlinear Vibration Analysis of a Generally Restrained Axially Loaded Beam Structure With a Local Uniform Nonlinear Foundation
Authors: Du Jingtao , Zhao Yuhao , Chen Yilin , Liu Yang
Published: August 2022

Beam structures are widely used in various engineering occasions to model various structures. Numerous researchers have studied dynamic responses of beam structures with nonlinear supports or nonlinear foundations. In engineering, nonlinear supports were subjected to the beam structure through the surface contact rather than the point connection. Few works studied the dynamic behavior of the beam structure with local uniform cubic nonlinear stiffness foundations. Additionally, the boundary rotational restraints of the beam structure are ignored. To improve the engineering acceptance of the beam structure with nonlinearity, it is of great significance to study the dynamic behavior of the generally restrained axially loaded beam structure with a local uniform nonlinear foundation. This work establishes a nonlinear dynamic model of the beam structure with a local uniform nonlinear foundation. Dynamic responses of the beam structure are predicted through the Galerkin truncated method. In Galerkin truncated method, mode functions of the axially loaded beam structure without the local uniform nonlinear foundation are selected as the trail and weight functions. The harmonic balance method is employed to verify the correctness of the Galerkin truncated method. The influence of the sweeping ways and local uniform nonlinear foundation on dynamic responses of the generally restrained axially loaded beam structure is investigated. Dynamic responses of the generally restrained axially loaded beam structure with a local uniform nonlinear foundation are sensitive to its calculation initial values. Suitable parameters of the local uniform nonlinear foundation can suppress the vibration response and transform the vibration state of the beam structure.
Multifidelity Physics-Constrained Neural Networks With Minimax Architecture
Authors: Liu Dehao , Pusarla Pranav , Wang Yan
Published: August 2022

Data sparsity is still the main challenge to apply machine learning models to solve complex scientific and engineering problems. The root cause is the “curse of dimensionality” in training these models. Training algorithms need to explore and exploit in a very high-dimensional parameter space to search the optimal parameters for complex models. In this study, a new scheme of multifidelity physics-constrained neural networks with minimax architecture is proposed to improve the data efficiency of training neural networks by incorporating physical knowledge as constraints and sampling data with various fidelities. In this new framework, fully connected neural networks with two levels of fidelities are combined to improve the prediction accuracy. The low-fidelity neural network is used to approximate the low-fidelity data, whereas the high-fidelity neural network is adopted to approximate the correlation function between the low-fidelity and high-fidelity data. To systematically search the optimal weights of various losses for reducing the training time, the Dual-Dimer algorithm is adopted to search high-order saddle points of the minimax optimization problem. The proposed framework is demonstrated with two-dimensional heat transfer, phase transition, and dendritic growth problems, which are fundamental in materials modeling. With the same set of training data, the prediction error of the multifidelity physics-constrained neural network with minimax architecture can be two orders of magnitude lower than that of the multifidelity neural network with minimax architecture.
Realistic simulation of reflection high-energy electron diffraction patterns for two-dimensional lattices using Ewald construction
Authors: Liu Chong , Chang Kai , Zou Ke
Published: August 2022

Reflection high-energy electron diffraction (RHEED) is a powerful tool for characterizing crystal surface structures. However, the setup geometry leads to distorted and complicated patterns, which are not straightforward to link to the real-space structures. A program with a graphical user interface is provided here to simulate the RHEED patterns. Following the Ewald construction in the kinematic theory, we find out the exact geometric transformation in this model that determines the positions of diffraction spots. The program can deal with many forms of surface structures, including surface reconstructions or domains. The simulations exhibit great agreement with the experimental results in various cases. This program will benefit the structure analysis in thin-film growth and surface science studies.
Rickettsia
-Host-Tick Interactions: Knowledge Advances and Gaps
Authors: Kim Hwan Keun
Published: August 2022

Ticks are hematophagous ectoparasites capable of transmitting multiple human pathogens. Environmental changes have supported the expansion of ticks into new geographical areas that have become the epicenters of tick-borne diseases (TBDs).
Collaboration between Antagonistic Cell Type Regulators Governs Natural Variation in the Candida albicans Biofilm and Hyphal Gene Expression Network
Authors: Do Eunsoo , Cravener Max V. , Huang Manning Y. , May Gemma , McManus C. Joel , Mitchell Aaron P.
Published: August 2022

Clinical isolates of all pathogens vary in the strength of traits linked to disease. In this study, we focused on variation in a pathogenicity trait of the fungal pathogen
Candida albicans
, biofilm formation.
Reworking of Yangtze crust into the mantle lithosphere of the North China Craton along the Dabie–East Qinling Orogen: Evidence from the Early Cretaceous volcanic rocks
Authors: Zhang Feifei , Wang Yifan , Cawood Peter A. , Dong Yunpeng , Xin Chenghui
Published: August 2022

Mineral chemistry, zircon U-Pb geochronology, and elemental and Sr-Nd-Pb-Hf-O isotopic data for the Early Cretaceous volcanic rocks from the Dabie and East Qinling orogens of China constrain the reworking history of the Yangtze crustal materials in the North China lithosphere. These data provide new insights into the recycling of the deepsubducted crustal materials into the mantle and the transformation process from continental subduction to collision. Our data show that the Early Cretaceous volcanic rocks are characterized by shoshonitic and high-K calc-alkaline basaltic trachyandesite, trachyandesite, and trachyte. They synchronously erupted at ca. 135–120 Ma, and have zircon in situ εHf(t) values ranging from −29.0 to −17.2, and δ18O values from 4.89‰ to 6.84‰. These samples share similar “crust-like” geochemical signatures, whole-rock enrichment in the large-ion lithophile elements, depletion in high field strength elements (Nb/La = 0.12–0.38), highly enriched Sr-Nd isotopic compositions, as well as (206Pb/204Pb)i = 15.97–17.59, (207Pb/204Pb)i = 15.33–15.54, and (208Pb/204Pb)i = 36.87–38.59. The εNd(t) values range from −24.4 to −15.6, −21.8 to −13.1, and −16.8 to −10.9 for the eastern and western North Huaiyang belts of the Dabie Orogen and the East Qinling Orogen, respectively. Such geochemical similarities suggest that the northward deep-subduction of Yangtze crustal materials have been reworked into the North China Craton enriched lithospheric mantle. The spatial pattern of the Early Cretaceous volcanic rocks suggests that the Yangtze subduction extended northward beyond the southern margin of the North China Craton and ran into its interior. The surface and deep lithospheric boundaries are decoupled between the Yangtze Block and North China Craton. The Early Cretaceous igneous rocks in the Dabie–East Qinling Orogen were induced in response to the post-collisional unrooting of the Triassic over-thickened lithosphere coupling.
New insights into the source of gold in the Youjiang basin, SW China
Authors: Chen Jun , Du Li-Juan , Yang Rui-Dong , Zhou Mei-Fu , Lai Chun-Kit , Huang Zhi-Long
Published: August 2022

Mantle plume rich in gold is considered to be important for the formation of giant epigenetic gold deposits. The Youjiang basin, SW China, is the world’s second largest Carlin-type gold province, but the ultimate source of its gold remains enigmatic. In this study, we report that the Middle–Late Permian basaltic rocks in the basin are rich in native gold grains. These gold grains are scattered in the interstices of pyrite and marcasite and in the amorphous silica cavities. Mineralogy and S-Pb isotope geochemistry of the auriferous sulfides suggest that the gold was largely derived from the gold-rich Late Permian (ca. 260 Ma) Emeishan plume and was released to a near-surface volcanogenic massive sulfide (VMS) metallogenic system, where it accumulated. The native gold grains from the basalts may have been inherited by the younger (ca. 140 Ma) Carlin-type ores in the Youjiang basin, which are indicative of gold pre-enrichment in the basin. Our study highlights that golden plume upwelling could carry abundant gold into the upper crust, even into shallow-level metallogenic systems, and thus provides an alternative view on the source of gold in the Youjiang basin.
Mode of continental breakup of marginal seas
Authors: Mohn G. , Ringenbach J.C. , Nirrengarten M. , Lei C. , McCarthy A. , Tugend J.
Published: August 2022

We investigated the continent-ocean transition (COT) structure of three main marginal seas in the western Pacific Ocean (South China Sea, Coral Sea, and Woodlark Basin) to determine the tectono-magmatic processes acting during continental breakup. The COT formed from the activity of a low-angle normal fault system localizing deformation during final rifting. Extension was contemporaneous with magmatic activity, including volcanic edifices, dikes, and sills in the distalmost parts of these basins. The COT shows a sharp juxtaposition in space and time of continental crust against igneous oceanic crust, and its overall structure differs from that of magma-poor or magma-rich passive-margin archetypes. We propose that this mode of breakup is characteristic of marginal seas due to the high extension rates imposed by kinematic forces of nearby subduction zones. Revealed in the context of marginal seas, this mode of breakup and the resulting COT structures highlight the underestimated diversity of continental breakup mechanisms.
Sleep patterns and intraindividual sleep variability in mothers and fathers at 6 months postpartum: a population-based, cross-sectional study
Authors: Kalogeropoulos Christopher , Burdayron Rebecca , Laganière Christine , Dubois-Comtois Karine , Béliveau Marie-Julie , Pennestri Marie-Helene
Published: August 2022

Objectives

Given that postpartum sleep is an important family process, further investigations including both mothers and fathers are necessary. The present study aimed to describe and compare sleep patterns and intraindividual night-to-night variability in mothers and fathers at 6 months postpartum using subjective and objective sleep measures.

Design

Cross-sectional study.

Setting

General community-based study in Montreal, QC, Canada.

Participants

Thirty-three couples (mothers and fathers) with no self-reported history of medical and mental health conditions participated in this study.

Results

Parental sleep was measured across 10 consecutive nights using both a daily sleep diary and actigraphy. Results demonstrated that mothers’ subjective and objective sleep was more fragmented compared with fathers (shorter longest consecutive sleep duration and more nocturnal awakenings; p<0.001). While mothers and fathers did not differ in their self-reported nocturnal sleep duration (p>0.05), actigraphy indicated that mothers obtained significantly longer nocturnal sleep duration (448.07 min±36.49 min) than fathers (400.96 min±45.42 min; p<0.001). Intraindividual sleep variability was revealed by relatively high coefficients of variation for parents across both subjective and objective indices related to sleep fragmentation (between 0.25 and 1.32). Actigraphy also demonstrated variability by mothers sleeping 6 hours consecutively on less than 3 nights, 27.27% (±22.81), and fathers on less than 6 nights, 57.27% (±24.53), out of 10. Associations were also found between parental sleep and family factors, such as age and infant sleep location (p<0.05).

Conclusions

These findings advance our knowledge of how sleep unfolds within the family system beyond the early postpartum weeks and/or months. Given the link between disturbed sleep and family functioning, the current research accentuates the importance of examining postpartum sleep patterns and variability in parents.
Effectiveness of exercise and physical activity interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in people living with mild cognitive impairment: a protocol of a systematic review and meta-analysis
Authors: Dieckelmann Mirjam , Gonzalez-Gonzalez Ana Isabel , Banzer Winfried , Berghold Andrea , Jeitler Klaus , Pantel Johannes , Schall Arthur , Tesky Valentina A , Siebenhofer Andrea
Published: August 2022

Introduction

Mild cognitive impairment (MCI) is a clinical syndrome characterised by persistent cognitive deficits that do not yet fulfil the criteria of dementia. Delaying the onset of dementia using secondary preventive measures such as physical activity and exercise can be a safe way of reducing the risk of further cognitive decline and maintaining independence and improving quality of life. The aim is to systematically review the literature to assess the effectiveness of physical activity and exercise interventions to improve long-term patient-relevant cognitive and non-cognitive outcomes in people living with MCI, including meta-analyses if applicable.

Methods and analysis

We will systematically search five electronic databases from 1995 onward to identify trials reporting on the effectiveness of physical activity and exercise interventions to improve long-term (12+ months) patient-relevant cognitive and non-cognitive outcomes in adults (50+ years) with MCI. Screening procedures, selection of eligible full-texts, data extraction and risk of bias assessment will be performed in dual-review mode. Additionally, the reporting quality of the exercise interventions will be assessed using the Consensus on Exercise Reporting Template. A quantitative synthesis will only be conducted if studies are homogeneous enough for effect sizes to be pooled. Where quantitative analysis is not applicable, data will be represented in a tabular form and synthesised narratively. People living with MCI will be involved in defining outcome measures most relevant to them in order to assess in how far randomised controlled trials report endpoints that matter to those concerned.

Ethics and dissemination

Results will be disseminated to both scientific and lay audiences by creating a patient-friendly video abstract. This work will inform professionals in primary care about the effectiveness of physical activity and exercise interventions and support them to make evidence-based exercise recommendations for the secondary prevention of dementia in people living with MCI. No ethical approval required.

PROSPERO registration number

CRD42021287166.
Short-term and long-term impacts of COVID-19 on economic vulnerability: a population-based longitudinal study (COVIDENCE UK)
Authors: Williamson Anne E , Tydeman Florence , Miners Alec , Pyper Kate , Martineau Adrian R
Published: August 2022

Objective

To determine whether COVID-19 has a significant impact on adequacy of household income to meet basic needs (primary outcome) and work absence due to sickness (secondary outcome), both at the onset of illness (short term) and subsequently (long term).

Design

Multilevel mixed regression analysis of self-reported data from monthly online questionnaires, completed 1 May 2020 to 28 October 2021, adjusting for baseline characteristics including age, sex, socioeconomic status and self-rated health.

Setting and participants

Participants (n=16 910) were UK residents aged 16 years or over participating in a national longitudinal study of COVID-19 (COVIDENCE UK).

Results

Incident COVID-19 was independently associated with increased odds of participants reporting household income as being inadequate to meet their basic needs in the short term (adjusted OR (aOR) 1.39, 95% CI 1.12 to 1.73) though this did not persist in the long term (aOR 1.00, 95% CI 0.86 to 1.16). Exploratory analysis revealed a stronger short-term association among those who reported long COVID, defined as the presence of symptoms lasting more than 4 weeks after disease onset, than those reporting COVID-19 without long COVID (p for trend 0.002). Incident COVID-19 associated with increased odds of reporting sickness absence from work in the long term (aOR 4.73, 95% CI 2.47 to 9.06) but not in the short term (aOR 1.34, 95% CI 0.52 to 3.49).

Conclusions

We demonstrate an independent association between COVID-19 and increased risk of economic vulnerability among COVIDENCE participants, measured by both household income sufficiency and sickness absence from work. Taking these findings together with pre-existing research showing that socioeconomic disadvantage increases the risk of developing COVID-19, this may suggest a ‘vicious cycle’ of impaired health and poor economic outcomes.

Trial registration number

NCT04330599.
Clustering-based COPD subtypes have distinct longitudinal outcomes and multi-omics biomarkers
Authors: Gregory Andrew , Xu Zhonghui , Pratte Katherine , Lee Sool , Liu Congjian , Chase Robert , Yun Jeong , Saferali Aabida , Hersh Craig P , Bowler Russell , Silverman Edwin , Castaldi Peter J , Boueiz Adel
Published: August 2022

Introduction

Chronic obstructive pulmonary disease (COPD) can progress across several domains, complicating the identification of the determinants of disease progression. In our previous work, we applied k-means clustering to spirometric and chest radiological measures to identify four COPD-related subtypes: ‘relatively resistant smokers (RRS)’, ‘mild upper lobe-predominant emphysema (ULE)’, ‘airway-predominant disease (AD)’ and ‘severe emphysema (SE)’. In the current study, we examined the associations of these subtypes to longitudinal COPD-related health measures as well as blood transcriptomic and plasma proteomic biomarkers.

Methods

We included 8266 non-Hispanic white and African-American smokers from the COPDGene study. We used linear regression to investigate cluster associations to 5-year prospective changes in spirometric and radiological measures and to gene expression and protein levels. We used Cox-proportional hazard test to test for cluster associations to prospective exacerbations, comorbidities and mortality.

Results

The RRS, ULE, AD and SE clusters represented 39%, 15%, 26% and 20% of the studied cohort at baseline, respectively. The SE cluster had the greatest 5-year FEV1(forced expiratory volume in 1 s) and emphysema progression, and the highest risks of exacerbations, cardiovascular disease and mortality. The AD cluster had the highest diabetes risk. After adjustments, only the SE cluster had an elevated respiratory mortality risk, while the ULE, AD and SE clusters had elevated all-cause mortality risks. These clusters also demonstrated differential protein and gene expression biomarker associations, mostly related to inflammatory and immune processes.

Conclusion

COPD k-means subtypes demonstrate varying rates of disease progression, prospective comorbidities, mortality and associations to transcriptomic and proteomic biomarkers. These findings emphasise the clinical and biological relevance of these subtypes, which call for more study for translation into clinical practice.

Trail registration number

NCT00608764.
EP11 The impact of COVID-19 on emergency medical service led out of hospital cardiac arrest resuscitation: a qualitative study
Authors: Coppola Alison , Kirby Kim , Osborne Ria , Black Sarah
Published: August 2022

Background

Following the emergence of COVID-19, there have been local and national changes in the way emergency medical service staff respond to and treat patients in out-of-hospital cardiac arrest. The views of emergency medical service staff on the impacts of COVID-19 on out-of-hospital cardiac arrest resuscitation have not previously been explored. This study aimed to explore the views of emergency medical service staff on the impacts of COVID-19 on out-of-hospital cardiac arrest resuscitation.

Methods

A qualitative phenomenological enquiry was used to explore the views of emergency medical service staff. A purposive sample of n=20 participants of various clinical grades was selected from National Health Service emergency medical service providers in the UK. Data was collected using semi-structured interviews, transcribed verbatim and analysed using inductive thematic analysis.

Results

Three main themes were found; service pressures; decision-making and moral injury. The impacts varied according to clinical grade, location and guidelines.

COVID-19 reduced resources, availability of staff and in-hospital capacity. Change fatigue was found due to the continuous updates of clinical guidelines. There was a disconnect between guidelines and the clinical practice of staff. Staff generally felt supported to make best interest ethical decisions when resuscitation was ineffective. In certain patient groups, staff increased their risk of transmission, compromising recommended levels of personal protective equipment to improve communication and reduce delays to care. The emotional impacts of prolonged and frequent exposure to patient death were apparent.

Conclusion

This study found positive outcomes, but also negative impacts important to inform EMS systems. COVID-19 created delays to resuscitation which were multifaceted. Staff developed new ways of working to overcome the barriers of personal protective equipment. There was little impact on resuscitation procedures. Emergency medical service providers should consider how to limit organisational change and better support the emotional responses of staff.
PP13 A service evaluation exploring the factors paramedics consider when selecting a conveyance destination for survivors of out-of-hospital cardiac arrest
Authors: Zorab Ollie , Kirby Kim , Griggs Matthew
Published: August 2022

Background

National guidance suggests that adult survivors of medical out-of-hospital cardiac arrest (OHCA) should be considered for direct transport to a specialist centre. Much of the research that informs this recommendation originates from urban environments where patients achieve rapid access to hospital. Little evidence could be found describing the decision-making profile and experiences of paramedics caring for OHCA patients and how conveyance destinations are currently selected.

Methods

Qualitative inquiry was used to describe the experiences of paramedics caring for OHCA patients and to determine the factors which constrain or facilitate the direct conveyance to a specialist centre. Data was gathered from two socially distanced focus groups lead by a facilitator using a pre-determined topic guide. Nine paramedics took part in this service evaluation from a single regional UK ambulance service. Focus group conversations were recorded, transcribed, and coded using thematic analysis.

Results

Factors considered by participants could be broadly categorised under five primary themes; available guidance, hospital features, non-technical factors (e.g. dealing with conflict), patient condition and clinical skills. Factors including proximity to hospital, access to specialist services and the availability of pre-hospital enhanced care were identified which resonated with existing literature. Additional issues including managing resistance from other healthcare professionals, decision making based on experience and a reliance on local guidance emerged from the project and were felt to be unexpected.

Conclusion

Paramedics consider a range of factors when selecting a conveyance destination for survivors of medical OHCA, including the hospital’s distance from scene and access to specialist services. The patient’s stability and availability of enhanced care, in particular to manage agitation are also considered. Paramedics predominantly use local Trust guidance, rely on familiarity, or previous experience to help support their decision making and may need to overcome conflict from hospital colleagues to select an appropriate conveyance destination.
PP14 A step toward enhanced EMS telephone triage for chest pain: a Delphi study to define life-threatening conditions that must be identified
Authors: Alotaibi Ahmed , Body Richard , Carley Simon , Pennington Elspeth
Published: August 2022

Background

Improving telephone triage for patients with chest pain has been identified as a national research priority. However, there is a lack of strong evidence to define the life-threatening conditions (LTCs) that telephone triage ought to identify. Therefore, we aimed to build consensus for the LTCs associated with chest pain that ought to be identified during telephone triage for emergency calls.

Methods

We conducted a Delphi study in three rounds. Twenty experts in pre-hospital care and emergency medicine experience from the UK were invited to participate. In round I, experts were asked to list all LTCs that would require priority 1, 2, and 4 ambulance responses. Round II was a ranking evaluation, and round III was a consensus round. Consensus level was predefined at ≥ 70%.

Results

A total of 15 participants responded to round one and 10 to rounds two and three. Of 185 conditions initially identified by the experts, 26 reached consensus in the final round. Ten conditions met consensus for requiring priority 1 response: oesophageal perforation/rupture; ST elevation myocardial infarction; non-ST elevation myocardial infarction with clinical compromise (defined, also by consensus, as oxygen saturation <90%, heart rate <40/minute or systolic blood pressure <90mmHg); acute heart failure; cardiac tamponade; life-threatening asthma; cardiac arrest; tension pneumothorax and massive pulmonary embolism. An additional six conditions met consensus for priority 2 response, and three for priority 4 response.

Conclusion

Using expert consensus, we have defined the LTCs that may present with chest pain, which ought to receive a high-priority ambulance response. This list of conditions can now form a composite primary outcome for future studies to derive and validate clinical prediction models that will optimise telephone triage for patients with a primary complaint of chest pain.
PP15 Research priorities for prehospital care of older patients with injuries: scoping review
Authors: Harthi Naif , Goodacre Steve , Sampson Fiona C , Alharbi Rayan
Published: August 2022

Background

The use of ambulance services by older patients with injuries increases within the impacts of ageing-related changes leading to adverse patient outcomes. There is increasing recognition of the importance of prehospital trauma care for older patients, but little systematic research to guide practice. We aimed to review the published evidence on prehospital trauma care for older patients, determine the scope of existing research and identify research gaps in the literature.

Methods

A systematic scoping review guided by the Arksey and O’Malley framework reported in line with the PRISMA-ScR checklist. A systematic search was conducted of Scopus, CINAHL, MEDLINE, PubMed and Cochrane library databases to identify articles published between (2001-2021) years. Inclusion and exclusion criteria were applied independently by two reviewers. Data were extracted, charted and summarised from eligible articles.

Results

65 studies were identified and reviewed, and 25 included. Five categories were identified: ‘field triage, ‘ageing impacts’, ‘decision-making’, ‘paramedic’ awareness’ and ‘paramedic’s behaviour’. Undertriage & overtriage (sensitivity & specificity) were commonly cited as poorly investigated field-triage subthemes. Ageing-related physiologic changes, comorbidities and polypharmacy were the most widely researched. Inaccurate decision-making and poor early identification of major injuries were identified as potentially influencing patient outcomes. More research is required into paramedic knowledge of geriatric care & ageing changes and the potential impact of paramedic care.

Conclusion

This is the first study reviewing the published evidence on prehospital trauma care for older patients and identifying research priorities for future research. This review has identified the prehospital triage for older trauma victims and studies of paramedic knowledge of older trauma care as key priorities. Investigating and understanding these can improve providing prehospital care of the older patient with injuries for positive patient outcomes.
PP16 A comparison of Australasian jurisdictional ambulance services’ paramedic clinical practice guidelines series: adult anaphylaxis
Authors: Wilkinson-Stokes Matt , Rowland Desiree , Spencer Maddison , Maria Sonja , Colbeck Marc
Published: August 2022

Background

This article forms part of a series that seeks to identify interjurisdictional differences in the scope of paramedic practice and, consequently, differences in patient treatment based on which jurisdiction a patient is geographically located within at the time of their complaint.

Method

The current Clinical Practice Guidelines of each Australasian domestic jurisdictional ambulance service (JAS) were accessed during June 2020 and updated in August 2021. Content was extracted and verified by 18 paramedics or managers representing all 10 JASs.

Results

All JASs use intramuscular adrenaline as a first-line agent for adult anaphylaxis. Beyond this, significant differences exist in all treatments: five services provide nebulised adrenaline; 10 services provide adrenaline infusions (one requires doctor approval; one provides repeat boluses); six services provide nebulised salbutamol; two services provide salbutamol infusions (one requires doctor approval; one provides repeat boluses); five services provide nebulised ipratropium bromide; eight services provide corticosteroids (two restricted to intensive care paramedics (ICPs)); five services provide antihistamines for non-anaphylactic or post-anaphylactic reactions; four services provide glucagon (one requires doctor approval); magnesium is infused by ICPs in two services; 10 services allow unassisted intubation in anaphylactic arrest; one service allows ICPs to provide sedation-facilitated intubation or ketamine-only breathing intubation; eight services allow rapid sequence induction (two restricted to specialist roles).

Conclusion

The JASs in Australasia have each created unique treatment clinical practice guidelines that are heterogeneous in their treatments and scopes of practice. A review of the evidence underlying each intervention is appropriate to determining best practice.
PP17 Differential rater function over time (DRIFT) is not appreciated in paramedic raters using the global rating scale (GRS) during paramedic student simulations
Authors: Diebel Sebastian , Boissonneault Eve , Perreault Luc , Lapierre René
Published: August 2022

Background

The field of paramedicine continues to advance in scope. Simulation training is frequently used to teach and evaluate students. Simulation examinations are often evaluated using a standardized global rating scale (GRS) that is reliable and valid. However, the effects of differential rater function over time (DRIFT) have not been evaluated on the GRS during simulations. This study aimed to assess if DRIFT exists during a GRS.

Methods

Data was collected at Collège Boréal, Sudbury, Ontario, Canada during the 6 simulation evaluations within the scholastic year. Raters were randomly assigned to evaluate several students at the same station. Each station lasted 12-minutes in length and there was a total of 11-stations. A model to test the scores of DRIFT was created and was tested against both a leniency and perceptual model to explain DRIFT.

Results

Amongst the explored alternatives, a model that included students, the rater, and the dimensions had the greatest evidence (-3151 Bayes Factors). This model was then tested against leniency (K= -9.1 dHart) and perceptual models (K= -7.1 dHart) suggesting a substantial finding against DRIFT, however, the tested models used a wide parameter, therefore, the possibility of a minor effect is not fully excluded.

Conclusion

DRIFT was not found; however, further studies with multiple centres and longer evaluations should be conducted.
02 Service provider views of the safety, appropriateness and perceived acceptability of telephone advice for calls to the ambulance service triaged as low urgency
Authors: Coster Joanne , Sampson Fiona C , O’Cathain Alicia , Nicholl Jon
Published: August 2022

Background

High demand for ambulance care has led to changes in service provision, with calls identified as lower urgency increasingly being dealt with by telephone advice. A systematic review identified evidence of the feasibility of ambulance telephone advice but found little evidence around dimensions of quality e,g, safety This study uses interviews with service providers to explore the safety, appropriateness and acceptability of ambulance telephone advice.

Methods

Semi-structured interviews were undertaken with 16 staff involved in the telephone advice process, including Call Handlers, Clinical Advisors and staff with a strategic service overview. Interviews were undertaken in one English ambulance service during the last quarter of 2020. Definitions of safety, appropriateness and acceptability were developed from a narrative review and applied to the interview findings. Interviews were analysed thematically using Framework.

Results

Service provider interviews identified safety mechanisms at service, team and individual levels that enhance safety e.g. call auditing, clinical governance processes, multi-disciplinary Clinical Advisor team, and providing all calls with advice about what to do if a problem worsens. However, some staff perceived some gaps in service safety relating to under-triage, long waits for a clinical call back and concerns about the triage Concerns Process. Interviewees perceived telephone advice as mostly appropriate but identified mental health calls as very challenging for non-mental health specialists. Interviewees perceived user acceptability of telephone advice as mixed and linked to expectations around receiving an ambulance, whether the caller is reassured and length of time to receive a clinical call back.

Conclusions

Service providers perceived that telephone advice was mostly a safe and appropriate method of handling lower urgency calls. The introduction of mental health nurses to the Clinical Advice team was perceived as beneficial to the overall safety and appropriateness of mental health calls.
PP31 Airway management at adult out-of-hospital cardiac arrest: a survey of current UK ambulance service policy
Authors: Aljanoubi Mohammed , Brown Terry , Couper Keith , Fothergill Rachel , Perkins Gavin
Published: August 2022

Background

Over 80% of the 30,000 out-of-hospital cardiac arrest (OHCA) patients treated in the UK each year receive advanced airway management (tracheal tube or supraglottic airway). Recent data from large randomised control trials have highlighted uncertainty regarding the clinical benefits of tracheal intubation and may have driven changes in ambulance service policy. We conducted a survey study to investigate the current UK ambulance service policy on the use of tracheal intubation during adult cardiac arrest.

Methods

We surveyed all UK ambulance services using an online survey platform to determine which staff groups are permitted to perform tracheal intubation and associated information linked to advanced airway management in adult cardiac arrest. A single representative of each ambulance service was requested to respond to the survey. The University of Warwick Biomedical & Scientific Research Ethics Committee provided ethical approval for the study.

Results

We received survey responses from all 14 UK NHS ambulance services (response rate 100%).

Five ambulance services (35.71%) do not permit non-specialist paramedics to perform tracheal intubation at adult out-of-hospital cardiac arrest. Of these services, the first service to withdraw tracheal intubation did so in 2010, whilst the remaining four did so from 2019 onwards. One further ambulance service stated they are currently in the process of withdrawing tracheal intubation.

Of the five services that have withdrawn tracheal intubation, cited reasons for the policy change were challenges in providing ongoing training (n=5, 100%), results of clinical trials (n=4, 80%), clinical incidents of tracheal tube misplacement (n=4, 80%), and low tracheal intubation success rate (n=3, 60%).

All 14 ambulance services (100%) reported that waveform capnography was available to ambulance crews.

Conclusion

This study identified UK ambulance service policy variations concerning non-specialist paramedic use of tracheal intubation in adult cardiac arrest. The clinical impact of this variation requires further research.