bluuebunny/crossref_metadata_2025 huggingface dataset:
126 A Laboratory Procedure and a Recording System for the Maintenance of Personal, Hand-Held and Benchtop Time-Resolved Aerosol Instruments
Authors: Hunwin Graeme , Hall Samantha , Saunders John , Bard Delphine
Published: May 2023

The HSE Science and Research Centre use time-resolved instruments to collect aerosol data for research and to support the sampling of aerosols in workplace environments. The performance of these instruments (traditional and low cost sensor devices) is dependent on regular maintenance and calibration. However, it can deteriorate within the recommended manufacturer calibration period, particularly if they have been exposed to high concentration of dust, or exposed for extended periods. This poster will describe the practical strategy developed at HSE for the maintenance of time-resolved devices and the lessons learnt. HSE owns a range of hand-held or compact time-resolved instruments, which are optical particle counters (OPCs), condensation particle counters (CPCs), diffusion chargers as well as photometers measuring particle number, surface area and mass concentrations. Some of the instruments are size-resolved devices. Photometers and OPCs were benchmarked using SPHERIGLASS ® A- 5000 in a calm-air chamber for a wide range of concentrations against a dedicated reference photometer or OPC, not necessarily of the same model or size range characteristic. For devices, measuring in the nanometre size range (CPCs and Diffusion Chargers), a salt nanoparticle aerosol was generated using a Collison nebulizer and a CPC used as the reference. Acceptable tolerances from the reference concentration were established for the CPCs and Diffusion Chargers. For each photometer model, an average ratio of the evaluated photometers concentrations by the reference photometers concentrations was calculated and a linearity plot of the photometer concentration versus the reference photometer concentration was established.

© Crown Copyright (2022)
144 Development of a New Hs-Gc-Ms Method for Concurrent Analysis of Acetone, Methylethylketone, Methylisobutylketone and Cyclohexanone in Urine
Authors: Erb Amandine , Ndaw Sophie
Published: May 2023

Mixed exposure to chemical products is a topical issue for occupational health. Because very few methods are available for evaluating these mixed exposures, the aim of this work was to develop a simple biomonitoring method for assessing simultaneous occupational exposures to four ketones: acetone, methylethylketone (MEK), methylisobutylketone (MIBK) and cyclohexanone in urine. These ketones were selected for their industrial use and their adverse effects on the workers’ health. Some sectors of activity, like the plastic industry for instance, may even expose workers simultaneously to several of these ketones. Volatile organic compounds were analyzed using static headspace gas chromatography coupled to mass spectrometry (sHS-GC-MS), and the four unmetabolized ketones were measured in the headspace phase, after an in-vial pentafluorobenzylhydroxylamine (PFBHA) derivatization step. The calibration was performed using synthetic urines spiked with known amounts of the four ketones. A satisfactory level of sensitivity, whose limits of quantification (LOQ) were between 5 and 20 µg/L was achieved. Calibration curves were linear in the 5-2000 µg/L range, with R2 correlation coefficients from 0.9967 to 0.9990. At 20 µg/L, within-day precision varied from 1.7 to 5.6 % and between-day precision ranged from 4.5 to 9.5 %. Tests on real urinary samples obtained from unexposed persons showed concentrations coherent with those of the general population for acetone and MEK. In conclusion, a fast, sensitive, specific and easy-to-use method was developed for extracting and quantifying simultaneously four ketones from urinary samples using sHS-GC-MS. This method will be a valuable tool for the monitoring of occupational exposures.
161 Keynote: Characterising Microplastic Exposure and Hazards: Challenges and Opportunities
Authors: Wright Stephanie
Published: May 2023

Plastic is the third most abundant manmade material on the planet. Whilst often considered durable, it sheds micro- and nanoscopic debris (‘microplastic’) to the environment, which contaminates water, dust, and food globally. Recently, microplastic has been reported in atmospheric deposition and airmasses around the globe, suggesting a complex cycle before it reaches its environmental – or biological – fate. Furthermore, the discovery of microplastic in ambient and indoor air has raised concern for public exposure via inhalation and potential impacts on health. In laboratory studies, exposure to high levels of certain types of microplastic can cause adverse effects, primarily oxidative stress, and metabolic disruption.  However, there are critical physicochemical factors which govern both the fate and effects of inhaled material in the body and very little is known for microplastic. This talk will give an overview of the progress in plastic aerosol research, from early environmental measurements to analytical and data science advances to hazard characterisation. It will highlight challenges, knowledge gaps, and opportunities for research. As discussions for a proposed UN Treaty on Plastic Pollution develop and the rate of plastic production continues to grow, it is timely to consider microplastic exposure and its potential role in disease pathways.
11 Raman Spectroscopy to Monitor Short-Term and Transient RCS Aerosol Exposure
Authors: Schweinar Kevin , Manole Mihaela , Szakács Zoltán , Altmaier Ralph , O'Shaugnessy Patrick T , Bieri Rudolf
Published: May 2023

Exposure to respirable crystalline silica (RCS) at concentrations at or below the OSHA permissible exposure limit (PEL) of 50 µg/m3 are challenging to monitor with the current industry standard methods X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). In particular, the assessment of short-term or transient exposure to RCS concentration calls for more sensitive analytical methods that are able to quantify RCS from low dust amounts within the desired uncertainty limits. Here, we present results from a verification study of a Raman spectroscopy-based Identifier system including dedicated respirable air samplers (badges) for the collection of airborne RCS. The air sampling badges concentrate the analyte onto dedicated 1 mm2 collection membranes suitable for direct-on-filter (DOF) Raman analysis. The sampling efficiency of the badges was assessed experimentally and shown to closely adapt the respirable sampling convention according to ISO 7708, with a low sampler bias of < 10%. Using a fully automated Raman-based bench-top reader, the limit of detection (LOD) and limit of quantification (LOQ) were determined empirically with 0.1 and 0.3 µg, respectively. The limits are approx. an order of magnitude lower than for the current industry standards and enable the relevant monitoring of short-term or transient exposure of workers to RCS, as they typically occur in construction or mining environments. The optimized workflow of the Identifier system makes it an attractive alternative to the industry standards XRD and FTIR, with the opportunity to monitor exposure down to the action level.
34 Placental-Fetal Distribution of Carbon Particles in a Pregnant Rabbit Model After Repeated Exposure to Diluted Diesel Engine Exhaust
Authors: Bongaerts Eva , Nawrot Tim , Wang Congrong , Chavatte-Palmer Pascale , Ameloot Marcel , Bové Hannelore , Roeffaers Maarten , Couturier-Tarrade Anne , Cassee Flemming
Published: May 2023

Airborne pollution particles have been shown to translocate from the mother’s lung to the fetal circulation but their placental-fetal distribution and internal tissue load remain poorly explored. Here, we investigated the placental-fetal distribution of diesel engine exhaust particles during gestation under controlled exposure conditions using a pregnant rabbit model. Pregnant dams were exposed by nose-only inhalation to either clean air (controls) or diluted and filtered diesel engine exhaust (1 mg/m3) for 2h/day, 5 days/week, from gestational day (GD) 3 to GD27. At GD28, placental and fetal tissues (i.e., heart, kidney, liver, lung and gonads) were collected for biometry and to study the accumulation of carbon particles (CPs) using white light generation by carbon particles under femtosecond pulsed laser illumination. CPs were detected in the placenta, fetal heart, kidney, liver, lung and gonads in significantly higher amounts compared with controls. By using multiple factor analysis, we were able to discriminate the diesel engine-exposed pregnant rabbits from the control group taking all variables related to fetoplacental biometry and CP load into consideration. Although our findings did not reveal a sex effect, a potential interaction effect might be present between exposure and fetal sex. The results confirm the translocation of maternally inhaled CPs from diesel engine exhaust to the placenta and the ability to reach fetal organs during late-stage pregnancy. The differential particle load in the fetal organs may contribute to the disruption of blood flow in the placenta with possible effects on fetoplacental biometry and placental function.
86 Persistent Macrophage Depletion and Arrested Replenishment is Dependent on Carbon Nanotube type as Shown by Single Cell Transcriptomics
Authors: Voss Carola , Han Lianyong , Ansari Meshal , Liu Qiongliang , Ballester-Lopez Carol , Conlon Thomas M , Haefner Verena , Strunz Maximilian , Angelidis Ilias , Mayr Christoph , Rehberg Markus , Yildirim Ali Önder , Schiller Herbert B , Stoeger Tobias
Published: May 2023

Inhalation of carbon nanomaterials (NMs) can cause severe health effects, including chronic inflammation and fibrosis. We aim for a better understanding of NM specific cellular perturbation patterns. Therefore, we exposed mice intratracheally to soot like carbon black, tangled double-walled (DWCNT) and rigid, multi-walled carbon nanotubes (MWCNT). All lungs underwent single cell RNA sequencing and BAL analysis at 12h, 6d and 28d.  At the chosen doses, all NMs caused comparable airspace neutrophilia at 12h, which increased until d6 for CNTs and remained elevated until d28 for MWCNT. We observed a significant increase in total BAL macrophages, however, exclusively after 6d CNT instillation. This d6 peak coincided with the loss of F4/80+/CD11c+/CD11b- alveolar macrophages (AMs) for MWCNTs, and to a lesser extent DWCNTs, in lung FACS.  In parallel, we noticed the pulmonary accumulation of a transitional macrophage population at d6 uniquely after MWCNT instillation, and not DWCNTs. According to RNA velocity analysis, blood monocytes differentiate into Lyve1-/CD163- interstitial macrophages and subsequently give rise to this transitional population which fails to replenish the CD11c+/SiglecFhigh AM pool. These cells show high similarity with the initiating monocyte-derived macrophage population necessary for bleomycin- and asbestos-induced lung fibrosis (Misharin et al.,JEM,2017.214(8)). The pro-fibrotic role of this population also has been demonstrated in context of SARsCoV2 infection-associated acute respiratory distress (Wendisch et al.,Cell,2021.184(26)).

We summarize, that this transitional cell population are monocyte-derived AM precursors, which lack the ability to differentiate into mature AMs being the decisive mechanism for MWCNT induced, not resolving lung fibrosis.
146 Meteorological Influence on Measurement Strategy and Estimated Respirable Dust and Respirable Crystalline Silica Exposure Levels Within the European Minerals Industry
Authors: Blagrove-Hall Nicola , Houba Remko , Kromhout Hans
Published: May 2023

The evidence of meteorological conditions on occupational exposure measurements is limited, despite is expected to be important determinants of long-term exposures. We describe meteorological conditions for measurement and non-measurement days and evaluate associations between temperature and total precipitation and respirable dust and respirable crystalline silica (RCS) concentrations of the European Industrial Minerals Association-Dust Monitoring Programme.   Geo-matched RCS and dust measurements were evaluated against meteorological data (archived satellite observations and weather station measurements). Temperature(0C) and total precipitation (mm) for RCS measurement and non-measurement days were described. A linear regression model was used to investigate the association between dust and RCS concentration and meteorological conditions.  Overall, 2,840 dust measurements (GM=0.20mg/m3; GSD=3.43mg/m3) and 2,658 quartz measurements (GM=0.01mg/m3; GSD=5.23mg/m3) were collected across 96 an 94 industrial mineral sites over 262 and 259 days in 2011. Mean temperature and precipitation for dust and RCS measurements were similar for measurement and non-measurement days (dust: 10.490C and 10.830C, 2.23mm and 2.12mm; RCS: 11.050C and 10.820C, 2.08mm and 2.12mm).  For respirable dust concentrations a 6.4% decrease per 1°C was estimated for temperatures<200C (p<0.001) and an 8.2% increase for temperatures≥200C (p=0.002). For RCS a 2% decrease in was estimated for every 1mm increase in total precipitation (p=0.02).  No difference in meteorological conditions were seen between measurements days and non-measurement days. Associations of these conditions with exposure concentrations with showed differences between agents despite being collected and measured on the same filter.  Long-term changes in meteorological conditions might be an important factor when estimating long term exposures.
153 Nearly free Surface Silanols: from Silica Towards a new Paradigm for Particle Toxicity
Authors: Pavan Cristina , Bellomo Chiara , Cananà Stefania , Tomatis Maura , Escolano-Casado Guillermo , Mino Lorenzo , Lison Dominique , Turci Francesco
Published: May 2023

Respirable crystalline silica (RCS) is the leading cause of occupational respiratory diseases worldwide. RCS is associated with inflammatory lung reactions, which can lead to silicosis, cancer, and autoimmune diseases. The extreme variability of silica specimens, including its amorphous forms, the surface heterogeneity, and variable toxicity effects, generated one of the most intriguing enigmas in particle toxicology, i.e., deciphering which physico-chemical features explain and predict the variable hazard of silica. Using a set of ad hoc prepared synthetic and natural quartz particles, we have identified a unique subfamily of surface silanols as a key initiator of the toxicity of silica particles. These moieties, namely the "nearly-free silanols" (NFS), appear on the surface of quartz when crystals are fractured, and their amount can be modulated by physico-chemical processes. The peculiar spatial arrangement of NFS was demonstrated as the most energetically favorable and selective for interacting zwitterionic phospholipids that make up cell membranes. The toxic activity of NFS was also confirmed with amorphous nanosilica synthesized at high temperatures, and our recent findings suggest that NFS could impart toxic properties to other silica polymorphs and hydroxylated surfaces, including aluminosilicates and engineered stones. Overall, NFS occurrence accounts for the origin and variability of the toxicity of silica, opening perspectives for controlling RCS hazard, and may contribute to understand other important interfacial phenomena of hydroxylated materials.
19 Does Developmental Status and age of the Lung Influence the Hazard Elicited by Exposure to Both Indoor and Outdoor Pollutants?
Authors: Meldrum Kirsty , Doak Shareen H , Clift Martin J D
Published: May 2023

Many in vitro studies that focus upon lung toxicology use models that assume, or are specifically based upon adult lung structure, function, and physiology. Yet, the most vulnerable groups of the human population (i.e., young, elderly, and diseased) have an altered lung structure and function. Notably, the developing lung (in utero) and infant lungs exhibit notable differences in term of cell type, number, ratio, organ size and surface area. Recent work has identified the detrimental implications of being exposed to AP while the lung is developing. To elucidate the mechanisms associated with AP exposure to the developing lung, the aim of this study will create and characterise an in vitro model of the foetal human bronchial region composed of cells physiologically appropriate to various stages of development, as well as an older child’s airway, notably the developing alveoli. This will allow us to determine the developmental effects of air pollution particles at an air-liquid interface (ALI) utilising a physiologically relevant aerosol exposure and standardised particulate aiming to mimic indoor and outdoor air pollution. For this work, a global approach will be utilised to determine up and down regulation of various pathways associated with both development and exposure to AP. A further aim will include comparison with an “adult” lung to analysis the potential developmental implications exposure to AP may illicit. 

This project is funded by the recently initiated RESPIRE project (NE/W002264/1), as part of the SPF Clean Air Programme.
26 An Advanced Triple Cell co-Culture of the Alveolar Epithelial Barrier for Inhalation Hazard Assessment in Vitro
Authors: Bateman Joshua , Doak Shareen H , Clift Martin J D
Published: May 2023

In vitro lung models are a valuable tool to assess the inhalation hazard of air pollutants, bioaerosols, chemicals and nanomaterials. Though it is essential that these models are characterised and anatomically relevant to the area of the human lung they seek to represent. Previously within inhalation toxicology, focus has been placed on the use of monocultures of alveolar epithelial cells, however use of alveolar co-culture models have been presented as more realistic and sensitive models. Here, we present the development of a novel triple cell co-culture system, cultured at the air-liquid interface that is sensitive to LPS and particulate matter. This co-culture contains alveolar type 1 cells (hAELVi), alveolar type 2 cells (NCI-H441) and alveolar macrophages (differentiated THP-1 (dTHP-1) using PMA (20 nM)). Using CellTrackers™ with confocal microscopy, the ratio of hAELVi cells to NCI-H441 cells was confirmed to be a histologically relevant 16:1 ratio forming a tight monolayer shown through blue dextran membrane permeability assay. Macrophages were seeded on top of the epithelial co-culture at an anatomically relevant density of 1 macrophage per 18x103 μm2 (confirmed via confocal microscopy) to form the triple cell co-culture. The model, when challenged, released more interleukin-8 and TNF-α than the epithelial mono- and bi-culture systems when exposed to LPS (1 μg/mL for 24 hrs) (p<0.05), suggesting that the macrophages do mount the theoretical (pro-)inflammatory response. This anatomically relevant in vitro model forms the basis to investigate inhaled exogenous substances, such as the differential toxicology impacts of particulate matter and nitrogen dioxide.
41 The Mechanisms of Allergy to Fungal Bioaerosols in the Lung
Authors: Goode Emma-Jane , Marczylo Emma
Published: May 2023

Allergic airways disease (AAD) is a collective term for respiratory disorders that can be exacerbated upon exposure to airborne allergens. The contribution of fungal allergens to the pathogenesis of AAD has become well established over recent years and can be present in the air we breathe as bioaerosols. Understanding the mechanisms allergy to fungal bioaerosols can help to better manage symptoms and conditions, reducing the burden of disease. We conducted a comprehensive review to collate the current understanding of mechanisms involved in the allergic response to fungal bioaerosols in airway epithelia. To be included in the final analysis, studies were compared to defined inclusion/exclusion criteria, relevant data was extracted, and each paper was assessed using a quality scoring tool. The search string provided 440 initial results with 60 studies selected for final analysis. 120 potential target mechanisms were identified within the selected studies and 17 were identified in more than 5 studies. The major pathways identified in allergic response include 1) a role for proteases and the activation of the PAR2 receptor, 2) release of IL33, 3) EGFR pathway and mucin expression, and 4) a skewing towards a Th2 profile promoting eosinophil recruitment. However, there was conflicting evidence when comparing results from individual studies. Thus, further research is required to better understand which fungi/fungal components drive the allergic response.

Funding: This work has been funded under the NIHR Health Protection Research Unit for Environmental Exposures and Health with Imperial College London
67 Development of a Physiologically-Relevant in Vitro Model of the Lung, Incorporating Novel Peptide Hydrogels as Biomimetic Extracellular Matrix Scaffolds
Authors: Murphy Fiona
Published: May 2023

The vast number of different nanomaterials (NMs) in production and under development precludes the complete hazard assessment of each individual substance according to current regulatory standards which require long term in vivo studies. To reduce the burden of in vivo toxicity testing more physiologically relevant in vitro pulmonary models are required to predict the inhalation hazard posed by aerosolized particles, including NMs. Recently significant progress has been made in the development of multi-cell 3D models which mimic the cellular constituents of tissues and organs, few models under development concomitantly take into account the functional role of the extracellular matrix (ECM) in determining the tissue microenvironment and behaviour of cells. This project specifically aims to develop an in vitro model composed of multiple cells-types grown directly in contact with hydrogel scaffolds which mimic the ECM to better replicate the in vivo microenvironment. We hypothesize the novel addition of an ECM mimetic will influence cell phenotype and activation after exposure to NMs. Preliminary data summarising the process of model building and characterisation including selection of appropriate cell lines and gel formulations, optimisation of culture conditions and evaluation of the integrity of the hydrogel scaffolds is presented. This application of this model will then be evaluated for use in toxicology testing of NMs and predictivity of hazard compared to existing data from both simple 2D in vitro systems and in vivo toxicology studies. In future the potential advantages and limitations of the approach will be evaluated and relevant adaptions to be further explored.
81 Traac Framework and tool for Regulatory Acceptance and Wider Usability of Tools/Methods for safe Innovation and Sustainability of Nanomaterials
Authors: Shandilya Neeraj , Barreau Marie-Sophie , Suarez-Merino Blanca , Porcari Andrea , Pimponi Daniela , Jensen Keld , Dekkers Susan , Fransman Wouter , Kalkman Gino , Otto Marlies , van Someren Eugene , Franken Remy
Published: May 2023

There has been an increasing use of manufactured nanomaterials in industrial applications and consumer products. It has instigated concerns about the sustainability, risks and uncertainties regarding the interactions of the nanomaterials with humans and the environment. Consequently, significant resources in Europe have been invested into tool and method development to support risk mitigation and management, facilitating the research and innovation process of manufactured nanomaterials. Extended risk analysis, including socio-economic impact and sustainability assessment is moving the conventional risk-based approach towards a wider safety-and-sustainability-by-design perspective. Despite growing tool and method developments, the level of awareness and use by stakeholders is still limited. Regulatory compliance and acceptance, reliability and trust, user-friendliness and compatibility with the users’ needs are important factors traditionally known to hinder their widespread use. Therefore, a framework is presented to quantify the readiness of different tools and methods towards their wider regulatory acceptance and downstream use by different stakeholders. The framework, developed within Gov4Nano, diagnoses barriers which hinder regulatory acceptance and wider usability of a tool/method based on their Transparency, Reliability, Accessibility, Applicability and Completeness (TRAAC framework). An online TRAAC tool is being developed within HARMLESS that will be freely available on https://diamonds.tno.nl/#traac. Fourteen tools and methods were assessed using the TRAAC framework as proof-of-concept. The results provide insights into any gaps, opportunities, and challenges in the context of each of the 5 pillars of the TRAAC framework.
120 An Evaluation of Uncertainty Within Control Banding Tools used for Occupational Exposure Assessment of Nanoforms and Nano-Enabled Products
Authors: Nebbia Rebecca , Hanlon James , Boyles Matthew , Genta Gianfranco , Galetto Maurizio , Bergamaschi Enrico , Tran Lang
Published: May 2023

The use of control banding tools to aid in diminishing risks to nanomaterial exposure play an important part in early-stage risk assessment. With the inclusive nature of these tools, comes a certain amount of uncertainty with their findings, and uncertainty evaluation is an aspect which has scope for improvement in the current tools. The European Chemicals Agency provide three types of uncertainty to be assessed for chemical safety: Model uncertainty which relates to simplifications the model makes, Parameter uncertainty which relates to individual model parameters and Scenario uncertainty which is user dependent. To define possible improvements, the SAbyNA project has made investigations into Parameter uncertainty, and have used the Theory of Scales of Measurement, developed by Stevens. The identification of the measurement scale leads to the understanding of the permissible statistics (e.g., standard deviation) that can be performed with the data. To facilitate the assessment of the scale and the statistics, a check list was produced. Several control banding tools were analysed, and these tools employ ordinal scoring scales, which means that calculating average values and confidence intervals is not permissible. As evaluating the uncertainty in results greatly helps the exposure assessment, because it would describe the “quality” of the data and allow definitive comparisons among each other, it is recommended to improve the quantitative exposure estimation through sampling methods to get more measurements, which are beneficial for the uncertainty evaluation and for which the uncertainty can be evaluated according to the Guide to the expression of uncertainty in measurement.
144 Occupational Exposure to Particles Measured by Nanoparticles Tracking Analysis (NTA) in Exhaled Breath Condensate (EBC).
Authors: Panizzolo Marco , Barbero Francesco , Squillacioti Giulia , Ghelli Federica , Bono Roberto , Bellisario Valeria , Guseva-Canu Irina , Fenoglio Ivana , Bergamaschi Enrico
Published: May 2023

The production of paints, coatings and construction materials may generate nanoparticles (NP) with potential adverse health effects. We carried out a study aimed at investigating exposure biomarkers reflecting the internal dose of inhaled particles and NP. NTA was used to quantify particle number concentration and size in EBC collected at the end of shift in 81 workers employed in companies producing technological materials. External exposure was characterized in terms of particle number concentration, size and lung deposited surface area (LDSA) in the near operational field by using a set of DiSCmini. Three subgroups were identified: Low-Exposure (LE, n=30), High-Exposure (HE n=35), and non-occupationally exposed (UC, n=16). Comparisons between groups were made using non-parametric analyses. LE and HE workers showed significantly higher number of NP in EBC (p=0.024, p=0.041, respectively) as compared to UC. The HE groups showed higher levels of inflammatory biomarkers, such as IL-1β and IL-10 as compared to LE and UC (p=0.02, p<0.01, respectively). Positive correlations were observed between particle number concentration recorded by DiscMini and NTA data (Rho=0,225, p=0.04) and between the NTA and IL-10 and IL-1β (Rho=0.246, p=0.012; Rho=0.223, p=0.022, respectively). In contrast, LDSA did not correlate with NTA data. These findings provide evidence of the relationship between increasing exposure to NP and the burden of particles in the airways which, in turn, results in sustained inflammation. Given the lack of exposure biomarkers for dusts, these results are promising to investigate the relationship between internal dose of particles and changes in lung pathobiology.
O003 Comprehensive assessment of the management of acute cholecystitis in Scotland: a population wide cohort study of 47,558 patients
Authors: Rajan S , Bekheit M , Wohlgemut J M , Watson A J M , Ramsay G
Published: May 2023

Introduction

Acute cholecystitis (AC) is one of the most common diagnoses within Emergency General Surgery, managed either operatively (cholecystectomy) or conservatively. Surgery in the acute phase has been shown to be safe and superior, however, operative rates vary widely. Furthermore, medium-long term survival rates with each approach are still not definitively established. This real-world population analysis aims to describe the current management and outcomes of patients with AC across Scotland.

Methods

This was a national cohort study using data obtained from Information Services Division, Scotland. All adult patients with the admission diagnostic code for AC were included. Patient level data were used to identify all patients admitted to Scottish hospitals between 1997–2019 and outcomes tracked for inpatients or after discharge through the unique patient identifier. This was mapped to mortality data to establish date and cause of death.

Results

47558 patients diagnosed with AC, admitted in one of 46 hospitals were included. These patients accounted for 58824 episodes (27.2% of patients encountered >1 episode). The study population had a median age of 58 years (IQR=43-71), 64.4% were female, and most had no comorbidities. 28741(60.4%) patients had an operative intervention during the index admission. Patients who had an operation during their index admission had a lower risk of 90-day mortality compared to non-operative management (OR=0.62, 95%CI=0.55-0.70).

Conclusion

In this comprehensive analysis of AC in Scotland, 60% of patients had an index cholecystectomy. Patients undergoing surgery had a superior survival to those managed conservatively, further advocating for an operative approach in this cohort.
O013 Omental-derived stromal-vascular cell fraction / alginate gel composite vs control to improve murine colonic anastomotic leak rate - a randomised controlled study
Authors: Burke J , Maisey T , Khalil M , Karki B , Wong J , Quyn A , Herrick S , Jayne D
Published: May 2023

Introduction

Colorectal anastomotic leak (AL) remains a significant challenge. The M-OMENTUM study compared omental-derived stromal-vascular cell-fraction (OSVCF) / alginate gel composite vs control subgroups to prevent murine AL.

Methods

C57BL-6 mice were subjected to an AL model with a leak rate (LR) of 40% and randomised (1:1) to OSVCF / alginate gel or control subgroups (gel alone and no treatment) powered to detect a 20% minimum difference (50% absolute reduction in LR); HO Licence PP9886008. Mice underwent laparotomy and colo-colonic anastomoses. In the intervention group, OSVCF was harvested and applied to the anastomosis in an alginate gel. Mice underwent schedule 1 killing at day 7 or earlier if they failed to meet wellness thresholds. The primary outcome was LR. Secondary outcomes included leak severity, weight, and adhesion score. An intention-to-treat analysis was performed.

Results

128 mice (M:64/F:64), mean age 13.1 weeks (SD,1.2), mean weight, 24.1g (SD,4.3) were randomised. OSVCF/Gel containing mean 3.3×103cells/mg (SD,0.3×103) was applied in the intervention group. Overall LR was 49.2%. There was a numerical difference in LRs between the intervention group (30/64, 46.9%) and control groups (33/64, 51.5%) with a LR reduction of 9.1% (RR 0.91 [95%CI:0.64-1.69]; P=0.72). 12/33(36.4%) that received gel alone and 5/33(15.2%) that received no treatment developed an abscess rather than feculent peritonitis (RR 2.26 [95%CI:1.11-5.20]; P=0.04).

Conclusion

OSVCF/gel produced a 9.1% reduction in LR, but this did not reach statistical significance. The application of gel to an anastomosis alters the severity of anastomotic leak, favouring abscess formation rather than faecal peritonitis.
O022 Real-time artificial intelligence instructor vs expert instruction in teaching of expert level tumour resection skills – a randomized controlled trial
Authors: Yilmaz R , Bakhaidar M , Alsayegh A , Del Maestro R
Published: May 2023

Introduction

Competency-based approach in surgical training still lacks objective quantifiable methodologies to assess surgical technical skills and train residents, a limitation that can be addressed with the adaptation of artificial intelligence (AI). In this randomized controlled, the efficacy of learning by a real-time intelligent instruction system was compared to learning with in-person human instructor-mediated training.

Methods

The study was ethics approved. Ninety-eight medical students performed five virtually simulated brain tumour resections, randomly allocated into three feedback groups: (1) no-real-time feedback, (2) real-time intelligent instruction, and (3) in-person human instruction. The first task was considered as baseline performance, done with no feedback. Group-1 received expert benchmark feedback only after each procedure. Group-2 was instructed in real-time by the AI system. After each task, the students were shown their error-video clips generated by this system alongside the expert-level demonstrations relating to each error. Group-3 was instructed by human instructors during the tasks. After each task, instructors summarized the areas of improvement and demonstrated how to expertly perform the tumour resections. Participant data in all tasks were scored by the AI system to assess learning.

Results

Students in Group-2 and Group-3 significantly improved their performance score by the third and second task, respectively (p<0.01, p=0.01), compared to the baseline performance. Group-2 achieved significantly higher scores than Group-3 in the final/fifth task (p<0.01).

Conclusion

AI-powered systems may increase efficiency in learning by providing objective, and action-oriented real-time feedback. Such systems may aid the shift towards competency-based surgical curricula.
O030 DIEP flap reconstruction- a single-centre comparison of unipedicled and bipedicled DIEP flaps
Authors: Ahmed Z , Ioannidi L , Hamilton S , Ghali S , Shtarbanov P , Nikkhah D
Published: May 2023

Introduction

The deep inferior epigastric perforator (DIEP) flap is the gold standard for autologous breast reconstruction. One or two pedicles may be used. Our study is the first to compare unipedicled vs bipedicled DIEP flaps on donor site morbidity and breast outcomes in the same set of patients.

Methods

A retrospective cohort study comparing outcomes of DIEP flaps between 2019–2022 at our hospital.

Results

There were 98 patients, categorised differently based on breast or donor site. The three breast groups were unilateral unipedicled (N=52), bilateral unipedicled (N=15) and unilateral, bipedicled (N=31) and donor site groups were, unipedicled (N=52) and bipedicled (N=46, bilateral unipedicled and unilateral bipedicled). Bipedicled DIEPs had 1.15 times greater odds of a donor site complication than unipedicled DIEPs (95% CI 0.52, 2.55). Adjusting for operative time which was longer in bipedicled DIEPS (p<0.001), odds ratio decreased and there was a lower probability of developing a donor site complication for bipedicled (OR 0.84, 95% CI 0.31, 2.29). Odds of developing a breast complication were not significantly different between groups. Unilateral unipedicled DIEPs had a significantly higher rate of revisional elective surgery than unilateral bipedicled DIEPs (40.4% vs 12.9%, p=0.029).

Conclusion

Our study shows no significant difference in donor site morbidity between unipedicled and bipedicled DIEP flaps. Bipedicled DIEPS have slightly higher donor site morbidity rates, which can be partly explained by longer operative times. There is no significant difference in breast complications and bipedicled DIEP flaps can reduce rates of further elective surgery.
O047 Outcomes of bulbar artificial urinary sphincter in older men following prostate cancer
Authors: Shah D , Omar I , Pati-Alam A , Gresty H , Noah A , Nobrega R , Pakzad M , Ockrim J , Greenwell T
Published: May 2023

Introduction

The gold standard treatment for stress urinary incontinence (SUI) in men is a bulbar artificial urinary sphincter (AUS). With an aging population, we must ensure efficacious solutions for older men with SUI are available. Our study assessed whether age influenced the outcomes of AUS for SUI post-prostate cancer (PCa) treatment.

Methods

Retrospective notes review of all patients having AUS for SUI following PCa treatment between 2006-2019. A 7-point Patient Global Impression of Improvement assessment (PGII) comparing pre-operative and post-operative conditions (1: very much better, 4: the same and 7: very much worse). This was completed a minimum of 6 months following AUS insertion. PGII score of 1 or 2 was recorded as a successful AUS. Older men were defined as ≥75 years. Statistical analysis was via Students T-Test, Chi-Square, and Mann Whitney with significance determined as P<0.5.

Results

184 men, median 69 years (range 31-87) were included. 150 men were aged <75 years and 34 were ≥75 years. Patients had prior prostatectomy and/or radiotherapy. No significant difference in median PGII score (score 2) or overall AUS success between the 2 groups. Overall AUS success was 73.3% in <75 years and 73.5% in ≥75 years.

Conclusions

No significant difference was seen in success between older and younger men. Bulbar AUS had an overall success rate of 73.4%, described as very much improved or much improved condition, a minimum of 6 months after insertion. Older age should not be a deterrent to offering AUS surgery.
O060 High intensity interval training in patients with intermittent claudication (INITIATE): a multicentre, proof-of-concept, prospective interventional study
Authors: Pymer S , Harwood A , Ibeggazene S , McGregor G , Huang C , Twiddy M , Nicholls A , Ingle L , Carroll S , Long J , Rooms M , Chetter I
Published: May 2023

Introduction

Provision, uptake, adherence, and completion rates for supervised exercise programmes (SEP) for intermittent claudication (IC) are low. For patients, SEPs are too time intensive. High-intensity interval training (HIIT) may be a time-efficient, effective alternative.

Methods

This was an NIHR funded, multicentre, proof-of-concept study. HIIT was performed three times per week for six-weeks and involved a 1:1 work to rest ratio. Outcomes were feasibility, tolerability, safety and potential efficacy.

Results

279 patients were screened, 59% were eligible and 25% were recruited for HIIT. 78% of patients completed HIIT, though 3 patients (7.5%) were unable to tolerate it. Patients attended 99% of training sessions, with 84% of sessions completed in full, largely at the required intensity. There were no related serious adverse events.

The mean improvements in MWD and physical functioning were 94m (95%CI=66.6-120.8m), and 4.4% (95%CI=-1.1–9.9%) respectively.

Conclusion

Uptake to HIIT was comparable to SEPs, but completion rates were higher. Most sessions were completed in full with no related serious adverse events. There was an improvement in MWD.

HIIT appears feasible, safe, tolerable and potentially beneficial for patients with IC. It may provide a more deliverable, more acceptable, SEP. A non-inferiority trial of HIIT vs. SEPs appears warranted.
O061 A dilemma faced by vascular surgeons - biodegradable versus non-biodegradable drug-releasing stents: a systematic review and meta-analysis
Authors: Shah A , Kumar N S
Published: May 2023

Introduction

Vascular stents are the best-known interventional treatment for cardiovascular disease, with variation in available stents increasing significantly over time. Despite the rapidity of new prototype releases, critical cross-comparisons fail to uphold the same rate, therefore causing confusion for vascular surgeons. Research is lacking between biodegradable-polymer sirolimus-eluting stents (BP-SES) and permanent-polymer sirolimus-eluting stents (PP-SES). Subsequently, a systematic review with meta-analysis was conducted evaluating clinical outcomes.

Methods

Medline, Embase, and Scopus databases were searched using relevant synonyms of biodegradable, sirolimus and stent, with the final search being conducted on the 4th of November 2022. Reference lists were also screened. The clinical outcomes investigated were stent thrombosis, myocardial infarction, target vessel revascularisation, target lesion revascularisation, and death. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

Results

Five clinical trials directly comparing clinical outcomes between BP-SES and PP-SES were ultimately identified for inclusion. For all five outcomes investigated, no statistically significant difference (p>0.05) was found between the BP-SES and the PP-SES recipients. Pooled odds ratios of 0.86 (95% CI:0.44-1.65), 0.75 (95% CI:0.32-1.74), 1.12 (95% CI:0.54-2.32), 1.14 (95% CI:0.38-3.38) and 0.95 (95% CI:0.51-1.77) were calculated for stent thrombosis, myocardial infarction, target vessel revascularisation, target lesion revascularisation and death respectively.

Conclusion

Although there is some evidence to suggest BP-SES are noninferior to PP-SES, concrete conclusions cannot yet be drawn due to the paucity of research in this field. Further clarity from randomised control trials will aid additional examination and improvement in stent materials and outcomes.
O065 Does modified Rankin score (mRS) matter? the impact of stroke severity on carotid endarterectomy (CEA) outcomes
Authors: Cruddas L , Baker D
Published: May 2023

Introduction

Carotid endarterectomy (CEA) is recommended to reduce the risk of future stroke in patients with non-disabling ischaemic stroke events (modified Rankin Score mRS<3). We reviewed CEA outcomes in patients with more devastating consequences of stroke (mRS 3+).

Methods

Data from 1021 consecutive CEA cases at a single unit were collected from the UK National Vascular Registry, over a 15-year period. Patient demographics, co-morbidities and postoperative outcomes were compared in those with pre-operative mRS <3 (Group 1) and those with mRS 3+ (Group 2). P<0.05 was considered significant.

Results

91 (9%) patients with mRS 3+ underwent CEA. Age, gender ratio and operated side were not significantly different between the two groups. Group 2 had significantly higher rates of diabetes, atrial fibrillation, renal failure, lung disease, frailty and a higher ASA score. Time to surgery from the stroke event was similar in the two groups, but time spent on high dependency and overall in hospital following surgery was longer in Group 2. There was no difference in the type of anaesthetic given. Group 2 had a higher incidence of postoperative confusion, but there was no significant difference between the two groups in cardiac, respiratory, operative complications and 30-day mortality. Fewer patients in Group 2 returned to their home on discharge.

Conclusion

Patients with a higher mRS are frailer and have more pre-operative co-morbidities. Surgery is associated with delayed discharges, but in the short-term, perioperative complication rate is not significantly different. Patient selection, however, should be undertaken withcare.
O069 Patient prompt sheets to improve communication between surgeons and their patients: a quality improvement project
Authors: Seddon I , Parker K
Published: May 2023

Introduction

Surgical ward rounds are typically fast-paced and time-limited - so much so that The Royal College of Surgeons Edinburgh developed a checklist to improve their delivery and safety. During our general surgery rotations, we observed how the nature of surgical ward rounds can contribute to poor communication between surgeons and patients. Our aim was to create a simple tool to improve patient understanding in the emergency surgery setting.

Methods

An initial audit, conducted via pre-discharge questionnaires, assessed patients’ understanding of their diagnosis, investigations done, interventions received and expected follow-up plan. A prompt sheet suggesting questions patients may want to ask was designed and given to patients 1-2 days prior to discharge. A second audit was conducted with the same pre-discharge questionnaire.

Results

The cohort for the study was a total of 28 patients (admitted for a variety of conditions such as appendicitis and diverticulitis) on an emergency general surgery ward in a district general hospital. Audit 1 - 40-65% of patients provided correct answers (50% identified the correct diagnosis/investigations and 40% identified the correct follow up plan). Audit 2 - 75-100% of patients answered questions correctly (88% identified the correct diagnosis and 100% identified the correct follow up plan).

Conclusion

Despite the limitations of this data, including sample size, there was a substantial improvement in patient understanding after the introduction of this simple intervention. We believe this tool could be easily adapted and implemented both within and beyond surgical settings to improve doctor-patient communication and patient care.
O077 Accuracy of intraoperative techniques for margin assessment in breast cancer surgery
Authors: Dowling G , Hogan R , Keelan S , Daly G , Giblin K , Boland F , Hennessy B , Hill A
Published: May 2023

Introduction

There are a wide variety of intraoperative techniques available in breast surgery to achieve low rates for positive margins of excision. The objective of this systematic review was to determine the diagnostic accuracy of intraoperative breast margin assessment techniques, establishing a benchmark against which novel techniques may be compared.

Methods

A systematic search of the literature was conducted to identify studies assessing the diagnostic accuracy of intraoperative margin assessment (IOMA) techniques. Only clinical studies with raw diagnostic accuracy data as compared with final permanent section histopathology were included in the meta-analysis. A bivariate model for diagnostic meta-analysis was used to determine overall pooled sensitivity and specificity for each technique.

Results

Sixty-two studies were included for meta-analysis. The majority of studies evaluated specimen radiography (n= 20), frozen section (n= 14) and cytology (n= 13). Other techniques such as intraoperative ultrasound (n= 7), optical spectroscopy (n= 5), margin probe (n= 3) and micro-CT (n= 3) were less commonly evaluated. Frozen section, optical spectroscopy and cytology had the greatest diagnostic accuracy with sensitivities of 80%, 89% and 88%, respectively, and specificities of 97%, 94% and 93%, respectively.

Conclusion

Pooled data indicate that optical spectroscopy, cytology and frozen section have the greatest diagnostic accuracy of currently available IOMA techniques. However, long turnaround time for results and their resource intensive nature has prevented widespread adoption of these methods. The aim of emerging technologies is to challenge the diagnostic accuracy of these established techniques, while improving speed, cost and usability.