Impact of Pre-ablation Weight Loss on the Success of Catheter Ablation for Atrial FibrillationAbdul Hafiz Al Tannir BS, Marwan M. Refaat MDDepartment of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, LebanonRunning Title: Pre-ablation Weight Loss and Success of AF AblationDisclosures: NoneFunding: NoneKeywords: Cardiac Arrhythmias, Cardiovascular Diseases, Heart Diseases, Weight Loss, Catheter Ablation, Atrial FibrillationWords: 621 (excluding references)Correspondence:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCPAssociate Professor of MedicineDirector, Cardiovascular Fellowship ProgramDepartment of Internal Medicine, Cardiovascular Medicine/Cardiac ElectrophysiologyDepartment of Biochemistry and Molecular GeneticsAmerican University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonFax: +961-1-370814Clinic: +961-1-759616 or +961-1-355500 or +961-1-350000/+961-1-374374 Extension 5800Office: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)Email: mr48@aub.edu.lbIn the United States, the prevalence of obese individuals has risen 3-fold since 1960, with 1 in every 3 persons being obese. The effect of weight changes on the progression on atrial fibrillation is well-established but the effect of pre-ablation weight loss on the recurrence of atrial fibrillation is not well-studied. Atrial fibrillation is the most frequently encountered cardiac arrhythmia [1]; it currently affects around 2.7 million people in the United States of America and is estimated that 6-12 million people will suffer from this condition by 2050 [2, 3]. Pulmonary vein isolation is the primary target for cardiac ablation; it can be achieved either by radiofrequency (RF) or cryoballoon ablation (CBA) [4, 5]. The FIRE and ICE trial conducted by Kuck et al showed that CBA therapy was associated with significantly fewer recurrence, rehospitalization, and cardioversion rates [6]. Several studies suggest the preferred use of CBA in treating atrial fibrillation in obese patients due to the increased surface area for ablation [4].Obesity has adverse effects on the structure and hemodynamics of the heart and it is a well-established risk factor for the development of atrial fibrillation [3]. A prospective cohort study performed by Pathak et al showed that progressive weight loss in obese and overweight patients resulted in dose-dependent effects on freedom from atrial fibrillation (FFAF) [7]. Similarly, Middeldrop et al, concluded that obesity is associated with the progression of the disease while weight loss is associated with reversal of the progression [8]. Limited data is available regarding the effect of weight loss on the recurrence of atrial fibrillation post-ablation. Current guidelines recommend lifestyle modifications, including a healthy diet and exercise, for overweight and obese patients before ablation [8, 9].The study of Peigh et al. is a retrospective cohort study from 2012-2017; 607 patients met the inclusion criteria. The aim of the study is to assess the impact of patient-directed weight loss 1 year before CBA on FFAP 15 months after ablation. The authors addressed an important topic that is poorly understood. Obese patients have a significantly lower FFAF rate 40-50% than the overall population 60-80%. The study selectively included patients undergoing CBA therapy. The follow-up time was 1-year post-ablation. The study concluded that, with the exception of non-obese patients with persistent atrial fibrillation, weight loss is associated with a significantly increased FFAF while weight gain led to a decrease in FFAF. A similar study assessed the impacted of physician-mediated risk control in patients undergoing RF ablation for atrial fibrillation [10]. A total of 149 patients were included in the prospective cohort study. The study showed a positive association between physician-directed weight loss (≥ 10%) and FFAF in symptomatic obese patients. The study performed by Peigh et al, included though a larger subject group (607) than LEGACY (141); however, the LEGACY is a prospective cohort study that is more suitable to monitor the fluctuation in patients’ variables before ablation.This study was well conducted but has the limitations of retrospective studies; a prospective cohort study would better monitor the variations in patients’ variables pre-ablation. In addition, as the authors stated, asymptomatic atrial fibrillation episodes may go unnoticed.Patients with atrial fibrillation, particularly those who are obese, should be advised to lose weight prior to catheter ablation. Lifestyle modifications should not be limited to patients undergoing ablation; the effect of weight loss on disease progression is well-established. Due to the overgrowing prevalence of atrial fibrillation and obesity worldwide, more studies are encouraged to better understand the ideal lifestyle management in patients. Larger prospective cohort studies should be conducted in order to validate the results. There is also an ongoing randomized clinical trial BAROS (Bariatric Atrial Return of Sinus Trial) [NCT 04050969] which will provide more data on this topic.

Anthropogenic climate change has led to unprecedented shifts in temperature across many ecosystems. In a context of rapid environmental changes, acclimation is an important process as it may influence the capacity of organisms to survive under novel thermal conditions. Mechanisms of acclimation could involve upregulation of stress response genes involved in protein folding, DNA damage repair and the regulation of signal transduction genes, along with a simultaneous downregulation of genes involved in growth or cell cycle, in order to maintain cellular functions and equilibria. We transplanted Lobaria pulmonaria lichens originating from different forests to determine the relative effects of long-term acclimation and genetic factors on the variability in expression of mycobiont and photobiont genes. We found a strong response of mycobiont and photobiont to high temperatures, regardless of sample origin. The green-algal photobiont had an overall lower response than the mycobiont. The gene expression of both symbionts was also influenced by acclimation to transplantation sites and by genetic factors. Lobaria pulmonaria seems to have evolved powerful molecular pathways to deal with environmental fluctuations and stress and can acclimate to new habitats by transcriptomic convergence. Although L. pulmonaria has the molecular machinery to counteract short-term thermal stress, survival of lichens like L. pulmonaria depends mostly on their long-term positive carbon balance, which can be compromised by warmer temperatures and reduced precipitation, and both these outcomes have been predicted for Central Europe in connection with global climate change

Ventricular tachycardia (VT) normally occurs from an abnormal structural substrate. We report a case in which VT was caused by a large tumor in the interventricular septum. Surgical intervention was not an option due to the location of the tumor and its proximity to the coronary arteries. The patient underwent ablation and upgrade to CRT before ultimately receiving a heart transplant.

It is well known that the left internal mammary artery (LIMA) should be the first conduit of choice. Similarly, especially in patients younger than 70 years, other conduits should be search among arterial grafts such as right internal mammary artery (RIMA) or radial artery (RA). If the RA can be harvested in the meanwhile of LIMA harvesting without time consuming, it is well established that former one has to be grafted only on presence of a good run-off. One of the main criticisms moved to the use of RIMA are linked to technical difficulties in its harvesting it. Edgar Aranda-Michel and coworkers tried to answer to the age-old question is “RIMA has to be used in situ or free-graft?” In a retrospective study on 667 patients (442 had free RIMA and 245 had free RIMA) that were also matched through propensity analysis (202 patients per group), they did not find any differences between the two groups in the major outcomes, including heart failure specific readmissions. This finding is consistent with the literature, hence the take-home message is whatever happens, two mammary is better than one.

Telemedicine, telehealth and artificial intelligence in healthcare are becoming commonly utilized in various medical specialties. The article authored by Dr. Aminah Sallam and colleagues in the Journal provides data in support of the cardiac surgical patients, and the caring cardiac surgeons willingness to adopt telemedicine as a method of connectivity between patient and surgeon.

Abstract Objective: This study aims to investigate the factors that lead to poor compliance in initiating the treatment in patients with newly diagnosed head and neck cancers. Design: Retrospective cohort study Particpants: Data from a total of 271 patients were retrieved and analyzed. After excluding patients with (1) multiple cancers (2) inconclusive diagnoses, (3) rare primary cancer sites, such as the nasal cavity, paranasal sinuses, or salivary glands and (4) primary site unknown, a total of 194 patients were included in this study. Main outcome measures: The variables included in the analysis were age, gender, primary cancer site, T stage, N stage, M stage, overall stage (I-IV), patient’s residential distance, and the impact of COVID-19. Univariate and multivariate analyses were employed to evaluate the significance of these variables in regard to affecting the time to receiving on-time treatment based on the specialist’s suggestion. Results: Upon multivariate analysis, the primary site, stage, and residential distance were significantly associated with initial compliance (P<0.05). The impact of COVID-19 showing a borderline significance (p=0.137). Conclusion: The primary site, overall stage, patient living distance to the healthcare facility, and the impact of COVID-19 might affect the compliance of initiating a curative-intent treatment in patients with newly diagnosed head and neck cancers.

We describe two cases of microlaryngeal surgery under general anesthesia in severe obese elite vocal performers. Microlaryngeal surgery under general anesthesia is feasible in patients with severe obesity, provided that the anesthesiologist and nurse work together to perform preoperative simulations and take into consideration the position and anesthesia.

Background: There is limited data to inform minimum case requirements for training in robotically-assisted coronary artery bypass grafting (RA-CABG). Current recommendations rely on non-clinical endpoints and expert opinion. Objectives: To determine the minimum number of RA-CABG procedures required to achieve stable clinical outcomes. Methods: We included isolated RA-CABG in The Society of Thoracic Surgeons (STS) registry performed between 2014 and 2019 by surgeons without prior RA-CABG experience. Outcomes were approach conversion, reoperation, major morbidity or mortality, and procedural success. Case sequence number was used as a continuous variable in logistic regression with restricted cubic splines with fixed effects. Outcomes were compared between operations performed earlier versus later in case sequences using unadjusted and adjusted metrics. Results: There were 1195 cases performed by 114 surgeons. A visual inflection point occurs by a surgeon’s 10th procedure for approach conversion, major morbidity or mortality, and overall procedural success after which outcomes stabilize. There was a significant decrease in the rate of approach conversion (7.7% and 2.5%), reoperation (18.9% and 10.8%), and major morbidity or mortality (21.7% and 12.9%), as well as an increase in rate of procedural success (72.9% and 85.3%) with increasing experience between groups. In a multivariable logistic regression model case sequences of >10 was an independent predictor of decreased approach conversion (OR 0.27, 95% CI 0.09 to 0.84) and increased rate procedural success (OR 1.96, 95% CI 1.00 to 3.84).

This clinical case first time reports a coexistence of FANCD2 and NF1 mutations in malignant triton tumor (MTT) patient and as the initial operation, the complete resection has crucial influences on the prognosis and recurrence of MTT.

Mosquito allergy can rarely give raise to severe clinical manifestations.Here we describe the case of a patient suffering from relapsing anaphylaxis after mosquito bites, who completely responded to off label therapy with anti-IgE monoclonal antibody.This is the first demonstration of the efficacy of omalizumab in such unusual life-threatening allergy.

Rainfall erosivity is defined as the potential of rain to cause erosion. It has great potential for application in studies related to landslides and floods, in addition to water erosion. The objectives of this study were: i) to model the Rday using a seasonal model for the Mountainous Region of the State of Rio de Janeiro (MRRJ); ii) to adjust thresholds of the Rday index based on catastrophic events which occurred in the last two decades; and iii) to map the maximum daily rainfall erosivity (Rmaxday) to assess the region’s susceptibility to rainfall hazards according to the established Rday limits. The fitted Rday model presented a satisfactory result, thereby enabling its application as an estimator of the daily rainfall erosivity in MRRJ. Events that resulted in Rday > 1,500 MJ.ha-1.mm.h-1.day-1 were those with the highest number of fatalities. The spatial distribution of Rmaxday showed that the entire MRRJ has presented values that can cause major rainfall. The Rday index proved to be a promising indicator of rainfall hazards, which is more effective than those normally used that are only based on quantity (mm) and/or intensity (mm.h-1) of the rain.

Understanding how urbanization alters functional interactions among pollinators and plants is critically important given increasing anthropogenic land use and declines in pollinator populations. Pollinators often exhibit short-term specialization, and visit plants of the same species during one foraging trip. This facilitates plant receipt of conspecific pollen -- pollen on a pollinator that is the same species as the plant on which the pollinator was foraging. Conspecific pollen receipt facilitates plant reproductive success and is thus important to plant and pollinator persistence. We investigated how urbanization affects short term specialization of insect pollinators by examining pollen loads on insects' bodies and identifying the number and species of pollen grains on insects caught in urban habitat fragments and natural areas. We then assessed possible drivers of differences between urban and natural areas, including frequency dependence in foraging, species richness and diversity of the plant and pollinator communities, floral abundance, and the presence of invasive plant species. Pollinators were more specialized in urban fragments than in natural areas, despite no differences in the species richness of plant communities across site types. These differences were likely driven by higher specialization of common pollinators, which were more abundant in urban sites. Pollinators were also more specialized when foraging on invasive plants across sites, and floral abundance of invasive plants was higher in urban sites. Our findings reveal strong effects of urbanization on pollinator fidelity to individual plant species and have implications for the maintenance of plant species diversity in small habitat fragments. The higher fidelity of pollinators to invasive plants suggests that native species may receive fewer visits by pollinators. Therefore, native plant species diversity may decline in urban sites without continued augmentation of urban flora or removal of invasive species.

High rates of erosion and runoff production on road infrastructure have been documented, indicating that unpaved roads might be significant sources of sediment in catchments. In this paper, the production of surface sediments from unpaved rural roads at different scales is assessed. The study took place in northeastern Brazil, in a semiarid area of the Caatinga biome, vulnerable to desertification. Sediment production data from road surface segments were monitored for two years (2013-2014) under conditions of natural precipitation. By using hydrosedimentological modeling and Geographic Information System (GIS), the sediment budget was calculated at the meso-scale basin (aprox. 930 km²), in order to identify the relative contribution of roads to the sediment balance. Universal Soil Loss Equation (USLE) associated with Maner’s sediment delivery ratio (SDR) equation, proved to be an adequate approach for predicting sediment yield on the road segment scale; the best results were obtained for the road without traffic, due to the non-interference in this segment of external factors, such as traffic and maintenance activities, not explicitly considered in the model formulation. The modeling procedure showed that the roads, which occupy only 0.7% of the catchment surface, were responsible for approximately 7% of soil loss in the area. Furthermore, sediment connectivity might be enhanced by roads, which cross the river network and, therefore, deliver more directly the sediment generated at hillslopes. This is particularly important in the studied environment, where sediment connectivity is low due to limited runoff and the existence of a dense network of surface water reservoir

Dominant and non-dominant plants could be subject to different biotic and abiotic influences, partially because dominant plants modify the environment where non-dominant plants grow, causing an interaction asymmetry. Among other possibilities, if dominant plants compete strongly, they should deplete most resources forcing non-dominant plants into a more constrained niche space. Conversely, if dominant plants are constrained by the environment, they might not fully deplete available resources but instead ameliorate some of the environmental constraints limiting non-dominants. Hence, the nature of the interactions between the non-dominants could be modified by dominant species. However, when plant competition and environmental constraints have similar effects on dominant and non-dominant species no difference is expected. By estimating phylogenetic dispersion in 78 grasslands across five continents, we found that dominant species were clustered (underdispersed), suggesting dominant species are likely organized by environmental filtering, and that non-dominant species were either randomly assembled or overdispersed. Traits showed similar trends, but insufficient data prevented further analyses. Furthermore, several lineages scattered in the phylogeny had more non-dominant species, suggesting that traits related to non-dominants are phylogenetically conserved and have evolved multiple times. We found some environmental drivers of the dominant—non-dominant disparity. Our results indicate that assembly patterns for dominants and non-dominants are different, consistent with asymmetries in assembly mechanisms. Among the different mechanisms we evaluated, the results suggest two complementary hypotheses seldom explored: (1) Non-dominant species include lineages adapted to thrive in the environment generated by the dominant species. (2) Even when dominant species reduce resources to non-dominant ones, dominant species could have a stronger effect on—at least—some non-dominants by ameliorating the impact of the environment on them, than by depleting resources and increasing the environmental stress to those non-dominants. The results show that the dominant–non-dominant asymmetry has ecological and evolutionary consequences fundamental to understand plant communities.

Background: The introduction of integrated thoracic surgery residency programs has led to increased recruitment efforts of medical students to pursue a career in cardiac surgery. With little representation of cardiac surgery in medical school curriculum, we assessed a cardiac surgery mini-elective’s efficacy in improving perceived knowledge among medical students. Methods: Preclinical medical students were offered the opportunity to participate in a cardiac surgery mini-elective, which consisted of five 2-hour sessions. These sessions consisted of didactic and simulation components and covered topics including cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), aortic disease, aortic valve replacement (AVR), transplant and left ventricular assist devices (LVAD), and coronary artery bypass grafting (CABG). Students completed pre- and post-session survey’s describing their perceived knowledge in these topics. Results: Overall, 22 students completed at least one session of the mini-elective. Fourteen (73.7%) of the students were male. Fifteen (68.2%) students completed at least three out of five sessions. The post-session survey responses showed significantly higher perceived knowledge compared to pre-session responses for all survey prompts of all five sessions. The CPB/ECMO and aortic disease sessions showed the greatest increase in post-session familiarity and perceived knowledge after the session (p<0.001) compared to the CABG, AVR, and transplant/LVAD sessions (p<0.05). Conclusions: Beyond developing interest in cardiac surgery, these data indicate that a well-planned didactic and surgical simulation program may build confidence in students’ knowledge of various cardiac surgical topics. Further studies will need to address how this increase in perceived ability lasts over time and impacts career selection.

BACKGROUND: Oak and birch pollens are known to have strong cross-reactivity. It is unknown how robust this cross-reactivity is in subjects without natural exposure to pollen of both trees. We aimed to assess in an Allergen Challenge Chamber (ACC), the symptomatic responsiveness to birch pollen in subjects allergic to and naturally exposed to Virginia Live Oak (VLO) pollen and SPT-sensitive but not naturally exposed to birch pollen. METHODS: Subjects underwent SPT and blood draw for ssIgE to oak and birch antigens. Residential historical data were obtained. Subjects were exposed to birch pollen (3,500 ±700 gr/m 3) in 2 consecutive 3-hour challenges. Symptoms were recorded at baseline and 30-minute intervals. RESULTS: Twenty-four subjects, 12 males, age 20-58 yrs, completed the study. Sixteen subjects (66.7%) responded with high total symptom scores (TSS) ≥10 of max 21. Twelve subjects (50%) had ssIgE ≥0.70 kU/L to oak. Subjects with a Class II ssIgE to oak pollen had a significantly higher max TSS than those without. Fifteen subjects without natural exposure to birch pollen responded with TSS equivalent to 9 with previous natural exposure. Those without natural birch exposure also responded similarly to subjects in birch endemic areas reported in the literature. CONCLUSION: Subjects allergic to oak pollen residing in South Texas, responded to birch pollen in an ACC with symptoms comparable to both those with previous exposure and also those residing in endemic areas and reported by other researchers. This robust response of cross-reactivity in oak-allergic subjects, without prior endemic exposure, suggests that a cross-reactive intervention could be efficacious.

Automatic identification of VT substrate in the era of ultra-high-density mapping: Do Humans or Machines emerge victorious?Richard G. Bennett, BSc, MBChB,a Timothy G. Campbell, BSc,a Saurabh Kumar, BSc(Med)/MBBS, PhDaaDepartment of Cardiology, Westmead Hospital, Westmead Applied Research Centre, University of Sydney, Australia.Correspondence: Associate Professor Saurabh Kumar, Department of Cardiology, Westmead Hospital, Westmead Applied Research Centre, University of Sydney, Darcy Road, Westmead, New South Wales, Australia, 2145. Phone +612 8890 8140; Fax: +612 8890 8323; email: saurabh.kumar@sydney.edu.auDisclosures: Timothy Campbell has received speakers’ honoraria for Biosense Webster, Inc. in the last 12 monthsFunding: Dr Saurabh Kumar is supported by the NSW Early-mid Career FellowshipKeywords: Ventricular tachycardia, local abnormal ventricular activities, electroanatomic mapping, catheter ablation, structural heart disease

Background: 64 million pharmacy filled multicompartment medication compliance aids (MCAs) are dispensed by pharmacies in England each year as a method to improve medication adherence. Despite the widespread use of MCAs and evidence that their use may be associated with harm there is no national consensus regarding MCA provision by acute hospital Trusts in England. Aim: To determine current practice for initiation and supply of MCAs in acute hospital Trusts in England and the potential consequences for patients and hospitals. Methods: A 26 item survey was distributed to all acute hospital Trusts in England. The questionnaire covered policy, initiation, supply and review of MCAs; alternatives offered; and pharmacy staffing and capacity related to MCAs. Results: 72 out of 138 (52%) Trusts responded to the survey. 60/70 (86%) had a policy for the provision of MCAs. 33/55 (60%) that supplied MCAs on discharge supplied a different prescription length for MCA vs. non-MCA prescriptions. 49/55 (89%) Trusts provided only one brand of MCA. 47/55 (85%) MCA-supplying Trusts identified frequent difficulties with MCAs and 13/55 (24%) reported employing staff specifically to complete MCAs. 30/35 (86%) MCA-initiating Trusts had an assessment process for initiation, with care agency request as the most common reason. Conclusion: There is a lack of a national approach to MCA provision and initiation by acute hospital Trusts in England. This leads to significant variation in care and has the potential to put MCA users at an increased risk of medication related harm.

It is easy to measure annual growth of a tree stem. It is hard to measure its daily growth. The reason for this difficulty is the microscopic scale and the need to separate processes that simultaneously result in reversible and irreversible stem expansion. Here we present a model that separates reversible from irreversible cell expansion. Our model is novel, because it explains reversible expansion as consequence of longitudinally and, importantly, radially transmitted changes of hydraulic and osmotic pressures in xylem and bark. To capture and quantify these changes, we manipulated daily stem growth by applying a phloem girdle to stems of 9-m tall trees. The model was informed by measurements of radial movement in stem tissues and sap flow before and after and positions below and above the girdle. Additional measurements of whole-crown fluxes of H2O and CO2, leaf water potentials, non-structural carbohydrates and respiration were used to document the physiological impacts of girdling. This work sheds new light on the role of radial transport processes underpinning daily growth of tree stems. The model helps explain diel patterns of stem growth in trees.

A document by Pranav Vatsa. Click on the document to view its contents.

Link to published versionUse of airborne precautions for COVID-19 outside “AGPs” in healthcare settingsTom Lawton, Consultant Critical Care, Bradford Teaching Hospitals NHS Foundation TrustMatt Butler, Consultant Geriatrician, Cambridge University Hospitals NHS Foundation TrustChristine Peters, Consultant Microbiologist, NHS Greater Glasgow and ClydeEilir Hughes, General Practitioner, Ty Doctor, Nefyn, GwyneddHuw Waters, Consultant Risk Analytics, FreshAir.WalesDavid Tomlinson, Consultant Cardiologist, University Hospitals Plymouth NHS TrustLindsay Fraser-Moodie, GP Trainee, East of England DeaneryOn behalf of FreshAir NHS28th June 2021Since the early days of the pandemic there has been debate as to whether COVID-19 transmission can be airborne, and whether healthcare workers require routine airborne precautions, or if respiratory PPE can be preserved for a small list of “Aerosol Generating Procedures”.[1] The former question is now largely satisfied - COVID-19 is airborne[2] - but the latter remains and official UK guidance leaves the matter up to individual NHS Trusts to decide.[3]FreshAir NHS is a group of frontline NHS workers who wrote an open letter signed by over 1,600 colleagues to all governments of the UK nations in January 2021 requesting airborne mitigations to prevent infections in healthcare staff and reduce nosocomial infection risk to patients.[4]We therefore welcome pragmatic data from Ferris, Ferris et al showing that a simple substitution of filtering face piece (FFP3) respirators for fluid resistant surgical masks (FRSM) appeared to eliminate 100% of the 47-fold increase in excess risk of COVID-19 infection in healthcare workers (HCWs) caring for patients on COVID-19 “red” wards.[5] Prior to the introduction of FFP3, HCW infection rates on “red” wards were greater than those on “green” wards, and also demonstrated no correlation with community case rates, suggesting infections resulted from direct patient care - in line with genomic evidence that a large proportion of HCW infections are transmitted from patients.[6] Some studies have suggested that staff infection rates merely reflect transmission in the community such that staff rates increase as community rates rise and are therefore inevitable.[7,8] This study highlights that this is only true for non-COVID-19 facing staff, with exposure to infected patients being the driving factor for infections in COVID-19 facing staff.This has important implications for healthcare worker protection as the UK copes with what is hopefully an “exit wave” as well as trying to reduce the massive backlog of other work whilst coping with inevitable staff sickness and isolation. It also touches on our responsibility as a learning healthcare system to ensure preparedness for future epidemics and pandemics.However, if the precautionary principle were the only factor to consider then the UK would have used airborne precautions from the start of the pandemic - so clearly there are other factors to address. PPE was in short supply in early 2020,[9] which may have made rationing more appropriate, but supply chains have largely recovered - and reusable PPE has both environmental and cost savings.[10] Fit-testing staff adds burden to infection control teams, but NHS trusts which have made the switch have demonstrated it is possible, and there is evidence that reusable elastomeric respirators (but not disposable FFP3 masks) may be used safely with a “fit check” alone.[11] It is clear that tighter-fitting masks can be less comfortable - particularly if the fit is not suitable for the user, but surveyed staff appear in general to prefer the higher level of protection.[12] Most healthcare staff are now vaccinated, but the B1.617.2 (delta) variant appears to reduce vaccine effectiveness at a time when staff absences due to sickness and isolation can critically hamper NHS recovery as patients await delayed treatment.[13]The only remaining argument appears to be that we are beholden to the past; that to change guidance now would be to admit that mistakes were made. Whilst this may have a powerful emotional hold on local and national policymakers and leaders; the best pandemic responses have come when we have learned and changed course when necessary: “Progress is impossible without change; and those who cannot change their minds cannot change anything.”[14]Competing interestsTL, MB, CP, EH, DT, LF-M are practising NHS clinicians and subject to UK PPE guidanceReferences[1] Hamilton F, Arnold D, Bzdek BR, Dodd J, White C, Murray J, et al. Aerosol generating procedures: are they of relevance for transmission of SARS-CoV-2? Lancet Respir Med 2021. https://doi.org/10.1016/S2213-2600(21)00216-2. [2] Tang JW, Marr LC, Li Y, Dancer SJ. Covid-19 has redefined airborne transmission. BMJ 2021;373:n913. https://doi.org/10.1136/bmj.n913. [3] COVID-19 infection prevention and control guidance - Version 1.2. London: PHE; 2021. Report No.: GOV-8505.[4] Wise J. Covid-19: Doctors and nurses demand better PPE for wider range of procedures. BMJ 2021;372:n30. https://doi.org/10.1136/bmj.n30. [5] Ferris M, Ferris R, Workman C, O’Connor E, Enoch DA, Goldesgeyme E, et al. FFP3 respirators protect healthcare workers against infection with SARS-CoV-2. Authorea Prepr 2021. https://doi.org/10.22541/au.162454911.17263721/v1. [6] Illingworth C, Hamilton W, Warne B, Routledge M, Popay A, Jackson C, et al. Superspreaders drive the largest outbreaks of hospital onset COVID-19 infection. OSF Prepr 2021. https://doi.org/10.31219/osf.io/wmkn3. [7] Treibel TA, Manisty C, Burton M, McKnight Á, Lambourne J, Augusto JB, et al. COVID-19: PCR screening of asymptomatic health-care workers at London hospital. The Lancet 2020;395:1608–10. https://doi.org/10.1016/S0140-6736(20)31100-4. [8] Brown CS, Clare K, Chand M, Andrews J, Auckland C, Beshir S, et al. Snapshot PCR surveillance for SARS-CoV-2 in hospital staff in England. J Infect 2020;81:427–34. https://doi.org/10.1016/j.jinf.2020.06.069. [9] Hoernke K, Djellouli N, Andrews L, Lewis-Jackson S, Manby L, Martin S, et al. Frontline healthcare workers’ experiences with personal protective equipment during the COVID-19 pandemic in the UK: a rapid qualitative appraisal. BMJ Open 2021;11:e046199. https://doi.org/10.1136/bmjopen-2020-046199. [10] Higgins GC, Ho J, Robertson E, McLean N, Horsley C, Douglas J. Covid-19: Health and social care workers need, want, and deserve reusable FFP3 respirators. BMJ 2021;372:n759. https://doi.org/10.1136/bmj.n759.[11] McMahon K, Jeanmonod D, Check R, Rivard L, Balakrishnan V, Kelly B, et al. The pragmatic use of industrial elastomeric facemasks in health care practice during the COVID-19 pandemic. Am J Emerg Med 2021;48:273–5. https://doi.org/10.1016/j.ajem.2021.05.025.[12] Butler M, Inkster T, Foster C, Lawton T, Hughes E, Waters H, et al. Effect of Implementation of Aerosol Respiratory Protective Equipment, Vaccination and Natural Infection on a Covid-19 Cohort Ward: A Retrospective Observational Cohort Study. OSF Prepr 2021. https://doi.org/10.31219/osf.io/nh5sr.[13] SARS-CoV-2 variants of concern and variants under investigation. London: PHE; 2021. Report No.: GOV-8715.[14] Shaw GB. Everybody’s political what’s what. Constable and Company Limited, London; 1945.

Background: The purpose of this study was to evaluate the quantitative diagnostic performance of computed tomography (CT) densitometry in pediatric bronchiolitis obliterans (BO) patients. Methods: A retrospective chart review was performed on 109 children under age 18 who underwent 3D chest CT from March 2019 to March 2021. We measured the mean lung density (MLD) and calculated the difference of MLD (MLDD) in expiratory and inspiratory phase, the expiratory to inspiratory ratio of mean lung density (E/I MLD), and the relative volume percentage of lung density at 50 HU intervals (E600 to E950). We calculated the sensitivity, specificity, and diagnostic accuracy of lung density indices for the diagnosis of BO. Results: A total of 81 patients, 51 BO patients and 30 controls, were included in this study (mean age: 12.7 vs 11.4 years). Expiratory (EXP) MLD, MLDD, E/I MLD, and E900 were all statistically significantly worse in the BO group. Multivariate logistic regression analysis showed that MLDD (odds ratio [OR] = 0.98, p < .001), E/I MLD (OR = 1.39, p < .001), and E850 (OR = 1.54, p = 0.003) were significant densitometry parameters for BO diagnosis. In ROC analysis, E900 (cut-off 1.4%; AUC = 0.920), E/I MLD (cut-off 0.87; AUC = 0.887), and MLDD (cut-off 109 HU; AUC = 0.867) showed high accuracy in diagnosis of BO. Conclusion: The quantification of lung density with chest CT complements the diagnosis by providing additional indications of expiratory airflow limitation in pediatric BO patients.

ST-segment changes may provide a clue to the presence of pneumopericardium accompanying SPM. These EKG changes associated with SPM are rare. The management in SPM with concurrent pneumopericardium is mainly supportive. We describe two SP cases with concomitant pneumopericardium that presented with a deceptive clinical spectrum, closely mimicking acute pericarditis.

Background Although several studies discussed new-onset thrombocytopenia in the setting of COVID-19 infection, the course of chronic ITP in patients with COVID-19 and the propensity to relapse remains not well addressed. Methods This a retrospective study that included all adult patients with the diagnosis of chronic ITP who admitted to