Outdoor Temperature Influences Cold Induced Thermogenesis in Humans

Objective: Energy expenditure (EE) increases in response to cold exposure, which is called cold induced thermogenesis (CIT). Brown adipose tissue (BAT) has been shown to contribute significantly to CIT in human adults. BAT activity and CIT are acutely influenced by ambient temperature. In the present study, we investigated the long-term effect of seasonal temperature variation on human CIT.Materials and Methods: We measured CIT in 56 healthy volunteers by indirect calorimetry. CIT was determined as difference between EE during warm conditions (EEwarm) and after a defined cold stimulus (EEcold). We recorded skin temperatures at eleven anatomically predefined locations, including the supraclavicular region, which is adjacent to the main human BAT depot. We analyzed the relation of EE, CIT and skin temperatures to the daily minimum, maximum and mean outdoor temperature averaged over 7 or 30 days, respectively, prior to the corresponding study visit by linear regression.Results: We observed a significant inverse correlation between outdoor temperatures and EEcold and CIT, respectively, while EEwarm was not influenced. The daily maximum temperature averaged over 7 days correlated best with EEcold (R2 = 0.123, p = 0.008) and CIT (R2 = 0.200, p = 0.0005). The mean skin temperatures before and after cold exposure were not related to outdoor temperatures. However, the difference between supraclavicular and parasternal skin temperature after cold exposure was inversely related to the average maximum temperature during the preceding 7 days (R2 = 0.07575, p = 0.0221).Conclusion: CIT is significantly related to outdoor temperatures indicating dynamic adaption of thermogenesis and BAT activity to environmental stimuli in adult humans.Clinical Trial Registration:www.ClinicalTrials.gov, Identifier NCT02682706

The impact of tubal ectopic pregnancy in Papua New Guinea - a retrospective case review

BACKGROUND: Ectopic pregnancy (EP) is an important cause of morbidity and mortality amongst women of reproductive age. Tubal EP is well described in industrialised countries, but less is known about its impact in low-resource countries, in particular in the South Pacific Region. METHODS: We undertook a retrospective review of women with tubal EP treated at a provincial referral hospital in coastal Papua New Guinea over a period of 56 months. Demographic and clinical variables were obtained from patients’ medical records and analysed. The institutional rate of tubal EP was calculated, and diagnosis and management reviewed. Potential risk factors for tubal EP were identified, and delays contributing to increased morbidity described. RESULTS: A total of 73 women had tubal EP. The institutional rate of tubal EP over the study period was 6.3 per 1,000 deliveries. There were no maternal deaths due to EP. The mean age of women was 31.5+/−5.7 years, 85% were parous, 67% were rural dwellers and 62% had a history of sub-fertility. The most commonly used diagnostic aid was culdocentesis. One third of women had clinical evidence of shock on arrival. All women with tubal EP were managed by open salpingectomy. Tubal rupture was confirmed for 48% of patients and was more common amongst rural dwellers. Forty-three percent of women had macroscopic evidence of pelvic infection. Two-thirds of patients received blood transfusions, and post-operative recovery lasted six days on average. Late presentation, lack of clinical suspicion, and delays with receiving appropriate treatments were observed. CONCLUSIONS: Tubal EP is a common gynaecological emergency in a referral hospital in coastal PNG, and causes significant morbidity, in particular amongst women residing in rural areas. Sexually transmitted infections are likely to represent the most important risk factor for tubal EP in PNG. Interventions to reduce the morbidity due to tubal EP include the prevention, detection and treatment of sexually transmitted infections, identification and reduction of barriers to prompt presentation, increasing health workers’ awareness of ectopic pregnancy, providing pregnancy test kits to rural health centres, and strengthening hospital blood transfusion services, including facilities for autotransfusion

Real-Time GPU-Based Digital Image Correlation Sensor for Marker-Free Strain-Controlled Fatigue Testing

Digital image correlation (DIC) is a highly accurate image-based deformation measurement method achieving a repeatability in the range of σ= 10−5 relative to the field-of-view. The method is well accepted in material testing for non-contact strain measurement. However, the correlation makes it computationally slow on conventional, CPU-based computers. Recently, there have been DIC implementations based on graphics processing units (GPU) for strain-field evaluations with numerous templates per image at rather low image rates, but there are no real-time implementations for fast strain measurements with sampling rates above 1 kHz. In this article, a GPU-based 2D-DIC system is described achieving a strain sampling rate of 1.2 kHz with a latency of less than 2 milliseconds. In addition, the system uses the incidental, characteristic microstructure of the specimen surface for marker-free correlation, without need for any surface preparation—even on polished hourglass specimen. The system generates an elongation signal for standard PID-controllers of testing machines so that it directly replaces mechanical extensometers. Strain-controlled LCF measurements of steel, aluminum, and nickel-based superalloys at temperatures of up to 1000 °C are reported and the performance is compared to other path-dependent and path-independent DIC systems. According to our knowledge, this is one of the first GPU-based image processing systems for real-time closed-loop applications

Impact of 2020 EUCAST criteria on meropenem prescription for the treatment of Pseudomonas aeruginosa infections: an observational study in a university hospital.

We aimed to evaluate the impact of the 10th version of European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints table, where most antipseudomonal drugs but meropenem are now categorised as "Susceptible, increased exposure" and labelled I, on meropenem prescription for Pseudomonas aeruginosa infections. In this retrospective single-centre observational study, we analysed antimicrobial therapies prescribed after susceptibility testing in all consecutive adult patients treated for P. aeruginosa infections between 01.08.2019 and 30.07.2020 in Lausanne University Hospital, Switzerland. We collected epidemiological, microbiological, clinical data, antimicrobial therapy, and infectious diseases specialists (IDs) consultations' data. The primary outcome was the prescription of meropenem to treat P. aeruginosa infections after release of susceptibility testing results. Secondary outcomes were: the use of increased dosage for non-meropenem anti-pseudomonal drugs, and IDs' consultations rates after susceptibility testing was made available. Among the 264 patients included, 40 (15.2%) received meropenem, 3.4% (5/148) before EUCAST update versus 30.2% (35/116) after (p < 0.001). Supervision and counselling from IDs and the use of increased dosages of non-carbapenem antibiotics also increased respectively (40.5% (60/148) vs 62.9% (73/116), P < 0.001); (55.5% (76/148) vs 88.9% (72/116), P < 0.001). Factors associated with these increments could not be adequately modelled. The change to 2020 EUCAST criteria might be associated with increased odds of meropenem prescription for the treatment of P. aeruginosa infections stressing the need of prescribers' education and the importance of antibiotic stewardship interventions

GPU-based digital image correlation system for real-time strain-controlled fatigue and strain field measurement

This article reports a novel GPU-based 2D digital image correlation system (2D-DIC) overcoming two major limitations of this technique: It measures marker-free, i.e. without sample preparation, and the sampling rate meets the recommendations of ASTM E606. The GPU implementation enables zero-normalized cross correlation (ZNCC) calculation rates of up to 25 kHz for 256 × 256 pixel ROIs. This high-speed image processing system is combined with a high-resolution telecentric lens observing a 10 mm field-of-view, coaxial LED illumination, and a camera acquiring 2040 × 256 pixel images with 1.2 kHz. The optics resolve the microstructure of the surface even of polished cylindrical steel specimen. The displacement uncertainty is below 0.5 μm and the reproducibility in zero-strain tests approximately 10-5 (1 σ) of the field-of-view. For strain-controlled testing, a minimum of two displacement subsets per image are evaluated for average strain with a sampling rate of 1.2 kHz. Similar to mechanical extensometers, an analogue 0-10V displacement signal serves as a feedback for standard PID controllers. The average latency is below 2 ms allowing for cycle frequencies up to 10 Hz. For strain-field measurement, the number of ROIs limits the frame rate, e.g., the correlation rate of 25 kHz is sufficient to evaluate 10 images per second with 2500 ROIs each. This frame rate is still sufficient to compare the maximum and minimum strain fields within a cycle in real-time, e.g. for crack detection. The result is a marker-free and non-contact DIC sensor suitable for both strain-controlled fatigue testing and real-time full-field strain evaluation

MRI characteristics of supraclavicular brown adipose tissue in relation to cold-induced thermogenesis in healthy human adults

Brown adipose tissue (BAT) has been proposed as a target to treat obesity and metabolic disease. Currently,; 18; F-Fluordeoxyglucose positron emission tomography (FDG-PET) is the standard for BAT-imaging. MRI might be a promising alternative, as it is not associated with ionizing radiation, offers a high resolution, and allows to discriminate different types of soft tissue.; We sought to evaluate whether supraclavicular BAT (scBAT) volume, fat-fraction (FF), and relaxation rate (R2*) determined by MRI can predict its metabolic activity, which was assessed by measurement of cold-induced thermogenesis (CIT).; Prospective cohort study.; Twenty healthy volunteers (9 female, 11 male), aged 18-47 years, with a body mass index (BMI) of 18-30 kg/m; 2; .; Multiecho gradient MRI for water-fat separation was used on a 3T device to measure the FF and T; 2; * of BAT.; Prior to imaging, CIT was determined by measuring the difference in energy expenditure (EE) during warm conditions and after cold exposure. Volume, FF, and R2* of scBAT was assessed and compared with CIT. In 11 participants, two MRI sessions with and without cold exposure were performed and the dynamic changes in FF and R2* assessed.; Linear regression was used to evaluate the relation of MRI measurements and CIT. P-values below 0.05 were considered significant; data are given as mean ± SD.; R2* correlated positively with CIT (r = 0.64, R; 2; = 0.41 P = 0.0041). Volume and FF did not correlate significantly with CIT. After mild cold exposure EE increased significantly (P = 0.0002), with a mean CIT of 147 kcal/day. The mean volume of scBAT was 72.4 ± 38.4 ml, mean FF was 74.3 ± 5.8%, and the mean R2* (1/T; 2; *) was 33.5 ± 12.7 s; -1; .; R2* of human scBAT can be used to estimate CIT. FF of scBAT was not associated with CI

Marker-free GPU-based digital image correlation system for high-temperature strain-controlled fatigue measurements: Presentation held at Annual International DIC Society Conference 2017, November 6-9, 2017, Barcelona, Spain

In contrast to tactile extensometers 2D digital image correlation (2D-DIC) works contactless and thus without slip. It measures not only the average strain between two points, it also allows for full-field analysis, e.g. the analysis of material failure cause. While these advantages also apply to the standard DIC systems available today, such systems so far have a significant disadvantage – their slow measuring speed with maximum sampling rates below 100 Hz. Strain-controlled fatigue measurements with such sensors are possible but limited by their low speed. According to ASTM E 606, at least 400 images per fatigue cycle are necessary to resolve strain amplitude better than 1 %. Hence the fatigue cycle frequency is limited to 0.25 Hz for such DIC systems resulting in a measurement time of more than 11 h for a typical strain-controlled low cycle fatigue experiment with 10.000 cycles. So far, mechanical extensometers have sampling frequencies in the kHz range and thus accelerate those experiments to less than 1 h. To overcome this limitation of slow optical measurement, the 2D-DIC evaluation was implemented on a NVIDIA GeForce GTX 1080 graphics processing unit (GPU) allowing for up to 25.000 FFT evaluations per second (both, forward and backward) of 256 x 256 pixel ROIs. For subpixel displacement calculation, 2D polynomials of second order are fitted to the 3 x 3 pixel area surrounding the correlation maximum. The standard deviation of the “Low Contrast Subpixel Contrast Images” was below 0.01 pixels (1 sigma) for a 30 x 30 pixel kernel size. This high-speed GPU evaluation was paired with a high-resolution telecentric lens with 10 mm FOV minimizing the out-of-plane error, coaxial LED illumination allowing for an exposure time of 300 µs, and a fast CameraLink camera acquiring 2040 x 256 pixel images with 1.3 kHz. This is sufficient to resolve the microstructure even on polished cylindrical samples. A blue LED was used to separate the blackbody radiation from the illumination light by a short pass filter. The result is a high-speed DIC system with a strain measurement rate of 1.2 kHz, 6 ms delay time and a total error in the range of 2*10(-5) (1 sigma). The strain signals were even less noisy than those measured mechanically and they were sufficient to resolve the turning points of a 10 Hz triangular force controlled measurement. So the DIC sensor is well suited for strain-controlled measurements combing the advantages of both, marker-free optical and fast tactile mechanical extensometers

SARS-CoV-2 seroprevalence in healthcare workers of a Swiss tertiary care centre at the end of the first wave: A cross-sectional study

Objective To assess the SARS-CoV-2 transmission in healthcare workers (HCWs) using seroprevalence as a surrogate marker of infection in our tertiary care centre according to exposure. Design Seroprevalence cross-sectional study. Setting Single centre at the end of the first COVID-19 wave in Lausanne, Switzerland. Participants 1874 of 4074 responders randomly selected (46% response rate), stratified by work category among the 13 474 (13.9%) HCWs. Main outcome measures Evaluation of SARS-CoV-2 serostatus paired with a questionnaire of SARS-CoV-2 acquisition risk factors internal and external to the workplace. Results The overall SARS-CoV-2 seroprevalence rate among HCWs was 10.0% (95% CI 8.7% to 11.5%). HCWs with daily patient contact did not experience increased rates of seropositivity relative to those without (10.3% vs 9.6%, respectively, p=0.64). HCWs with direct contact with patients with COVID-19 or working in COVID-19 units did not experience increased seropositivity rates relative to their counterparts (10.4% vs 9.8%, p=0.69 and 10.6% vs 9.9%, p=0.69, respectively). However, specific locations of contact with patients irrespective of COVID-19 status - in patient rooms or reception areas - did correlate with increased rates of seropositivity (11.9% vs 7.5%, p=0.019 and 14.3% vs 9.2%, p=0.025, respectively). In contrast, HCWs with a suspected or proven SARS-CoV-2-infected household contact had significantly higher seropositivity rates than those without such contacts (19.0% vs 8.7%, p<0.001 and 42.1% vs 9.4%, p<0.001, respectively). Finally, consistent use of a mask on public transportation correlated with decreased seroprevalence (5.3% for mask users vs 11.2% for intermittent or no mask use, p=0.030). Conclusions The overall seroprevalence was 10% without significant differences in seroprevalence between HCWs exposed to patients with COVID-19 and HCWs not exposed. This suggests that, once fully in place, protective measures limited SARS-CoV-2 occupational acquisition within the hospital environment. SARS-CoV-2 seroconversion among HCWs was associated primarily with community risk factors, particularly household transmission. © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ

Patient Safety Event Reporting and Opportunities for Emergency Medicine Resident Education

Introduction: Healthcare systems often expose patients to significant, preventable harm causing an estimated 44,000 to 98,000 deaths or more annually. This has propelled patient safety to the forefront, with reporting systems allowing for the review of local events to determine their root causes. As residents engage in a substantial amount of patient care in academic emergency departments, it is critical to use these safety event reports for resident-focused interventions and educational initiatives. This study analyzes reports from the Virginia Commonwealth University Health System to understand how the reports are categorized and how it relates to opportunities for resident education.Methods: Identifying categories from the literature, three subject matter experts (attending physician, nursing director, registered nurse) categorized an initial 20 reports to resolve category gaps and then 100 reports to determine inter-rater reliability. Given sufficient agreement, the remaining 400 reports were coded individually for type of event and education among other categories.Results: After reviewing 513 events, we found that the most common event types were issues related to staff and resident training (25%) and communication (18%), with 31% requiring no education, 46% requiring directed educational feedback to an individual or group, 20% requiring education through monthly safety updates or meetings, 3% requiring urgent communication by email or in-person, and <1% requiring simulation.Conclusion: Twenty years after the publication of To Err is Human, gains have been made integrating quality assurance and patient safety within medical education and hospital systems, but there remains extensive work to be done. Through a review and analysis of our patient safety event reporting system, we were able to gain a better understanding of the events that are submitted, including the types of events and their severity, and how these relate to the types of educational interventions provided (eg, feedback, simulation). We also determined that these events can help inform resident education and learning using various types of education. Additionally, incorporating residents in the review process, such as through root cause analyses, can provide residents with high-quality, engaging learning opportunities and useful, lifelong skills, which is invaluable to our learners and future physicians

SARS-CoV-2 seroprevalence in healthcare workers of a Swiss tertiary care centre at the end of the first wave: a cross-sectional study.

To assess the SARS-CoV-2 transmission in healthcare workers (HCWs) using seroprevalence as a surrogate marker of infection in our tertiary care centre according to exposure. Seroprevalence cross-sectional study. Single centre at the end of the first COVID-19 wave in Lausanne, Switzerland. 1874 of 4074 responders randomly selected (46% response rate), stratified by work category among the 13 474 (13.9%) HCWs. Evaluation of SARS-CoV-2 serostatus paired with a questionnaire of SARS-CoV-2 acquisition risk factors internal and external to the workplace. The overall SARS-CoV-2 seroprevalence rate among HCWs was 10.0% (95% CI 8.7% to 11.5%). HCWs with daily patient contact did not experience increased rates of seropositivity relative to those without (10.3% vs 9.6%, respectively, p=0.64). HCWs with direct contact with patients with COVID-19 or working in COVID-19 units did not experience increased seropositivity rates relative to their counterparts (10.4% vs 9.8%, p=0.69 and 10.6% vs 9.9%, p=0.69, respectively). However, specific locations of contact with patients irrespective of COVID-19 status-in patient rooms or reception areas-did correlate with increased rates of seropositivity (11.9% vs 7.5%, p=0.019 and 14.3% vs 9.2%, p=0.025, respectively). In contrast, HCWs with a suspected or proven SARS-CoV-2-infected household contact had significantly higher seropositivity rates than those without such contacts (19.0% vs 8.7%, p<0.001 and 42.1% vs 9.4%, p<0.001, respectively). Finally, consistent use of a mask on public transportation correlated with decreased seroprevalence (5.3% for mask users vs 11.2% for intermittent or no mask use, p=0.030). The overall seroprevalence was 10% without significant differences in seroprevalence between HCWs exposed to patients with COVID-19 and HCWs not exposed. This suggests that, once fully in place, protective measures limited SARS-CoV-2 occupational acquisition within the hospital environment. SARS-CoV-2 seroconversion among HCWs was associated primarily with community risk factors, particularly household transmission