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Introduction: The manufacture of cell-based products requires assuring sterility through all processes, with aseptic processing in a cleanroom. The environment consists of a critical processing zone (CPZ) that can ensure a level of cleanliness that allows cell culture containers to be opened, and a support zone (SZ) adjacent to it and accessed by an operator. In this study, an environment for cell manufacturing was proposed by designing an air mass balance in an aseptic processing area (APA). Methods: We considered the distribution of particle concentration related to the airflow of clean air passing through a high efficiency particulate air (HEPA) filter and the location of the particle emission sources and set up a model dividing the SZ into two zones vertically: the upper and lower zones in a cleanroom, considering three cases practically. Both the air inlet and outlet were located outside the cleanroom and were connected to the CPZ directly by air ducts (Case 1). The inlets of the CPZ were located in the lower or upper zones of the SZ inside the cleanroom, and the outlets were located in the upper zone (Case 2 or Case 3, respectively). We analyzed how the cleanliness of the APA was affected by different locations of the inlet and outlet of the CPZ by varying the particle emission rate or air change rate. Results: In Case 1, changes in the particle emission rate or air change rate within the SZ did not affect the particle concentration in the CPZ. In Case 2, an increase in the particle emission rate led to an increase in the particle concentration of the CPZ. In Case 3, the particle concentration of the CPZ was not affected by the particle emission rate. Cases 2 and 3 showed differences in particle concentrations between the CPZ and SZ, indicating that the location of the air inlet of the CPZ had an impact on the cleanliness of both zones. The partial circulation of air between the SZ and CPZ exhibited an additional air cleaning effect, leading to a reduction in the particle concentration in the SZ in Cases 2 and 3. Conclusions: These results suggest that the appropriate location of the air inlet and outlet can construct the cleanliness of the APA, which reduces the risk of microbial contamination. In addition, we consider that this approach can realize an APA design policy, which eliminates the need for air ducts between the outside of the cleanroom and the equipment for the CPZ, reduces the requirements for gowning, thereby reducing the required air change rate.

Summary: Background: The COVID-19 pandemic highlighted the need for improved infectious aerosol concentrations through interventions that reduce the transmission of airborne infections. The aims of this review were to map the existing literature on interventions used to improve infectious aerosol concentrations in hospitals and understand challenges in their implementation. Methods: We reviewed peer-reviewed articles identified on three databases, MEDLINE, Web of Science, and the Cochrane Library from inception to July 2024. 6417 articles were identified, 160 were reviewed and 18 were included. Findings: Results on aerosol concentration were discussed in terms of three categories: (1) filtration and inactivation of aerosol particles; (2) effect of airflow and ventilation on aerosol concentrations; and (3) improvements or reduction in health conditions. The most common device or method that was outlined by researchers was high efficiency particulate air (HEPA) filters which were able to reduce aerosol concentrations under investigation across the included literature. Some articles were able to demonstrate the effectiveness of interventions in terms of improving health outcomes for patients. Interpretation: The key finding is that infectious aerosol concentration improvement measures based on filtration, inactivation, improved air flow dynamics, and ventilation reduce the likelihood of nosocomial infections. However limitations of such approaches must be considered such as noise pollution and effects on ambient humidity. Whilst these efforts can contribute to improved air quality in hospitals, they should be considered with the other interacting factors such as microclimates, room dimensions and use of chemical products that effect air quality. Funding: This study is funded by the National Institute for Health and Care Research (NIHR) (NIHR205439).

Objective: We aimed to (1) determine the association between cumulative PaO2 and PaCO2 exposure 24 h post-return of circulation and survival with favorable neurologic outcome. And (2) to assess adherence to American Heart Association post-cardiac arrest care treatment goals (PaO2 75–100 mmHg and PaCO2 35–45 mmHg). Design and setting: Prospectively collected data were analysed from five Pediatric Resuscitation Quality collaborative sites supplemented with retrospective PaO2 and PaCO2 data. Patients: Children aged 1 day–17 years with return of circulation after cardiac arrest, admitted 2019–2022, with ≥ 4 arterial blood gasses spanning at least 12 h within 24 h post-return of ciculation, were eligible. Congenital cyanotic heart disease events were excluded. Measurements: Area under the curve calculation provided hourly cumulative PaO2 and PaCO2 exposures per child and similarly guideline recommended cumulative ranges. The primary outcome was survival to hospital discharge with favorable neurologic outcome defined as a Pediatric Cerebral Performance Category 1–3, or no pre-arrest baseline difference. Main results: Among 292 included children (median age 2.6 years (IQR 0.4–10.9)), 57 % survived to discharge and 48 % had favorable neurologic outcome (88 % of survivors). Cumulative PaO2 and PaCO2 exposure 0–24 h post-return of circulation were not significantly associated with favorable neurologic outcome in multivariable analysis (OR 1.0, 95 %CI 0.98–1.02 and OR 0.97, 95 %CI 0.87–1.09 respectively). Cumulative PaO2 and PaCO2 remained within guideline recommended ranges for 24 % and 58 % of children respectively with median areas under the curve over 0 – 24 h of 2664 mmHg (2151 – 3249 mmHg) for PaO2 and 948 mmHg (853 – 1051 mmHg) for PaCO2. AHA post-cardiac arrest care guideline recommendations for PaO2 (1800–2400 mmHg) and PaCO2 (840–1080 mmHg) were recalculated as area under the curve ranges. Achieving both normoxia and normocapnia was observed in 12 % of children. Conclusions: Cumulative PaO2 and PaCO2 exposure in the first 24 h post-return of circulation was not associated with survival with favorable neurologic outcome. Pediatric AHA post-cardiac arrest care guideline normoxia and normocapnia goals were often not met. Larger cohort studies are necessary to improve the accuracy of cumulative exposure calculations, assess the long-term effects of PaO2 and PaCO2 exposure, and explore the influence of other post-cardiac arrest care therapeutic strategies.

In comparison with other European countries, Ireland has a disproportionately high number of poorly performing energy-inefficient buildings. Consequently, Ireland has one of the most ambitious energy retrofit programmes in Europe. The aim of this study was to evaluate the impact of deep energy renovation measures i.e. (replacement of heating system and upgrade to building envelope) on indoor air quality, thermal comfort and ventilation in a sample of primarily social housing in Ireland. A mixed methods approach including measurement of indoor air quality and a thermal comfort questionnaire survey was employed. Indoor concentration measurements of PM2.5, carbon dioxide, formaldehyde, and radon along with measurements of air temperature and relative humidity were made (N=14). Occupants (n=56) completed a thermal comfort questionnaire survey pre- and post-retrofit. Data collection ran from autumn 2020 until autumn 2023.Thermal comfort improved post-retrofit along with occupant satisfaction with the indoor thermal environment and heating-systems. Post-retrofit, higher bedroom CO2, and higher PM2.5 concentrations were recorded in both living areas and bedrooms. Occupant behaviours e.g. blocking wall vents were significant predictors of poorer ventilation while smoking indoors was related to higher concentrations of PM2.5. In general, homes that had mechanical ventilation systems installed were better ventilated. Underventilation, as indicated by visible condensation or mould was observed in half of the social homes surveyed and reported by questionnaire respondents (26 %). Tailored communications to occupants regarding the important role of ventilation and indoor air quality is required as part of retrofit to optimise impacts on IEQ.

Ensuring sustainability and reducing energy consumption in the built environment is essential for achieving energy efficiency and comfort. To obtain a healthy and sustainable urban environment, indoor air quality and ventilation play a crucial role inside buildings since billions of people live in urban environments worldwide and spend significant time indoors. Considering the relevance of this theme, the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was adopted to conduct a review regarding air quality and ventilation and their impacts on urban environments. The search identified 7568 articles related to the topic, of which 103 were selected after applying the criteria defined to answer four research questions. The main findings of this research are: (I) Analysis of design strategies related to indoor air quality shows that ventilation plays a key role in promoting healthy and comfortable conditions; (II) Air distribution involves controlling temperature, velocity, humidity and pollutant concentration, thus creating an indoor environment with low energy consumption and high air quality; (III) The Covid-19 pandemic has emphasized the urgency of addressing Indoor Air Quality (IAQ) and ventilation as crucial strategies in reducing the spread of respiratory viruses; (IV) Climate change and the global energy crisis have imposed significant pressure on the construction industry to design buildings with low energy consumption, especially in developed countries with high levels of energy consumption.

Scientific evidence suggests that SARS-CoV-2 is transmitted primarily through close contact with susceptible individuals and that the risk of transmission increases during prolonged exposure in confined, inadequately ventilated and densely occupied spaces. In response to concerns related to inadequate ventilation for students and staff, CO2 concentrations were measured in all of Montreal’s public elementary and high schools during winter of 2020–21. This study aims to evaluate the associations between ventilation system types, mid-class CO2 concentrations and SARS-CoV-2 transmission amongst Montreal's public school’s attendees during the 2020–2021 school year. Data on building ventilation types, CO2 measurements and school characteristics such as total enrollment and socioeconomic status (SES), were sourced from Ministry of Education’s administrative data for the 2020–2021 school year. During this pandemic period, the Montreal Public Health Department investigated COVID-19 cases among students and staff in public elementary and high schools, gradually developing a regional database of school cases and outbreaks from intervention files. Negative binomial regression models were employed to examine associations between mid-class CO2 concentrations and COVID-19 incidence rates for both total cases and those acquired within schools. Regression models were adjusted for school types, neighborhood COVID-19 incidence rates and school SES. The mid-class CO2 concentrations median was 1050 ppm in the 384 school buildings. CO2 concentrations were associated with ventilation systems, with schools using natural ventilation exhibiting higher concentrations compared to three other types of mechanical ventilation. No positive association was observed between the incidence rates of school-acquired cases and higher mid-class CO2 concentrations in both unadjusted and adjusted models.

A recent article published in Science urges mandatory indoor air quality (IAQ) standards in public spaces, focusing on protecting public health, especially against diseases such as COVID-19, but also IAQ in general (1). Given the significance of this topic to our society, this short communication aims to provide commentary on the article and further discuss the importance of establishing IAQ standards. Citing a lack of legislated standards globally, the authors (1) propose numerical limits for four IAQ parameters: particulate matter (PM2.5), carbon dioxide (CO2), carbon monoxide (CO), and ventilation rate (VR). While recognizing that most of the countries do not have any mandatory IAQ standards, it is also noteworthy that IAQ regulations or guidelines exist in more than 40 countries. We like to emphasize that successful IAQ management requires recognizing, sharing, and reviewing openly available, existing regulations and guidelines, while adapting them to regional characteristics.

To clear the influences of ventilation performance on COVID-19 outbreaks in hospitals, the ventilation characteristics were investigated in a ward of an over-30-year-old hospital where a large outbreak occurred in the winter of 2020. At the early stage of the outbreak, nasal high-flow (NHF) was used in a treatment room for a week, and many patients stayed in multi-bed rooms during the outbreak. The viruses could expand not only with the infected staff or patients but also with the virus-contained air. To make an emergent ventilation measure plan, which the hospital requested, the actual performance of the air-conditioning and ventilation system and the ventilation characteristics were investigated using airflow volume meters, smoke testers, and a tracer gas CO2. The results of the measurements and the analysis showed the following. The ventilation rates had decreased to 30 % of the design value in the ward. The ventilation rate was decreased to 10 % in the treatment room where NHF was used, and the ventilation rates were decreased to 4–31 % in the rooms with six beds. The room doors were usually opened, and the opening had the effect of increasing the ventilation rate of the room. However, the virus-contained air could expand to the corridor and the other spaces. The air supply is stopped to keep room temperature at night, and the ventilation is thought to be very poor, especially if the doors are closed. Inadequate ventilation in the old buildings may have affected the hospital outbreak cases. It is essential to check the ventilation characteristics regularly, especially in old buildings. The result contributed to the administrative notice “The Emergent Ventilation Measures to Control COVID-19 in Hospitals” in April 2021 in Japan.

The development of modern life requires new energy sources, and one of this energy is renewable solar energy uses in solar chimney for natural ventilation, but at the present time it is not greatly invested, taking into account the weather conditions of the region and the physical characteristics of solar radiation and air in the area in which the study will be conducted. The current study was carried out in Basrah city- Iraq, at longitude 47.749° and latitude 30.568°, where the solar chimney was facing south. The investigation was conducted using both theoretical and experimental studied. In the theoretical study, the solar chimney with the room in the presence and absence of PCM was simulated numerically using the finite volume method using the soft package ANSYS-Fluent/2021/R2. The effect of different tilt angles (α = 30°, 45°, and 60°), solar chimney air gap (gab = 10 cm, 15 cm, and 20 cm), and PCM basin thickness (tPCM = 3 cm, 4 cm, and 5 cm) were investigated. The results were presented in the form of contours of the distribution of streamlines, velocity, temperature, and liquid fraction of the solar chimney with the room, rate of temperature of the absorber plate with time and the rate of temperature of the PCM (TPCM) with time, rate of air change per hour (ACH). As for the experimental side, the device was built, and the intensity of solar radiation was studied for several days on 30 Sep. and 15 Oct. 2023, the temperature distribution rate of the absorbent plate over time, the PCM temperature rate, and the air change per hour (ACH). The theoretical results were compared with the experimental results, where there was good agreement, and the theoretical comparison was also made with several researchers. Significant results showed that the optimal ratio of the air gap width of the solar chimney is 15 cm, the inclination angle of the solar chimney α = 30°, and the thickness of the PCM basin (tPCM = 4 cm) to obtain the maximum ventilation rate. The thickness of the PCM basin = 4 cm gives the largest liquid fraction along time and maximum average temperature of the absorber plate. On the experimental, it was found that PCM convert into the liquid phase after its melting point, which is 340 K, after 12 noon, and the highest value of ACH reached 37 on September 30/2023 at midday.

The importance of aerosols (particles suspended in air) produced during dental procedures became more apparent than ever during the COVID-19 pandemic. Concerns over transmission of infection in these aerosols led to unprecedented disruption to dental services across the world, adversely impacting patients’ oral health. This article discusses the evidence related to airborne transmission of infectious diseases and the relevance to dentistry. The production of bioaerosols (aerosols carrying biological material) during dental procedures is explored, as well as how the potential risks posed by these bioaerosols can be controlled. A better understanding of dental bioaerosols is needed to prevent similar disruption to dental services in future outbreaks, and to reduce the risk of infection of dental professionals when treating patients with active infections who require urgent or emergency dental care.

Background: The relaxation of strict COVID-19 control measures has led to a considerable increase in the number of influenza cases in 2023. This worrisome situation has posed a greater burden on public health and healthcare systems. Understanding environmental drivers of influenza epidemics can provide valuable insights for developing effective interventions. Methods: We conducted an online survey from April 13th to 14th, 2023 to investigate the incidence of influenza-like illness (ILI) and influenza A within the past two months. A total of 4916 valid questionnaires were collected in mainland China. The questionnaire explored the relationship between the spread of ILI/Influenza A and factors including personal attributes, living environment, indoor ventilation, and personal behaviours. Results: Out of the 4916 respondents, 1583 reported having ILI in the past two months, and among them, 456 were infected with influenza A. The multivariate logistic regression analysis revealed significant associations with a lower likelihood of reporting ILI for the following variables: being female (Adjusted OR (aOR) = 0.834), having bedroom ventilation time exceeding 12 hours (aOR = 0.782), wearing masks in public places (aOR = 0.646), and using surgical masks (aOR = 1.417). Conversely, variables associated with an increased risk of ILI included larger household size (>4: aOR = 2.405), presence of odours in the bathroom (aOR = 1.163), commuting by bus (aOR = 1.265), longer indoor stay during weekdays (>18 h: aOR = 1.969), and a history of COVID-19 infection (aOR = 1.459). Furthermore, handwashing after toileting (aOR = 0.694) was associated with a lower reporting of influenza A. Conclusions: Our study innovatively examined the impact of personal and environmental factors on influenza transmission. These observational findings can provide a scientific guidance for preventive measures against influenza.

It is important to quantify uncertainty in the viable genomic material encapsulated in the respiratory particles emitted by infected people so that it can be converted into an emission rate as a function of respiratory and metabolic activities and used to estimate the probability of infection for an indoor scenario. Clinical measurements of viral loads for SARS-CoV-2 made using infection surveys, Gesundheit-II samplers, and human challenge studies are evaluated and a mathematical model is derived to estimate the quantum emission rate as a function of the genomic and viable viral loads. Modelled emission rates for SARS-CoV-2 agree with clinical data above detection limits. The viral load is found to vary over at least 6 orders of magnitude because it is person and time dependent, and contingent on many other factors that are difficult to quantify. It is similarly large for other respiratory pathogens. Therefore, the genomic and viable-virion emission rates display similar heterogeneity. When emission rates are used to estimate absolute infection risk using the Wells-Riley model, the predictions are so uncertain that they cannot be used in any meaningful way to provide useful quantitative guidance for designing indoor spaces.

Indoor environmental quality (IEQ) has a profound impact on occupant health, comfort, and performance. Various methods are employed to collect feedback from building users, ranging from conventional questionnaires, increasingly utilized physiological monitoring, to recently developed automatic facial expression recognition. This study explores the feasibility of detecting environmental perception and satisfaction by continuous monitoring of facial expression and physiological parameters and compares the results with questionnaire results. Using independently controlled twin climate chambers, we established two distinct air pollution and noise exposure conditions and invited 25 participants to experience them in counter-balanced orders. They engaged in different activities including resting, taking cognitive tests, and watching a relaxing landscape video. Survey results suggested stark differences in self-reported environmental perceptions between the two conditions. Among the 31 unique facial action units (FAU) identified, some showed significant differences between the two air pollution and noise exposure conditions, especially during cognitive tests, while changes in physiological parameters were minor. We also established a model for predicting dissatisfaction with overall IEQ based on facial and physiological data and achieved an accuracy of 0.71, despite the weak correlation between individual FAUs and self-assessed perceptions. Our findings underscore the potential and the challenges of innovative methods for characterizing human responses to indoor environmental stimuli.

The effects of ceiling fans on the transmission of infectious aerosols remain poorly understood, leading to conflicting recommendations. We conducted repeated experiments in a well-controlled chamber with a typical mixing ventilation system at three different ventilation rates with and without ceiling fans. We evaluated airborne infection risks for short- and long-range transmission routes based on size-resolved tracer particles measured at various locations. We found that the mixing ventilation without fans only effectively diluted the airborne particle concentration for the long-range route but not for the short-range. By using ceiling fans to enhance air mixing, tracer particles were distributed more homogeneously throughout the room, leading to up to 77 % reduction in short-range particle exposure while a slight increase of less than 14 % in long-range exposure. Based on the dilution-based Wells-Riley model, the changes in particle concentration translated to a maximum 47 % reduction in short-range infection risk and a marginal 4 % increase for long-range transmission. Based on the dilution factors obtained from the experiments, we developed a decision-making tool that uses the ventilation rate, the number of individuals at short- and long-range, and the disease's transmissibility to decide whether the use of ceiling fans is beneficial. Deploying ceiling fans always reduces the concentration of particles in the short range and, assuming a relationship between particles and pathogens, this directly translates to a diminished short-range risk. Based on the modeling of the overall risk, the benefits of fans are highest when the room is ventilated according to code, when masking measures are in place, and when the pathogen is not highly contagious.

Overhead gaspers with adjustable open ratios and flow directions can alter the airflow pattern in aircraft cabins and consequently influence airborne infectious diseases transmission. To achieve the optimal operations of gaspers for minimizing the passengers’ exposure risks, this study developed a Bayesian optimization method based on computational fluid dynamics (CFD). A seven-row, single-aisle, fully occupied, economy-class aircraft cabin was used for the numerical investigation. Two air distribution systems, i.e., a mixing ventilation system and a personalized displacement ventilation system, were considered. First, the open ratios of all the gaspers were optimized by the CFD-based Bayesian optimization method. The optimal operations of gaspers were determined with only 20 trials calculated by CFD using the Bayesian optimization. With the optimal open ratios of all the gaspers, the number of relatively high-risk passengers (exposure index over 0.95) was effectively reduced by at least 55% and 86% under the mixing ventilation and the personalized displacement ventilation, respectively, when compared with the results with all the gaspers turned off. Next, the optimal open ratios and flow directions of the gaspers near the index passenger were also determined by the proposed method. With the optimized operations of gaspers, the number of relatively high-risk passengers was effectively reduced by at least 50% and 67% under the mixing ventilation and the personalized displacement ventilation, respectively.

Background: There is a lack of bench systems permitting to evaluate ventilation devices in the specific context of cardiac arrest. Objectives: The objective of the study is to assess if a new physiological manikin may permit to evaluate the performances of medical devices dedicated to ventilation during cardiopulmonary resuscitation (CPR). Methods: Specific CPR-related features required to reproduce realistic ventilation were implemented into the SAM (Sarthe Anjou Mayenne) manikin. In the first place, the manikin ability to mimic ventilation during CPR was assessed and compared to real-life tracings of airway pressure, flow and capnogram from three out of hospital cardiac arrest (OHCA) patients. In addition, to illustrate the interest of this manikin, ventilation was evaluated during mechanical continuous chest compressions with two devices dedicated to CPR: the Boussignac cardiac arrest device (B-card − Vygon; Ecouen France) and the Impedance Threshold Device (ITD − Zoll; Chelmsford, MA). Results: The SAM manikin enabled precise replication of ventilation tracings as observed in three OHCA patients during CPR, and it allowed for comparison between two distinct ventilation devices. B-card generated a mean, maximum and minimum intrathoracic pressure of 6.3 (±0.1) cmH2O, 18.9 (±1.1) cmH2O and −0.3 (±0.2) cmH2O respectively; while ITD generated a mean, maximum and minimum intrathoracic pressure of −1.6 (±0.0) cmH2O, 5.7 (±0.1) cmH2O and −4.8 (±0.1) cmH2O respectively during CPR. B-card allowed to increase passive ventilation compared to the ITD which resulted in a dramatic limitation of passive ventilation. Conclusion: The SAM manikin is an innovative model integrating specific physiological features that permit to accurately evaluate and compare ventilation devices during CPR.

Objective: The aim of this study was to analyze the feasibility of a new resuscitation strategy in which breaths are provided during automated external defibrillator (AED) rhythm analysis, and to evaluate its impact on chest compressions (CC) quality and the peri-analysis time. Method: A randomized simulation study, comparing two cardiopulmonary resuscitations strategies, has been conducted: the standard strategy (S1) with strategy involving ventilation during AED analysis (S2). Thirty lifeguards have performed both strategies in a cross-over study design during 10 min of CPR. Results: The number of ventilations per 10 min increases from 47 (S1) to 72 (S2) (p

The presence of air in the peritoneal cavity demonstrated radiographically as the crescent of air under the diaphragm is termed pneumoperitoneum. The causative agents may be divided into spontaneous, traumatic, iatrogenic, and miscellaneous. The majority (∼ 90%) of cases are attributed to hollow viscus perforation which requires immediate surgical attention. Neonatal pneumoperitoneum is a surgical emergency unless proven otherwise. A distinct entity termed benign pneumoperitoneum occurs in the absence of clinical and paraclinical features of peritonitis. Benign pneumoperitoneum may be caused by various thoracic, abdominal, and gynecological conditions. In neonates with respiratory distress pneumoperitoneum is a frequent association especially when treated with mechanical ventilation. The air leak phenomenon leads to air tracking from the ruptured alveoli along the interstitium to the mediastinum then to the retroperitoneum and ultimately into the peritoneal cavity. Such patients usually do not require surgical intervention and are managed conservatively. Knowledge of the existence of benign pneumoperitoneum helps to avoid unnecessary surgery thereby reducing operative morbidity and mortality.

Background: COVID-19 is the largest recorded pandemic in history. It causes several complications such as shock, pneumonia, acute respiratory distress syndrome, and organ failure. The objective was to determine COVID-19 outcomes and risk factors in the intensive care (ICU) setting. Methods: A retrospective review of prospectively collected data was conducted. Adult patients with a positive RT-PCR test for COVID-19 admitted to ICUs of a tertiary care hospital between 2020 and 2022 were included. Patients who had severe complex trauma were excluded. The outcomes examined included ventilation use and duration, length of stay (LOS), and mortality. Results: A total of 964 patients were included. The mean ( ± standard deviation, SD) age was 63.7 ± 16.9 years. The majority of the patients were males (59.0 %) and Saudi (75.7 %). Ventilation use was documented in 443 (57.1 %) patients, with a mean ( ± SD) ventilation duration of 9.7 ± 8.4 days. Death occurred in 361 (37.4 %) patients after a mean ( ± SD) of 33.3 ± 44.5 days from infection. The mean ( ± SD) LOS was 30.6 ± 54.1 days in hospital and 5.2 ± 5.4 days in ICU. Ventilation use was associated with older age, males, longer ICU LOS, mortality, and admission to medical-surgical ICU. Crude mortality use was associated with older age, longer ICU LOS, use of ventilator, shorter ventilation duration, and admission to medical-surgical or respiratory ICUs. Conclusions: COVID-19 patients admitted to adult ICUs are at high risk of death and mechanical ventilation. The crude risks of both outcomes are higher in older age and longer ICU LOS and are very variable by ICU type.

We perform direct numerical simulations to study the effect of increasing airflow rate on CO2 concentration in downflow and displacement ventilation in a room with one occupant. Often, CO2 concentration is used as a proxy for the concentration of bio-aerosols of respiratory droplets, and therefore, tracking the CO2 concentration in ventilation strategies can be useful to understand and quantify the risk of spread of communicable respiratory illnesses. At low to moderate airflow rates, the flow in the downflow setup is not mixed, but stratified. The CO2 concentration in the upper and lower layers is determined by the strength of the thermal plume originating from the occupant. We provide a simple theoretical model to predict the height of the stratified interface, the volumetric flux of the ascending plume, and the CO2 concentration in the lower and upper layers. At very high airflow rates, the flow is well-mixed and the average CO2 concentration in the room can be predicted with the mixing ventilation assumption. We demonstrate that at low to moderate airflow rates, displacement ventilation more effectively maintains lower CO2 concentrations in the lower layer compared to downflow ventilation.

To address the issues of heat and humidity hazards, as well as insufficient air volume in deep mining operations, a novel cooling method combining spray and chord grid is proposed. To investigate the cooling dynamics, an experimental platform integrating both spray and chord grid components is independently developed. Field boundary conditions are simulated to conduct orthogonal experimental research. Under the experimental parameters of an inlet air temperature of 32 °C, relative humidity of 88 %, and initial spray water temperature of 26 °C, the effects of water-air ratio, nozzle distance, and other parameters on inlet and outlet temperature, as well as moisture content, are quantified. These influencing factors are analyzed through range analysis. Results demonstrate that the water-air ratio has a greater impact on cooling compared to the nozzle distance. Notably, when the water-air ratio and nozzle distance reach critical values of 0.6 and 70 cm respectively, the cooling rate begins to plateau. Furthermore, comparative analysis of the cooling and dehumidification effects of single spray versus spray + chord grid reveals that the cooling capacity of single spray systems can be surpassed by incorporating a chord grid. Specifically, the combination of spray + chord grid achieves superior cooling effects with lower water consumption.

Aim: To determine whether targeting mild hypercapnia (PaCO2 7 kPa) would yield improved cerebral blood flow and metabolism compared to normocapnia (PaCO2 5 kPa) with and without targeted temperature management to 33 °C (TTM33) in a porcine post-cardiac arrest model. Methods: 39 pigs were resuscitated after 10 minutes of cardiac arrest using cardiopulmonary bypass and randomised to TTM33 or no-TTM, and hypercapnia or normocapnia. TTM33 was managed with intravasal cooling. Animals were stabilized for 30 minutes followed by a two-hour intervention period. Hemodynamic parameters were measured continuously, and neuromonitoring included intracranial pressure (ICP), pressure reactivity index, cerebral blood flow, brain-tissue pCO2 and microdialysis. Measurements are reported as proportion of baseline, and areas under the curve during the 120 min intervention period were compared. Results: Hypercapnia increased cerebral flow in both TTM33 and no-TTM groups, but also increased ICP (199% vs. 183% of baseline, p = 0.018) and reduced cerebral perfusion pressure (70% vs. 84% of baseline, p

Recent studies show that artificial intelligence (AI), such as machine learning and deep learning, models can be adopted and have advantages in fault detection and diagnosis for building energy systems. This paper aims to conduct a comprehensive and systematic literature review on fault detection and diagnosis (FDD) methods for heating, ventilation, and air conditioning (HVAC) systems. This review covers the period from 2013 to 2023 to identify and analyze the existing research in this field. Our work concentrates explicitly on synthesizing AI-based FDD techniques, particularly summarizing these methods and offering a comprehensive classification. First, we discuss the challenges while developing FDD methods for HVAC systems. Next, we classify AI-based FDD methods into three categories: those based on traditional machine learning, deep learning, and hybrid AI models. Additionally, we also examine physical model-based methods to compare them with AI-based methods. The analysis concludes that AI-based HVAC FDD, despite its higher accuracy and reduced reliance on expert knowledge, has garnered considerable research interest compared to physics-based methods. However, it still encounters difficulties in dynamic and time-varying environments and achieving FDD resolution. Addressing these challenges is essential to facilitate the widespread adoption of AI-based FDD in HVAC.

ABSTRACT: Heat abatement (e.g., soakers, fans) effectively reduces the negative physiological and production effects of heat stress, but no previous studies have documented effective interventions for the reduced lying times observed in response to hot weather. Although likely adaptive for heat dissipation, the reduction in motivated lying behavior may be an animal welfare concern. We evaluated the effect of air speed from fans with variable frequency drives on the heat stress responses of cows in a naturally ventilated freestall barn. Eight groups of lactating Holsteins (16 cows/group) were exposed to 3 treatments in a replicated crossover design: control (fans off, 0.4 ± 0.2 m/s, measured 0.5 m above the stall surface to represent cow resting height) versus 60% (1.7 ± 0.5 m/s; ≥1 m/s in all stalls) and 100% (2.4 ± 0.8 m/s) fan power. Each treatment was applied for 3 d of acclimation and 4 d of data collection. The effects of treatment on daily maximum vaginal temperature (VT) and lying time (LT; both measured with data loggers), respiration rate (RR; recorded from video), unshaved scapular skin temperature (ST), milk yield (MY), and dry matter intake (DMI) were analyzed using linear mixed models. All models included the fixed effect of treatment and a repeated term for treatment day within group of cows, with group as the subject. The models for LT, VT, and RR also included a fixed effect for same-day temperature-humidity index (THI; recorded in the pens with data loggers) and the THI × treatment interaction. The models for DMI and MY, using data from the latter 3 d of each treatment period, also included a fixed effect for the previous day's THI and the −1 d THI × treatment interaction. Lying time differed among treatments (100% vs. 60% fan power vs. control: 14.2 vs. 13.9 vs. 13.2 h/d, respectively, SEM = 0.15 h/d), but both fan treatments prevented the reduction in LT observed in the control treatment as THI increased. Relative to the control, both fan treatments effectively reduced ST, RR, and VT and increased DMI and MY. In the control, average values were elevated for both RR (68.7 ± 1.5 breaths/min, mean ± SEM, greater than a common benchmark of 60 breaths/min) and VT (39.3 ± 0.05°C) but remained in the normal range in both fan treatments (54.2 vs. 50.7 breaths/min in the 60% vs. 100% fan power treatments; 39.0°C in both fan treatments). Both fan treatments resulted in greater overall MY (42.6 vs. 43.0 ± 0.4 kg/d in the 60% vs. 100% fan power treatments) relative to the control (41.0 kg/d) and similarly avoided the reduction in MY when −1 d THI increased. Compared with natural ventilation alone, fans delivering air speeds of at least 1 m/s at cow resting height were effective not only for reducing thermoregulatory responses, but also for maintaining lying time, DMI, and MY in heat stress conditions. This is the first study to demonstrate an intervention to improve animal welfare by maintaining lying times during periods of heat stress.

The aim of this study was to assess the effectiveness of air cleaning in reducing the risk of respiratory infection in two day care centres using a simple and robust calculation model. Additionally, we aimed to identify potential hotspots for infections in indoor setting and focus countermeasures accordingly. Initial results from an interventional clinical study are provided as proof-of-concept for the model. We constructed a mathematical model to assess the number of persons at risk for airborne infection transmission in day care. Utilizing the model, we used portable air cleaners in two day care units (A and B, number of children participating in the study n = 43) and compared infection incidents between the two intervention units to the rest of the units in city of Helsinki (n = 607). The intervention buildings had mechanical supply and exhaust air ventilation. The risk modelling suggests that the use of air cleaners reduced the expected number of persons at infection transmission risk significantly. At day care centre A the average reduction was 60% (range 52% - 88%) and at day care centre B 53% (range 14% - 59%). During the approximately six month study period, we observed a significant difference in the days absent from day care due to infections between the intervention and reference day care units. On average, the parents were absent from work due to child’s illness in reference day care centers for 5.53 days and 3.77 days in intervention day care centers during the study period (p=0.009). In relative terms the reduction was approximately 32%. Our study offers compelling evidence to support increasing non-infectious air flow rates in daycare centers during periods requiring infection risk management. This can be implemented with portable air cleaners as an effective and cost-efficient strategy for mitigating the spread of respiratory infections among children. The clinical results support the findings suggested by the theoretical model. Implications and impacts: – Air cleaning seems to be an effective way to reduce infection risk in day cares – Identification of infection risk hotspot will help in desgining the preventive methods – Portable air cleaners offer an affordable and versatile solution also in buildings where existing ventilation is insufficient for infection risk management”

Aim: Compare lung injury and hemodynamic effects in synchronized ventilations (between two chest compressions) vs. unsynchronized ventilations during cardiopulmonary resuscitation (CPR) in a porcine model of cardiac arrest. Methods: Twenty pigs were randomized to either synchronized or unsynchronized group. Ventricular fibrillation was induced electrically and left for 1.5 minutes. Four minutes of basic chest compression:ventilation (30:2) CPR was followed by eight minutes of either synchronized or unsynchronized ventilations (10/min) during continuous compressions before defibrillation was attempted. Aortic, right atrial and intracerebral pressures, carotid and cerebral blood flow and cardiac output were measured. Airway monitoring included capnography and respiratory function monitor. Macro- and microscopic lung injuries were assessed post-mortem. Results: There were no significant differences between groups in any of the measured hemodynamic variables or inspiration time (0.4 vs. 1.0 s, p = 0.05). The synchronized ventilation group had lower median peak inspiratory airway pressure (57 vs. 94 cm H2O, p

Background: During cardiopulmonary resuscitation, following advanced airway placement, chest compressions and ventilations are performed simultaneously. During inspiration, chest compressions and positive pressure ventilation exert opposite forces on the respiratory system, frequently resulting in reversed airflow. Methods: Following endotracheal intubation, a flow sensor was connected to the respiratory circuit of intubated, adult out-of-hospital cardiac arrest patients receiving manual chest compressions and manual ventilations. Chest compression parameters were measured using an accelerometer. Inspiratory and expiratory volumes during the inspiratory phase of positive pressure ventilations were quantified. Duration of the inspiratory and expiratory phases was calculated. Results: In this study, 25 patients were included, 682 ventilations were analyzed. Reversed airflow was observed in 23 patients, occurring 389 times during 270 ventilations. Median volume of reversed airflow was 2 mL (IQR 1.4–7 mL). There was no difference between net tidal volumes of ventilations during which reversed airflow did (median 420 mL, IQR 315–549) or did not occur (median 406 mL, IQR 308–530). When reversed airflow occurred, the duration of the inspiratory phase was longer (median 1.2 sec, IQR 0.9–1.4) compared to ventilations without reversed airflow (median 0.9 sec, IQR 0.9–1.4). Univariate analysis showed a weak correlation between chest compression depth and volume of reversed airflow. Conclusion: Reversed airflow frequently occurs during cardiopulmonary resuscitation. Volumes of reversed airflow were small, showing a weak correlation with chest compression depth. The occurrence of reversed airflow was not associated with reduced net tidal volumes.

Ventilation strategies for infection control in hospitals has been predominantly directed towards isolation rooms and operating theatres, with relatively less emphasis on perceived low risk spaces, such as general wards. Typically, the ventilation systems in general wards are intended to optimize patient thermal comfort and energy conservation. The emission of pathogens from exhalation activity, such as sneezing, by an undiagnosed infectious patient admitted to general wards, is a significant concern for infection outbreaks. However, the ventilation guidelines for general wards with respect to infection control are vague. This research article presents a numerical study on the effect of varying air change rates (3 h−1, 6 h−1, 9 h−1, 13 h−1) and exhaust flow rates (10%, 50% of supply air quantity) on the concentration of airborne pathogens in a mechanically ventilated general inpatient ward. The findings imply that the breathing zone directly above the source patient has the highest level of pathogen exposure, followed by the breathing zones at the bedside and adjacent patients close to the source patient. The dispersion of pathogens throughout the ward over time is also apparent. However, a key difference while adopting a lower ACH (3 h−1) and a higher ACH (13 h−1) in this study was that the latter had a significantly lower number of suspended pathogens in the breathing zone than the former. Thus, this research suggests high ventilation rates for general wards, contrary to current ventilation standards. In addition, combining a higher air change rate (13 h−1) with a high exhaust flow rate (50% of supply air) through a local exhaust grille dramatically reduced suspended pathogens within the breathing zone, further mitigating the risk of pathogen exposure for ward users. Therefore, this study presents an effective ventilation technique to dilute and eliminate airborne infectious pathogens, minimizing their concentration and the risk of infection.

In this study, physical aspects of a ventilated supercavity behind different cavitator geometries such as the hydrodynamic characteristics, distribution of pressure within the cavity, hysteresis phenomenon, and gas leakage mechanism were qualitatively and quantitatively investigated using experimental and numerical methods. For the simulation and tunnel tests, we employed five cavitators, each with different angles (45°, 60°, 90°, 135°, and a 180° cavitator, commonly referred to as a disk cavitator), all sharing the same diameter. The results revealed that the drag force experienced on the cavitator decreased linearly with an increase in the ventilation rate, and a consistent trend was observed for all test cavitator angles. Through experimental measurements, a universal equation has been derived to predict the drag force exerted on a supercavitating vehicle employing a cavitator. In addition, the pressure distribution inside the supercavity was significantly influenced by the angle of the cavitator. The pressure kept almost unchanged in the first half of supercavity; a slight increase in pressure occurred in the remainder of the supercavity. Twin-vortex gas leakage mode was clearly observed. The distance between the two hollow vortices increased significantly, whereas the incline angle of these vortices and the horizontal line changed insignificantly.

Isolation rooms are crucial in healthcare facilities to prevent the spread of infectious diseases. Infectious diseases can be transmitted to humans from humans or through animals known as zoonoses. With the increase in the number of COVID-19 cases, isolation rooms have become one of the most critical facilities in hospitals. Maintaining the correct temperature and humidity in these isolation rooms is a challenge, considering the heating, ventilation, and air conditioning (HVAC) systems that continuously consume large amounts of energy. With the application of energy conservation methods, the total energy consumption of HVAC systems can be reduced. Many studies have shown that the heat pipe heat exchanger (HPHE) technology can contribute significantly to energy savings using HVAC systems. In this study, the effectiveness of an HPHE on an HVAC system in an isolation room was examined, and the total energy reduction was quantified. The HPHE consisted of two rows with ten heat pipes in each row, arranged in a staggered configuration with fresh air temperature and mass flow variations. The inlet fresh air temperatures varied at 32, 35, 37, and 40 °C and fresh air velocities at 1.2, 1.6, 2.2, and 2.6 m/s. Using a chiller, the inlet fresh air was cooled to a comfortable temperature zone, approximately 24.4–25.2 °C, in the isolation room. Notably, higher velocities decreased the effectiveness of the HPHE. An increase in the flow rate enhanced the system, thereby improving the heat recovery value. The increase in the inlet fresh air temperature from 32 °C, that yielded an energy saving of 1.23 W, to 40 °C, resulted in a further energy saving of 1.85 W. The application of the HPHE in the HVAC system in isolation rooms represents a significant innovation that contributes to a reduction in total energy consumption.

Reinforced concrete elements located in enclosed spaces with medium to high humidity, inside air chambers beneath sanitary floors, are shielded from rainfall. However, the longevity of these elements, as estimated by durability models for predicting the corrosion of their reinforcement due to carbonation, significantly exceeds the actual service lives observed. The discrepancy between estimated and actual service lives often results in structural failures of sanitary floors, which may collapse without warning, given the inherent challenges associated with inspection and maintenance. This study thoroughly examined the condition of reinforced concrete elements beneath sanitary floors in four educational institutes located in the Valencian Community, where corrosion of reinforcement due to carbonation was present. The study entailed an analysis of the relative humidity, temperature, and presence of CO2 within these enclosed spaces, in comparison to exterior areas or other parts of the building. Furthermore, tests were conducted to assess the characteristic strength of the concrete and the depth of carbonation. Additionally, the surface area of the chamber used for ventilation was assessed in light of the minimum requirements. Notwithstanding, the concrete cover of the beams and columns exhibited carbonation, with the reinforcement's corrosion in a propagation period. The study's findings revealed that the service life of the structural elements is substantially shorter than initially anticipated, in part due to advanced carbonation processes that are attributable to the harsh environment in which they are located.

Thermal performance of densely populated underground buildings is normally influenced by various factors, including the surrounding rock (SR), ventilation, and indoor heat sources. It is recognized that little experimental studies on thermal control for the above building was reported. In this article, a full-size 50-person mine refuge chamber (MRC) was newly constructed to test the thermal performance under natural convection and ventilation. The heat ducts were used to simulate the heat released from human body. Experimental results indicated that: (1) the intensity of the heat transfer between rock and air increases with the rise in heat source rate and ventilation temperature (VT), while it decreases as the initial surrounding rock temperature (ISRT) increases; (2) when considering the joint temperature control of pre-cooled SR, it is recommended to reduce the VT linearly during the evacuation period in order to ensure the thermal safety of personnel. During the non-refuge period, the cold amount should be stored as far as possible into the shallow SR body to make full use of it; (3) to ensure the thermal safety of an MRC with a capacity of 30 people for 96 h, cooling measures are required when the ISRT exceeds 21.3 °C. In addition, when the ISRT reaches 27.6 °C, the per capita ventilation is 0.19 m3/min, and the temperature is 26 °C, which can also meet the requirements. This study provides experimental verification as a basis for future research on underground space temperature control considering the influence of SR.

Background: Risk factors for invasive fungal infections (IFIs) after chimeric antigen receptor-modified T cells (CAR-T) treatment have been poorly studied. Here we are investigating the risk factors and prognosis of IFIs following CAR-T therapy. Material and Methods: A case-control study was conducted on the medical records of CAR-T patients admitted to our center between June 2018 and December 2020. The case group (32) consisted of patients who developed IFIs within 60 days after CAR-T infusion, while the control group (298) consisted of patients who did not develop IFIs. The Cox Proportional Hazard Regression model was utilized to analyze the risk factors for the occurrence of IFIs, as well as the factors affecting the 1-year survival rate of patients. Result: Cumulatively, 364 patients were included. Inflammatory cytokine release syndrome (CRS) grade (hazard ratio (HR) 2.34 confidential interval (CI)（1.03–5.30) P = 0.042), ventilation (HR 3.23 CI (1.20–8.71) P = 0.020) and lymphocyte deficiency duration (HR 1.06 CI (1.01–1.10) P = 0.015) were associated with IFIs. IFIs (HR 1.12 CI (0.52–2.41) P = 0.767) did not affect a patient's one-year survival, which was associated with lymphocyte deficiency (HR 1.04 CI (1.01–1.07) P = 0.004) and treatment with broad-spectrum antibacterial (HR 1.80 CI (1.03–3.11) P = 0.038) within 30 days prior to CAR-T infusion. Conclusion: There is an increased risk of IFIs in patients with hematologic malignancies due to ventilation, high-grade CRS, and prolonged lymphocyte deficiency within 60 days after CAR-T infusion. Invasive fungal infection was not a risk factor for death within 1 year of CAR-T therapy, while broad-spectrum antibacterial therapy prior to infusion and prolonged lymphocyte deficiency were risk factors.

Background/objectives: Occupational exposure of employees to residual anesthetic gases in the operating room without a proper ventilation system can adversely affect their health. The purpose of this study was to assessment the environmental factors and monitoring the concentration of anesthetic gases in the operating rooms. Methods: Twenty-three operating rooms were examined. Simultaneously with each sampling, the temperature and humidity were measured with a moisture meter, a psychrometer, IR thermometer (Triplett MS475). The data was then analyzed using the Mann-Whitney and Pearson correlation tests. Results: The findings showed that the average concentration of isoflurane (P-value = 0.036) and sevoflurane (P-value = 0.049) were significantly higher in hospitals without ventilation system. Also, result of this study showed that the average level of isoflurane and sevoflurane (P-value = 0.315 and P-value = 0.120), there was no significant relationship in hospitals without cooler than hospitals with cooler system.Based on result this study, there was not found significant relationship between isoflurane and humidity (P-value = 0.586), isoflurane and temperature (P-value = 0.890), sevoflurane and humidity (P-value = 0.692), and sevoflurane and temperature (P-value = 0.199). Conclusion: According to the results, the most important ways to reduce adverse health effects and reduce occupational exposure levels among employees and patients including the use of modern equipment, improvement of the operating room ventilation system, the use of a cleaning system closes to the exit pipe of the anesthesia machine, employee training, control of environmental factors (temperature and humidity), and frequent monitoring of anesthetic gases.

Background: Postoperative pulmonary complications (PPCs) are known to adversely affect surgical outcomes and patient prognoses, yet no published study provides a qualitative and quantitative analysis of the latest trends and developments in the field of PPCs. Therefore, we conducted a bibliometric analysis of 20 years of publications related to PPCs. Methods: We examined publications on PPCs published between 2003 and 2022 in the Web of Science Core Collection database to assess trends in the field in four dimensions: trends in publications, major research power, keywords, and co-cited publications. Results: A total of 1881 articles were analyzed using CiteSpace and VOSviewer. Overall, the number of publications on PPCs has increased in the last two decades, with 42.72% of the publications being produced in the last five years. The United States of America had the highest number of articles, accounting for 21.91% of the total. The institution with the highest number of publications was the University of Genoa, which published 54 articles and showed a general lack of inter-institutional collaboration. The most productive author was Paolo Pelosi, with no core group of authors identified in the field of PPCs. The keyword co-occurrence analysis indicated that the focus of research has shifted over the past 20 years in terms of risk factors, type of surgery, and so on, while “enhanced recovery”, “prehabilitation”, “driving pressure” and “sugammadex” have received the most recent attention. In the analysis of co-cited literature, the most recent clusters that received attention were driving pressure, lung cancer patient, enhanced recovery, and neuromuscular blockade. Conclusion: This bibliometric study suggests that pulmonary protective ventilation strategies, neuromuscular blockade reversal, and pulmonary prehabilitation strategy will be the focus of attention in the coming period. More large-scale studies and strengthened institutional collaboration are necessary to generate robust evidence for guiding individualized prevention of PPCs.

Background: The efficacy and safety profiles of prone ventilation among intubated Coronavirus Disease 2019 (COVID-19) patients remain unclear. The primary objective was to examine the effect of prone ventilation on the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) in intubated COVID-19 patients. Methods: Databases of MEDLINE, EMBASE and CENTRAL were systematically searched from inception until March 2021. Case reports and case series were excluded. Results: Eleven studies (n = 606 patients) were eligible. Prone ventilation significantly improved PaO2/FiO2 ratio (studies: 8, n = 579, mean difference 46.75, 95% CI 33.35‒60.15, p < 0.00001; evidence: very low) and peripheral oxygen saturation (SpO2) (studies: 3, n = 432, mean difference 1.67, 95% CI 1.08‒2.26, p < 0.00001; evidence: ow), but not the arterial partial pressure of carbon dioxide (PaCO2) (studies: 5, n = 396, mean difference 2.45, 95% CI 2.39‒7.30, p = 0.32; evidence: very low), mortality rate (studies: 1, n = 215, Odds Ratio 0.66, 95% CI 0.32‒1.33, p = 0.24; evidence: very low), or number of patients discharged alive (studies: 1, n = 43, Odds Ratio 1.49, 95% CI 0.72‒3.08, p = 0.28; evidence: very low). Conclusion: Prone ventilation improved PaO2/FiO2 ratio and SpO2 in intubated COVID-19 patients. Given the substantial heterogeneity and low level of evidence, more randomized- controlled trials are warranted to improve the certainty of evidence, and to examine the adverse events of prone ventilation.

Introduction: Periodontitis is a chronic inflammatory disease caused by biofilm accumulation resulting in loss of periodontal attachment which could be linked to systemic implications. Coronavirus disease of 2019 (COVID-19) is a disease caused by SARS-CoV-2 that triggers damage to the lungs and other organs. COVID-19 and periodontitis share similar risk factors such as smoking, obesity, old age, and diabetes mellitus. Studies noted that periodontitis along with some systemic diseases has increased mortality. Thus, this study aims to examine the association of periodontitis with COVID-19 outcomes. Methods: This observational study included periodontitis group and non-periodontitis group for COVID-19 outcome assessment. Inclusion criteria were applied to select adults (≥18 years old) who showed at least one dental visit, and were isolated or admitted due to a COVID-19 complication (i.e. in-ward, ICU, or death). Exclusion criteria were patients with no active dental records. The periodontal status was examined from posterior bitewings and panoramic radiographs. The primary outcome assessed was COVID-19 complications versus no admission. Results and discussion: This study was the first of its kind as a retrospective cohort study to assess the association between periodontitis and COVID-19 severity in Riyadh, Saudi Arabia. Our findings revealed that periodontitis is statistically associated with COVID-19 severity. Periodontitis patients were three times more likely to have COVID-19 complications (p = 0.025). Diabetes (p = 0.004) and hypertension (p = 0.016) patients were 3.5 times more likely to have COVID-19 complications. Conclusion: Understanding the potential association between periodontitis and COVID-19 through systemic inflammation might be a pathway to achieve high quality medical care.

A green building is a structure that avoids or eliminates negative environmental impacts and generates environmental benefits through its design, construction, or functioning. The use of ecologically friendly building materials increases the quality of life. The overuse of electronic equipment hinders the achievement of the overall green aim, even if smart buildings are a beneficial stimulus for sustainability. Demand-side management and green building energy consumption prediction are connected and depend on accurate estimates of how much energy a facility will need. While several approaches have been offered for predicting energy use, each method has advantages and disadvantages, and there is always room for improvement. This paper suggests the Artificial Intelligence-based Energy Management Model (AI-EMM) in green building. Adaptable to human choices, it can act intelligently to increase user comfort, safety, and energy efficiency. One of the key components of the AI-EMM model is a universal infrared communication system and subsystems for smart user identification and monitoring of the internal and exterior surroundings. Long Short-Term Memory (LSTM) models are used to enhance energy consumption. A green building’s energy usage data is analysed using the suggested approach. For a better interior climate, studies examining the relationship between Heating, Ventilation, and Air Conditioning (HVAC) system should focus on airside design optimization. According to the findings, economic gains and environmentally sustainable building coexist harmoniously. A green or sustainable building is one whose structure and characteristics preserve or enhance the local environment. The experimental outcome of the AI-EMM achieved a high-performance ratio of 94.3%, less energy consumption ratio of 15.7%, accuracy ratio of 97.4%, energy management level of 95.7%, and prediction ratio of 97.1%.

Summary: Background: Factors associated with mortality and intensive care unit (ICU) admission due to Coronavirus Disease 2019 (COVID-19) in Jordanian patients are not known particularly among unvaccinated patients. Aim: To examine predictors of mortality and ICU stay in unvaccinated COVID-19 patients in the north of Jordan. Methods: Patients admitted with COVID-19 between October–December 2020 were included. Data on baseline clinical and biochemical characteristics, length of ICU stay, COVID-19 complications and mortality were collected retrospectively. Findings: 567 COVID-19 patients were included. The mean age was 64.64±0.59 years. 59.9% of patients were males. The mortality rate was 32.3%. Underlying cardiovascular disease or diabetes mellitus was not associated with mortality. The mortality increased with the number of underlying diseases. Independent predictors of ICU stay were neutrophil/lymphocyte ratio, invasive ventilation, the development of failure, myocardial infarction, stroke and venous thromboembolism. The use of multivitamins was observed to be negatively associated with ICU stay. Independent predictors of mortality were age, underlying cancer, severe COVID-19, neutrophil/lymphocyte ratio, C-reactive protein (CRP), creatinine level, pre-use of antibiotics, ventilation during hospitalisation, and length of ICU stay. Conclusion: COVID-19 was associated with an increased length of ICU stay and mortality among unvaccinated COVID-19 patients. The prior use of antibiotics was also associated with mortality. The study highlights the need for close monitoring of respiratory and vital signs, inflammatory biomarkers such as WBC and CRP, and prompt ICU care in COVID-19 patients.

This study monitored indoor environmental data in 144 classrooms in 31 schools in the Midwestern United States for two consecutive days every fall, winter, and spring during a two-year period; 3,105 pupils attended classrooms where the measurements were conducted. All classrooms were ventilated with mechanical systems that had recirculation; there were no operable exterior windows or doors. The daily absence rate at the student level and demographic data at the classroom level were collected. The overall mean ventilation rate, using outdoor air, was 5.5 L/s per person (the corresponding mean carbon dioxide concentrations were

Emergency departments (EDs) in hospitals are hotspots for highly transmissible infectious diseases and pose the most significant risk of viral infection spreading. With the recent COVID-19 outbreak, it became clear that emergency department design must evolve in order to be adequately prepared to handle the epidemic. The purpose of this research is to examine the design of the emergency department at a university hospital using a computational fluid dynamics (CFD) simulation based on the ANSYS CFX package. Turbulence Kinetic Energy and Velocity profiles were analyzed to determine which areas of the ED were most susceptible to virus spread. The analysis revealed that three critical areas of the emergency department, namely overnight patient beds, operating rooms, and resuscitation rooms, had significantly higher air velocity, dispersion, and mixing levels than the rest of the department's spaces. According to the two scenarios examined, the possibility of air transmission from these locations to neighboring areas becomes apparent, increasing the likelihood of transmitting the virus from these locations and infecting people in the adjacent areas, including patients and health care providers. Using the results of CFD simulations, a solution in the form of instructions for the arrangement of inlets and outlets, the separation of spaces, and the interior design of the spaces and hallways can be presented to the hospital administration. All of which can be implemented in the current design of the emergency department.

Introduction: The dangers of hyperventilation during resuscitation are well known. Traditional bag valve mask (BVM) devices rely on end users to control tidal volume (Vt), rate, and peak inspiratory pressures (PIP) of ventilation. The Butterfly BVM (BBVM) is a novel device intending to give greater control over these parameters. The objective of this pilot study was to compare the BBVM against a traditional device in simulated resuscitations. Methods: Senior emergency medicine residents and fellows participated in a three-phase simulation study. First, participants used the Ambu Spur II BVM in adult and pediatric resuscitations. Vt, PIP, and rate were recorded. Second, participants repeated the resuscitations after a brief introduction to the BBVM. Third, participants were given a longer introduction to the BBVM and were tested on their ability to adjust its various settings. Results: Nineteen participants were included in the adult arm of the study, and 16 in the pediatric arm. The BBVM restricted Vt delivered to a range of 4–8 ml/kg vs 9 ml/kg and 13 ml/kg (Ambu adult and Ambu pediatric respectively). The BBVM never exceeded target minute ventilations while the Ambu BVMs exceeded target minute ventilation in 2 of 4 tests. The BBVM failed to reliably reach higher PIP targets in one test, while the pediatric Ambu device had 76 failures of excessive PIP compared to 2 failures by the BBVM. Conclusion: The BBVM exceeded the Ambu Spur II in delivering appropriate Vts and in keeping PIPs below target maximums to simulated adult and pediatric patients in this pilot study.

Clean air is a requirement for life, and the quality of indoor air is a health determinant since people spend most of their daily time indoors. The aim of this study was to systematically review the available evidence regarding the sources, determinants and concentrations of indoor air pollutants in a set of scenarios under study in K-HEALTHinAIR project. To this end, a systematic review was performed to review the available studies published between the years 2013-2023, for several settings (schools, homes, hospitals, lecture halls, retirement homes, public transports and canteens), conducted in Europe, where sources and determinants of the indoor pollutants concentrations was assessed. After a two-stage screening in abstract and full-text, 148 papers were included for data extraction. For particulate matter, carbon dioxide and volatile organic compounds, several emission sources were identified (occupancy, human activities, resuspension, cleaning products, disinfectants, craft activities, cooking, smoking), with ventilation, number of occupants, building characteristics, being considered as important determinants. This review made also possible to discuss some of the actions that are already in place or should be implemented in the future to prevent and control the presence of pollutants indoors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 The Authors. Published by Elsevier B.V. All rights reserved.)

Acute hypoxic ventilatory response is an important reflex that helps maintain breathing during low oxygen levels, but it is attenuated by most general anaesthetics. Analgesic doses of ketamine and esketamine are known to have respiratory stimulant effects. In their recent study in the British Journal of Anaesthesia, Jansen and colleagues show that low-dose esketamine preserved the acute hypoxic ventilatory response, while increasing breathing rate, systolic blood pressure, and heart rate. Participants also exhibited higher levels of alertness and unpleasant psychotropic effects compared with the control condition. We review the pharmaco-physiological effects of acute hypoxia and its interactions with esketamine. We provide a summary of the effects of hypoxia and esketamine on the neurocircuitry that leads to arousal, activation of the sympathetic nerve system, and increased drive to upper airway dilator and respiratory pump muscles., Competing Interests: Declaration of interest ME is a member of the associate editorial board of the British Journal of Anaesthesia., (Copyright © 2024 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: Patients receiving intraoperative ventilation during general anesthesia often have low end-tidal CO 2 (etCO 2 ). We examined the association of intraoperative etCO 2 levels with the occurrence of postoperative pulmonary complications (PPCs) in a conveniently-sized international, prospective study named 'Local ASsessment of Ventilatory management during General Anesthesia for Surgery' (LAS VEGAS)., Methods: Patients at high risk of PPCs were categorized as 'low etCO 2 ' or 'normal to high etCO 2 ' patients, using a cut-off of 35 mmHg. The primary endpoint was a composite of previously defined PPCs; the individual PPCs served as secondary endpoints. The need for unplanned oxygen was defined as mild PPCs and severe PPCs included pneumonia, respiratory failure, acute respiratory distress syndrome, barotrauma, and new invasive ventilation. We performed propensity score matching and LOESS regression to evaluate the relationship between the lowest etCO 2 and PPCs., Results: The analysis included 1843 (74 %) 'low etCO 2 ' patients and 648 (26 %) 'normal to high etCO 2 ' patients. There was no difference in the occurrence of PPCs between 'low etCO 2 ' and 'normal to high etCO 2 ' patients (20 % vs. 19 %; RR 1.00 [95 %-confidence interval 0.94 to 1.06]; P = 0.84). The proportion of severe PPCs among total occurring PPCs, were higher in 'low etCO 2 ' patients compared to 'normal to high etCO 2 ' patients (35 % vs. 18 %; RR 1.16 [1.08 to 1.25]; P < 0.001). Propensity score matching did not change these findings. LOESS plot showed an inverse relationship of intraoperative etCO 2 levels with the occurrence of PPCs., Conclusions: In this cohort of patients at high risk of PPCs, the overall occurrence of PPCs was not different between 'low etCO 2 ' patients and 'normal to high etCO 2 ' patients, but severe PPCs occurred more often in 'low etCO 2 ', with an inverse dose-dependent relationship between intraoperative etCO 2 levels and PPCs., Funding: This analysis was performed without additional funding. LAS VEGAS was partially funded and endorsed by the European Society of Anesthesiology and Intensive Care (ESAIC) and the Amsterdam University Medical Centers, location 'AMC'., Registration: LAS VEGAS was registered at Clinicaltrials.gov (NCT01601223), first posted on May 17, 2012., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Competing Interests: The authors declare that they have no conflicts of interest.

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an indoor ship CO 2 dataset for inferring thermal comfort, ventilation and infectious disease transmission risk evaluation. Indoor air quality (IAQ) monitoring was conducted in nine environments (three cabins, buffet, gym, bar, restaurant, pub and theatre), on board a cruise ship voyaging across the UK and EU, with the study conducted in the framework of the EU HEALTHY SAILING project. CO 2 concentrations, temperature and relative humidity (RH) were simultaneously monitored to investigate thermal characteristics and effectiveness of ventilation performance. Results show a slightly higher RH of 68.2 ± 5.3 % aboard compared to ASHRAE and ISO recommended targets, with temperature recorded at 22.3 ± 1.4 °C. Generally, good IAQ (<1000 ppm) was measured with CO 2 mainly varying between 400 and 1200 ppm. The estimated air change rates (ACH) and ventilation rates (VR) implied sufficient ventilation was provided in most locations, and the theatre (VR: 86 L s -1  person -1 ) and cabins (VR: >20 L s -1  person -1 ) were highly over-ventilated. Dining areas including the pub and restaurant recorded high CO 2 concentrations (>2000 ppm) potentially due to higher footfall (0.6 person m -2 and 0.4 person m -2 ) and limited ACH (2.3 h -1 and 0.8 h -1 ), indicating a potential risk of infection; these areas should be prioritised for improvement. The IAQ and probability of infection indicate there is an opportunity for energy saving by lowering hotel load for the theatre and cabins and achieving the minimum acceptable VR (10 L s -1  person -1 ) for occupants' comfort and disease control. Our study produced a first-time dataset from a sailing cruise ship's ventilated areas and provided evidence that can inform guidelines about the optimisation of ventilation operations in large passenger ships, contributing to respiratory health, infection control and energy efficiency aboard., Competing Interests: Declaration of competing interest The authors declare that there are no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: COVID-19 pandemic research efforts have mainly focused on adults, but data in paediatric populations are sparse., Methods: We used the German nationwide-inpatient-sample analysing all hospitalized children ≤18 years with confirmed COVID-19-diagnosis in Germany during the year 2020, stratified for intensive care unit (ICU) admission., Results: Overall, 3360 hospitalization-cases of children ≤18 years with COVID-19-infection were diagnosed in Germany 2020 (median age 7.0 [IQR 0.0-15.0] years, 49.8 % female); among them 4.3 % were admitted on an ICU. In-hospital death occurred in five patients with and three without ICU admission (3.5 % vs. 0.1 %, P < 0.001) and ICU admission was independently associated with increased case-fatality (OR 21.573 [95%CI 4.191-111.044], P < 0.001). Obesity (OR 3.419 [95%CI 1.300-8.993], P = 0.013), diabetes mellitus (OR 6.929 [95%CI 3.327-14.432], P < 0.001), pneumonia (OR 7.373 [95%CI 4.823-11.271], P < 0.001), acute respiratory distress syndrome (ARDS) (OR 48.058 [95%CI 11.689-197.588], P < 0.001) and multisystem inflammatory syndrome caused by COVID-19 (OR 9.573 [95%CI 3.036-30.191], P < 0.001), heart failure (OR 64.509 [95%CI 24.462-170.121], P < 0.001), myocarditis (OR 4.682 [95%CI 1.278-17.149], P = 0.020), acute and/or chronic kidney failure (OR 7.946 [95%CI 3.606-17.508], P < 0.001), cancer (OR 5.220 [95%CI 2.599-10.485], P < 0.001) and liver diseases (OR 5.501 [95%CI 2.177-13.899], P < 0.001) were associated with an ICU admission., Conclusion: Proportion of hospitalized paediatric COVID-19-patients admitted on ICU in Germany was low with 4.3 % accompanied by 3.5 % case-fatality rate. Independent factors for ICU admission comprised cardio-vascular risk factors, comorbidities, and complications of COVID-19., Competing Interests: Declaration of Competing interest KK, ISa, VHS, VS, ITF, OH, SeKö, FPS, and TM and report no conflict of interests. CEK reports having from Amarin Germany, Amgen GmbH, Bayer Vital, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo, Leo Pharma, MSD Sharp & Dohme, Novartis Pharma, Pfizer Pharma GmbH, Sanofi-Aventis GmbH. StKo reports institutional grants and personal lecture/advisory fees from Bayer AG, Daiichi Sankyo, and Boston Scientific; institutional grants from Inari Medical; and personal lecture/advisory fees from MSD and Bristol Myers Squibb/Pfizer. PL has received institutional fees and research grants from Abbott Vascular, Edwards Lifesciences, and ReCor, honoraria from Edwards Lifesciences, Abbott Medical, Innoventric, ReCor and Boehringer Ingelheim and has stock options with Innoventric. LH received lecture/consultant fees from MSD and Actelion, outside the submitted work., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Teachers are among the most stressed professionals, for whom the built environment has an influence. In addition, the COVID-19 pandemic has increased the pressure on schools, where enhanced ventilation is deemed essential to help reduce virus-laden particles in classrooms. Good Indoor Air Quality (IAQ) is required to maintain an adequate level of comfort, health, and well-being. Therefore, solutions to improve IAQ quickly and cheaply are essential. As such, the Scottish Government has funded Local Authorities to purchase CO 2 sensors for school classrooms. This study explores two interventions designed to improve the quality of indoor air. The first one by raising the awareness of the teachers on ventilation strategies via a webinar. The second one by deploying devices that visually inform the occupants of the indoor conditions: Temperature, Relative Humidity, and CO 2 levels in the classrooms. The novelty of this study is that it evaluated the influence of engaging teachers in the management of their working indoor environments. This paper presents the results of the perceived health, comfort, and well-being of teachers from two primary schools built before 1919 located in Edinburgh, Scotland. Visual feedback sensors improved the perceived air quality of teachers in their classrooms but increased pressure on their workload and were a potential distraction for their pupils. In contrast, raising the awareness of the teachers via the webinar improved their perception of their indoor environment without added pressure. Therefore, awareness programs should be devised to educate school staff on Indoor Air Quality in addition to the development of sensors with visual feedback., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The lack of knowledge on quanta generation rates presents a major obstacle to specifying the minimum ventilation required to prevent airborne infections. The expected largest quanta generation rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by a super-spreader remains unknown. Here we investigated a SARS-CoV-2 outbreak during lunch in a restaurant using epidemiological, whole-genome sequencing and environmental analyses. Both tracer gas and fine particles were used in field experiments to quantify aerosol dispersion and removal across three interconnected zones: Zone A, Zone B and Zone C. All 21 secondary patron infections occurred in Zone B. This unique infection feature and measured dilution flow rates allowed us to estimate the largest reported quanta generation rates to date, ranging from 1724 to 1968 quanta/h. These rates were sufficiently high to cause a high attack rate in Zone B but did not cause infections in Zones A and C, likely due to sufficient dilution and insignificant contaminated airflow from Zone B, respectively. Our finding of the largest quanta generation rate so far suggests that avoiding secondary infection by dilution alone in the presence of a super-emitter might not be possible in typical air-conditioned buildings and other prevention strategies need to be developed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)