Type Of Ventilation Research Articles

The role of near-façade flow in wind-dominant single-sided natural ventilation for an isolated three-storey building: An LES study

Wind-driven single-sided ventilation is present in many existing buildings globally, and its performance can be unreliable and challenging to improve. To address these performance challenges, a better understanding of the interconnected relationship between the external and internal flows is required. Therefore, a detailed assessment of this type of natural ventilation is vital. A detailed CFD analysis of wind-dominant single-sided natural ventilation is presented by adopting the Large Eddy Simulation method, validated using previous wind tunnel studies. An isolated cube, representing a three-storey building, was used to investigate four case studies with different opening positions on the building façade. The presence of parallel flow near the building façade and the effect this has, both on the structure of the flow at the opening and the internal secondary flow, is investigated. Results demonstrate that a mixing layer jet of air is the main structure of the flow at the opening. The flow characteristics of this jet are a function of how the external near-façade flow interacts with the building. It can be deflected or attenuated by the near-façade fluctuating pressure and vortex structures close to the opening. Tracer gas decay results show that only 3/5 of the flow at the opening contributes to effective ventilation in this type of natural ventilation. Comparisons between the ventilation rates for openings at different positions on the building façade demonstrate the importance of the pressure role at the opening in single-sided natural ventilation.

An optimal internal model proportional integral controller to improve pressure tracking profile of artificial ventilator.

Mechanical ventilator (MV) is a breathing support medical equipment used during medical surgery or in an intensive care unit (ICU) for critical patients to reduce the breathing work of the patient under ventilation. In this work, a piston-driven mechanical ventilator is studied. Such types of ventilators are generally used as anaesthesia ventilators with volume-controlled modes. A modern ventilator can operate in different modes, such as volume control, pressure control, or both. Pressure-controlled mode may be better suited for some cases, such as patients undergoing laparoscopic surgery, as compared to volume-controlled mode because it may increase compliance during pneumoperitoneum, enhance oxygenation, and lower the stress response postoperatively. The pressure profile of a PCV must exactly track the pressure profile of a patient under ventilation to avoid ventilator-induced diaphragmatic dysfunction. Therefore, an optimal internal model control base proportional integral (IMC-PI) controller is proposed. The optimum parameter of the filter component of the IMC-PI controller is found by an enhanced class topper optimization (ECTO) algorithm. The performance of the proposed controller is analyzed in different scenarios and compared with existing results. Graphical Abstract Optimal internal model proportional integral controller for human respiratory ventilator.

Response of drip water Mg/Ca and Sr/Ca variations in ventilated caves to hydroclimate

Mg/Ca and Sr/Ca in speleothems which record valuable information regarding past variations of precipitation and cave air pCO2 are promising proxies because the degrees of water-rock interaction (WRI) and prior calcite precipitation (PCP) are directly and indirectly related to these changes. However, the controls on Mg/Ca and Sr/Ca can be complex, and most studies ignored the combined effects of rainfall and cave air pCO2. Moreover, knowledge of the influence of seasonal rainfall and cave air pCO2 on seasonal fluctuations in drip water Mg/Ca and Sr/Ca are limited for caves with different regions and ventilation types. Drip water Mg/Ca and Sr/Ca were monitored for five years at Shawan Cave. The results indicate that the irregular seasonal oscillation in drip water Mg/Ca and Sr/Ca is controlled by inverse-phase seasonal changes between rainfall and cave air pCO2. The rainfall amount may be the primary controlling factor of the interannual variation in drip water Mg/Ca, whereas the interannual variation in drip water Sr/Ca is most likely controlled by cave air pCO2. Furthermore, we compared drip water Mg/Ca and Sr/Ca of caves in different regions to fully understand how drip water Mg/Ca and Sr/Ca respond to hydroclimate changes. The drip water element/Ca, for seasonal ventilation caves with a fairly narrow range of cave air pCO2 respond well to the local hydroclimate associated with rainfall variation. If the range of cave air pCO2 is considerably large, the element/Ca in seasonal ventilation caves of subtropical humid regions may not reflect hydroclimate and that of Mediterranean and semi-arid regions may be primarily controlled by cave air pCO2. The element/Ca in the low year-round pCO2 caves could reflect the hydroclimate associated with surface temperature. Therefore, observations of drip water monitoring and comparative analysis can provide a reference for the explanation of speleothems element/Ca ratios from seasonally ventilated caves worldwide.

Associations of body mass index with severe outcomes of COVID-19 among critically ill elderly patients: A prospective study.

Few studies assessed the associations of overweight and obesity with severe outcomes of coronavirus disease 2019 (COVID-19) among elderly patients. This study was conducted to assess overweight and obesity in relation to risk of mortality, delirium, invasive mechanical ventilation (IMV) requirement during treatment, re-hospitalization, prolonged hospitalization, and ICU admission among elderly patients with COVID-19. This was a single-center prospective study that was done on 310 elderly patients with COVID-19 hospitalized in the intensive care unit (ICU). We collected data on demographic characteristics, laboratory parameters, nutritional status, blood pressure, comorbidities, medications, and types of mechanical ventilation at baseline. Patients were followed up during ICU admission and until 45 days after the first visit, and data on delirium incidence, mortality, need for a form of mechanical ventilation, discharge day from ICU and hospital, and re-hospitalization were recorded for each patient. During the follow-up period, we recorded 190 deaths, 217 cases of delirium, and 35 patients who required IMV during treatment. After controlling for potential confounders, a significant association was found between obesity and delirium such that obese patients with COVID-19 had a 62% higher risk of delirium compared with normal-weight patients (HR: 1.62, 95% CI: 1.02-2.57). This association was not observed for overweight. In terms of other outcomes including ICU/45-day mortality, IMV therapy during treatment, re-hospitalization, prolonged hospitalization, and ICU admission, we found no significant association with overweight and obesity either before or after controlling for potential confounders. We found that obesity may be a risk factor for delirium among critically ill elderly patients with COVID-19.

Association of Interventions With Outcomes in Children At-Risk for Pediatric Acute Respiratory Distress Syndrome: A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study.

Describe the frequency with which transfusion and medications that modulate lung injury are administered to children meeting at-risk for pediatric acute respiratory distress syndrome (ARF-PARDS) criteria and evaluate for associations of transfusion, fluid balance, nutrition, and medications with unfavorable clinical outcomes. Secondary analysis of the Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology study, a prospective point prevalence study. All enrolled ARF-PARDS patients were included unless they developed subsequent pediatric acute respiratory distress syndrome (PARDS) within 24 hours of PICU admission or PICU length of stay was less than 24 hours. Univariate and multivariable analyses were used to identify associations between therapies given during the first 2 calendar days after ARF-PARDS diagnosis and subsequent PARDS diagnosis (primary outcome), 28-day PICU-free days (PFDs), and 28-day ventilator-free days (VFDs). Thirty-seven international PICUs. Two hundred sixty-seven children meeting Pediatric Acute Lung Injury Consensus Conference ARF-PARDS criteria. None. During the first 2 days after meeting ARF-PARDS criteria, 55% of subjects received beta-agonists, 42% received corticosteroids, 28% received diuretics, and 9% were transfused. Subsequent PARDS (15%) was associated with platelet transfusion (n = 11; adjusted odds ratio: 4.75 [95% CI 1.03-21.92]) and diuretics (n = 74; 2.55 [1.19-5.46]) in multivariable analyses that adjusted for comorbidities, PARDS risk factor, initial oxygen saturation by pulse oximetry:Fio2 ratio, and initial type of ventilation. Beta-agonists were associated with lower adjusted odds of subsequent PARDS (0.43 [0.19-0.98]). Platelets and diuretics were also associated with fewer PFDs and fewer VFDs in the multivariable models, and TPN was associated with fewer PFDs. Corticosteroids, net fluid balance, and volume of enteral feeding were not associated with the primary or secondary outcomes. There is an independent association between platelet transfusion, diuretic administration, and unfavorable outcomes in children at risk for PARDS, although this may be related to treatment bias and unmeasured confounders. Nevertheless, prospective evaluation of the role of these management strategies on outcomes in children with ARF-PARDS is needed.

Association Between Mortality and Ventilator Parameters in Children With Respiratory Failure on ECMO.

In refractory respiratory failure, extracorporeal membrane oxygenation (ECMO) is a rescue therapy to prevent ventilator-induced lung injury. Optimal ventilator parameters during ECMO remain unknown. Our objective was to describe the association between mortality and ventilator parameters during ECMO for neonatal and pediatric respiratory failure. We performed a secondary analysis of the Bleeding and Thrombosis on ECMO dataset. Ventilator parameters included breathing frequency, tidal volume, peak inspiratory pressure, PEEP, dynamic driving pressure, pressure support, mean airway pressure, and FIO2 . Parameters were evaluated before cannulation, on the calendar day of ECMO initiation (ECMO day 1), and the day before ECMO separation. Of 237 included subjects analyzed, 64% were neonates, of whom 36% had a congenital diaphragmatic hernia. Of all the subjects, 67% were supported on venoarterial ECMO. Overall in-hospital mortality was 35% (n = 83). The median (interquartile range) PEEP on ECMO day 1 was 8 (5.0-10.0) cm H2O for neonates and 10 (8.0-10.0) cm H2O for pediatric subjects. By multivariable analysis, higher PEEP on ECMO day 1 in neonates was associated with lower odds of in-hospital mortality (odds ratio 0.77, 95% CI 0.62-0.92; P = .01), with a further amplified effect in neonates with congenital diaphragmatic hernia (odds ratio 0.59, 95% CI 0.41-0.86; P = .005). No ventilator type or parameter was associated with mortality in pediatric subjects. Avoiding low PEEP on ECMO day 1 for neonates on ECMO may be beneficial, particularly those with a congenital diaphragmatic hernia. No additional ventilator parameters were associated with mortality in either neonatal or pediatric subjects. PEEP is a modifiable parameter that may improve neonatal survival during ECMO and requires further investigation.

Impacts of Tariffs on Energy Conscious Behavior with Respect to Household Attributes in Saudi Arabia

Historically, the combination of generous subsidies along with extreme climate has led to unsustainable domestic electricity consumption in Saudi Arabia. The residential sector constitutes a significant portion of this consumption. Amid the economic challenges, the country enforced a new electricity tariff for residential consumers in 2018. This study thus leverages change in 2018–2020 by collecting and analyzing the electricity consumption data of 73 households in the Eastern Province of Saudi Arabia. The energy consumption is modeled based on the households’ attributes (e.g., dwelling type, ownership, number of residents, rooms, ventilation type, etc.) and applied tariffs using a machine learning technique. The extreme learning machine (ELM) is employed in solving the overfitting problem due to low-volume data. The correlation matrix is also constructed to determine the relationship between the household attributes. The ELM model developed in this study extracts the correlation between the input variables in determining energy consumption and also predicts the energy consumption related to low consumption data. The findings indicated that the electricity consumption between the pre-revised tariff year and the revised tariff enforcement year saw a reduction which was consistent in the subsequent years. This was also validated by the paired sample t-test, which showed a significant decrease in electricity consumption for the study period. The analysis also revealed that several household attributes had a relatively high impact on the reduction in the electricity consumption level following the revised tariffs, whereas the majority of the attributes had a moderate impact. In addition to these key findings, the demonstrated pathway adopted in this study is itself a methodological contribution that provides critical information about the sensitivity of the impacts of tariffs on energy consumption with respect to different household attributes. Economic factors being the critical stress need to be blended with existing energy consciousness for positive changes in favor of energy-saving behavior of the household members. The study does not attempt to represent the population of concern, but demonstrates a methodology that would help unleash inherent energy consciousness in favor of sustainable and energy-efficient behavior.

Emergency Care for Burn Patients-A Single-Center Report.

We performed a retrospective observational study of 2021. All patients admitted to our six-bed intensive care unit (ICU) were included. The following data were collected for further analysis: demographics, burn pattern (etiology, size, depth, affected body region), type of ventilation, ABSI (Abbreviated Burn Severity Index) score, comorbidities, bioumoral parameters, and hospitalization days. There were 93 burned patients included in our study that were divided into two groups: alive patients' group (63.4%) and deceased patients' group (36.6%). The mean age was 55.80 ± 17.16 (SD). There were 65.6% male patients, and 39.8% of the patients were admitted by transfer from another hospital. Further, 59 patients presented third-degree burns, from which 32.3% died. Burns affecting >37% of the total body surface area (TBSA) were noticed in 30 patients. The most vulnerable regions of the body were the trunk (p = 0.003), the legs (p = 0.004), the neck (p = 0.011), and the arms (p = 0.020). Inhalation injury was found in 60.2% of the patients. The risk of death in a patient with an ABSI score > 9 points was 72 times higher. Comorbidities were present in 44.1% of the patients. We observed a median LOS (length of stay) of 23 days and an ICU-LOS of 11 days. Logistic regression analysis showed that admission protein, creatinkinase, and leukocytes were independent risk factors for mortality. The general mortality rate was 36.6%. A thermal factor was responsible for the vast majority of burns, 94.6% of cases being accidents. Extensive and full-thickness burns, burns affecting the arms, inhalation injuries, the need for mechanical ventilation, and a high ABSI score represent important risk factors for mortality. Considering the results, it appears that prompt correction of protein, creatinkinase, and leukocytes levels may contribute to improvement in severe burn patients' outcomes.

Research of thermal and hydrodynamic flows of heat exchangers for different air cooling systems in poultry houses

Increasing the productivity of poultry farms is connected with the need to create an optimal regulated microclimate in poultry houses. This problem becomes of primary importance due to the decrease in the productivity of poultry farming due to the imperfection of the existing systems. The purpose of the study was the development and numerical modeling of a shell-and-tube heat exchanger of a new design for cooling supply air as an element of the air conditioning system used in ventilation systems of various types in the summer period. Two types of ventilation systems are considered, namely tunnel and lateral. For these ventilation systems, heat exchangers designed to cool incoming air in the summer season have been developed. A total of 80 automatic inlet valves measuring 0.3 × 0.85 m were arranged in the side walls. In addition, evaporative cooling systems 5.3 × 1.1 m were located on the front end walls. When considering these two separate systems, the heat exchangers were installed instead of the evaporative cooling system and automatic supply valves. The processes of heat and mass transfer in developed heat exchangers for various types of ventilation systems were investigated. Numerical modeling of hydrodynamics and heat transfer was carried out, as well as analysis of the operation of heat exchangers of two different designs for tunnel and side ventilation systems. Velocity, temperature, and pressure fields in the studied channels were obtained. The conditions of the hydrodynamic flow in the channels of the heat exchangers were analyzed. In the case of the tunnel ventilation system, the pressure drop is 991 Pa, which is 3.3 times less compared to the side ventilation system. The outlet temperature is +23 ℃, which meets the design requirements. The main disadvantage is the financial costs for the purchase, cutting of pipes and, actually, their welding. Both the tunnel and side ventilation systems are quite effective. In order to ensure standardized conditions of the air environment in the poultry house, taking into account all aspects of technical and economic analysis, it is proposed to choose a heat exchanger for the tunnel ventilation system. In practice, such heat exchange devices can be used not only in microclimate systems of poultry houses, but also in the industrial, energy industry and critical infrastructure facilities

Experimental study on augmentation of mixing within a stratified indoor environment by erosion of density interface

The current study aims to address the problem associated with warm air heating in passive houses. Warm air eating is cheaper and easy to operate in passive houses, however, this creates problems of shortcut ventilation and thermal discomfort due to stratification as warm air is confined to the ceiling. In the current study, we explore a new method of creating resonance between stratification frequency and the periodic variation of the ventilation supply frequency to increase mixing of the supplied warm air and the room air consequently destratifying the room conditions. A basic water model study is used to understand the interaction between the frequency variations and the resulting standing waves with stratification characteristics in a room. Measurements at three different input frequencies and at three input paddle locations have been performed, gathering vertical temperature gradients and visualization data from them. The results show the shift in the inversion point because of an increase augmentation across the inversion between the fluids with different densities close to resonance. There is also a dependency on paddle location showing that the type of ventilation system will have different mixing rates due to different fluid energetic behaviours.

Post-natal prognostic factors in CDH: experience of 11 years in a referral center in Brazil

ObjectiveTo describe post-natal risk factors associated with death in Newborns (NB) with Congenital Diaphragmatic Hernia (CDH) in a Brazilian reference center. MethodsIn this retrospective cohort study, post-natal clinical factors of all NB diagnosed with CDH were reviewed in an 11-year period (2007‒2018). The primary outcome was death. Secondary outcomes included clinical features, prognostic indexes, type of mechanical ventilation, complications during hospitalization and surgical repair. ResultsAfter applying the exclusion criteria, the authors analyzed 137 charts. Overall mortality was 59% (81/137), and the highest rates were observed for low-birth-weight NB (87%), syndromic phenotype (92%), and those with major malformations (100%). Prognostic indexes such as Apgar, SNAPPE-II and 24hOI (best oxygenation index in 24 hours) were all associated with poor evolution. In a multivariate analysis, only birth weight and 24hOI were statistically significant risk factors for mortality, with a reduction in mortality risk of 17.1% (OR = 0.829, 95% IC 0.72‒0.955, p = 0.009) for each additional 100g at birth and an increase by 26.5% (OR = 1.265, 95% IC 1.113‒1.436, p = 0.0003) for each unitary increase at the 24hOI. ConclusionPrognostic indexes are an important tool for predicting outcomes and improving resource allocation. Post-natal risk factors may be more suitable for settings where antenatal diagnosis is not universal. Classical risk factors, such as prematurity, low birth weight, higher need for supportive care, and poorer prognostic indexes were associated with mortality in our CDH population.

Antimalarials and macrolides: a review of off-label pharmacotherapies during the first wave of the SARS-CoV-2 pandemic

We critically analyzed clinical trials performed with chloroquine (CQ) and hydroxychloroquine (HCQ) with or without macrolides during the first wave of COVID-19 and discussed the design and limitations of peer-reviewed studies from January to July 2020. Seventeen studies were eligible for the discussion. CQ and HCQ did not demonstrate clinical advantages that justified their inclusion in therapeutic regimens of free prescription for treatment or prophylactic purposes, as suggested by health authorities, including in Brazil, during the first wave. Around August 2020, robust data had already indicated that pharmacological effects of CQ, HCQ and macrolides as anti-SARS-CoV-2 molecules were limited to in vitro conditions and largely based on retrospective trials with low quality and weak internal validity, which made evidence superficial for decision-making. Up to that point, most randomized and nonrandomized clinical trials did not reveal beneficial effects of CQ or HCQ with or without macrolides to reduce lethality, rate of intubation, days of hospitalization, respiratory support/mechanical ventilation requirements, duration, type and number of symptoms, and death and were unsuccessful in increasing virus elimination and/or days alive in hospitalized or ambulatory patients with COVID-19. In addition, many studies have demonstrated that side effects are more common in CQ-or HCQ-treated patients.

Association between coronary artery calcium score and COVID-19 prognosis

Background: Research has examined the relationships between coronary artery calcium (CAC) scores and mortality, mechanical ventilation, and intensive care unit admissions. This paper summarizes the predictive value of coronary artery calcification scoring for hospitalized COVID-19 patients in terms of mortality, mechanical ventilation, and intensive care unit admission. Methods: The patients in this single-center retrospective analysis have COVID-19 and were hospitalized at the Firouzabadi hospital in Tehran between 2019 and 2020. coronary artery calcificationscore was estimated based on chest non-contrast CT scans on the day of admission. Based on the coronary artery calcification score, the patients were categorized into Very Low, Mild to Moderate, and Moderate to Severe. After a univariate analysis of the critical factors, odds ratio (OR) analysis and multivariate analysis of variables that could be linked to COVID-19 advancement were carried out. Results: a total of 719 patients were examined. Among them, 414 patients were men. Mortality with a 17.1 % prevalence was statistically significant between CAS score levels (P < 0.001). This factor has high OR with mild to moderate and moderate to severe CAS (OR: 2.14; 95% CI: 1.71 to 3.06, and OR: 2.31; 95% CI: 1.84 to 3.57). Oxygen saturation was a significant statistic between CAS score levels (P = 0.02). This factor has a high OR with mild to moderate and moderate to severe CAS (OR: 1.09; 95% CI: 0.71 to 3.60, and OR: 2.38; 95% CI: 0.89 to 2.9). There was no statistical difference between the groups’ outcomes of mechanical ventilation and admission types. Conclusion: In this study, the coronary artery calcification scores of patients with COVID-19 were compared, while the outcomes of interest mortality, mechanical ventilation, and intensive care unitU admission were closely investigated. In light of these findings, coronary artery calcificationscoring can help in patient stratification, enabling earlier therapies for disorders to progress quickly.

Development of Jet Stream Attraction Type Ventilation System to Suppress Down Capture Efficiency of Exhaust Hood by Disturbance Airflow

Development of Jet Stream Attraction Type Ventilation System to Suppress Down Capture Efficiency of Exhaust Hood by Disturbance Airflow

Integrating building information modeling and life cycle assessment to analyze the role of climate and passive design parameters in energy consumption

With the Architecture, Engineering, and Construction industry representing a significant share of global energy consumption and greenhouse gas emissions, developing sustainable design and reducing buildings’ environmental impacts has become a priority over the past decades. Adopting building information modeling tools and implementing them into life cycle analysis techniques at the early stages of design has been an effective method for buildings sustainability evaluation. With our environment constantly changing, it is reasonable that the construction industry should also aim to adapt to these changes and use them. However, the role of local climate features and their effects on a building's energy output is often neglected. By using building information modeling–life cycle analysis integration techniques, this research aims to consider the role of climatic attributes along with some passive design strategies in the life cycle assessment of the building and see how it affects that building's energy performance. By only applying passive design strategies (not including heating, ventilation, and air conditioning system type), the models’ energy demand was reduced up to 30% of the original value. It is also witnessed that by using the proper equipment and construction materials that match the respective climate, up to 28% of the building's energy consumption during the operational phase, can be saved. Although insulation of the walls does reduce energy consumption values, it also contributes to more greenhouse gas emissions. The increase in greenhouse gas emissions was estimated to be around 3%, but since the insulation boards make up only 2% of the building's area, it is a considerable amount.

High-frequency oscillatory ventilation versus conventional ventilation in pediatric patients with acute lung injury: outcomes evaluation

BackgroundWith the development of medical technology and advancements of intensive care units, many types of mechanical ventilators are recruited in the management of acute respiratory distress syndrome (ARDS)/acute lung injury (ALI). We evaluated the outcome of the high-frequency oscillatory ventilation (HFOV) compared to conventional mechanical ventilation (CMV) in pediatric patients with critical respiratory situations mainly ALI or ARDS. A prospective cohort study was performed from 2019 to 2020 in the pediatric intensive care unit (PICU). The following data were recorded: demographic and clinical data, length of PICU stay, mechanical ventilation days, and mortality percentages.ResultsFifty cases who fulfilled the inclusion criteria were divided into two groups, 24 patients on HFOV from the start and the other 26 were admitted on rescue HFOV after the failure of CMV. There was no statistically significant difference between the two groups regarding the age (p = 0.571) and the oxygenation index (OI) (p = 0.651). Early HFOV demonstrated shorter length of PICU stay and fewer days on mechanical ventilation. The mortality rate was less with the application of early HFOV compared to rescue HFOV.ConclusionsEarly admission on HFOV can be a safe option in the management of patients with critical lung situation as ARDS/ALI.

1942. Effect of SARS-CoV-2 Vaccination in a Frailty COVID-19 Cohort: a Real Life Experience in a Northern Italy Hospital

Abstract Background Clinical trial demonstrated that SARS-CoV-2 vaccines have the ability of reduce mortality and morbidity due to COVID-19. The aim of this study is to describe the effect of vaccination in term of mortality, type of ventilation and ICU admission among patients hospitalized for COVID-19 from May to December 2021 in a Ligurian Hospital. Methods This is a retrospective, single-center study conducted in San Martino Hospital (Genoa, Italy), including patients ≥ 18 years hospitalized for COVID-19 in Infectious Disease and Emergency Units from 1st May to 31st December 2021. We collected demographical data, multimorbidity and disability score, vaccination time (“vaccinated” all patients hospitalized ≥ 14 days after first dose or ≥ 7 days after second/third dose), therapy for COVID-19, mortality at 7 and 30 days, ICU admission, ventilation type. Characteristics of vaccinated (group A) versus non vaccinated (group B) patients were compared using Chi-squared/Fisher's exact test for categorical variables and t-test /Kruskal-Wallis test for the continuous ones. Cox proportional hazards models for death at 30 days were performed as univariate analysis as well as adjusting for age, Cumulative Illness Rating Scale [CIRS], gender, Remdesivir, Monoclonal antibodies, Tocilizumab use. Results Overall, 405 patients SARS-CoV-2 infected were enrolled. Data about timing of vaccination were available for 360 patients (89%). We compared clinical characteristics and outcomes of group A (32%) versus group B (68%). In group A patients were older (p< 0.001) and frailer (higher CIRS score and lower Barthel index, p< 0.001) than in group B. Among patients requiring oxygen, 76 (31.5%) in group B vs 26 (22.41%) in group A needed high flow ventilation (p=0.036); 33 (13.52%) vs 3 (2.59%) respectively were admitted to ICU (Figure 1). Mortality at 30 days after hospitalization was higher in group A at univariate analysis [HR(95%CI) 1.44(0.82; 2.53), p=0.208], lower at multivariate analysis [0.57(0.31; 1.02), p=0.059]. Conclusion The results of this study confirm that SARS-CoV-2 vaccination reduces rate of admission to ICU and 30 days mortality among patients hospitalized for COVID-19. In our cohort mortality among vaccinated patients remains high and we hypothesized this is due to high frailty of evaluated population. Disclosures Chiara Dentone, CD, Angelini: Advisor/Consultant|Gilead: Advisor/Consultant|Menarini: Advisor/Consultant|Novartis: Advisor/Consultant Matteo Bassetti, PhD, Angelini: Advisor/Consultant|Astellas: Grant/Research Support|Bayer: Advisor/Consultant|Bayer: Honoraria|BioMe ́ rieux: Advisor/Consultant|BioMe ́ rieux: Honoraria|Cidara: Advisor/Consultant|Cidara: Honoraria|Cipla: Advisor/Consultant|Cipla: Honoraria|Gilead: Advisor/Consultant|Gilead: Honoraria|Menarini: Advisor/Consultant|Menarini: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Nabriva: Advisor/Consultant|Pfizer: Advisor/Consultant|Pfizer: Board Member|Pfizer: Grant/Research Support|Pfizer: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Honoraria|Tetraphase: Advisor/Consultant.

Essentials of ventilator graphics

Respiratory function monitoring involves the integration of information such as airway pressures, flow and volume to evaluate changes in pulmonary mechanics. Ventilator graphics are an essential and valuable tool in the care of mechanically ventilated patients. Clinicians responsible for both setting up the ventilators and managing the patients should have a thorough understanding of the different waveforms to be able to recognise mechanical and/or clinical abnormalities. The scalar graphics allow the assessment of each variable (pressure, flow and volume) over time. Despite the ability to customise graphics on modern ventilators, scalars are typically displayed together in the same screen. There are an innumerable number of changes that can be detected in the scalars that may facilitate the management of the mechanical ventilator, and thus optimise the care of the ventilated patient. The loops provide a two-dimensional view of two variables plotted against each other. Understanding how the patient and the ventilator interact must be considered a critical component of the overall assessment of patients undergoing any type of mechanical ventilation since detection and management of asynchrony impacts important clinical outcomes in the ICU.

SARS-CoV-2 surface and air contamination in an acute healthcare setting during the first and second pandemic waves

Surfaces and air in healthcare facilities can be contaminated with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Previously, the authors identified SARS-CoV-2 RNA on surfaces and air in their hospital during the first wave of the coronavirus disease 2019 pandemic (April 2020). To explore whether the profile of SARS-CoV-2 surface and air contamination had changed between April 2020 and January 2021. This was a prospective, cross-sectional, observational study in a multi-site London hospital. In January 2021, surface and air samples were collected from comparable areas to those sampled in April 2020, comprising six clinical areas and a public area. SARS-CoV-2 was detected using reverse transcription polymerase chain reaction and viral culture. Sampling was also undertaken in two wards with natural ventilation alone. The ability of the prevalent variants at the time of the study to survive on dry surfaces was evaluated. No viable virus was recovered from surfaces or air. Five percent (N=14) of 270 surface samples and 4% (N=1) of 27 air samples were positive for SARS-CoV-2, which was significantly lower than in April 2020 [52% (N=114) of 218 surface samples and 48% (N=13) of 27 air samples (P<0.001, Fisher's exact test)]. There was no clear difference in the proportion of surface and air samples positive for SARS-CoV-2 RNA based on the type of ventilation in the ward. All variants tested survived on dry surfaces for >72h, with a <3-log10 reduction in viable count. This study suggests that enhanced infection prevention measures have reduced the burden of SARS-CoV-2 RNA on surfaces and air in healthcare facilities.

Occupant’s thermal comfort in a radiant ceiling cooling room with hot wall surface

A radiant ceiling cooling (CC) system integrated with a mechanical ventilation system was extensively applied in a modern office in a glass curtain wall building. Thermal comfort in a radiant ceiling cooling room with mixing ventilation (MV) or underfloor air distribution (UFAD) was investigated by objective measurements and subjective questionnaires. The external wall surface temperature and mean radiant temperature were 33.9–34.6°C and 27.2–27.4°C, respectively, with a heat transfer of 41.5 W/m2 from the external wall and 37.8–38.6°C and 27.4–28.2°C with a heat transfer of 69.5 W/m2 from the external wall. The indoor air velocity in the occupied zone was 0.17–0.23 m/s in the room with CC+MV and 0.09–0.16 m/s in the room with CC + UFAD. There was a considerable difference between occupants’ thermal perceptions with different distances away from the external wall. Both the ventilation system type and hot wall surface temperature did not influence occupants’ overall thermal perceptions, but their local thermal sensation and skin temperature. The results suggest that the impacts of ventilation system type and hot wall surface temperature on occupants’ local thermal response should be considered during the design of a radiant ceiling cooling system combined with a mechanical ventilation system.