Ventilation Index Research Articles

Study of Physiological Adaptations in Vertical Kilometer Runners: Focus on Cardiorespiratory and Local Muscle Demands.

Background: Research into key performance factors in trail running, particularly in vertical kilometer (VK) races, is crucial for effective training and periodization. However, recent studies on metabolic and cardiorespiratory responses during VK races, especially using field tests, are limited. Objectives: Therefore, the aim of this study is to evaluate the metabolic and cardiorespiratory responses during a VK field test, identifying differences based on sex and performance level, as well as key performance factors and their deterioration due to fatigue. Fifteen trained trail runners (ten males and five females, 19 to 38 years old) perform a VK race. Methods: The global physiological response is evaluated using the portable gas analyzer Cosmed K5 and the local response using near-infrared spectroscopy technology. Results: In gender comparisons, the ANCOVA test shows significant differences (p < 0.05) in the ventilation, tidal volume, expiratory time-to-inspiratory time ratio, inspiratory flow rate, end-tidal CO2 partial pressure, heart rate, oxygen pulse, and total hemoglobin. Additionally, the performance comparison reveals significant differences in the variables' velocity, oxygen consumption, carbon dioxide production, ventilation, dead space-to-tidal volume ratio, total time of the breathing cycle, expiratory time-to-inspiratory time ratio, inspiratory duty cycle, expiratory fractions of CO2, quadriceps saturation index, and VE/VCO2 ratio. Finally, the correlation analysis shows oxygen consumption (r = -0.80 mean; r = -0.72 peak), carbon dioxide production (r = -0.91 mean; r = -0.75 peak), expiratory time-to-inspiratory time ratio (r = 0.68 peak), ventilation (r = -0.58 mean), and quadriceps saturation index (r = 0.54 mean; r = -0.76 coefficient of variation) as the key performance factors in the VK race. Conclusions: Overall, the physiological analysis indicates the importance of local muscular adaptations and respiratory system capacity in this type of short-duration race.

Study on the clinical characteristics, treatment, and outcome influencing factors of severe pneumonia complicated with ARDS.

To investigate the clinical characteristics, treatment methods, and factors influencing the prognosis of patients with severe pneumonia complicated by Acute Respiratory Distress Syndrome (ARDS), aiming to provide references for clinical decision-making and improve patient outcomes. A retrospective analysis was conducted on 118 patients with severe pneumonia complicated by ARDS treated at our hospital from June 2018 to December 2022. Based on treatment outcomes, patients were divided into a death group (n = 75) and a survival group (n = 43). General data and clinical laboratory indicators, including blood urea nitrogen, serum creatinine, C-reactive protein, procalcitonin, arterial partial pressure of oxygen, and arterial partial pressure of carbon dioxide, were collected and compared between the 2 groups to identify independent factors affecting prognosis. Among the 118 patients, the mortality rate was 63.56%. Patients in the death group had a significantly higher average age (57.15 ± 13.38 years) and a higher proportion of severe ARDS (66.67%) compared to the survival group (40.02 ± 11.41 years, 30.23%, P < .001). The death group had significantly lower white blood cell counts (8.10 ± 1.64 × 109/L), oxygenation index (19.82 ± 2.29), and duration of mechanical ventilation (7.79 ± 2.11 days) compared to the Survival group (8.92 ± 1.22 × 109/L, 13.42 ± 1.82, 12.23 ± 3.05 days, P < .05). Conversely, the death group had significantly higher levels of blood urea nitrogen (6.87 ± 1.80 mmol/L), C-reactive protein (130.55 ± 50.28 mg/L), procalcitonin (5.50 ± 2.11 ng/mL), arterial partial pressure of carbon dioxide (41.12 ± 5.56 mm Hg), and a higher proportion of viral infections (48.00%) compared to the survival group (5.90 ± 1.72 mmol/L, 101.77 ± 55.56 mg/L, 3.98 ± 1.15 ng/mL, 35.59 ± 6.22 mm Hg, 27.91%, P < .05). Logistic regression analysis revealed that age (odds ratios [OR] = 1.990, 95% confidence interval [CI]: 1.306-3.033, P < .001), oxygenation index (OR = 1.426, 95% CI: 1.123-1.649, P < .001), and duration of mechanical ventilation (OR = 0.694, 95% CI: 0.557-0.864, P < .001) were independent factors influencing patient prognosis. This indicates that an increase in age and a decrease in oxygenation index are associated with a significantly higher risk of mortality, while shorter mechanical ventilation duration is related to poorer prognosis. Advanced age, lower oxygenation index, and shorter duration of mechanical ventilation are unfavorable prognostic factors in patients with severe pneumonia complicated by ARDS. These findings aid clinicians in identifying high-risk patients, optimizing treatment plans, and improving patient prognosis.

Correlation of Impulse oscillometry system indices with conventional pulmonary function tests in patients with obstructive pulmonary ventilation dysfunction

Objective: To investigate the correlation between impulse oscillometry system examination indicators and conventional pulmonary ventilation function. Methods: The pulmonary ventilation function data of 10 883 patients from January 1, 2020 to December 31, 2022 at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology were included. The one-second rate [ratio of forced expiratory volume in the first second (FEV1) to forced vital capacity (FVC)] measured as a percentage of the predicted value was ≥92% for the control group (n=3 478) and <92% for the pulmonary obstruction group (n=7 405). The obstruction group was subdivided into five groups according to the degree of pulmonary dysfunction: mild group (n=3 938),moderate group (n=1 142),oderate-severe group (n=917),severe group (n=737),and extremely severe group (n=671). Conventional pulmonary ventilatory function FVC, FEV1, one-second rate, and forced expired flow at 50% of FVC (MEF50%), forced expired flow at 75% FVC (MEF25%), maximal mid-expiratory flow (MMEF), peak expiratory flow (PEF), and pulsed oscillation pulmonary function test were detected in both groups of patients. Impedance at 5 Hz (Z5) means total respiratory resistance, resistance at 5 Hz (R5) means total airway resistance, reactance at 5 Hz (X5) indicates the elastic recoil of the peripheral airways, and resistance at 20 Hz (R20) represents resistance of the central airways. R5-R20 reflects resistance in the small airways. Additionally, peripheral resistance (Rp), respiratory resonance frequency (Frex), and area under the reactance curve (Ax) were also measured. Correlation between the indicators of the two groups and the sensitivity and specificity of the impulse oscillometry system parameters for the diagnosis of obstructive pulmonary ventilation dysfunction were analyzed. Results: Pulmonary function force expiratory volume in the first second as a percentage of predicted value (FEV1%Pre) [80.10 (54.95,97.10)%],one-second rate [62.43(48.67, 67.02)%],MEF50% [1.33 (0.62,1.97)L/s],MEF25% [0.28 (0.17,0.41)L/s], MMEF [0.85 (0.43,1.29)L/s],and PEF [5.64 (3.73,7.50)]L/s in the obstruction group were significantly lower than those in the control group (P<0.05). The differences within the subgroups of the obstruction group were also significant (P<0.05). Pulsed oscillation Z5 [0.42 (0.33,0.55)kPa·L-1·s-1],Rp [0.25 (0.20,0.45)kPa·L-1·s-1], R5 [0.39 (0.31,0.49)kPa·L-1·s-1], R20 [0.28 (0.24,0.34)kPa·L-1·s-1], R5-R20 [0.09 (0.05,0.17)kPa·L-1·s-1],Frex [16.32 (13.07,20.84)Hz], and Ax [0.67 (0.28,1.64)] indices in the obstruction group were significantly higher than those in the control group. X5 [-0.14 (-0.23, -0.10)kPa·L-1·s-1] was significantly lower than that in the control group (P<0.05). Z5, Rp, X5, R5, R5-R20, Frex, and Ax were statistically significant between different degrees of obstruction in the obstruction group (P<0.05). The impulse oscillometry system parameters Z5, Rp, R5, R20, R5-20, Frex, and Ax were negatively correlated with the indices of conventional pulmonary ventilation (r=-0.21-0.68, P<0.05), and the parameter X5 was positively correlated with the indices of conventional pulmonary ventilation (r=0.41-0.68, P<0.05). The pulsed oscillation pulmonary function test parameters X5 (58.60%-95.68%) and Ax (57.08%-98.06%) presented the best sensitivity; X5 (86.29%-98.82%), Frex (86.69%-94.71%), and Ax (88.10%-98.53%) displayed the best specificity; and R20 presented the worst sensitivity and specificity. The sensitivity and specificity were slightly better in female patients than in male patients. Conclusion: The technical parameters of the impulse oscillometry system showed significant correlation with relevant indices of conventional pulmonary ventilation function detection. These well reflect the changes of different degrees of pulmonary ventilation function and have greater significance for reference in evaluating the degree of pulmonary function impairment.

Prevalence and risk factors associated with nasal carriage of methicillin-resistant staphylococci in horses and their caregivers

Antimicrobial resistance is a global threat, and pet-associated strains may pose a risk to human health. Equine veterinarians are at high risk of carrying methicillin-resistant staphylococci (MRS), but specific risk factors remain elusive, and few data are available for other personnel involved in the horse industry. The prevalence, characteristics, and risk factors for nasal carriage of MRS in horses and their caregivers were studied in northwestern Italy. Nasal swabs from 110 asymptomatic horses housed at 21 barns and 34 human caregivers were collected. Data on barns, horses, and personnel were acquired through questionnaires. The samples were incubated in selective media, and the bacterial isolates were identified by mass spectrometry. Risk factors were investigated by Poisson regression. MRS were isolated from 33 horses (30%), 11 humans (32.4%) and 3 environmental samples (14.2%). Most isolates were multidrug resistant (MDRS). The prevalence of MRS and MDRS was greater in racehorses and their personnel than in pleasurable and jumping/dressing horses. MRS carriage in caregivers was associated with an increased prevalence of MRS carriage in horses. The frequency of antimicrobial treatments administered in the barn during the last 12 months was a risk factor for MRS carriage in horses [prevalence ratio (PR) 3.97, 95% CI 1.11, 14.13] and caregivers (PR 2.00, 95% CI 1.05, 3.82), whereas a good ventilation index of the horse tabling environment was a protective factor (PR 0.43, 95% CI 0.20, 0.92). Our data reveal relevant interactions occurring between bacterial communities of horses and humans that share the same environment, suggesting that One Health surveillance programs should be implemented.

High-exchange ULTrafiltration to enhance recovery after paediatric cardiac surgery (ULTRA): study protocol for a Canadian double-blinded randomised controlled trial

IntroductionSurgical repair is the standard of care for most infants and children with congenital heart disease. Cardiopulmonary bypass (CPB) is required to facilitate these operations but elicits a systemic inflammatory...

Physiological effects of high-flow nasal cannula during sustained high-intensity exercise in healthy volunteers: a randomised crossover trial

IntroductionHigh-flow nasal cannula (HFNC) has increased exercise capacity in patients with chronic respiratory diseases. However, it remains unknown whether HFNC impacts respiratory physiological variables during exercise. This study aimed to evaluate the effect of HFNC on respiratory physiological variables during sustained high-intensity exercise in healthy volunteers.MethodsWe performed a single-center, open-label, and randomised crossover trial to compare HFNC (60 L·min−1) and Sham-HFNC (2 L·min−1) interventions during a constant work-rate exercise (CWRET) through randomised order. The primary outcome was ΔPes, and the secondary outcomes were other variables of inspiratory effort, ventilation distribution, ventilatory variables, and clinical assessment. We evaluated volunteers at seven-time points (Baseline= T0; CWRET= T1-T2-T3 (minutes: 1′, 4′ and 6′); Cooldown-period= T4-T5-T6 (minutes: 1′; 6′;10′)) in both interventions.ResultsFourteen healthy volunteers (50% women; age: 22 [21–27] years) were enrolled. Mean differences in ΔPes decreased to favor the HFNC intervention compared to Sham-HFNC at T2 (−2.8 cmH2O; 95%CI −5.3 to −0.3), as well as the sPTPmin at T2 (−86.1 cmH2O×s·min−1;95%CI −146.2 to −26.1), and T3 (−79.9 cmH2O×s·min−1;95%CI −142.3 to −17.6). The standard deviation of the regional ventilation delay index was also lower with HFNC compared to Sham-HFNC (T1: −1.38; 95%CI −1.93 to −0.83; T2: −0.71; 95%CI −1.27 to −0.16). There was decreased dyspnea to favor the HFNC, but sPTP-per-breath, spatial distribution ventilation indexes, ventilatory variables, and clinical assessments were nonsignificant between interventions.ConclusionHFNC intervention reduces respiratory effort, dyspnea and improves temporal ventilation distribution in healthy volunteers during CWRET.

A new ventilation performance index considering relative changes in environmental parameters: A numerical study

The ventilation index plays a crucial role in evaluating and selecting ventilation systems. However, existing studies focus only on the "effectiveness" of ventilation systems but usually ignore the "extent of the effect" caused by ventilation, and no relevant indexes are available. To address this issue, this study aims to propose a new ventilation index named the equivalent ventilation number (EVN), which considers the relative change in environmental parameters. The application potential of the EVN index was numerically examined in a virtual hospital ward setting with varying air changes per hour (ACH), thermal loads, air distribution patterns, contaminant source intensities, and local air supply rates. The results demonstrate that the highest average temperature-based EVN and CO2-based EVN are obtained when ACH increases from 6 h−1 to 12 h−1 and local supply air velocity increases from 0 m/s to 1 m/s, with values of 0.66 and 1.49 respectively. Furthermore, EVN values differ across different ventilation conditions and locations. The effect of changing ventilation conditions on ventilation performance assessed by heat removal effectiveness and temperature-based EVN, as well as contaminant removal effectiveness and CO2-based EVN, is opposite in 4 out of 10 cases and 3 out of 10 cases, respectively. The average EVN values calculated based on temperature and contaminant changes differ among all cases, with the largest difference of 1.2. The proposed EVN is anticipated to be an effective index for quantifying and comparing the "extent of the effect" caused by ventilation systems under various ventilation conditions.

Net escape velocity, transfer probability, and travel time distributions within a cross-ventilated room model sheltered by urban-like block array

Natural ventilation offers significant advantages, especially in terms of energy conservation. However, most published articles have focused on the ventilation flow rate to determine the average contaminant concentration, while few have examined local ventilation distributions. Therefore, isothermal steady-state Reynolds-averaged Navier–Stokes simulations were conducted to analyze the airflow and scalar concentration fields of a cross-ventilation model sheltered by buildings. Based on these fields, we generated the spatial distributions of ventilation indices, namely, the net escape velocity (NEV), point-to-point indices transfer probability (TP), and travel time (TT), to discuss the dispersion of scalars emitted from local points in a room with natural ventilation. The NEV, which indicates the direction of the scalar discharge from each cell, exhibited a distribution distinct from the advection velocity because of concentration gradient effect. Higher TPs were observed when evaluated from a contaminant source to a target point following the NEV streamlines. Meanwhile, lower TTs were observed when evaluated in a point near the source and also from a contaminant source to a target point following the NEV streamlines. Although TP and TT are independent ventilation indices, a negative correlation between them was observed. Instead of the ventilation flow rate, the detailed structure of scalar dispersion can now be described by simultaneously analyzing the ventilation efficiency indices, which provide information on the general contaminant transport direction, and the probability and duration of transfer from a source to a target point. This potentially helps in the design of ventilation system especially in room lay-out to avoid cross-contamination.

SCARLET (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial): study protocol for a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 trial of i.v. citicoline (CDP-choline) in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure

BackgroundThe SARS CoV-2 pandemic has resulted in more than 1.1 million deaths in the USA alone. Therapeutic options for critically ill patients with COVID-19 are limited. Prior studies showed that post-infection treatment of influenza A virus-infected mice with the liponucleotide CDP-choline, which is an essential precursor for de novo phosphatidylcholine synthesis, improved gas exchange and reduced pulmonary inflammation without altering viral replication. In unpublished studies, we found that treatment of SARS CoV-2-infected K18-hACE2-transgenic mice with CDP-choline prevented development of hypoxemia. We hypothesize that administration of citicoline (the pharmaceutical form of CDP-choline) will be safe in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure (HARF) and that we will obtain preliminary evidence of clinical benefit to support a larger Phase 3 trial using one or more citicoline doses.MethodsWe will conduct a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 dose-ranging and safety study of Somazina® citicoline solution for injection in consented adults of any sex, gender, age, or ethnicity hospitalized for SARS CoV-2-associated HARF. The trial is named “SCARLET” (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial). We hypothesize that SCARLET will show that i.v. citicoline is safe at one or more of three doses (0.5, 2.5, or 5 mg/kg, every 12 h for 5 days) in hospitalized SARS CoV-2-infected patients with HARF (20 per dose) and provide preliminary evidence that i.v. citicoline improves pulmonary outcomes in this population. The primary efficacy outcome will be the SpO2:FiO2 ratio on study day 3. Exploratory outcomes include Sequential Organ Failure Assessment (SOFA) scores, dead space ventilation index, and lung compliance. Citicoline effects on a panel of COVID-relevant lung and blood biomarkers will also be determined.DiscussionCiticoline has many characteristics that would be advantageous to any candidate COVID-19 therapeutic, including safety, low-cost, favorable chemical characteristics, and potentially pathogen-agnostic efficacy. Successful demonstration that citicoline is beneficial in severely ill patients with SARS CoV-2-induced HARF could transform management of severely ill COVID patients.Trial registrationThe trial was registered at www.clinicaltrials.gov on 5/31/2023 (NCT05881135).Trial statusCurrently enrolling.

Role of air stagnation in determining daily average PM2.5 concentrations in areas with significant impact of long-range transport

In areas where the regional transport of air pollutants exerts a significant impact, ascertaining whether short-term air stagnation affects PM2.5 concentrations is crucial for accurate air quality forecasting and effective management planning. However, this research area remains underexplored. In this study, we analyzed the relationship between stagnant atmospheric conditions and daily average PM2.5 concentrations in areas with a substantial long-range transport impact (LRT). Specifically, we focused on days with elevated PM2.5 concentrations (daily average ≥ 35 μg/m3) from January to March 2019 in South Korea. The analysis was performed using the Weather Research and Forecasting and the Community Multiscale Air Quality Modeling System. Stagnant conditions were quantified using ventilation index (VI), calculated as the product of planetary boundary layer height and 10-m wind speed. The correlation coefficient between daily average VI and PM2.5 concentration (r = −0.23) was lower than that between VI and NO2 concentration (r = −0.60). This can be attributed to the fact that LRT was 2.9-fold higher than local emission impact (LEI) during days of elevated PM2.5 concentrations. Notably, the correlation coefficient between LRT and VI (r = −0.03) was considerably lower than that of LEI (r = −0.70). Hence, predicting the daily average PM2.5 concentration solely based on VI proved challenging in an area characterized by substantial LRT. For future research, in areas where LRT plays a substantial role, accurate prediction of PM2.5 concentrations requires distinguishing the effects of LRT and LEI on PM2.5 concentrations.

Awake pronation with helmet CPAP in early COVID-19 ARDS patients: effects on respiratory effort and distribution of ventilation assessed by EIT.

Prone positioning with continuous positive airway pressure (CPAP) is widely used for respiratory support in awake patients with COVID-19-associated acute respiratory failure. We aimed to assess the respiratory mechanics and distribution of ventilation in COVID-19-associated ARDS treated by CPAP in awake prone position. We studied 16 awake COVID-19 patients with moderate-to-severe ARDS. The study protocol consisted of a randomized sequence of supine and prone position with imposed positive end-expiratory pressure (PEEP) of 5 and 10 cmH2O delivered by helmet CPAP. Respiratory mechanics and distribution of ventilation were assessed through esophageal pressure (PES) and electrical impedance tomography (EIT). At the end of each 20-min phase, arterial blood gas analysis was performed, and PES swing and EIT tracings were recorded for the calculation of the respiratory mechanics and regional ventilation. The patient's position had no significant effects on respiratory mechanics. EIT analysis did not detect differences among global indices of ventilation. A significant proportion of pixels in the sternal region of interest showed an increase in compliance from the supine to prone position and PaO2/FIO2 increased accordingly. The best improvement of both PaO2/FIO2 and sternal compliance was obtained in the prone position with PEEP 10 cmH2O. In the studied subjects, prone positioning during CPAP treatment raised oxygenation without improvement of "protective" ventilation or global ventilatory inhomogeneity indices. Prone positioning with higher PEEP significantly increased the compliance of sternal regions.

Lung transcriptomics reveals the underlying mechanism by which aerobic training enhances pulmonary function in chronic obstructive pulmonary disease

BackgroundAerobic training is the primary method of rehabilitation for improving respiratory function in patients with chronic obstructive pulmonary disease (COPD) in remission. However, the mechanism underlying this improvement is not yet fully understood. The use of transcriptomics in rehabilitation medicine offers a promising strategy for uncovering the ways in which exercise training improves respiratory dysfunction in COPD patients. In this study, lung tissue was analyzed using transcriptomics to investigate the relationship between exercise and lung changes.MethodsMice were exposed to cigarette smoke for 24 weeks, followed by nine weeks of moderate-intensity treadmill exercise, with a control group for comparison. Pulmonary function and structure were assessed at the end of the intervention and RNA sequencing was performed on the lung tissue.ResultsExercise training was found to improve airway resistance and lung ventilation indices in individuals exposed to cigarette smoke. However, the effect of this treatment on damaged alveoli was weak. The pair-to-pair comparison revealed numerous differentially expressed genes, that were closely linked to inflammation and metabolism.ConclusionsFurther research is necessary to confirm the cause-and-effect relationship between the identified biomarkers and the improvement in pulmonary function, as this was not examined in the present study.

Correlation Between Lung Clearance Index (LCI) and Forced Expiratory Volume (FEV1) in Children with Cystic Fibrosis (CF): A Cross-sectional Study

Background: The Lung Clearance Index (LCI) serves as a non-uniform ventilation index utilized for monitoring pulmonary function in patients with cystic fibrosis (CF). Lung Clearance Index exhibits higher sensitivity compared to forced expiratory volume in 1 second (FEV1) for early detection of lung disease and does not necessitate active patient cooperation, as required for FEV1 measured through spirometry. Presently, FEV1 is the standard parameter employed for monitoring lung function in CF patients. Objectives: The objective of this study was to assess the correlation between LCI and FEV1 in patients with cystic fibrosis. Methods: This cross-sectional study enrolled children aged 6 to 18 years with confirmed CF diagnosis, who were referred to the CF clinic at Children's Medical Center Hospital (Tehran, Iran). Participants completed consent forms and subsequently underwent pulmonary function tests. Lung Clearance Index was calculated using the exhaling-D device via the Multiple Breath Washout (MBW) method, followed by FEV1 assessment through spirometry. Results: The study included 52 patients with an average age of 12 years, among whom 52% were males. The mean ± standard deviation of FEV1 and LCI were 80.2% ± 25.3 and 8.9 ± 2.8, respectively. A significant inverse relationship was observed between these two parameters in the study (r = -0.49, P = 0.001). Conclusions: These findings further underscore the potential utility of LCI, which offers ease of administration and demonstrates high reliability and accuracy compared to FEV1 for monitoring pulmonary function in CF patients.

Urban-canopy airflow dynamics: A numerical investigation of drag forces and distribution for generic neighborhoods, and their relationships with breathability

Thorough investigations of urban-canopy drag primarily stemming from pressure drag on building surfaces are necessary given the turbulent flows within complex urban areas. Moreover, a gap persists regarding the relationships between canopy drag and breathability. Therefore, this work delves into the canopy-layer airflow dynamics for generic urban neighborhoods by performing three-dimensional Reynolds-Averaged Navier-Stokes simulations. A total of 32 subcases are examined, encompassing uniform- and varying-height and diverse plan area densities (λp, categorized into groups of sparse: 0.0625/0.067, medium: 0.23/0.25, and dense: 0.53/0.56). Results for the drag distribution highlight the windward-row shelter effect for the medium and the dense, local shelter by taller buildings, and distinct shapes of sectional drag forces (F⁎Z). Local velocity and mean age of air are found strongly positively and negatively correlated to F⁎Z, respectively, with distinct slopes in relation to λp. For the uniform-height, the normalized bulk drag (F⁎bulk, referred to as drag coefficient in literature) peaks for the medium with wake-interference regime; F⁎bulk demonstrates a maximum increase of over two times with height variation; moreover, F⁎bulk for varying-height groups exhibits a marked increase from the sparse to the medium, while remaining comparable values for the dense. The frontal area averaged drag (FAf,ave) exhibits a decreasing trend against λp across all cases. Further, FAf,ave exhibits strong correlations with λp and porosity, and with bulk ventilation indices such as spatially averaged velocity, air change rate, and normalized net escape velocity. Throughout the ‘suburban-urban-suburban’ canopy, medium neighborhoods exerting larger drag cause greater streamwise outdoor pressure drops and flow reductions compared to the sparse. However, dense neighborhoods with lower drag exhibit even larger pressure losses, which should be carefully scrutinized. The findings can inform urban planners in designing more aerodynamically efficient neighborhoods and guide strategies for improving air quality within urban environments.

Climate change-induced impacts on PM2.5 in Taiwan under 2 and 4 °C global warming

Climate change can perturb meteorological parameters and affect air quality, human health, and the economy. This study examined the climate change-induced meteorological impacts on PM2.5 in Taiwan, an island with a dense population and complex topography. We conducted high-resolution simulations of the current and future climate using the National Center for Atmospheric Research's Weather Research and Forecasting model and the Community Multiscale Air Quality Modeling System. As verified by observations, the model could reproduce the spatial and seasonal characteristics of PM2.5 in Taiwan, including higher concentrations in cold seasons and lower concentrations in warm seasons. The number of polluted days in the current climate was more than 30 days per season in central Taiwan and more than 70 days in southern Taiwan in autumn and winter. Under the 2 °C and 4 °C global warming scenarios, climate change-induced impacts worsened the PM2.5 air quality in Taiwan in cold seasons. In winter, the number of polluted days increased by 3–6 days in the whole of Taiwan, while it decreased by 3–5 days in southern Taiwan in autumn. Analysis of climate change-induced impacts on northeasterly days, air stagnation, and ventilation indices revealed that the weaker low-level wind in cold seasons was the dominant factor of the worsened PM2.5 air quality under global warming in Taiwan. In addition, the climate change-induced worsening of PM2.5 air quality could be locally mitigated by northeasterly days and nighttime warming in urban areas in northern Taiwan and by precipitation in southern Taiwan. Overall, these findings indicated that climate change-induced impacts on air quality cover both urban and global scales. To better adapt to climate change, discussing interactions between the responses to global warming in urban areas using hierarchical models and high-resolution simulations is necessary.

Optimization of lung ventilation and perfusion in anesthetized horses using a ventilation mode with flow-limited expiration.

To investigate the mechanisms underlying the improved arterial oxygenation described with flow-limited expiration (FLEX) ventilation in anesthetized horses. 5 healthy adult research horses. Horses underwent volume-controlled ventilation for 60 minutes (VCV1), followed by 60 minutes of FLEX, and 30 minutes of VCV (VCV2). Main outcomes included the arterial partial pressure of oxygen-to-Fio2 (PF) ratio and electrical impedance tomography (EIT)-derived functional indices at the end of each phase. The EIT data were used to create regional maps of relative lung ventilation and perfusion as well as regional maps of ventilation/perfusion (V/Q) ratios. Ventilation indices derived from EIT included the fraction of expired volume in 1 second (FEV1; %) and the time it took for the EIT signal to drop to 50% of the peak signal at end-inspiration (TClose50; seconds). Data were analyzed with 2-way ANOVA for repeated measures. P < .05 was considered significant. The PF ratio increased significantly with FLEX compared to both VCV1 and VCV2 (P < .01). There were no differences in the relative distribution of ventilation nor perfusion between ventilation strategies. However, when ventilation and perfusion were superimposed and V/Q ratio maps were constructed, FLEX had a homogenizing effect toward values of 1.0. The FEV1 was shorter (P < .01) and the TClose50 was longer (P < .001) in all regions during FLEX compared to both VCV1 and VCV2. Our findings suggest that FLEX ventilation in anesthetized horses enhances regional V/Q matching, likely by prolonging expiratory aeration and reducing airway closure.

Nursing Care of Children Post-Cardiac Surgery in Intensive Care Units: An Integrative Review

Introduction: Congenital heart disease is one of the most common congenital disorders, affecting between 0.8% and 1.2% of live births worldwide. The treatment of children with congenital heart defects is highly specialized and includes, among others, surgical treatment as the first-choice approach and postoperative care in intensive care units. The aim of this review is to explore nursing care plans for post-cardiac surgery children during their stay in intensive care units. Methods: An integrative review was performed to obtain articles from the online databases SCOPUS, ScienceDirect, Scielo, PubMed, EMBASE, and Redalyc. The synthesis of information was performed based on diagnoses and interventions. In addition, complications and associated factors were identified. Results: Nursing diagnoses and interventions focus on problem-centered care to respond to cardiovascular and ventilatory needs, sedation and analgesia, infection control, and nutrition. The main complications identified were increased time on mechanical ventilation, postoperative infection, renal failure, and mortality. Complications were associated with intrinsic conditions such as age, gender, or type of malformation and clinical and procedural conditions such as extracorporeal circulation, mechanical ventilation, or higher postoperative risk index. Discussion: This review identified problem-focused nursing diagnoses and interventions with a strong focus on the physiological conditions of the child. Although the results of this study show the conceptual level of nurses for specialized care, it denotes the need to complement the nursing process through diagnoses and interventions that promote the transversality of care beyond the problem-centered approach based on the possibilities of the response of the child and the family.

Fyzická aktivita detských pacientov s nešpecifickými črevnými zápalovými ochoreniami – výhody a limitácie

Summary: Introduction: Inflammatory bowel diseases (IBDs) are a group of diseases including Crohn’s disease, ulcerative colitis and unclassified IBD. They are chronic, immune-mediated inflammatory diseases of the gastrointestinal tract. Due to their extraintestinal manifestation, they are considered to be systemic diseases. IBD has a negative impact on health-related quality of life. The treatment is life-long and may be accompanied by side effects. Low-intensity activity of moderate duration is sufficient to elicit improvements in fitness, decrease stress, and improve symptoms. In this study, the relationship between physical activity and IBD development and course is described. Aims: To assess the relationship between physical activity and exercise capacity and the severity and course of IBD. Methods: Probands with IBD and healthy controls underwent pulmonary function testing (PFT) and cardiopulmonary exercise testing (CPET). The results were compared between these two groups; in the IBD group, the results were correlated with disease activity parameters as well. In the IBD group, the probands were encouraged to perform regular physical activity. After 0.5–1 year, they underwent another CPET. Their exercise capacity development was objectively assessed and it was correlated with their IBD development. Results: Forty-one children were included in the study. Twenty of them were healthy controls, while 21 comprised the IBD patient group. These probands underwent the PFT and CPET. When comparing healthy controls and IBD patients, significant differences were found in peak oxygen uptake and peak work rate. In the IBD group, a negative correlation was found between peak work rate and C-reactive protein concentration. In faecal calprotectin, a significant correlation was found only in the subgroup with ulcerative colitis – the negative correlation with peak oxygen uptake and partial pressure of CO2 in exhaled air in the peak of the exercise. PCDAI correlated positively with ventilatory index, peak dead space and tidal volume ratio but negatively with peak work rate, work rate at the time of anaerobic threshold, peak oxygen uptake and oxygen uptake efficacy slope. In PUCAI, we found a positive correlation with CO2 ventilatory uptake at the time of anaerobic threshold and negative correlations with peak oxygen uptake and oxygen uptake efficacy slope. In further CPET in the IBD group, a significant decrease was found in faecal calprotectin and PCDAI or PUCAI; there were also positive correlations between PCDAI/PUCAI changes and resting heart rate changes. The negative correlation was found in the correlation with the changes in peak oxygen uptake, metabolic index and ventilatory equivalent for CO2 at the time of anaerobic threshold. Conclusion: These results suggest that regular recreational physical exercise positively impacts IBD. When adhering to treatment recommendations, doing sport professionally is also possible. Key words: inflammatory bowel diseases – physical activity

Sex-Linked Differences in Pulmonary Functions of COVID-19 Patients After a Six-Minute Walk Test.

Coronavirus disease 2019 (COVID-19) predominantly impacts the respiratory system. Historically, numerous lung diseases have shown sex-related differences throughout their progression. This study aimed to identify sex-linked disparities in pulmonary function tests (PFTs) among individuals who have recovered from COVID-19 when subjected to a six-minute walk test (6MWT). In this observational cross-sectional study, we analyzed 61 participants, consisting of 39 (64%)males and 22 (36%) females, all of whom previously contracted COVID-19 three months or more prior. We measured vitals such as blood pressure, pulse, oxygen saturation, and PFT values before and after the 6MWT. The post-6MWT evaluation revealed notable mean differences between males and females in parameters systolic blood pressure (SBP) (p = 0.003), diastolic blood pressure (DBP) (p = 0.026), forced expiratory volume in the first second (FEV1) (p = 0.038), forced vital capacity (FVC) (p = 0.041), and maximum voluntary ventilation (MVV) index (p = 0.011). PFT outcomes indicated sex-based variations among post-COVID-19 subjects. Specifically, post-stress values for FEV1, FVC, MVV index, SBP, and DBP were more elevated in males than in females. However, females presented with higher oxygen saturation levels post-COVID-19 compared to males. Using multiple linear regression modeling, sex was not found to be a strong predictor of PFT results. However, individual regression analyses for FEV1, FVC, and MVV index consistently showcased higher values in males. In conclusion, significant PFT differences exist between males and females after recovery from COVID-19 when exposed to stress induction via the 6MWT.

A randomized controlled trial of nebulized surfactant for the treatment of severe COVID-19 in adults (COVSurf trial)

SARS-CoV-2 directly targets alveolar epithelial cells and can lead to surfactant deficiency. Early reports suggested surfactant replacement may be effective in improving outcomes. The aim of the study to assess the feasibility and efficacy of nebulized surfactant in mechanically ventilated COVID-19 patients. Patients were randomly assigned to receive open-labelled bovine nebulized surfactant or control (ratio 3-surfactant: 2-control). This was an exploratory dose–response study starting with 1080 mg of surfactant delivered at 3 time points (0, 8 and 24 h). After completion of 10 patients, the dose was reduced to 540 mg, and the frequency of nebulization was increased to 5/6 time points (0, 12, 24, 36, 48, and an optional 72 h) on the advice of the Trial Steering Committee. The co-primary outcomes were improvement in oxygenation (change in PaO2/FiO2 ratio) and ventilation index at 48 h. 20 patients were recruited (12 surfactant and 8 controls). Demographic and clinical characteristics were similar between groups at presentation. Nebulized surfactant administration was feasible. There was no significant improvement in oxygenation at 48 h overall. There were also no differences in secondary outcomes or adverse events. Nebulized surfactant administration is feasible in mechanically ventilated patients with COVID-19 but did not improve measures of oxygenation or ventilation.