Respiratory Characteristics Research Articles

Isolated respiratory tract microorganisms and clinical characteristics in asthma exacerbation of obese patients: a multicenter study.

Viral infection is a risk factor for asthma exacerbation (AE). However, bacterial infections related to AE in adults are poorly known. On the other hand, obese patients with asthma have their own clinical and biological characteristics compared with non-obese patients. We investigated the differences in isolated pathogens for AE between obese and non-obese patients with asthma. We included 407 patients with AE from 24 medical centers in Korea. Microorganisms isolated from culture, RT-PCR or serologic tests using lower respiratory tract specimens were retrospectively investigated. A total of 171 obese and 236 non-obese patients with asthma were included for analysis. Compared to non-obese patients, obese patients were associated with women (77.2% vs. 63.6%), never smoker (82.5% vs. 73.9%), shorter duration of asthma (7.9 ± 8.4 vs. 10.5 ± 10.1 years), less history of pulmonary tuberculosis (8.8% vs. 17.4%), and more comorbidity of allergic rhinitis (48.5% vs. 0.8%). Viral and/or bacterial infections were detected in 205 patients (50.4%) with AE. The numbers of patients with viral only, bacterial only, or both infections were 119, 49, and 37, respectively. The most commonly isolated bacterium was Streptococcus pneumoniae, followed by Pseudomonas aeruginosa and Chlamydia pneumoniae. Obese patients showed a lower incidence of Chlamydia pneumoniae infection. In the non-obese group, bacterial infection, especially Chlamydia pneumoniae infection, was significantly associated with the duration of systemic corticosteroid use (13.6 ± 19.8 vs. 9.7 ± 6.7 days, p = 0.049). Bacterial infection was associated with a longer period of corticosteroid use in the non-obese group. Acute Chlamydia pneumoniae infection was less associated with obese patients with AE. Further well-designed studies are needed to evaluate microorganisms and the efficacy of antibiotics in patients with AE.

Respiratory Muscle Contraction Characteristics and Potential Mechanisms in Severely Burned Rats.

Postburn hypermetabolism remains an important clinical problem. During this phase, there is a significant loss of diaphragmatic proteins. Better understanding of respiratory muscle dynamics and potential mechanisms affecting respiratory muscle function is necessary for the development of effective therapeutic approaches. Male Wistar rats were subjected to 50% TBSA burns and sham injuries, and respiratory muscle function was assessed with 0, 1, 4, 7, and 14 days postinjury, including pulmonary function, blood gas analysis, transdiaphragmatic pressure, diaphragm ultrasonography, isolated diaphragm contractility, fatigue index, protein oxidative stress content, and ATP levels. Burned rats had significantly reduced inspiratory time, expiratory time, and tidal volume and significantly increased respiratory rate and minute ventilation. At the same time, the isolated diaphragm contractility, specific force during fatigue, and fatigue index were significantly decreased in the burned rats. Pdi, Pdimax, diaphragm thickness, diaphragm thickening fraction, and diaphragm excursion also decreased significantly postburn, whereas the Pdi/Pdimax ratio increased significantly. Finally, the content of protein carbonyls and lactic acid of burned rats was increased, and ATP levels of burned rats were decreased. The present study demonstrates the dynamic changes in diaphragm contractile properties postburn from both in vivo and in vitro perspectives, while cursorily exploring the possibility that protein oxidative stress and reduced ATP production may be the cause of diaphragm dysfunction. This understanding contributes to the development of methods to mitigate the extent of diaphragmatic function loss after severe burns.

Simulation of human breathing gas exchange for the ventilation regulation study

The chemoreflex control of breathing plays a major role in human lung ventilation adjustment in response to metabolic demands and CO2, O2 partial pressure changes in the inhaled air. The extreme conditions, e.g. emergency work in mines or deep-sea diving, space flights, can change the respiratory system reaction to CO2 and O2. The study of the relevant respiratory system characteristics is an important fundamental and practical task. One of the convenient ways of research is mathematical simulation, which allows to reduce the number of experiments in extreme conditions or experiments for the personal protective equipment testing, as well as to forecast the estimated time of effective human work in such conditions. The model describes the dynamics of the gas content in the 3 compartments of the biological system and the external environment represented by the 4th compartment. The external environment can be limited by the volume of the device to which a person is connected, or by the volume of a closed hermetic object, or represented by a sufficiently large volume, conditionally being an atmosphere with appropriate parameters. A mathematical model of the breathing gas exchange with the external environment (the atmosphere or any other limited space) is presented. It is the first time, the simulation results of breathing at rest, during hyperventilation and rebreathing tests are presented, including gas dynamics in the pulmonary and tissue compartments, as well as in the brain compartment. Hypercapnia ventilation reaction during rebreathing tests with a hyperoxic - hypercapnic gas mixtures and different rebreathing bags in comparison with stationary methods of breathing control study. Verification of the model by simulation results with the literature data comparison showed the simulation model’s adequacy. A sensitivity table of the simulation model behavior in response to parameters changes is presented.

Respiratory mechanics characteristics at the time of barotrauma presentation in patients with critical COVID-19 infection.

To evaluate how ventilatory support, the duration of invasive ventilatory support use and lung mechanics are related to barotrauma development in patients who are severely infected with COVID-19 and who are admitted to the intensive care unit and develop pulmonary barotrauma. Retrospective cohort study of patients who were severely infected with COVID-19 and who developed pulmonary barotrauma secondary to mechanical ventilation. This study included 60 patients with lung barotrauma who were divided into two groups: 37 with early barotrauma and 23 with late barotrauma. The early barotrauma group included more individuals who needed noninvasive ventilation (62.2% versus 26.1%, p = 0.01). The tidal volume/kg of predicted body weight on the day of barotrauma was measured, and 24 hours later, it was significantly greater in the late barotrauma group than in the early barotrauma group. During the day, barotrauma was accompanied by plateau pressure and driving pressure accompanied by tidal volume, which significantly increased in the late barotrauma group. According to the SAPS 3, patients in the early barotrauma group had more pulmonary thromboembolism and more severe illness. However, the intensive care unit mortality rates did not significantly differ between the two groups (66.7% for early barotrauma versus 76.9% for late barotrauma). We investigated the effect of respiratory mechanics on barotrauma in patients with severe COVID-19 and found that 25% of patients were on nonprotective ventilation parameters when they developed barotrauma. However, 50% of patients were on protective ventilation parameters, suggesting that other nonventilatory factors may contribute to barotrauma.

Respiratory mechanics characteristics at the time of barotrauma presentation in patients with critical COVID-19 infection

RESUMO Objetivo: Avaliar como o suporte ventilatório, o tempo de uso do suporte ventilatório invasivo e a mecânica pulmonar estão relacionados ao desenvolvimento de barotrauma em pacientes com infecção grave pela COVID-19 admitidos na unidade de terapia intensiva. Métodos: Trata-se de estudo de coorte retrospectivo de pacientes com infecção grave pela COVID-19 que desenvolveram barotrauma pulmonar secundário à ventilação mecânica. Resultados: Este estudo incluiu 60 pacientes com barotrauma pulmonar divididos em dois grupos: 37 com barotrauma precoce e 23 com barotrauma tardio. O grupo com barotrauma precoce incluiu mais indivíduos que precisaram de ventilação não invasiva (62,2% versus 26,1%, p = 0,01). O volume corrente/kg de peso corporal previsto no dia do barotrauma foi medido e, 24 horas depois, foi significativamente maior no grupo com barotrauma tardio do que no grupo com barotrauma precoce. Durante o dia, o barotrauma foi acompanhado pela pressão de platô e pela pressão de distensão acompanhada do volume corrente, o qual aumentou significativamente no grupo com barotrauma tardio. De acordo com o SAPS 3, os pacientes do grupo com barotrauma precoce apresentaram mais tromboembolia pulmonar e doença mais grave. Entretanto, as taxas de mortalidade na unidade de terapia intensiva não diferiram significativamente entre os dois grupos (66,7% para barotrauma precoce versus 76,9% para barotrauma tardio). Conclusão: Investigamos o efeito da mecânica respiratória no barotrauma em pacientes com COVID-19 graves e descobrimos que um quarto dos pacientes estava em parâmetros de ventilação não protetores quando desenvolveram barotrauma. No entanto, 50% dos pacientes estavam em parâmetros de ventilação protetora, sugerindo que outros fatores não ventilatórios podem contribuir para o barotrauma.

Clinical features of sleep apnea syndrome and cognitive impairment in multiple sclerosis

Background: Complications of obstructive sleep apnea (OSA) have been reported in patients with multiple sclerosis (MS). Patients with sleep apnea syndrome (SAS) due to OSA also show cognitive decline, with similar clinical characteristics to that manifested in MS. SAS due to OSA is a treatable condition, and the associated cognitive decline is expected to improve. This study investigates clinical features of SAS in people living with MS and contribute to improve cognitive dysfunction of MS.Methods: A case-control study was conducted. Cognitive functions were evaluated by the Symbol Digit Modalities Test (SDMT) and the Paced Auditory Serial Addition Test 2 (PASAT-2) and 3 (PASAT-3). The Respiratory Event Index (REI) was measured using Out of Center Sleep Testing (OCST). We defined subjects with REI ≥ 5 as OSA and divided participants into two groups with or without SAS due to OSA. Cognitive and respiratory characteristics were statistically compared between patients with MS and healthy controls.Results: We enrolled 67 people living with MS and 31 age- and sex-matched controls. OCST detected OSA in people living with MS and controls, and the prevalence rates were 28.4 % and 25.8 %, respectively. REI values (5.2 ± 7.9 vs 3.9 ± 5.2, p = 0.509) and number of participants with REI ≥ 5 (19 vs 8, p = 0.793) were similar between the MS and control group. The SDMT, PASAT-2, and PASAT-3 scores were significantly lower in the MS group than the control group (p < 0.001, p = 0.001, and p < 0.001, respectively). The interaction effect of MS and SAS on cognitive function was not significant in the SDMT (p = 0.078), but in the PASAT-2 (p = 0.043) and PASAT-3 (p = 0.020).Conclusion: This study revealed the prevalence rates of SAS in Japanese people living with MS and the usefulness of OCST for detection of SAS. This study also revealed that concomitant SAS can facilitate cognitive decline in people living with MS. These findings suggest that an appropriate intervention for OSA can be beneficial for people living with MS with cognitive decline.

HISTORY OF PRETERM INFANTS WITH HYPOXIC BRAIN DAMAGE

Relevance. According to the experts of World Health Organization, diseases linked to perinatal hypoxic brain damage account for 70-80% of cases of childhood disability.&#x0D; This study aims to explore the historical records of heart rate and respiratory characteristics in preterm infants with hypoxic brain damage.&#x0D; Subjects and Methods. A prospective cohort study was conducted involving 160 preterm infants categorized into three groups: group I comprised conditionally healthy children, group II included children with hypoxic-ischemic central nervous system lesions, and group III involved children with hypoxic-hemorrhagic central nervous system lesions.&#x0D; Results. The analysis of heart rate parameters according to the data of daily monitoring of electrocardiogram has revealed a positive dynamic of reduction of heterotopic activity and a significant (p&lt;0.05) improvement in the functional state of the conduction system of the heart in all preterm infants aged 20-30 months after a course of timely rehabilitation therapy of hypoxic brain damage. The presence of periodic breathing with respiratory pauses in preterm patients in the neonatal period was established, and a significantly longer duration of apnea was found in children with hypoxic-hemorrhagic central nervous system damage. There has been found an inverse correlation of moderate strength between gestational age and the amount of apnea during the day. Throughout the observation period, there was a gradual establishment of the sleep profile and its structural characteristics, indicating a physiological consolidation process marked by a regular alternation of stable rhythm phases. However, in newborns with hypoxic brain damage, autonomic dysregulation of heart rhythm persisted in the form of hypersympathicotonia. This suggests a high level of electrical instability of the myocardium, underscoring the necessity for ongoing clinical monitoring.

Effect of combined side-wall air supply on ventilation and respiratory pollutant dispersion characteristics of high-speed trains

The ventilation system significantly affects the energy saving, thermal comfort, and pollutant dispersion characteristics of high-speed trains. Using Computational Fluid Dynamics (CFD), the effects of combining side-wall air supply with side roof or ceiling air supply, on the performance of a high-speed train ventilation system is studied. The results show that the addition of side-wall air supply aids energy saving and emission reduction, resulting in an increase in energy utilisation coefficient of between 5% and 30%. The number of measurement points with wind speed less than 0.3 m/s increases by 3%∼9%, which can improve passenger comfort. Also, the concentration of pollutants can be reduced by 6%∼29%, and the diffusion distance along the length of the train can be reduced by 18%∼45%, which means more efficient ventilation and a shorter diffusion range of pollutants. However, it reduces temperature uniformity. The results of this study can be used for ventilation optimisation of high-speed trains, to reduce ventilation energy consumption, improve thermal comfort, and increase ventilation efficiency.

Effect of high-flow nasal cannula oxygen therapy in combination with non-invasive ventilation on critically ill patients with acute respiratory failure: a retrospective study.

Acute respiratory failure (ARF) is a respiratory disease in which ventilation dysfunction of the lungs occurs at rest due to various factors, resulting in oxygen deprivation and carbon dioxide (CO2) retention. In recent years, high-flow nasal cannula (HFNC), as a new type of oxygen therapy, has attracted increasing attention. Compared with traditional oxygen therapy, HFNC adopts nasal catheter to make it more in line with the physiological and respiratory characteristics of the human body, and thus can provide a higher and more constant inhalation of oxygen. This retrospective study was conducted to explore the clinical effect of HFNC combined with non-invasive ventilation (NIV) in the treatment of critically ill patients with ARF. A total of 532 critically ill patients with ARF treated in our hospital from January 2019 to December 2020 were screened for the suitability for being included in the study. Of these, 261 patients in this study received NIV. In total, 151 patients were included after applying the inclusion and exclusion criteria. NIV was generally given intermittently, and the daily duration of application was determined according to the patient's condition. The NIV-treated patients were assigned into two groups according to the oxygen inhalation mode during intermittent NIV: (I) standard group: normal oxygen inhalation was applied at the NIV interval; and (II) research group: patients treated with HFNC at the NIV interval. The respective basic data and outcome observation indices were collected. In terms of the clinical outcome, the number of NIV treatment days in the research group was lower (P<0.05). At 30 min, 1 h, and 24 h after treatment, the partial pressure of arterial oxygen (PaO2), arterial oxygen saturation (SaO2), oxygenation index (P/F) indices in the research group were higher, while the CO2 partial pressure (PaCO2) was lower (P<0.05). Finally, the 28- and 90-day survival rates were compared between the groups and the results indicated no significant difference in the 28-day survival rates, but the 90-day survival rates of the research group were considerably higher (P<0.05). The use of HFNC combined with NIV to treat ARF in critically ill patients can effectively improve the ARF-related respiratory indicators in critically ill patients.

Laryngeal, Respiratory, and Acoustic Characteristics of Vocal Trillo With Simultaneous High-Speed Videoendoscopy, Inductive Plethysmography, and Acoustic Recordings

ObjectiveThis study aimeed to examine the characteristics of formed and unformed trillo, an essential ornament found in 17th-century Italian vocal music, using simultaneous multimodality voice measurements. Participant and MethodsA 28-year-old female with 12 years of classical voice training and 7 years of advanced training in historical performance produced formed trillo, unformed trillo, oscillating trill, vibrato, and straight tone on the vowel /i/. Simultaneous high-speed videoendoscopy, inductive plethysmography, and acoustic recordings were conducted to examine the laryngeal motion, respiratory kinematics, and output sound characteristics. ResultsThe study findings reveal that trillo in this single participant is not only produced by the periodic adduction/abduction of the vocal fold but also with underlying differences in oscillatory mechanisms and increased glottal flow (use of percent vital capacity) controlled by increased activation of abdominal muscles and/or decreased activation (inspiratory braking) of the diaphragm relative to tidal breathing when compared with straight tone, vibrato, and oscillating trill. The formed trillo differs from the unformed trillo in the oscillatory mechanisms and glottal airflow utilization. ConclusionsThe physiological mechanism responsible for trillo is more complex than simply adduction and abduction. Future studies with a greater number of participants are needed to evaluate the mechanisms responsible for the formation of and the auditory-perceptual differences between the formed versus unformed trillo.

Evaluation of Respiratory Support Methods and Characteristics of Pneumothorax in Late Preterm and Term Newborns within the First 48 hours of Life

AbstractThis study aims to evaluate risk factors, respiratory support procedures, and characteristics of pneumothorax in late preterm and term newborns diagnosed with pneumothorax within the first 48 hours of life. The study included late preterm and term newborns diagnosed with pneumothorax within the first 48 hours of life. The neonates diagnosed with pneumothorax within the first 24 hours of life (Group 1) and those diagnosed between 24 and 48 hours (Group 2) were analyzed in terms of risk factors, respiratory support procedures, and characteristics of pneumothorax. Twenty newborns, 11 in Group 1 and 9 in Group 2, with a mean gestational age of 37.9 ± 1.2 weeks and birth weight of 3,133 ± 464 g, were included the study. The resuscitation rate in the delivery room was insignificantly higher in Group 1. There was no significant difference between the two groups in terms of respiratory support methods (mechanical ventilation [MV], noninvasive ventilation, oxygen) on admission and at the time of diagnosis. The rate of receiving MV during treatment was significantly higher in Group 2 (p = 0.014). Although duration of MV and chest drainage were significantly shorter in Group 1 (p = 0.026 and p = 0.026, respectively), when we considered only survivors (all three deceased newborns died within the first day of life), these durations were still shorter; however, the difference was no longer significant. Pneumothorax should be suspected in late preterm and term newborns with respiratory distress within the first 2 days of life, especially in the presence of risk factors.

Monitoring low O2 stress in apples – What we can learn from chlorophyll fluorescence and respiratory characteristics

Dynamic controlled atmosphere (DCA) is becoming a storage method of choice for apple producers seeking to store long-term. There is limited prior work comparing DCA monitoring chlorophyll fluorescence yield (DCA-CF) and respiratory characteristics (DCA-RQ), particularly for the popular UK-grown apple cultivars ‘Gala’ and ‘Braeburn’. However, these techniques can give an insight into the physiological response of apples to low O2 storage, which could help to design more efficient and sustainable storage regimes. In this study the chlorophyll fluorescence (CF) and respiratory quotient (RQ) responses of ‘Gala’ and ‘Braeburn’ are compared in typical and exaggerated DCA conditions. Results show that not only do the two techniques differ in their detection of low O2 stress but the two cultivars studied also differ noticeably in their behaviour. CF increase was confirmed to be a reaction to a stress signal from inside the fruit. Respiration rate curves were found to reflect the internal structure of the fruit, with ‘Gala’’s more homogeneous tissues and greater gas permeability resulting in a strongly bimodal O2 consumption rate where the change in rate hypothetically corresponds with the majority of the fruit tissue switching to anaerobic respiration at the same time. CF and RQ showed noticeable differences between cultivars, agreeing with previous observations that ‘Braeburn’ is less tolerant of low O2 and elevated CO2 than ‘Gala’ (CF Lower O2 Limit (LOL) for Braeburn of approximately 0.75 kPa O2 relative to 0.5 kPa O2 for Gala). Additionally, the CF and RQ responses indicated different LOLs for ‘Gala’, at approximately 0.5 kPa O2 for CF and 0.25 kPa O2 for RQ. Elevated CO2 depressed both the CF and RQ response, with a strong depressive effect on the rate of CO2 evolution but little effect on the rate of O2 consumption.

Investigating unsteady airflow characteristics in the human upper airway based on the clinical inspiration data

To enhance understanding of the airflow characteristics in the human respiratory system during realistic inspiration, we investigated the airflow field in a human upper airway model using large eddy simulation and the dynamic grid method, taking into account clinically measured inspiratory characteristics. The results reveal the following novel findings: (1) The laryngeal jet and recirculation zone exhibit significant unsteadiness, with their dynamic characteristics primarily influenced by the transient inspiration flow rate and glottis motion. This pattern holds true for other airflow characteristics as well. (2) Glottis expansion reduces the energy consumed during inhalation for both steady and unsteady inspiratory flow rates, with the degree of expansion being directly related to the reduction in energy. We can accurately predict power loss by considering the glottis area and inspiratory flow rate. (3) Analysis of spectral entropy clearly demonstrates that the flow transitions from the laminar to turbulence earlier when using clinical inspiration data. Turbulence intensity in the trachea increases when either glottis motion or the transient inspiratory is ignored. In conclusion, the airflow dynamics are significantly more unsteady compared to cases where we ignore either glottis motion or the transient inspiratory flow rate. A precise understanding of realistic respiratory airflow cannot be achieved by assuming either a rigid glottis or a steady inspiration pattern. Therefore, it is crucial to use accurate inspiratory data when studying the properties of airflow structures in the human respiratory system. Moreover, incorporating more physiological data is also essential to obtain realistic respiratory airflow characteristics.

Circulation of Respiratory Viruses in the City: Towards an Agent-Based Ecosystem model.

Mathematical models play an important role in management of outbreaks of acute respiratory infections (ARI). While such models are generally used to study the spread of a solitary virus, in reality multiple viruses co-circulate in the population. These viruses have been studied in detail, including the course of infection and immune defense mechanisms. We developed an agent-based model, called ABM-ARI, assimilating heterogeneous data and theoretical knowledge into a biologically motivated system, that allows to reproduce the seasonal patterns of ARI incidence and simulate interventions. ABM-ARI uses city-specific data to create a synthetic population and to construct realistic contact networks in different activity settings. Characteristics of infection, immune protection and non-specific resistance were varied between individuals to account for the population heterogeneity. For the calibration, we minimised the normalised mean absolute error between simulated and observed epidemic curves. ABM-ARI was built based on the quantitative assessment of features of predominant respiratory viruses and epidemiological characteristics of the population. It provides a good fit to the observed epidemic curves for different age groups and viruses. We also simulated one-week school closures when student absences were at or above 10%, 20% or 30% and found that only 10% and 20% thresholds resulted in a reduction of the incidence. ABM-ARI has a great potential in tackling the challenge of emerging infections by simulating and evaluating the effectiveness of various interventions.

Role of respiratory characteristics in treatment adherence with noninvasive home mechanical ventilation in myotonic dystrophy type 1, a retrospective study

Chronic respiratory insufficiency is common in patients with myotonic dystrophy type 1 (DM1) and can be treated with noninvasive home mechanical ventilation (HMV). HMV is not always tolerated well resulting in low treatment adherence. We aimed to analyze if baseline respiratory characteristics such as pulmonary function, level of pCO2 and presence of sleep apnea are associated with HMV treatment adherence in DM1 patients. Pulmonary function testing, polysomnography and blood gas measurement data of DM1 patients were retrospectively collected. Initiation of HMV and treatment adherence after one year was documented. Patients with low treatment adherence (average daily use of HMV <5 h) were grouped with patients that discontinued HMV and compared with patients with high treatment adherence (average daily use of HMV >5 h). HMV was initiated in 101 patients. After one year, 58 patients had low treatment adherence. There were no differences between the low and high treatment adherence group regarding the respiratory characteristics. None of the included predictors (gender, age, body mass index, cytosine-thymine-guanine repeat length, FVC, daytime pCO2, bicarbonate, nighttime pCO2, nighttime base excess, apnea-hypopnea index and mean saturation during sleep) was able to significantly predict high treatment adherence. In conclusion, the respiratory characteristics are not associated with treatment adherence with HMV in DM1 patients and cannot be used to identify patients at risk for low HMV treatment adherence.

Study on the causes of growth differences in three conifers after the rainy season in the Xiong'an New Area.

The implementation of the Millennium Forestry Plan was accompanied by growth discomfort exhibiting varying degrees of symptoms in some coniferous forests after the rainy season. High soil water content affects the underground root growth and distribution characteristics of conifers, and the above-ground parts show corresponding variability. To determine the factors contributing to the significant growth disparities among the three conifers in Xiong'an New Area after the rainy season, we conducted a study investigating the growth characteristics of conifers. This study involved analyzing the external morphology of the plants, assessing leaf pigment content, measuring the root morphological index and root vigor, as well as respiratory characteristics, to evaluate the growth attributes of their root systems in a high soil moisture environment. In the "Millennium Forest" area of Xiong'an New Area, we selected three coniferous trees, Pinus tabuliformis, Pinus bungeana and Pinus armandii, and set up three standard sample plots for each conifer. The conifers were classified into 3 levels according to their growth performance (vigorous or suppressed), leaf condition (color change, wilting or not) and relevant grading criteria. (1) The growth of the three conifers displayed discernible differences in external morphology. Moreover, a decrease in growth condition corresponded to a reduction in crown size, ground diameter, diameter at breast height, leaf length, and new growths. (2) The root biomass, length, surface area, and root volume of conifers growing N class were significantly reduced than those of L class conifers. Conifers with a higher proportion of root systems in the 40-60cm soil layer experienced more severe stress. (3) The significant decline in root respiration and vigor among all three conifer growth classes (M and N) suggested that the root system was undergoing anoxic stress, particularly at a soil depth of 40-60cm where root respiration and vigor were notably reduced. (4) The persistent anoxic stress created by long-term exposure to high soil moisture content primarily impacted P. armandii to a greater extent than P. tabuliformis and P. bungeana. Additionally, the transporting and absorbing root ratios varied among conifers with differing growth conditions. The long-term high moisture environment also caused partial death of absorbing roots, which played a key role in the observed differences in growth. (5) As the soil depth increases, the soil water content increases accordingly. Plants with more root distribution in the deeper soil layers grow worse than those distributed in the top soil layers. Soil water content is related to aeration, root distribution, growth and growth of above-ground parts. The variability of root distribution and growth led to the differentiation of the growth of the above-ground part of the plant in terms of external morphology, which inhibited the overall plant growth. The results of the study provide a theoretical basis for the cultivation and management of three conifers in high soil moisture environments.

Radiological findings based comparison of functional status in patients who have post-covid lung injury or idiopathic pulmonary fibrosis

BackgroundFollowing COVID-19 infection, some patients acquired lung injury and fibrosis. Idiopathic pulmonary fibrosis is characterized by lung fibrosis. Both post-COVID lung injury and idiopathic pulmonary fibrosis cause loss of respiratory function and involvement of the lung parenchyma. We aimed to compare respiratory related functional characteristics and radiological involvement between post-COVID lung injury and idiopathic pulmonary fibrosis.MethodsA single center, cross-sectional study was applied. Patients with post-COVID lung injury and idiopathic pulmonary fibrosis included in the study. All patients underwent the 6-minute walk test, as well as the Borg and MRC scales. Radiological images were evaluated and scored for lung parenchymal involvement. The impact of post-COVID lung injury and idiopathic pulmonary fibrosis on respiratory functions of were compared. The relationship of functional status and radiological involvement, as well as the effect of potential confounding factors were investigated.ResultsA total of 71 patients were included in the study. Forty-eight (67.6%) of the patients were male and the mean age was 65.4 ± 10.3 years. Patients with post-COVID lung injury had greater 6-minute walk test distance and duration, as well as higher oxygen saturations. The MRC and Borg dyspnea scores were comparable. At radiologic evaluation, ground glass opacity scores were higher in patients with post-COVID lung injury, whereas pulmonary fibrosis scores were higher in patients with idiopathic pulmonary fibrosis. However, the total severity scores were similar. While pulmonary fibrosis score was found to have a negative correlation with 6-minute walk test distance, test duration, and pre- and post-test oxygen saturation levels, there was a positive correlation with oxygen saturation recovery time and MRC score. There was no relationship between ground glass opacity and the functional parameters.ConclusionsDespite having equal degrees of radiological involvement and dyspnea symptom severity, PCLI patients exhibited higher levels of functional status. This might be due to different pathophysiological mechanisms and radiological involvement patterns of both diseases.

Altered Respiratory Microbiomes, Plasma Metabolites, and Immune Responses in Influenza A Virus and Methicillin-Resistant Staphylococcus aureus Coinfection.

Influenza A virus (IAV)-methicillin-resistant Staphylococcus aureus (MRSA) coinfection causes severe respiratory infections. The host microbiome plays an important role in respiratory tract infections. However, the relationships among the immune responses, metabolic characteristics, and respiratory microbial characteristics of IAV-MRSA coinfection have not been fully studied. We used specific-pathogen-free (SPF) C57BL/6N mice infected with IAV and MRSA to build a nonlethal model of IAV-MRSA coinfection and characterized the upper respiratory tract (URT) and lower respiratory tract (LRT) microbiomes at 4 and 13 days postinfection by full-length 16S rRNA gene sequencing. Immune response and plasma metabolism profile analyses were performed at 4 days postinfection by flow cytometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships among the LRT microbiota, the immune response, and the plasma metabolism profile were analyzed by Spearman's correlation analysis. IAV-MRSA coinfection showed significant weight loss and lung injury and significantly increased loads of IAV and MRSA in bronchoalveolar lavage fluid (BALF). Microbiome data showed that coinfection significantly increased the relative abundances of Enterococcus faecalis, Enterobacter hormaechei, Citrobacter freundii, and Klebsiella pneumoniae and decreased the relative abundances of Lactobacillus reuteri and Lactobacillus murinus. The percentages of CD4+/CD8+ T cells and B cells in the spleen; the levels of interleukin-9 (IL-9), interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-6, and IL-8 in the lung; and the level of mevalonolactone in plasma were increased in IAV-MRSA-coinfected mice. L. murinus was positively correlated with lung macrophages and natural killer (NK) cells, negatively correlated with spleen B cells and CD4+/CD8+ T cells, and correlated with multiple plasma metabolites. Future research is needed to clarify whether L. murinus mediates or alters the severity of IAV-MRSA coinfection. IMPORTANCE The respiratory microbiome plays an important role in respiratory tract infections. In this study, we characterized the URT and LRT microbiota, the host immune response, and plasma metabolic profiles during IAV-MRSA coinfection and evaluated their correlations. We observed that IAV-MRSA coinfection induced severe lung injury and dysregulated host immunity and plasma metabolic profiles, as evidenced by the aggravation of lung pathological damage, the reduction of innate immune cells, the strong adaptation of the immune response, and the upregulation of mevalonolactone in plasma. L. murinus was strongly correlated with immune cells and plasma metabolites. Our findings contribute to a better understanding of the role of the host microbiome in respiratory tract infections and identified a key bacterial species, L. murinus, that may provide important references for the development of probiotic therapies.

Pediatric in-hospital cardiac arrest: Respiratory failure characteristics and association with outcomes

AimsTo characterize respiratory failure prior to pediatric in-hospital cardiac arrest (IHCA) and to associate pre-arrest respiratory failure characteristics with survival outcomes. MethodsThis is a single-center, retrospective cohort study from a prospectively identified cohort of children <18 years in intensive care units (ICUs) who received cardiopulmonary resuscitation (CPR) for ≥1 minute between January 1, 2017 and June 30, 2021, and were receiving invasive mechanical ventilation (IMV) in the hour prior to IHCA. Patient characteristics, ventilatory support and gas exchange immediately pre-arrest were described and their association with the return of spontaneous circulation (ROSC) was measured. ResultsIn the 187 events among 154 individual patients, the median age was 0.9 [0.2, 2.4] years, and CPR duration was 7.5 [3, 29] minutes. Respiratory failure was acute prior to 106/187 (56.7%) events, and the primary indication for IMV was respiratory in nature in 107/187 (57.2%) events. Immediately pre-arrest, the median positive end-expiratory pressure was 8 [5, 10] cmH2O; mean airway pressure was 13 [10,18] cmH2O; peak inspiratory pressure was 28 [24, 35] cmH2O; and fraction of inhaled oxygen (FiO2) was 0.40 [0.25, 0.80]. Pre-arrest FiO2 was lower in patients with ROSC vs. without ROSC (0.30 vs. 0.99; p < 0.001). Patients without ROSC had greater severity of pre-arrest oxygenation failure (p < 0.001) as defined by oxygenation index, oxygen saturation index, P/F ratio or S/F ratio. ConclusionsThere was substantial heterogeneity in respiratory failure characteristics and ventilatory requirements pre-arrest. Higher pre-arrest oxygen requirement and greater degree of oxygenation failure were associated with worse survival outcomes.

0542 Obstructive sleep apnea in outpatients with COPD at Can Tho University of Medicine and Pharmacy Hospital – An Observational Study

Abstract Introduction The concurrence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) is generally identified as overlap syndrome.This study evaluated biometric characteristics, sleep disorders, and scores comorbidities on OS and OSA groups in outpatients at the Respiratory Units of Can Tho University of Medicine and Pharmacy Hospital (RU-CTUMP); surveyed respiratory symptom severity, airway obstruction, and aerosol treatment characteristics in OS patients; and determined the correlations between sleep disorder severity and specific patient characteristics. Methods A cross-sectional, single-center descriptive study was conducted. We enrolled 48 outpatients at the RU-CTUMP in the study in three months. The patients were divided into two groups with overlapped COPD and OSA (OS, n = 30) vs. OSA-only (n = 18). Patients were asked to complete the demographic questionnaires, Epworth Sleepiness Scale (ESS) scores, STOP-Bang questionnaire, and Snoring Severity Scale (SSS). They were assessed for pulmonary function tests (PFTs) to confirm their COPD diagnosis, overnight respiratory polygraphy (Nox T3x), and Apnea-Hypopnea Index (AHI) to evaluate the severity of OSA, Charlson index to evaluate comorbidities, and their medication history. Results In the OS group, 100% of the patients suffered from dyspnea with the mean mMRC scores of 2.83 ± 0.75, mean FEV1 was 60.07 ± 23.09%, and 86% received inhaled medicine. In both groups, all participants suffered from 1 - ≥ 2 comorbidities. Overlapped patients had more comorbidities than OSA-only patients (Charlson scores of 2.33 and 1.17, respectively). There were significant correlations between the AHI value and the body mass index, neck circumferences, STOP-Bang score, the value of the Snoring Severity Scale, and minimum SpO2 (r = 0.45, 0.43, 0.46, 0.44, -0.69, respectively). In addition, COPD was a risk factor for OSA (OR = 1.125). Conclusion Home sleep testing in outpatients with COPD in RU-CTUMP revealed an increased prevalence of OSA compared to the OSA-only group. One of the most common comorbidities in individuals with overlap syndrome is hypertension, which is at least as common as in sleep apneic-only patients and may contribute to the disease's overall severity and prognosis. Support (if any)