Ventilatory Pattern Research Articles

Anesthetic management for surgery in a nemaline myopathy patient with difficult airway: A CARE-compliant case report.

Nemaline myopathy (NM) is a congenital disease characterized by nonprogressive or slowly progressing muscle weakness and may increase the risk of anesthesia in case of respiratory muscle or cardiac involvement. Care should be taken to prevent respiratory failure after surgery. A 35-year-old man with NM, who had difficult airway, restrictive ventilatory pattern, and pulmonary hypertension, required general anesthesia for surgery because of limited mouth opening. The patient was diagnosed with NM (ACTA1 mutation) and coronoid hyperplasia. Awake fiberoptic nasal intubation was performed following preparations for analgesia. General anesthesia was maintained using inhalational anesthetics and opioids without using neuromuscular blocking agents. General anesthesia remained well maintained during surgery, with no movement or spontaneous breathing of the patient and he recovered from anesthesia uneventfully without complications. This report highlights the safe performance of anesthesia induction and recovery in a case where anesthesia management is necessary for surgery in a patient of NM at a high risk of anesthesia-related complications.

Investigation of the effectiveness of top-down natural ventilation of a poultry building in a hot-summer mediterranean climate

In this study, computational fluid dynamics (CFD) was used to examine the efficiency of ventilation and airflow patterns in a multi-level layer hen house. The utilization of windcatchers as a natural ventilation system was the main area of focus. By comparing CFD simulations with experimental data using ANSYS Fluent, the results were validated. The findings showed good agreement in airflow velocity within the windcatchers and throughout the entire building between the CFD calculations and the experimental tests, resulting in uniform airflow distribution and the absence of turbulence in the area where the chickens were kept. This setup provided the layer hens with an acceptable level of comfort by maintaining a consistent and steady temperature profile. The windcatcher-based model demonstrated better temperature uniformity than mechanical window ventilation. The study also emphasized the importance of maintaining appropriate humidity levels throughout the building to ensure the comfort and productivity of layer hens. The advantages of the windcatcher-based system in terms of temperature distribution and airflow control were highlighted by comparison with an alternative ventilation model. These results underscore the importance of using natural ventilation systems, such as windcatchers, to create optimal ventilation conditions and provide layer hens with a comfortable and productive environment (resulting in a temperature reduction from 29°C to 19.85°C with a low and uniform air velocity ranging from 0 m/s to 0.7 m/s at cage level). Practical application An effective and eco-friendly approach to enhance animal health and productivity in poultry farms is to install a natural ventilation system with wind collectors. This setup creates optimal conditions for the animals by improving air quality, regulating temperature, and fine-tuning ventilation. Additionally, it promotes overall sustainability in poultry facilities by lowering energy costs and advocating for environmentally friendly management, aligning agricultural practices with stringent environmental standards.

Abstract 252: End-Tidal CO2 and Glasgow Coma Scale in Non-Intubated Traumatic Brain Injury Patients: Evaluation of Prehospital Nasal Capnography and Level of Consciousness

Background: The EMS traumatic brain injury (TBI) guidelines recommend limiting intubation (ETI) to patients with profoundly-depressed level of consciousness (LOC) and who cannot protect their airway or adequately ventilate with basic maneuvers. Thus, many major TBIs are managed without ETI in the field. Monitoring ETCO2 via nasal sensors (NC-CO2) in non-ETI patients may provide valuable information about ventilatory status and trends. However, EMS NC-CO2 remains unstudied. Objective: To evaluate the association between LOC and NC-CO2 in non-intubated TBI. Methods: Cases from 7 EMS agencies reporting continuous monitor data (Philips MRx™) in the EPIC TBI Study (NIH 1R01NS071049) were evaluated (4/13-4/18). Comparisons in patient-level mean, median, lowest and highest NC-CO2 levels were made across GCS categories using clinically meaningful thresholds: <15, <12, <9, 3. Results: Included: 177 cases [median age: 52 (range: 9-94), 66% male]. Overall, while not statistically significant, NC-CO2 tended to be lower in patients with lower GCS (Table). In addition, minimum NC-CO2 was significantly lower (p=0.01) in patients with compromised LOC (Table). O2 management (Hi-flow/Lo-flow/No O2) was documented in 176 patients (99.4%). Among the 107 patients with all GCS = 15, 44 (41%) had Hi-flow administered compared to 47/69 (68%) with any GCS <15 (p=0.0008). Conclusion: The utility of prehospital capnography in non-intubated patients is unknown. In this study, NC-CO2 tended to be lower in TBI patients with lower GCS. Whether this reflects physiological/respiratory differences with changes in LOC, or variations in methods of managing oxygenation is unclear. These intriguing new findings require future study to determine if NC-CO2 is directly reflective of LOC-related ventilatory patterns. Furthermore, studies are needed to evaluate whether NC-CO2 monitoring has clinical utility as a non-invasive adjunct to care in spontaneously-breathing, non-ETI patients.

Oscillometry of the respiratory system in Parkinson's disease: physiological changes and diagnostic use

BackgroundLung function analysis in Parkinson's disease (PD) is often difficult due to the demand for adequate forced expiratory maneuvers. Respiratory oscillometry exams require onlyquiet tidal breathing and provide a detailed analysis of respiratory mechanics. We hypothesized that oscillometry would simplify the diagnosis of respiratory abnormalitiesin PD and improve our knowledge about the pathophysiological changes in these patients.Materials and methodsThis observational study includes 20 controls and 47 individuals with PD divided into three groups (Hoehn and Yahr Scale 1–1.5; H&Y scale 2–3 and PD smokers).The diagnostic accuracy was evaluated by investigating the area under the receiver operating characteristic curve (AUC).ResultsInitial stages are related to increased peripheral resistance (Rp; p = 0.001). In more advanced stages, a restrictive pattern is added, reflected by reductions in dynamic compliance (p < 0.05) and increase in resonance frequency (Fr; p < 0.001). Smoking PD patients presented increased Rp (p < 0.001) and Fr (p < 0.01). PD does not introduce changes in the central airways. Oscillometric changes were correlated with respiratory muscle weakness (R = 0.37, p = 0.02). Rp showed adequate accuracy in the detection of early respiratory abnormalities (AUC = 0.858), while in more advanced stages, Fr showed high diagnostic accuracy (AUC = 0.948). The best parameter to identify changes in smoking patients was Rp (AUC = 0.896).ConclusionThe initial stages of PD are related to a reduction in ventilation homogeneity associated with changes in peripheral airways. More advanced stages also include a restrictive ventilatory pattern. These changes were correlated with respiratory muscle weakness and were observed in mild and moderate stages of PD in smokers and non-smokers. Oscillometry may adequately identify respiratory changes in the early stages of PD and obtain high diagnostic accuracy in more advanced stages of the disease.

P024 The Obstructive Sleep Apnoea Endotypes are Similar in Elderly Veterans with and without PTSD.

Abstract Background Approximately 60% of veterans living with post-traumatic stress disorder (PTSD) experience obstructive sleep apnoea (OSA). Why OSA is so prevalent in individuals with PTSD remains unknown, though the presence of PTSD may influence the underlying endotypes known to cause OSA. We examined whether upper airway collapsibility, muscle compensation, loop gain, and the arousal threshold differ in trauma exposed elderly male veterans with OSA with and without comorbid PTSD. Methods Using the ventilatory flow pattern from diagnostic polysomnography, the four OSA endotypes were measured in a retrospective cohort of 21 OSA patients with PTSD and 27 OSA-only patients. All participants are male Vietnam War veterans with mild-to-severe OSA (AHI M=26.8, SD=18.6; range: 6.0-105.9 events/h). Age (M=71.3, SD=3.5) and BMI (M=27.4, SD=3.4 kg/m²) were similar between groups. Results There were no statistically significant differences (p-values&amp;gt;0.3) in the OSA endotype traits between OSA-only and OSA+PTSD patients for upper airway collapsibility (78.35 [72.81-83.82] vs. 76.68 [71.53-83.56]%eupnea), muscle compensation (5.41 [1.83-7.21] vs. 4.27 [0.34-9.18]%eupnea), arousal threshold (146.95 [128.64-151.28] vs. 135.76 [126.59-147.54]%eupnea), and loop gain (M=0.60, SD=0.14 vs. M=0.56, SD=0.17). Conclusion The endotypes underlying OSA in elderly male veterans with PTSD were similar to their trauma exposed OSA-only counterparts. PTSD may exert little influence on the OSA endotypes in elderly samples beyond the effect that age and trauma exposure may have in OSA patients. What underlies the increased prevalence of OSA in PTSD remains unclear and further work examining these endotypes using larger and more diverse samples is needed before robust conclusions can be made.

A cross-sectional study of inequalities in digital air pollution information access and exposure reducing behavior uptake in the UK

Air pollution is a pervasive global environmental challenge that presents substantial and differential risk across populations. Individual-level pollution exposure is a function of varying factors, including but not limited to geographic location, proximity to point sources, ventilation, and behavioral patterns. Mounting evidence suggests that informational interventions can play a substantial role in mediating exposures for specific population subgroups and reduce downstream adverse health outcomes. The literature has yet to address whether access to air quality information is sociodemographically stratified, and whether such access correlates with increased uptake of exposure reducing behaviors at the population level. This study represents a first step in answering these questions by analysing responses from the “Clean Air Public Insight Tracker” nationally representative survey (n = 1,993) of the UK population, administered by UK charity Global Action Plan. Results from logistic regression and zero-inflated negative binomial models estimate 28% of the population have accessed air pollution information, while the odds of younger individuals (ages 18–36), men, and non-white individuals of accessing digitally available air quality information are greater that those outside these categories. Additionally, the odds of behavior uptake is greater if an individual accesses digital information sources like the internet, mobile apps or social media, has a higher education qualification or cares for someone with a health condition. These findings contribute to the growing literature surrounding which population groups engage with environmental and health-relevant information channels, and what connects engagement with air quality channels and uptake of exposure reducing behaviors. These results reinforce the need for additional research around air pollution informational alerts and exploring causal links between specific exposure reducing behaviours and improved health outcomes. It can also help inform the flow of resources and targeting of informational campaigns towards sociodemographic groups that are less likely to engage with air quality information.

Ventilatory responses to independent and combined hypoxia, hypercapnia and hypobaria in healthy pre-term-born adults.

Pre-term birth is associated with physiological sequelae that persist into adulthood. In particular, modulated ventilatory responsiveness to hypoxia and hypercapnia has been observed in this population. Whether pre-term birth per se causes these effects remains unclear. Therefore, we aimed to assess pulmonary ventilation and blood gases under various environmental conditions, comparing 17 healthy prematurely born individuals (mean ± SD; gestational age, 28 ± 2weeks; age, 21 ± 4years; peak oxygen uptake, 48.1 ± 11.2mlkg-1 min-1 ) with 16 well-matched adults born at term (gestational age, 40 ± 1weeks; age, 22 ± 2years; peak oxygen uptake, 51.2 ± 7.7mlkg-1 min-1 ). Participants were exposed to seven combinations of hypoxia/hypobaria (equivalent to ∼3375m) and/or hypercapnia (3% CO2 ), at rest for 6min. Pulmonary ventilation, pulse oxygen saturation and the arterial partial pressures of O2 and CO2 were similar in pre-term and full-term individuals under all conditions. Higher ventilation in hypoxia compared to normoxia was only observed at terrestrial altitude, despite an equivalent (normobaric) hypoxic stimulus administered at sea level (0.138 ). Assessment of oscillations in key variables revealed that combined hypoxic hypercapnia induced greater underlying fluctuations in ventilation in pre-term individuals only. In general, higher pulse oxygen saturation fluctuations were observed with hypoxia, and lower fluctuations in end-tidal CO2 with hypercapnia, despite similar ventilatory oscillations observed between conditions. These findings suggest that healthy prematurely born adults display similar overall ventilation to their term-born counterparts under various environmental stressors, but that combined ventilatory stimuli could induce an irregular underlying ventilatory pattern. Moreover, barometric pressure may be an important factor when assessing ventilatory responsiveness to moderate hypoxic stimuli. KEY POINTS: Evidence exists for unique pulmonary and respiratory function under hypoxic conditions in adult survivors of pre-term birth. Whether pre-term birth per se causes these differences requires a comparison of conventionally healthy prematurely born adults with an appropriately matched sample of term-born individuals. According to the present data, there is no difference between healthy pre-term and well-matched term-born individuals in the magnitude of pulmonary ventilation or arterial blood gases during independent and combined hypobaria, hypoxia and hypercapnia. Terrestrial altitude (hypobaria) was necessary to induce differences in ventilation between normoxia and a hypoxic stimulus equivalent to ∼3375m of altitude. Furthermore, peak power in pulse oxygen saturation was similar between hypobaric normoxia and normobaric hypoxia. The observed similarities between groups suggest that ventilatory regulation under various environmental stimuli is not impaired by pre-term birth per se. Instead, an integrated combination of neonatal treatment strategies and cardiorespiratory fitness/disease status might underlie previously observed chemosensitivity impairments.

Комплексная оценка трудноформализуемых вентиляционно-технологических процессов на угольных шахтах

Introduction. Automated process control systems, as a set of characteristics related to the ability of an object to satisfy certain needs, are one of the most important indicators of the quality of complex technical systems consisting of a large number of interacting mechanisms, apparatus and instruments. Their failure can lead to accidents and emergencies, resulting in large economic losses, destruction of industrial facilities, and sometimes human casualties. Methodology and research methods. The solution to the assigned problems is based on modern methods of artificial intelligence, automatic control theory, mathematical modeling of technological processes, and mathematical statistics; graph theory; decision theories; apparatus of mathematical logic; set theory and systems analysis. Discussion of research results. The article presents the results of studies of the patterns of ventilation and technological processes in coal mines. It has been established that studies of patterns in coal mines are becoming more relevant in connection with the formulation of the task of modernizing production and the Russian economy as a whole. It has been revealed that the methodological foundations for the synthesis of control decisions that ensure the achievement of a stable state make it possible to formulate acceptable organizational and managerial decisions and evaluate their effectiveness using metered characteristics of the proximity of vaguely described states. Conclusion. Based on the research carried out, new theoretical and applied problems were posed and solved, system connections and patterns of the ventilation technological process (VTP) were identified, models, methods and algorithms for automated ventilation technological process control systems (ACVTP) were developed, aimed at increasing the efficiency of the technical air supply system coal mines. The theoretical foundations for modeling and controlling ventilation and technological processes have been created, including concepts, models, methods and control algorithms. The research results can be useful in controlling ventilation and technological processes. Conclusions on the article. The article presents the results of studies of ETP conducted in coal mines. It has been established that, using the developed methodology, it is possible to: design high-tech equipment with specified quality indicators for intelligent control systems; choose from a variety of structural diagram options the best in terms of operational efficiency; carry out structural-parametric adjustment and change the types of mathematical models, both for an individual element and for the ETP as a whole; identify the weakest points in the HTP automated control system and adapt the methodology for controlling ventilation and technological processes, evaluate the effectiveness of using structural redundancy. Suggestions for practical applications and directions for future research. The research results can be useful when carrying out mining operations at all enterprises where air supply is necessary.

Prevalence of risk for chronic obstructive pulmonary disease amongst carpenters using lung function questionnaire

Background: An obstructive ventilatory pattern is a hallmark of chronic obstructive pulmonary disease (COPD), a slow-progressing respiratory condition that is frequently linked to cigarette use and can result in chronic respiratory failure. A case-finding tool called the lung function questionnaire (LFQ) is being created to help doctors choose which patients should undergo spirometry testing to confirm the presence of chronic obstructive pulmonary disease (COPD). Methods: Survey research study of 185 convenient sampling. Results: The results were obtained using lung function questionnaire. Statistical analysis shows that there is prevalence of risk for COPD amongst the carpenters. Conclusions: This study concludes that there is a risk of developing chronic obstructive pulmonary disease (COPD) in carpenters who are exposed to saw dust as more than half the samples have scored less than or equal to 18 which indicates the risk for COPD.

Neck orthosis design for 3D printing with user enhanced comfort features

An area of interest in orthopaedics is the development of efficient customized neck orthoses, considered that pathologies which affect the neck area are widespread. Advanced acquisition and modelling approaches combined with Additive Manufacturing (AM) can potentially provide customized orthoses with improved performance and complexity. However, in the design of these devices, besides functional and structural requirements, benefit and comfort of the patient should be a main concern, in particular, at the early stage of design during the acquisition of the body’s part, and while using the printed orthosis. In this paper, a scanning system with three sensors was developed which allows a fast, about 5 s, and accurate acquisition of the neck area with minimum discomfort for the patient. A neck orthosis with a ventilation pattern obtained by Topology Optimization (TO), lightened by about 35%, was also established. In fact, a main role for comfort is played by the ventilation pattern which contributes both to lightness and breathability. Its structural and comfort performance was evaluated in comparison with an orthosis with a ventilation pattern configured by Voronoi cells. Structural assessment was carried out by means of finite element analysis under main loading conditions. An evaluation of neck temperatures in relation to wearing 3D printed prototypes, manufactured with Hemp Bio-Plastic® filament, was finally conducted by means of a thermal imaging camera. TO orthosis prototype showed a better performance regarding thermal comfort, with a maximum increase of neck temperature less than 1 °C, which makes the proposed configuration very promising for user's comfort.

Effect of ventilation patterns on indoor thermal comfort and air-conditioning cooling and heating load using simulation

Over the past three years, regulations have been implemented to combine natural ventilation (NV) and air conditioning to mitigate the risk of disease transmission, particularly in response to the COVID-19 outbreak. As we know, simultaneous use of NV and air conditioning can make it challenging to achieve indoor thermal comfort. This paper aims to analyze the effect of NV on the air conditioning`s cooling and heating load in a classroom through simulation. A simulation model was developed using EnergyPlus software with an OpenStudio interface software. Simulation results demonstrate that continuous use of NV alongside an air conditioner increases the cooling load from 1.06 to 1.75 times during summer and a 1.54 to 9.49 times heating load increase during winter. On the other hand, intermittent NV every hour results in a cooling load increase from 1.05 to 1.46 times in summer and a heating load increase from 1.13 to 4.63 times in winter. Moreover, employing NV based on the outside air temperature can reduce the cooling load at the air conditioner with set-point 26℃—28℃ from 0.94 to 0.88 times. The outcomes of this study are expected to serve as a reference for determining strategies that effectively combine NV and air conditioning to meet various needs without causing a significant increase in energy consumption. Additionally, the results are expected to be useful for reducing AC energy consumption in extremely hot and cold weather with some strategies of NV application.

Modeling the effects of urban form on ventilation patterns and traffic-related PM2.5 pollution in a central business area of Bangkok

Traffic-related PM exposure is a significant concern in several cities. This study used ENVI-met simulation to perform the airflow and PM2.5 dispersions in Bangkok's central business district during summer. The impact of urban forms and traffic pollution on airflow and PM2.5 distributions was assessed using correlation analysis. Results showed that during summer, road traffic contributed to urban PM2.5 concentrations. Sky view factor and road area significantly affected wind speeds and PM2.5 concentrations, and these two parameters positively correlated. High wind speeds and PM2.5 concentrations were found in the urban main road, while those levels in the areas far from the road dropped by 50% due to building obstacles. Large open spaces (high sky view factor) could improve wind speeds in inner-city areas by 63%. Based on wind and PM2.5 performance classification, this study introduced new performance-based zoning, including five subzones with design recommendations. Urban planners and architects can use this information to improve pedestrian wind comfort and control air pollution dispersion from road traffic.

Study on the migration characteristics of bioaerosols and optimization of ventilation patterns in a negative pressure isolation ward considering different patient postures.

Due to the serious global harm caused by the outbreak of various viral infectious diseases, how to improve indoor air quality and contain the spread of infectious bioaerosols has become a popular research subject. Negative pressure isolation ward is a key place to prevent the spread of aerosol particles. However, there is still limited knowledge available regarding airflow patterns and bioaerosol diffusion behavior in the ward, which is not conducive to reducing the risk of cross-infection between health care workers (HCWs) and patients. In addition, ventilation layout and patient posture have important effects on aerosol distribution. In this study, the spatial and temporal characteristics as well as dispersion patterns of bioaerosols under different ventilation patterns in the ward were investigated using the computational fluid dynamics (CFD) technique. It is concluded that changes in the location of droplet release source due to different body positions of the patient have a significant effect on the bioaerosol distribution. After optimizing the layout arrangements of exhaust air, the aerosol concentration in the ward with the patient in both supine and sitting positions is significantly reduced with particle removal efficiencies exceeding 95%, that is, the ventilation performance is improved. Meanwhile, the proportion of aerosol deposition on all surfaces of the ward is decreased, especially the deposition on both the patient's body and the bed is less than 1%, implying that the risk of HCWs being infected through direct contact is reduced.

Modeling Ventilator-Induced Lung Injury and Neutrophil Infiltration to Infer Injury Interdependence.

Acute respiratory distress syndrome (ARDS) and ventilator-induced lung injury (VILI) are heterogeneous conditions. The spatiotemporal evolution of these heterogeneities is complex, and it is difficult to elucidate the mechanisms driving its progression. Through previous quantitative analyses, we explored the distributions of cellular injury and neutrophil infiltration in experimental VILI and discovered that VILI progression is characterized by both the formation of new injury in quasi-random locations and the expansion of existing injury clusters. Distributions of neutrophil infiltration do not correlate with cell injury progression and suggest a systemic response. To further examine the dynamics of VILI, we have developed a novel computational model that simulates damage (cellular injury progression and neutrophil infiltration) using a stochastic approach. Optimization of the model parameters to fit experimental data reveals that the range and strength of interdependence between existing and new damaged regions both increase as mechanical ventilation patterns become more injurious. The interdependence of cellular injury can be attributed to mechanical tethering forces, while the interdependence of neutrophils is likely due to longer-range cell signaling pathways.

Data-Driven Estimation of Time-Varying Stochastic Effects on Building Heat Consumption Related to Human Interactions

Within the field of statistical modelling and data-driven characterisation of buildings’ energy performance, the focus is typically on parameter estimation of the building envelope and the energy systems. Less focus has been put on the stochastic human effect on energy consumption. We propose a new method for estimating the thermal building properties while, in parallel, estimating time-varying effects caused by the humans’ interactions with the building. We do that by combining a smooth, non-linear formulation of the energy signature method known from the literature with a hidden state formulated as a random walk to describe the human interactions with the building. The method is demonstrated on data obtained from autumn 2019 to late spring 2021 from a 900 m2 newly built school building located south of Oslo, Norway. The demonstration case has shown that the model accuracy increases and the model bias decrease when cross-validated. The estimated hidden state has also been shown to resemble the estimated combined mechanical and natural ventilation pattern controlled by the building users and operational staff. These human interactions have increased the total heat loss expressed in kilowatts per kelvin by around 50% over the course of one year from before the COVID-19 pandemic to after its outbreak.

Exercise Oscillatory Ventilation Improves Heart Failure Prognostic Scores.

Several heart failure (HF) prognostic risk scores are available to guide the ideal time for listing candidates for a heart transplant (HTx). The detection of exercise oscillatory ventilation (EOV) during cardiopulmonary exercise testing (CPET) is associated with advanced HF and a worse prognosis, and yet it is not accounted for in these risk scores. Therefore, this study aimed to assess whether EOV further adds prognostic value to HF scores. A single-centre retrospective cohort study was undertaken of consecutive HF patients with reduced ejection fraction (HFrEF) who underwent CPET from 1996 to 2018. The Heart Failure Survival Score (HFSS), Seattle Heart Failure Model (SHFM), Meta-analysis Global Group In Chronic Heart Failure (MAGGIC), and Metabolic Exercise Cardiac Kidney Index (MECKI) were calculated. The added value of EOV on top of those scores was assessed using a Cox proportional hazard model. The added discriminative power was also assessed by receiver operating characteristic curve comparison. A total of 390 HF patients with a median age of 58 (IQR 50-65) years were investigated, of whom 78% were male and 54% had ischaemic heart disease. The median peak oxygen consumption was 15.7 mL/kg/min (IQR 12.8-20.1). Exercise oscillatory ventilation was detected in 153 (39.2%) patients. Over a median follow-up of 2 years, 61 patients died (49 due to a cardiovascular reason) and 54 had a HTx. Exercise oscillatory ventilation independently predicted the composite outcome of all-cause death and HTx. Furthermore, the presence of this ventilatory pattern significantly improved the prognostic performance of both HFSS and MAGGIC scores. Exercise oscillatory ventilation was often found in a cohort of HF patients with reduced LVEF who underwent CPET. It was found that EOV added further prognostic value to contemporary HF scores, suggesting that this easily obtained parameter should be included in future modified HF scores.

Dynamics of ventilatory pattern variability and Cardioventilatory Coupling during systemic inflammation in rats.

Introduction: Biometrics of common physiologic signals can reflect health status. We have developed analytics to measure the predictability of ventilatory pattern variability (VPV, Nonlinear Complexity Index (NLCI) that quantifies the predictability of a continuous waveform associated with inhalation and exhalation) and the cardioventilatory coupling (CVC, the tendency of the last heartbeat in expiration to occur at preferred latency before the next inspiration). We hypothesized that measures of VPV and CVC are sensitive to the development of endotoxemia, which evoke neuroinflammation. Methods: We implanted Sprague Dawley male rats with BP transducers to monitor arterial blood pressure (BP) and recorded ventilatory waveforms and BP simultaneously using whole-body plethysmography in conjunction with BP transducer receivers. After baseline (BSLN) recordings, we injected lipopolysaccharide (LPS, n = 8) or phosphate buffered saline (PBS, n =3) intraperitoneally on 3 consecutive days. We recorded for 4-6h after the injection, chose 3 epochs from each hour and analyzed VPV and CVC as well as heart rate variability (HRV). Results: First, the responses to sepsis varied across rats, but within rats the repeated measures of NLCI, CVC, as well as respiratory frequency (fR), HR, BP and HRV had a low coefficient of variation, (<0.2) at each time point. Second, HR, fR, and NLCI increased from BSLN on Days 1-3; whereas CVC decreased on Days 2 and 3. In contrast, changes in BP and the relative low-(LF) and high-frequency (HF) of HRV were not significant. The coefficient of variation decreased from BSLN to Day 3, except for CVC. Interestingly, NLCI increased before fR in LPS-treated rats. Finally, we histologically confirmed lung injury, systemic inflammation via ELISA and the presence of the proinflammatory cytokine, IL-1β, with immunohistochemistry in the ponto-medullary respiratory nuclei. Discussion: Our findings support that NLCI reflects changes in the rat's health induced by systemic injection of LPS and reflected in increases in HR and fR. CVC decreased over the course to the experiment. We conclude that NLCI reflected the increase in predictability of the ventilatory waveform and (together with our previous work) may reflect action of inflammatory cytokines on the network generating respiration.

A comparative study of dynamic lung hyperinflation and tidal volume to total lung capacity ratios during exercise in patients with chronic respiratory disease and healthy individuals

BackgroundCurrent measures of tidal volume/forced vital capacity (VT/FVC) and VT/inspiratory capacity (VT/IC) at peak exercise cannot differentiate restrictive from obstructive ventilation patterns. This study aimed to investigate the utility of VT/total lung capacity (VT/TLC) as a marker for dynamic lung hyperinflation (DH) in patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). Methods267 subjects were screened: 23 ILD, 126 COPD, and 33 healthy individuals were enrolled. Lung function tests and cardiopulmonary exercise tests with repeated IC maneuver were conducted and compared at three exercise efforts: unloaded, middle of exercise, and peak exercise. ResultsDuring exercise, ILD patients demonstrated normal end-expiratory lung volume/TLC (EELV/TLC) ratios, but elevated end-inspiratory lung volume/TLC (EILV/TLC) ratios, except for peak exercise. COPD patients exhibited elevated ratios for both EELV/TLC and EILV/TLC during exercise with a larger EELV/TLC ratio compared to ILD patients at peak exercise (p < 0.05). The VT/TLC ratio distinguished ILD, COPD, and healthy controls at peak exercise (p < 0.05). A VT/TLC ratio of ≤ 0.22 or ≥ 0.30 indicated airflow obstruction with hyperinflation or normal lung expansion, respectively (AUC: 0.74 or 0.88). Furthermore, VT/TLC outperformed VT/FVC and VT/IC in differentiating lung expansion between ILD and COPD during exercise (all p < 0.05). ConclusionExercise-induced DH was absent in ILD patients but observed in COPD patients. Excessive lung expansion occurred in all patients during exercise, except for limited expansion in ILD at peak exercise probably due to specific lung properties. VT/TLC can distinguish between restrictive, obstructive, and normal ventilatory patterns.

Changes in pulmonary function in patients with breast cancer before and after radiation therapy

Background: The respiratory system is negatively affected by radiation exposure during the comprehensive treatment of breast cancer (BC), which has an effect on the treatment effectiveness and patients’ quality of life.Objective: To evaluate changes in pulmonary ventilation and diffusion characteristics and ventilation effectiveness in patients with BC before and after radiation therapy (RT).Methods: Our prospective cohort study included 232 women with BC admitted to the Meshalkin National Medical Research Center for an adjuvant RT after surgical treatment. Before and after the RT we conducted pulmonary function tests: body plethysmography, lung diffusion capacity testing, and cardiopulmonary exercise testing with measurement of peak oxygen consumption. We used multivariate regression analysis to determine predictors of pulmonary function decline during RT (decrease in the lung diffusion capacity &gt; 5% compared with baseline).Results: Pulmonary function tests prior to RT demonstrated that 15% of the patients with BC had pulmonary ventilation disorders, and 25% of the patients had pulmonary gas exchange abnormalities (most of them were newly diagnosed). In the general group following RT, we saw a significant decrease in the lung diffusion capacity (P = .044) and an increased incidence of obstructive breathing patterns among the examined patients (P = .036). Other pulmonary ventilation parameters, its effectiveness, and reserve capacity of the respiratory system after RT did not change significantly in the study group and corresponded to the reference values. The postradiation pulmonary function was negatively affected by the reduced level of pulmonary diffusion capacity at baseline (≤ 70% of the reference value) [OR 1.15 (1.03-1.34), P = .004], abnormal breathing pattern prior to RT [OR 1.08 (1.01-1.15), P = .029], involvement of regional lymph nodes (N1-3) [OR 1.10 (1.04-1.26), P = .003].Conclusion: Early postradiation respiratory disorders in patients with BC are marked by a decrease in the lung diffusion capacity and an increased incidence of obstructive patterns of pulmonary ventilation. The factors negatively affecting changes in pulmonary ventilation and diffusion characteristics after RT were the baseline pulmonary gas exchange disorders, obstructive breathing pattern prior to RT, and radiation exposure to lymph nodes. Received 28 December 2022. Revised 26 May 2023. Accepted 30 May 2023. Funding: The study did not have sponsorship. Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: O.V. Kamenskaya, V.V. Lomivorotov Data collection and analysis: S.S. Porotnikova, E.A. Samoilova, V.G. Tihomirov Statistical analysis: I.Yu. Loginova, A.S. Klinkova Drafting the article: I.Yu. Loginova, O.V. Kamenskaya Critical revision of the article: S.E. Krasilnikov, A.M. Chernyavskiy Final approval of the version to be published: O.V. Kamenskaya, I.Yu. Loginova, A.S. Klinkova, S.S. Porotnikova, E.A. Samoilova, V.G. Tihomirov, S.E. Krasilnikov, V.V. Lomivorotov, A.M. Chernyavskiy

Obstructive Sleep Apnea Is a Distinct Physiological Endotype in Individuals with Comorbid Insomnia and Sleep Apnea (COMISA).

With up to 40% of individuals with either insomnia or obstructive sleep apnea (OSA) demonstrating clinically significant symptoms of the other disorder, the high degree of comorbidity amongst the two most common sleep disorders suggests a bi-directional relationship and/or shared underpinnings. Whilst the presence of insomnia disorder is believed to influence the underlying pathophysiology of OSA, this influence is yet to be examined directly. To investigate whether the four OSA endotypes (upper airway collapsibility, muscle compensation, loop gain, and the arousal threshold) are different in OSA patients with and without comorbid insomnia disorder. Using the ventilatory flow pattern captured from routine polysomnography, the four OSA endotypes were measured in 34 OSA patients who met diagnostic criteria for insomnia disorder (COMISA) and 34 OSA patients without insomnia (OSA-only). Patients demonstrated mild-to-severe OSA (AHI: 25.8±2.0 events/h) and were individually matched according to age (50.2±1.5 years) sex (42M:26F), and body mass index (29.3±0.6 kg/m2). Compared to OSA patients without comorbid insomnia, COMISA patients demonstrated significantly lower respiratory arousal thresholds (128.9 [118.1-137.1] vs. 147.7 [132.3-165.0] %Veupnea, U=261, 95%CI[-38.3, -13.9], d=1.1, p<.001), less collapsible upper airways (i.e., higher Vpassive: 88.2 [85.5-94.6] vs. 72.9 [64.7-79.2] %Veupnea, U=1081, 95%CI[14.0, 26.7], d=2.3, p<.001) and more stable ventilatory control (i.e., lower loop gain: 0.51 [0.44-0.56] vs. 0.58 [0.49-0.70], U=402, 95%CI[-0.2, -0.01], d=.05, p=.03). Muscle compensation was similar between groups. Moderated linear regression revealed the arousal threshold moderated the relationship between collapsibility and OSA severity in COMISA, but not OSA-only patients. A low arousal threshold is an overrepresented endotypic trait in individuals with COMISA and may exhibit a greater relative contribution to OSA pathogenesis in these patients. Contrastingly, the prevalence of a highly collapsible upper airway in COMISA was low, suggesting that anatomical predisposition may contribute less to OSA development in COMISA. Based on our findings we theorise that conditioned hyperarousal perpetuating insomnia may translate to a reduced arousal threshold to respiratory events, thereby increasing the risk or severity of OSA. Therapies which target increased nocturnal hyperarousal (e.g., through CBT-I) may be effective in individuals with COMISA.