The inspiratory activity of respiratory center and respiratory muscles strength after COVID-19.

The respiratory pump that provides pulmonary ventilation includes the respiratory center, peripheral nervous system, chest and respiratory muscles. The aim of this study was to evaluate the activity of the respiratory center and the respiratory muscles strength after COVID-19 (COronaVIrus Disease 2019). Methods. The observational retrospective cross-sectional study included 74 post-COVID-19 patients (56 (76%) men, median age - 48 years). Spirometry, body plethysmography, measurement of lung diffusing capacity (DLCO), maximal inspiratory and expiratory pressures (MIP and MEP), and airway occlusion pressure after 0.1 sec (P0.1) were performed. In addition, dyspnea was assessed in 31 patients using the mMRC scale and muscle strength was assessed in 27 of those patients using MRC Weakness scale. Results. The median time from the COVID-19 onset to pulmonary function tests (PFTs) was 120 days. The total sample was divided into 2 subgroups: 1 - P0.1 <= 0.15 kPa (norm), 2 - > 0.15 kPa. The lung volumes, airway resistance, MIP, and MEP were within normal values in most patients, whereas DLCO was reduced in 59% of cases in both the total sample and the subgroups. Mild dyspnea and a slight decrease in muscle strength were also detected. Statistically significant differences between the subgroups were found in the lung volumes (lower) and airway resistance (higher) in subgroup 2. Correlation analysis revealed moderate negative correlations between P0.1 and ventilation parameters. Conclusion. Measurement of P0.1 is a simple and non-invasive method for assessing pulmonary function. In our study, an increase in P0.1 was detected in 45% of post-COVID-19 cases, possibly due to impaired pulmonary mechanics despite the preserved pulmonary ventilation as well as normal MIP and MEP values.Copyright © Savushkina O.I. et al., 2023.

Basic monitoring mechanical ventilation in patients with COVID-19, rethinking what we know

During the COVID-19 pandemic, 15% of hospitalized patients have required mechanical ventilation and because the reorganization of health services at COVID-19 centers, a large percentage of health personnel have assumed new functions in the care of the critical patient;situation that makes evident the need to analyze the different techniques, maneuvers and calculations for an adequate assessment and decision-making. A bibliographic review of the topic was made searching for references in Elsevier, Pubmed, SciELO, Medline, Nature, New England Journal of Medicine using the words mechanical ventilation, COVID-19, acute respiratory distress syndrome, lung protection strategy, airway pressures, pulmonary mechanics, published from 2010 to 201 9 in English and Spanish. During the COVID-1 9 pandemic, mechanical ventilation has been a fundamental procedure in the management of severe acute respiratory distress syndrome, becoming indispensable that health personnel who work in COVID-1 9 areas know and understand the different techniques, maneuvers and calculations used to determine the state of the respiratory system in the ventilated patient and apply treatments accordingly.Copyright © 2022 Comunicaciones Cientificas Mexicanas S.A. de C.V.. All rights reserved.

The inspiratory activity of respiratory center and respiratory muscles strength after COVID-19.

The respiratory pump that provides pulmonary ventilation includes the respiratory center, peripheral nervous system, chest and respiratory muscles. The aim of this study was to evaluate the activity of the respiratory center and the respiratory muscles strength after COVID-19 (COronaVIrus Disease 2019). Methods. The observational retrospective cross-sectional study included 74 post-COVID-19 patients (56 (76%) men, median age - 48 years). Spirometry, body plethysmography, measurement of lung diffusing capacity (DLCO), maximal inspiratory and expiratory pressures (MIP and MEP), and airway occlusion pressure after 0.1 sec (P0.1) were performed. In addition, dyspnea was assessed in 31 patients using the mMRC scale and muscle strength was assessed in 27 of those patients using MRC Weakness scale. Results. The median time from the COVID-19 onset to pulmonary function tests (PFTs) was 120 days. The total sample was divided into 2 subgroups: 1 - P0.1 <= 0.15 kPa (norm), 2 - > 0.15 kPa. The lung volumes, airway resistance, MIP, and MEP were within normal values in most patients, whereas DLCO was reduced in 59% of cases in both the total sample and the subgroups. Mild dyspnea and a slight decrease in muscle strength were also detected. Statistically significant differences between the subgroups were found in the lung volumes (lower) and airway resistance (higher) in subgroup 2. Correlation analysis revealed moderate negative correlations between P0.1 and ventilation parameters. Conclusion. Measurement of P0.1 is a simple and non-invasive method for assessing pulmonary function. In our study, an increase in P0.1 was detected in 45% of post-COVID-19 cases, possibly due to impaired pulmonary mechanics despite the preserved pulmonary ventilation as well as normal MIP and MEP values.Copyright © Savushkina O.I. et al., 2023.

Pulmonary Rehabilitation in Post-COVID-19 Patients Improves Lung Function and Mechanics and Skeletal Muscle, and Immune Response

COVID-19 let sequelae beyond the respiratory system, including in skeletal muscle and in immune response. We evaluated the effects of 12 weeks of pulmonary rehabilitation (PR), 3x/week, constituted by aerobic and resistance training on 28 moderate and severe post-COVID-19 patients. The results demonstrated that PR improved lung function, FVC (p<0.02), FEV1 (p<0.02), FEV1/FVC (p<0.01), MEF25% (p<0.006), MEF50% (p<0.03), and MEF75% (p<0.02). PR improved lung mechanics, respiratory impedance (Z5hz, p<0.03);respiratory reactance (X5Hz, p<0.01), resistance of the whole respiratory systems (R5Hz, p<0.03), central airway resistance (RCentral, p<0.03), and peripheral airway resistance (RPeripheral, p<0.02). PR improved peripheral muscle strength, increasing right (p<0.02) and left (p<0.01) hand grip strength and respiratory muscle strength, increasing maximum inspiratory (p<0.02) and expiratory (p<0.03) pressure. Of note, PR reduced pulmonary inflammation (breath condensate), reducing the levels of pro-inflammatory cytokine IL-1beta (p<0.0001) and IL-6 (p<0.0001), while increased the levels of anti-inflammatory cytokine IL-1RA (p<0.0004) and IL-10 (p<0.003), beyond to increase the levels of IFN-gamma (p<0.0002) and IFN-beta (p<0.008). PR reduced the serum levels of pro-inflammatory IL-1beta (p<0.006) and IL-6 (p<0.01), while increased the levels of anti-inflammatory cytokine IL-1RA (p<0.0001) and IL-10 (p<0.0001), increasing the levels of IFN-gamma (p<0.02) and IFN-beta (p<0.001). PR reveals to be beneficial for post-COVID-19 patients, mitigating the sequelae observed in the respiratory system, skeletal muscle and in the immune response.

Forced oscillation technique used for monitoring of covid19 pneumonia

Background: Forcrd oscillation technique (FOT) is a non-invasive method for investigation of lung mechanics without active participation of the patient. The objectives of the study were to find out whether FOT method could be used for monitoring of covid-19 pneumonia (CVP) course and how FOT indices correlate with other, commonly used indicators of disease severity. Method(s): During the hospital stay and 3 months after the discharge from hospital repeated measurements of lung mechanics were performed with portable device Tremoflo-100 (Thorasys, Canada). Result(s): Most relevant differences between disease stages reflected the lung reactance indices - Fres and AX. Indices characterizing the airflow resistance didn't reach the significance level. Correlation analysis also was performed between FOT indices and CT score, body mass index (BMI), patients age, blood CRP and ferritin levels, duration of hospital stay and patients oxygen demand (FiO2). Significant correlations View inline were found only between the last two. The highest significance showed Fres % pred and AX % pred. Fres correlated to FiO2 with R=0,498 and p-0,0000004, but AX% with r=0,502 Conclusion(s): The study has shown that FOT method reflects the changes in lung mechanics occurring during acute phase and recovery period from covid-19 pneumonia. FOT indices correlate with patients oxygen demand and hospital stay-time.

Administration of Exogenous Surfactant and Cytosolic Phospholipase A2alpha Inhibitors may Help COVID-19 Infected Patients with Chronic Diseases

Background: Coronavirus-19 (COVID-19) pandemic is a worldwide public health problem causing 347,070 deaths from December 25, 2019, till May 25, 2020. Phospholipids are structural components of mammalian cytoskeleton and cell membranes. Phosphatidylglycerol is an anionic lipid found in mammalian membranes in low amounts (1-2%) of the total phospholipids. Also, phosphatidylglycerol suppresses viral attachment to the plasma membrane and subsequent replication in lung cells. Phosphatidylglycerol depletion caused by over expression of cytosolic phos-pholipase A2alpha induces lipid accumulation in lung alveoli and promotes acute respiratory distress syndrome (ARDS). An exogenous-surfactant replacement has been successfully achieved in ARDS and improved oxygenation and lung mechanics. Inhibition of cytosolic phospholipase A2alpha impairs an early step of COVID-19 replication. Aim(s): The present study was carried out to explain the correlation between the administration of exogenous artificial surfactant as well as cytosolic phospholipase A2alpha inhibitors to improve oxygenation and lung mechanics and inhibit COVID-19 replication. Method(s): Database research was carried out on Medline, Embase, Cochrane Library, country-spe-cific journals, and following-up WHO reports published between December 25, 2019-May 25, 2020. Result(s): Till 25 May 2020, coronavirus cases were 5,307,298, with 347,070 deathsand 2,314,849 recovered cases. According to the WHO reports, most COVID-19 deaths seen are in people who suffered from other chronic diseases characterized by phospholipidosis and phosphatidylglycerol deficiency, including hypertension, liver, heart, and lung diseases and diabetes. Phospholipases A2 (PLA2) catalyze the cleavage of fatty acids esterified at the sn-2 position of glycerophospholipids leading to enhanced inflammation and lung damage. Also, cytosolic phospholipase A2alpha inhibitors may reduce the accumulation of viral proteins and RNA. In addition, administration of exogenous phospholipid surfactant may help COVID-19 infected patients with ARDS to remove inflammatory mediators. Conclusion(s): The present study showed a relation between phosphatidylglycerol deficiency in COVID-19 infected patients with ARDS and/or chronic diseases and their mortality. These findings also showed an important approach for the prevention and treatment of COVID-19 infections by using cytosolic phospholipase A2alpha inhibitors and exogenous administration of a specific phos-pholipid surfactant.Copyright © 2021 Bentham Science Publishers.

Regional peak flow as a novel approach to assess regional pulmonary mechanics by electrical impedance tomography: an observational validation study.

Background: Spontaneous breathing efforts during mechanical ventilation are a widely accepted weaning approach for acute respiratory distress syndrome (ARDS) patients. These efforts can be too vigorous, possibly inflicting lung and diaphragm damage. Higher positive end expiratory pressure (PEEP) levels can be used to lower the magnitude of vigorous breathing efforts. Nevertheless, PEEP titrating tools are lacking in spontaneous mechanical ventilation (SMV). Therefore, the aim is to develop an electrical impedance tomography (EIT) algorithm for quantifying regional lung mechanics independent from a stable plateau pressure phase based on regional peak flow (RPF) by EIT, which is hypothetically applicable in SMV and to validate this algorithm in patients on controlled mechanical ventilation (CMV). Methods: The RPF algorithm quantifies a cumulative overdistension (ODRPF) and collapse (CLRPF) rate and is validated in a prospective cohort of mechanically ventilated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients on CMV. ODRPF and CLRPF are compared with compliance-based cumulative overdistension (ODP500) and collapse (CLP500) rates from the Pulmovista 500 EIT device at multiple PEEP levels (PEEP 10 cmH2O to PEEP 24 cmH2O) in EIT measurements from CMV patients by linear mixed models, Bland-Altman analysis and intraclass correlation coefficient (ICC). Results: Seventy-eight patients were included. Linear mixed models revealed an association between ODRPF and ODP500 of 1.02 (0.98-1.07, P<0.001) and between CLRPF and CLP500 of 0.93 (0.80-1.05, P<0.001). ICC values ranged from 0.78 to 0.86 (P<0.001) for ODRPF and ODP500 and from 0.70 to 0.85 (P<0.001) for CLRPF and CLP500 (PEEP 10 to PEEP 24). The mean bias between ODRPF and ODP500 in these PEEP levels ranged from 0.80% to 4.19% and from -1.31% to 0.13% between CLRPF and CLP500. Conclusions: A RPF approach for quantifying regional lung mechanics showed a moderate to good agreement in coronavirus disease 2019 (COVID-19) related ARDS patients on CMV compared to the compliance-based approach. This, in addition to being independent of a plateau pressure phase, indicates that the RPF approach is a valid method to explore for quantifying regional lung mechanics in SMV.

MANAGEMENT OF PNEUMOTHORAX AND PNEUMOMEDIASTINUM IN COVID-19 PATIENTS WITH ARDS

SESSION TITLE: What Lessons Will We Take From the Pandemic? SESSION TYPE: Rapid Fire Original Inv PRESENTED ON: 10/19/2022 11:15 am - 12:15 pm PURPOSE: Since the emergence of COVID-19, many serious complications have arisen especially in the setting of Acute Respiratory Distress Syndrome (ARDS) in the intensive care unit. Historically, ARDS and mechanical ventilation is associated with higher rates of pneumothorax. It has been well described that ARDS is the result of inflammatory lung injury, with increased activation of circulating neutrophils, complement and proinflammatory mediators leading to loss of surfactant, alveolar atelectasis, and fibrin deposition. This leads to a less compliant lung parenchyma, and higher airway pressures, which has been attributed as a risk factor for pneumothorax. The management of pneumothorax varies depending on the etiology of the pneumothorax. In the case of iatrogenic pneumothorax (i.e. mechanical ventilation), tube thoracostomy is generally recommended, however the size of the chest tube inserted remains less clear. METHODS: This is a multi-center retrospective cohort study of 88 hospitalized patients with a diagnosis of COVID-19 and pneumothorax or pneumomediastinum between the dates of 3/11/2020 to 01/26/2021. Patient demographics, comorbidities, laboratory and hemodynamic data were collected as well as ventilator settings, lung mechanics, and clinical patient outcome data including type of intervention and rate of resolution of pneumothorax. Final statistical analysis is pending. RESULTS: Our preliminary results reveal that there was a higher rate of resolution of pneumothorax with a large bore chest tube (LBCT) compared to a small bore chest tube (SBCT). There was no significant difference in lung compliance or tidal volume in cc/kg between the patients with a resolving pneumothorax compared to the patients with a nonresolving pneumothorax. Overall mortality rate among all patients was 70.4%. CONCLUSIONS: Patients with a large bore chest tube placed are more likely to have resolution of pneumothorax compared to small bore chest tube or serial X-ray. Lung compliance and tidal volume were not significantly different between patients that had a resolving pneumothorax compared to nonresolving pneumothorax. It is important to manage a pneumothorax early on to reduce associated morbidity. CLINICAL IMPLICATIONS: The development of pneumothorax in COVID patients with ARDS has significant associated morbidity and mortality. Utilization of a large bore chest tube may result in improved rates of resolution of pneumothorax. DISCLOSURES: No relevant relationships by Nathalie Antonios No relevant relationships by Colby Baker No relevant relationships by Jessica Johnson No relevant relationships by Karen Sayad

Association of Ventilator Settings and Lung Mechanics During VV-ECMO Treatment with Short Term Pulmonary Function and Lung Imaging Outcomes in COVID-19 Survivors, a Retrospective Cohort Study

Background: Lung protective ventilation plays a crucial role in the management of patients with COVID-19 ARDS treated with VV-ECMO. We hypothesized that increasingly protective ventilator settings may be associated with improved lung recovery by reducing ventilator induced lung injury. Method(s): We performed a retrospective cohort study of all patients treated with VV-ECMO for COVID-19 at NYU Langone Medical Center from March 2020 to June 2020. Ventilator data including tidal volume (cc/ kg predicted body weight), peak airway pressure, PEEP, Driving pressure (DP), Respiratory Rate, FiO2, lung compliance, and mechanical power were obtained. Pulmonary function test (PFT) results, 6-minute walk test results, and quantitative chest CT scores were obtained from the first outpatient follow up assessment. Bivariate and multivariate analysis correlating ventilator data with lung function and CT outcomes was performed. Result(s): 30 COVID-19 patients were treated with VV-ECMO during the study period, of which 26 survived without lung transplantation and 12 completed follow up assessment at a median of 106 days post ECMO decannulation. Multivariate LASSO regression model results;FEV1: DP (beta=-5.535), Respiratory Rate (beta=-0.370), compliance (beta=0.467), FVC: DP (beta=-4.08), compliance (beta=0.875), preECMO tidal volume (beta=-0.0008), TLC: DP (beta=-4.518), ECMO sweep (beta=-0.598), DLCO: peak airway presure (beta=-1.836), 6MWT distance: compliance (beta=1.436), Chest CT total opacity score: DP(beta=-0.60), preECMO tidal volume(beta=-0.0033). Conclusion(s): Driving pressure and peak airway pressure during VV-ECMO had the strongest associations with improved short-term follow up lung volumes, DLCO, and chest CT outcomes in VV-ECMO treated COVID-19 survivors.

Assessment of hemodynamics, blood gases, and lung histopathology of healthy Pig model on two different mechanical ventilators.

In response to COVID-19 global crisis and arising from social responsibility, efforts have been exerted to promptly research, develop and manufacture ICU ventilators locally to meet the spike in demand. This study aimed at : Evaluating the safety and performance of a newly developed mechanical ventilator; EZVent compared to a commercial ventilator regarding hemodynamics, arterial blood gases (ABG), lung inflammatory markers, and histopathology in a healthy pig model using three different ventilation modes. Methods: Eight adult male pigs were anesthetized and randomly assigned into two equal groups: Commercial vent and EZVent group, the animals of which were ventilated using a standard commercial ventilator and EZVent, respectively. On every animal, three ventilation modes were tested, each mode for 30 min: CMV-VC, CMV-PC, and CPAP-PS modes. Vital signs, ECG, Lung Mechanics (LM), and ABG were measured before ventilation and after 30 min of ventilation of each mode. After animals' euthanasia, histological examinations of lung samples including morphometric assessment of alveolar edema, alveolar wall thickening, and the mean number of inflammatory cellular infiltrate/cm2 of lung tissue were analyzed. TNF-α and Il-6 expression and localization in lung tissue were assessed by western blot and immunohistochemistry. Results: The vital signs, LM, ABG, morphometric analysis, and histopathological score during the different ventilation modes showed non-significant differences between the study groups. TNF-α and IL-6 were minimally expressed in the bronchiolar epithelium and the alveolar septa. Their increased expression level was insignificant. Conclusion: EZVent is equivalent to the commercial ventilator regarding its safety and efficacy.

Pulmonary Rehabilitation in Post-Covid-19 Patients Improves Lung Function and Mechanics and Skeletal Muscle, and Immune Response

The COVID-19 let sequelae not only in the respiratory system but also in several other systems, for instance in the skeletal muscle and in the immune response. This study evaluated the effects of 12 weeks of pulmonary rehabilitation (PR), constituted by aerobic (30 minutes of treadmill training at 75% of maximum heart rate) and resistance training (30 minutes at 75% of 1 maximum repetition) on 33 moderate and severe post-COVID-19 patients. The results demonstrated that PR effectively improved lung function, denoted by improved FVC (p<0.02), FEV1 (p<0.02), FEV1/FVC (p<0.01), MEF25% (p<0.006), MEF50% (p<0.03), and MEF75% (p<0.02). PR also improved lung mechanics, denoted by improved respiratory impedance (Z5hz, p<0.03);respiratory reactance (X5Hz, p<0.01), resistance of the whole respiratory systems (R5Hz, p<0.03), central airway resistance (RCentral, p<0.03), and peripheral airway resistance (RPeripheral, p<0.02). In addition, PR improved peripheral muscle strength denoted by increased right (p<0.02) and left (p<0.01) hand grip strength and the respiratory muscle strength, denoted by increased maximum inspiratory pressure (p<0.02) and maximum expiratory pressure (p<0.03). Of note, PR reduced pulmonary (breath condensate) inflammation, as observed by reduced levels of the pro-inflammatory cytokine IL-1beta (p<0.0001), IL-6 (p<0.0001), while increased the levels of the anti-inflammatory cytokine IL- 1RA (p<0.0004) and IL-10 (p<0.003), beyond to increase the levels of the cytokines with anti-viral properties, IFN-gamma (p<0.0002) and IFN-beta (p<0.008). Such response was also observed in the serum, as denoted by reduced levels of pro-inflammatory IL-1beta (p<0.006), and IL-6 (p<0.01), while increased the levels of anti-inflammatory cytokine IL-1RA (p<0.0001), and IL-10 (p<0.0001). PR also increased the serum levels of the cytokines with anti-viral properties, IFN-gamma (p<0.02) and IFN-beta (p<0.001). In conclusion, PR reveals to be beneficial for post-COVID-19 patients, mitigating the sequelae observed in the respiratory system, skeletal muscle and in the immune response.

Human Versus Porcine Localized Strain Mechanics

Rationale: COVID-19 has inspired numerous studies on ventilated induced lung injury (VILI). To investigate the strains stimulating lung damage, animal lungs are often used as surrogate models for scarce human specimens. Such studies are restricted to bulk pressure and volume investigations instead of examining regional, real-time, and evolutionary pulmonary behavior offered by digital image correlation (DIC) techniques. Here we subject porcine lungs and a human lung case study to shared global loads and compare local strain distributions as yielded by DIC to assess the applicability of animal models to represent human pulmonary mechanics. Methods: One anonymized human cadaveric lung (854g) and four comparable sized Yorkshire Farm pig lungs (784-1218g) were tested ex vivo within 36hrs postmortem (no IACUC or IRB approval required). Specimens were ventilated at 15 breaths per minute to 675, 900 and 1350ml (6, 8, and 12mL/kg) using a recently established custom-designed electromechanical breathing apparatus interfaced with high resolution and high speed DIC cameras. Lungs were preloaded to 5cmH20 and preconditioned three times for reproducibility. The resulting local deformations associated with global ventilation loads were analyzed throughout the inflation cycle. Results: Similar peak inflation pressures were observed between human and porcine specimens (21-35 and 21±2 - 26±2cmH20 respectively) for the shared applied volumes. Despite comparable global mechanics, the topological strain distributions of human lungs were relatively reduced: when the applied global volume was doubled from 675 to 1350ml, the local averaged strain across the specimen surface increased from 19 to 28%, while porcine strains showed a greater increase from 21±4 to 42±4%. Also from 675 to 1350ml, the human lung surface strains were prominently homogenous with a range of 43 to 58%, compared to the observed heterogeneous porcine strain contours, quantified with a range of 92±15 to 124±24%. The maximum strain values of the human lung were also smaller than porcine specimens (58 versus 106±17%). Conclusion: Collateral ventilation and respective monopodial versus bipodial bronchial networks may explain the discrepancies noted between porcine and human lung strains. While a single human lung specimen is statistically inconclusive, pairing new DIC applications with conventional global metrics offers the ability to characterize the localized strain distribution of the breathing lung and evaluate the anisotropic and heterogenous deformation profiles correlated with VILI, previously uncharacterized to date. These results have implications for understanding the role of amplified strains in translational animal to human lung studies.

Utilizing Machine Learning and Esophageal Pressure to Detect Ventilator Dyssynchrony and Delineate the Potential for Ventilator Induced Lung Injury

Rationale: It is recognized that ventilator dyssynchrony (VD) may propagate ventilator induced lung injury (VILI). Yet some VD cannot be detected without advanced monitoring like measuring esophageal pressure (Pes) and it is unknown which types of VD propagate VILI. We describe the automated detection of VD using machine learning (ML) in patients with esophageal manometry to quantify the frequency and association between VD, tidal volume (VT) and transpulmonary driving pressure (ΔPdyn.tp). Methods: We enrolled 42 patients with ARDS or ARDS risk factors, including COVID-19. XGBoost, a ML algorithm, was trained to identify 7 types of breaths using a one-vs-all strategy, from a training set of 3500 random breaths. We compared the models' sensitivity and specificity with and without features derived from Pes. Finally, the association between each VD type and VT or ΔPdyn.tp was calculated using separate linear mixed-effect models. Temporally related breaths were nested by patient and modeled as random effects, accounting for repeat measures and changing pulmonary mechanics in each patient. Breaths without an adequate Pes signal were excluded from analysis Results: Patients were 37.5% female, 52±15 years old, had an initial P:F ratio of 140±64, and 24.2% of the 480, 976 breaths were dyssynchronous. Normal passive (Nlp), normal spontaneous (Nls), late reverse triggered (RTl), reverse triggered double triggered (DTr), mild flow limited (FLm), severe flow limited (FLs), and early ventilator terminated (EVT) account for 47.0%, 28.7%, 4.8%, 3.7%, 8.9%, 4.2%, and 2.5% of all breaths, respectively. ML training, VT and ΔPdyn.tp results are show in the table (∗p<0.001). Conclusion: ML algorithms can be trained using Pes to identify types of VD that traditionally need Pes measurements, although without Pes sensitivity may decrease. VD is frequent and DTr is associated with an increase in VT, while FLm and FLs are associated with an increased in ΔPdyn.tp. These data suggest that double triggered breaths and flow limited breaths have the potential to propagate VILI, while other types of VD may not be as deleterious. (Table Presented).

Pulmonary mechanics measured by forced oscillation technique (FOT) in post-acute COVID-19 period over 1 year- A prospective observational study

Introduction: Lung functions impairment in covid-19 pneumoniasurvivors cause continued symptoms.Forced oscillation technique (FOT) and impulse oscillometry are valuable in serial monitoring and management of postcovid respiratory symptoms. We aimed to study changes in pulmonary mechanics over 1 year period in covid-19 survivors. Methods: Covid-19 survivors of mixed severity of 18-80 age group underwent serial measurements of FOT using Antlia Caltech © device: on the first follow-up post-discharge, second at 4 weeks after the first and third one-year post-diagnosis of Covid-19. Demographic details, pulse oximetry at rest and modified medical research council scale (mMRC) for dyspnea were recorded at each visit. Pre and post-bronchodilator resistance and reactance were analysed. Results: Out of 94 patientsenrolled,17 completed 1-year follow-up post-covid. 3 patients had moderate, 1 severe and 13 mild covid-19 disease.Age group of participant was 45-75 years (Mean= 58.1±2.2) consisting of 13 males and 4 females. 4 had diabetes and an equal number had hypertension. Rest were without any comorbidity. Small airway resistance R5-R20 was0.87±0.57, [0.25-2.03] (Mean±SD, Range. (n=17), p=0.047), 0.79±0.52, [0.01- 1.93] and 0.66±0.49, [-0.05 - 1.59] similarly reactance-X5 was -0.18±0.12, [-0.43-(-0.04)], -0.16±0.1, [-0.36 - 0.001] and -0.16±0.13, [-0.47-(-0.03)] at first visit, 4 weeks and after 1 year respectively. Results of post-bronchodilator change in small airways are depicted in Figure-1. Conclusion: We found statistically significant change towards improvement in small airway resistance R5-R20. Reactance at 5Hz-X5during monitoring period showed decremental change over a year. Some post-bronchodilator reversibility persisted at the end of 1 year.

Towards a multi-scale computer modeling workflow for simulation of pulmonary ventilation in advanced COVID-19.

Physics-based multi-scale in silico models offer an excellent opportunity to study the effects of heterogeneous tissue damage on airflow and pressure distributions in COVID-19-afflicted lungs. The main objective of this study is to develop a computational modeling workflow, coupling airflow and tissue mechanics as the first step towards a virtual hypothesis-testing platform for studying injury mechanics of COVID-19-afflicted lungs. We developed a CT-based modeling approach to simulate the regional changes in lung dynamics associated with heterogeneous subject-specific COVID-19-induced damage patterns in the parenchyma. Furthermore, we investigated the effect of various levels of inflammation in a meso-scale acinar mechanics model on global lung dynamics. Our simulation results showed that as the severity of damage in the patient's right lower, left lower, and to some extent in the right upper lobe increased, ventilation was redistributed to the least injured right middle and left upper lobes. Furthermore, our multi-scale model reasonably simulated a decrease in overall tidal volume as the level of tissue injury and surfactant loss in the meso-scale acinar mechanics model was increased. This study presents a major step towards multi-scale computational modeling workflows capable of simulating the effect of subject-specific heterogenous COVID-19-induced lung damage on ventilation dynamics.

Clinical outcome of bronchoalveolar lavaged COVID ARDS patients.

Introduction: One of the biggest pandemics of the human race, Coronavirus disease, has reported mortality rates as high as 80% for critically ill patients. It has killed more than 3.9 million people worldwide with no strongly proven management options to decrease its mortality. One of the options gaining interest is fiberoptic bronchoscopy and bronchoalveolar lavage. Our study was conducted to assess the clinical outcome of intubated Coronavirus disease patients that had a fiberoptic bronchoscopy and bronchoalveolar lavage done. Methods and materials: A consecutive prospective case series of intubated patients with critical Coronavirus disease pneumonia were conducted at Bethzatha general hospital from April 20, 2021, to July 30, 2021 GC. Results: Five patients with a median age of 55 years were included in the study. The median APACHE II, SAPS II, and SOFA scores on admission were 13, 37, and 4 respectively. The difference in the mean values of; positive end-expiratory pressure, static compliance, plateau pressure, fractional inspired oxygen, and arterial oxygen tension to fractional inspired oxygen ratio between the time of intubation and the last fiberoptic bronchoscopy and bronchoalveolar lavage were 4.4 cmH2O, 11 ml/cmH2O, 6.2 cmH2O, 45%, and 76 mmHg. All patients were liberated from mechanical ventilation. Conclusion: - There was a numerically and clinically significant improvement in lung mechanics and oxygenation leading to a 100% ventilator liberation rate. Fiberoptic bronchoscopy and bronchoalveolar lavage in Coronavirus disease patients can improve lung mechanics, oxygenation, and rates of extubation.