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AIM: Physical activity attenuates hypertension in older adults, but its impact on pulmonary function and mechanics in hypertensive older adults is unknown. The study seeks to understand whether a physically active lifestyle can improve respiratory capacity, the mechanical efficiency of the lungs, and, consequently, the quality of life of these individuals, comparing data between groups of active and sedentary hypertensive older adults. METHODS: This is a cross-sectional study. We evaluated 731 older adults, stratified into two initial groups: hypertensive older adults (HE; n = 445) and non-hypertensive older adults (NHE; n = 286). For a secondary analysis, we used the International Physical Activity Questionnaire to sub-stratify HE and NHE into four groups: physically inactive hypertensive (PIH; n = 182), active hypertensive (AH; n = 110), physically inactive non-hypertensive (PINH; n = 104), and active non-hypertensive (ANH; n = 65). Lung function was measured by spirometry, and lung mechanics were assessed by impulse oscillometry. RESULTS: Hypertensive older adults presented reduced lung function compared to non-hypertensive older adults, and physical inactivity accentuated this decline. Regarding pulmonary mechanics, hypertensive older adults had higher resistance of the entire respiratory system (R5 Hz), the central airways (R20 Hz), and peripheral airways (R5-20 Hz), which may trigger bronchoconstriction. CONCLUSIONS: Hypertension is associated with impaired lung function and mechanics in older adults, and a physically active lifestyle attenuates these dysfunctions.

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BACKGROUND: Adjusting trunk inclination from a semi-recumbent position to a supine-flat position or vice versa in patients with respiratory failure significantly affects numerous aspects of respiratory physiology including respiratory mechanics, oxygenation, end-expiratory lung volume, and ventilatory efficiency. Despite these observed effects, the current clinical evidence regarding this positioning manoeuvre is limited. This study undertakes a scoping review of patients with respiratory failure undergoing mechanical ventilation to assess the effect of trunk inclination on physiological lung parameters. METHODS: The PubMed, Cochrane, and Scopus databases were systematically searched from 2003 to 2023. INTERVENTIONS: Changes in trunk inclination. MEASUREMENTS: Four domains were evaluated in this study: 1) respiratory mechanics, 2) ventilation distribution, 3) oxygenation, and 4) ventilatory efficiency. RESULTS: After searching the three databases and removing duplicates, 220 studies were screened. Of these, 37 were assessed in detail, and 13 were included in the final analysis, comprising 274 patients. All selected studies were experimental, and assessed respiratory mechanics, ventilation distribution, oxygenation, and ventilatory efficiency, primarily within 60 min post postural change. CONCLUSION: In patients with acute respiratory failure, transitioning from a supine to a semi-recumbent position leads to decreased respiratory system compliance and increased airway driving pressure. Additionally, C-ARDS patients experienced an improvement in ventilatory efficiency, which resulted in lower PaCO2 levels. Improvements in oxygenation were observed in a few patients and only in those who exhibited an increase in EELV upon moving to a semi-recumbent position. Therefore, the trunk inclination angle must be accurately reported in patients with respiratory failure under mechanical ventilation.

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OBJECTIVE: To investigate the effect of bronchodilator on the respiratory mechanics and pulmonary function of children and adolescents with cystic fibrosis. METHODS: Cross-sectional study on clinically stable children and adolescents with cystic fibrosis aged from six to 15 years. Participants underwent impulse oscillometry and spirometry evaluations before and 15 minutes after bronchodilator inhalation. The Kolmogorov-Smirnov test was applied to verify the sample distribution, and the Student's t-test and Wilcoxon test were used to compare the data before and after bronchodilator inhalation. RESULTS: The study included 54 individuals with a mean age of 9.7±2.8 years. The analysis showed a statistically significant improvement in impulse oscillometry and spirometry parameters after bronchodilator inhalation. However, according to the American Thoracic Society (ATS) and European Respiratory Society (ERS) recommendations (2020 and 2021), this improvement was not sufficient to classify it as a bronchodilator response. CONCLUSIONS: The use of bronchodilator medication improved respiratory mechanics and pulmonary function parameters of children and adolescents with cystic fibrosis; however, most patients did not show bronchodilator response according to ATS/ERS recommendations.

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INTRODUÇÃO: A interação coração-pulmão influenciada pela Ventilação Mecânica (VM), que impacta diretamente no retorno venoso e débito cardíaco através, e não somente, de ajustes da Pressão Positiva Expiratória Final (PEEP) e Pressão média nas vias aéreas (Pmed). Além disso, as pausas inspiratórias para avaliação da mecânica pulmonar interrompem o movimento torácico, pode impactar mais nesta interação. OBJETIVO: Comparar as alterações hemodinâmicas durante os tempos de 0,5 e 2,0 segundos de pausa inspiratória durante as mensurações de mecânica respiratória. MÉTODOS: Trata-se de um estudo transversal, realizado nas unidades de terapia intensivas de um hospital público de Salvador/BA. Foram incluídos pacientes em uso de VM e acima de 18 anos. Os excluídos foram aqueles que apresentassem instabilidade hemodinâmica e hipoxemia sustentada durante a avaliação. Para caracterização amostral, os pacientes foram divididos em grupos daqueles com e sem afecções pulmonares. Os principais dados coletados e analisados foram PEEP, Pmed, Pressão Arterial Sistólica (PAS), Pressão Arterial Diastólica (PAD), Pressão Arterial Média (PAM), Frequência Cardíaca (FC). Para comparação de dados foram utilizados os testes Wilcoxon-Rank e Mann-Whitney para dados pareados e não pareados, respectivamente. RESULTADOS: Foram incluídos 37 pacientes, mediana de idade 63 anos, 19 (51,4%) do sexo masculino, 30 (81,1%) com diagnóstico admissional de natureza clínica. Não foram identificadas alterações hemodinâmicas estatisticamente significantes entre os tempos de pausa inspiratória de 0,5 e 2,0 segundos nas variáveis PAS (p=0,99), PAD (p=0,11), PAM (p=0,29) e FC (p=0,25). CONCLUSÃO: Não foram identificadas variações hemodinâmicas durante as mensurações da mecânica respiratória nas pausas de 0,5 e 2,0 segundos.

INTRODUCTION: The heart-lung interaction is influenced by Mechanical Ventilation (MV), which directly impacts venous return and cardiac output through, but not limited to, adjustments in Positive End-Expiratory Pressure (PEEP) and mean airway pressure (Pmean). Additionally, inspiratory pauses for the assessment of pulmonary mechanics interrupt thoracic movement, potentially further impacting this interaction. OBJECTIVE: To compare hemodynamic changes during 0.5 and 2.0-second inspiratory pauses during respiratory mechanics measurements. METHODS: This is a cross-sectional study conducted in the intensive care units of a hospital in Salvador/BA. Patients on MV and over 18 years old were included. Exclusions were made for those with hemodynamic instability and sustained hypoxemia during the evaluation. For sample characterization, patients were divided into groups with and without pulmonary conditions. The main data collected and analyzed were PEEP, Pmean, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), and Heart Rate (HR). For data comparison, Wilcoxon-Rank and Mann-Whitney tests were used for paired and unpaired data, respectively. RESULTS: Thirty-seven patients were included, with a median age of 63 years, 19 (51.4%) males, and 30 (81.1%) with an admission diagnosis of a clinical nature. No statistically significant hemodynamic changes were identified between the 0.5 and 2.0-second inspiratory pause times in the variables SBP (p=0.99), DBP (p=0.11), MAP (p=0.29), and HR (p=0.25). CONCLUSION: No hemodynamic variations were identified during respiratory mechanics measurements at 0.5 and 2.0-second inspiratory pauses.

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Teiid lizards possess an incomplete post-hepatic septum (PHS) separating the lungs and liver from the remaining viscera, and within this group, Salvator merianae has the most complete PHS. In this study, we explored the combined effects of the presence of the PHS and alterations in abdominal volume on the mechanics of the respiratory system. The PHS is believed to act as a mechanical barrier, mitigating the impact of the viscera on the lungs. Using established protocols, we determined static (Cstat) and dynamic (Cdyn) compliance, lung volume and work of breathing for the respiratory system in tegu lizards with intact (PHS+) or removed (PHS-) PHS, combined with (balloon+) or without (balloon-) increased abdominal volume. The removal of the PHS significantly reduced resting lung volume and Cdyn, as well as significantly increasing the work of breathing. An increase in abdominal volume significantly reduced Cstat, Cdyn, and resting and maximum lung volume. However, the work of breathing increased less in the PHS+/balloon+ treatment than in the PHS- treatments. These results highlight the barrier function of the PHS within the tegu lizard's body cavity. The septum effectively reduces the impact of the viscera on the respiratory system, enabling the lungs to be ventilated at a low work level, even when abdominal volume is increased. The presence of the PHS in teiid lizards underscores how extrapulmonary structures, such as septal divisions of the body cavity, can profoundly affect pulmonary breathing mechanics.

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BACKGROUND: Ventilation configurations are of great clinical importance for adequate outcomes in mechanically ventilated patients, and they may even be used as specific physical therapy techniques. OBJECTIVES: To compare the effectiveness of lung hyperinflation through mechanical ventilation (HMV) with HMV plus flow bias optimization regarding respiratory mechanics, hemodynamics, and volume of secretion. METHODS: Patients mechanically ventilated > 24 h were included in this randomized crossover clinical trial. The following techniques were applied: HMV alone (control group) and HMV plus flow bias optimization (intervention group). RESULTS: The 20 included patients underwent both techniques, totaling 40 collections. A total of 52 % were women, the mean age was 60.8 (SD, 15.7) years, and the mean mechanical ventilation time was 4.3 (SD, 3.0) days. The main cause of mechanical ventilation was sepsis (44 %). Expiratory flow bias in optimized HMV was higher. than conventional HMV (p < 0.001). The volume of tracheal secretions collected was higher during optimized than conventional HMV. (p = 0.012). Significant differences in peak flow occurred at the beginning of the technique and a there was a significant decrease in respiratory system resistance immediately and 30 min after applying the technique in the intervention group. CONCLUSIONS: The volume of tracheal secretions collected was higher during optimized HMV, and, HMV with flow bias optimization resulted in lower respiratory system resistance and flow peaks and produced expiratory flow bias.

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Objective. Understanding a patient's respiratory effort and mechanics is essential for the provision of individualized care during mechanical ventilation. However, measurement of transpulmonary pressure (the difference between airway and pleural pressures) is not easily performed in practice. While airway pressures are available on most mechanical ventilators, pleural pressures are measured indirectly by an esophageal balloon catheter. In many cases, esophageal pressure readings take other phenomena into account and are not a reliable measure of pleural pressure.Approach.A system identification approach was applied to provide accurate pleural measures from esophageal pressure readings. First, we used a closed pressurized chamber to stimulate an esophageal balloon and model its dynamics. Second, we created a simplified version of an artificial lung and tried the model with different ventilation configurations. For validation, data from 11 patients (five male and six female) were used to estimate respiratory effort profile and patient mechanics.Main results.After correcting the dynamic response of the balloon catheter, the estimates of resistance and compliance and the corresponding respiratory effort waveform were improved when compared with the adjusted quantities in the test bench. The performance of the estimated model was evaluated using the respiratory pause/occlusion maneuver, demonstrating improved agreement between the airway and esophageal pressure waveforms when using the normalized mean squared error metric. Using the corrected muscle pressure waveform, we detected start and peak times 130 ± 50 ms earlier and a peak amplitude 2.04 ± 1.46 cmH2O higher than the corresponding estimates from esophageal catheter readings.Significance.Compensating the acquired measurements with system identification techniques makes the readings more accurate, possibly better portraying the patient's situation for individualization of ventilation therapy.

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The viscoelastic properties of the lung have important implications during respiratory mechanics in terms of lung movement or work of breathing, for example. However, this property has not been well characterized due to several reasons, such as the complex nature of the lung, difficulty accessing its tissues, and the lack of physical simulators that represent viscoelastic effects. This research proposes an electropneumatic system and a method to simulate the viscoelastic effect from temporary forces generated by the opposition of magnetic poles. The study was tested in a mechanical ventilation scenario with inspiratory pause, using a Hamilton-S1 mechanical ventilator (Hamilton Medical) and a simulator of the human respiratory system (SAMI-SII). The implemented system was able to simulate the stress relaxation response of a Standard Linear Solid model in the Maxwell form and showed the capacity to control elastic and viscous parameters independently. To the best of our knowledge, this is the first system incorporated into a physical lung simulator that represents the viscoelastic effect in a mechanical ventilation scenario.

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OBJECTIVE: To assess the rib cage expansion and respiratory rate in newborns using an abdominal stabilization band. METHODS: The study included 32 newborns of both genders, with gestational age between 35 and 41 weeks. The abdominal stabilization band was used for 15 minutes between the xiphoid process and the anterosuperior iliac crest, with an abdominal contention 0.5cm smaller than the abdominal circumference. The rib cage expansion was evaluated by a breathing transducer (Pneumotrace II™) three minutes before using the band, during the use (15 minutes), and ten minutes after removing the band. The Shapiro-Wilk test verified data normality, and the Wilcoxon test compared the variables considering rib cage expansion and respiratory rate. Significance was set to p<0.05. RESULTS: There was an increase in respiratory rate when comparing before and ten minutes after removing (p=0.008) the abdominal stabilization band, as well as when comparing during its use and ten minutes after its removal (p=0.001). There was also an increase in rib cage expansion when comparing before and during the use of the abdominal stabilization band (p=0.005). CONCLUSIONS: The use of the abdominal stabilization band promoted an increase in the rib cage expansion and respiratory rate in the assessed newborns and may be a viable option to improve the respiratory kinematics of this population.

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Scoliosis is a condition that affects the spine and causes chest rotation and trunk distortion. Individuals with severe deformities may experience dyspnea on exertion and develop respiratory failure. Respiratory oscillometry is a simple and non-invasive method that provides detailed information on lung mechanics. This work aims to investigate the potential of oscillometry in the evaluation of respiratory mechanics in patients with scoliosis and its association with physical performance. We analyzed 32 volunteers in the control group and 32 in the scoliosis group. The volunteers underwent traditional pulmonary function tests, oscillometry, and the 6-minute walk test (6MWT). Oscillometric analysis showed increased values of resistance at 4 Hz (R4, P<0.01), 12 Hz (R12, P<0.0001), and 20 Hz (R20, P<0.01). Similar analysis showed reductions in dynamic compliance (Cdyn, P<0.001) and ventilation homogeneity, as evaluated by resonance frequency (fr, P<0.001) and reactance area (Ax, P<0.001). Respiratory work, described by the impedance modulus, also showed increased values (Z4, P<0.01). Functional capacity was reduced in the group with scoliosis (P<0.001). A significant direct correlation was found between Cobb angle and R12, AX, and Z4 (P=0.0237, P=0.0338, and P=0.0147, respectively), and an inverse correlation was found between Cdyn and Cobb angle (P=0.0190). These results provided new information on respiratory mechanics in scoliosis and are consistent with the involved pathophysiology, suggesting that oscillometry may improve lung function tests for patients with scoliosis.

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