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BACKGROUND: Intra-breath oscillometry has been proposed as a sensitive means of detecting airway obstruction in young children. We aimed to assess the impact of early life wheezing and lower respiratory tract illness on lung function, using both standard and intra-breath oscillometry in 3 year old children. METHODS: History of doctor-diagnosed asthma, wheezing, bronchiolitis and bronchitis and hospitalisation for respiratory problems were assessed by questionnaires in 384 population-based children. Association of respiratory history with standard and intra-breath oscillometry parameters, including resistance at 7 Hz (R7), frequency-dependence of resistance (R7 - 19), reactance at 7 Hz (X7), area of the reactance curve (AX), end-inspiratory and end-expiratory R (ReI, ReE) and X (XeI, XeE), and volume-dependence of resistance (ΔR = ReE-ReI) was estimated by linear regression adjusted on confounders. RESULTS: Among the 320 children who accepted the oscillometry test, 281 (88%) performed 3 technically acceptable and reproducible standard oscillometry measurements and 251 children also performed one intra-breath oscillometry measurement. Asthma was associated with higher ReI, ReE, ΔR and R7 and wheezing was associated with higher ΔR. Bronchiolitis was associated with higher R7 and AX and lower XeI and bronchitis with higher ReI. No statistically significant association was observed for hospitalisation. CONCLUSIONS: Our findings confirm the good success rate of oscillometry in 3-year-old children and indicate an association between a history of early-life wheezing and lower respiratory tract illness and lower lung function as assessed by both standard and intra-breath oscillometry. Our study supports the relevance of using intra-breath oscillometry parameters as sensitive outcome measures in preschool children in epidemiological cohorts.
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Asma , Bronquiolite , Bronquite , Humanos , Pré-Escolar , Sons Respiratórios/diagnóstico , Espirometria , Sistema Respiratório , Asma/diagnóstico , Asma/epidemiologia , Mecânica Respiratória , Bronquite/diagnóstico , Bronquite/epidemiologiaRESUMO
Objective Different body positions can exert both positive and negative physiological effects on hemodynamics and respiration. This study aims to conduct a literature review and examine hemodynamic and respiratory alterations to different body positions.Methods The study protocol was registered with the International Prospective Registry of Systematic Reviews (register no. CRD42021291464). Two independent reviewers evaluated the methodological quality of all included studies using the Down and Black checklist, while the quality of evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluations approach. The overall effects of different body positions were reported from random effects meta-analysis.Results Three studies with low risk of bias and ten with high risk of bias met the eligibility criteria. The supine resulted in the highest cardiac output compared to the 70 deg head-up tilt, sitting, and standing positions (very low- to moderate-quality evidences) and the lowest systemic vascular resistance compared to the 70 deg head-up tilt and standing positions (moderate-quality evidence). Additionally, the supine was associated with the highest total respiratory resistance compared to the 70 deg head-up tilt, left lateral, and standing positions (very low-to moderate-quality evidence) and higher alveolar ventilation than the prone (low-quality evidence).Conclusions The supine position has the most positive association with hemodynamic variables, resulting in the highest cardiac output and the lowest systemic vascular resistance. The upright positions (70 deg head-up tilt and standing positions) has the most positive association with the respiratory variables, resulting in the lowest total respiratory resistance.
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Hemodinâmica , Postura , Respiração , Humanos , Hemodinâmica/fisiologia , Postura/fisiologia , Adulto , Débito Cardíaco/fisiologiaRESUMO
BACKGROUND: Low back pain (LBP) is a common musculoskeletal disorder, and respiratory exercise is considered a nonsurgical management method. Therefore, this systematic review and meta-analysis aims to estimate the results of randomized controlled trials on the effect of respiratory training in reducing LBP and its dose relationship. METHODS: The present study was conducted from January 2020 to January 2022, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (2020). Relevant studies were searched in multiple databases including PubMed, Web of Science, the Cochrane Library, EBSCO, Scopus, ScienceDirect, Wan Fang and China Knowledge Network, ClinicalTrials.gov, and Google Scholar, using a combination of MeSH/Emtree terms and free-text words. The heterogeneity of the studies was assessed using the I2 statistic. RESULTS: A total of 14 publications were included in the meta-analysis, with a total sample size of 698 individuals, aged 60-80 years. Respiratory exercise was effective in relieving LBP (standardized mean difference = -0.87, P < .00001) and improving physical disability (standardized mean difference = -0.79, P < .00001). The type of breathing and the total duration of breathing exercises were found to be the source of heterogeneity in this study by subgroup analysis. Subgroup analysis revealed that the most significant effect sizes of breathing resistance exercise to reduce LBP and the most significant effect sizes of breathing relaxation techniques to alleviate physical disability were performed 3 to 5 times per week and period >4 weeks. Respiratory exercise reducing LBP and improving functional disability was most effective when the total duration of the intervention was >500 minutes. Funnel plots showed that the results of the 2 overall studies were reliable without publication bias. CONCLUSIONS: Respiratory exercise can effectively reduce LBP and improve physical disability. Therefore, these exercises can be regarded as a part of a LBP management plan. We recommend an exercise program with 30 to 50 minutes, 3 to 5 times per week, and >4 weeks of breathing resistance exercise program as the most effective for treating LBP.
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Dor Lombar , Doenças Musculoesqueléticas , Humanos , Exercícios Respiratórios , Terapia por Exercício , Dor Lombar/terapia , RespiraçãoRESUMO
The three-layer surgical mask was recognized by the World Health Organization as an effective-protection tool for reducing SARS-CoV-2 transmission during the COVID-19 pandemic; however, the contribution of each layer of this mask to the particle size-dependent filtration performance resistance remains unclear. Here, both experimental work and numerical simulation were conducted to study the role of each mask layer in particle size-dependent filtration and respiratory resistance. By using scanning electron microscopy images of a commercial three-layer mask, composed of two spun-bond and one melt-blown nonwoven polypropylene fabric layers, four representative models were constructed, in which the computational fluid dynamics of multiphase flow were performed. The pressure drop of all models under different flow conditions was measured next. Numerical simulation was then verified by comparing the experimental results in the present study and other theoretical works. The filtration efficiency of the spun-bond polypropylene nonwoven fabric layer was much lower than that of the melt-blown nonwoven polypropylene fabric layer for the particle diameter in the range of 0.1-2.0 µm. Both the spun-bond and melt-blown nonwoven polypropylene fabric layers demonstrated extremely low filtration efficiency for particles was<0.3 µm in diameter, with the maximum filtration efficiency being only 30%. The present results may facilitate rational design of mask products in terms of layer number and structural design.
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OBJECTIVE: To compare pulmonary function tests (PFTs), specifically respiratory system resistance (Rrs) and compliance (Crs), in very low birth weight (VLBW) infants with and without pulmonary hypertension. STUDY DESIGN: Infants were included who underwent PFTs at 34-38 weeks postmenstrual age (PMA) as part of our pulmonary hypertension screening guidelines for infants born at ≤1500 g requiring respiratory support at ≥34 weeks PMA. One pediatric cardiologist reviewed and estimated right ventricular or pulmonary arterial pressure and defined pulmonary hypertension as an estimated pulmonary arterial pressure or right ventricular pressure greater than one-half the systemic pressure. Rrs and Crs were measured with the single breath occlusion technique and functional residual capacity with the nitrogen washout method according to standardized criteria. RESULTS: Twelve VLBW infants with pulmonary hypertension and 39 without pulmonary hypertension were studied. Those with pulmonary hypertension had significantly lower birth weight and a trend toward a lower gestational age. There were no other demographic differences between the groups. The infants with pulmonary hypertension had significantly higher Rrs (119 vs 78 cmH2O/L/s; adjusted P = .012) and significantly lower Crs/kg (0.71 vs 0.92 mL/cmH2O/kg; P = .04). CONCLUSIONS: In this pilot study of VLBW infants screened for pulmonary hypertension at 34-38 weeks PMA, those with pulmonary hypertension had significantly increased Rrs and decreased Crs compared with those without pulmonary hypertension. Additional studies are needed to further phenotype infants with evolving BPD and pulmonary hypertension.
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Resistência das Vias Respiratórias/fisiologia , Hipertensão Pulmonar/diagnóstico , Hipertensão Pulmonar/fisiopatologia , Doenças do Prematuro/diagnóstico , Doenças do Prematuro/fisiopatologia , Complacência Pulmonar/fisiologia , Estudos de Coortes , Feminino , Idade Gestacional , Humanos , Hipertensão Pulmonar/terapia , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/terapia , Recém-Nascido Pequeno para a Idade Gestacional , Recém-Nascido de muito Baixo Peso , Masculino , Triagem Neonatal , Projetos Piloto , Respiração Artificial , Testes de Função RespiratóriaRESUMO
BACKGROUND: Alveolar recruitment maneuvers enable easily reopening nonaerated lung regions via a transient elevation in transpulmonary pressure. To evaluate the effect of these maneuvers on respiratory resistance, we used an oscillatory technique during mechanical ventilation. This study was conducted to assess the effect of the alveolar recruitment maneuvers on respiratory resistance under routine anesthesia. We hypothesized that respiratory resistance at 5 Hz (R5) after the maneuver would be decreased after the lung aeration. METHODS: After receiving the ethics committee's approval, we enrolled 33 patients who were classified with an American Society of Anesthesiologists physical status of 1, 2 or 3 and were undergoing general anesthesia for transurethral resection of a bladder tumor within a 12-month period from 2017 to 2018. The recruitment maneuver was performed 30 min after endotracheal intubation. The maneuver consisted of sustained manual inflation of the anesthesia reservoir bag to a peak inspiratory pressure of 40 cmH2O for 15 s, including 5 s of gradually increasing the peak inspiratory pressure. Respiratory resistance was measured using the forced oscillation technique before and after the maneuver, and the mean R5 was calculated during the expiratory phase. The respiratory resistance and ventilator parameter results were analyzed using paired Student's t-tests, and p < 0.05 was considered statistically significant. RESULTS: We analyzed 31 patients (25 men and 6 women). R5 was 7.3 ± 1.6 cmH2O/L/sec before the recruitment maneuver during mechanical ventilation and was significantly decreased to 6.4 ± 1.7 cmH2O/L/sec after the maneuver. Peak inspiratory pressure and plateau pressure were significantly decreased, and pulmonary compliance was increased, although the values were not clinically relevant. CONCLUSION: The recruitment maneuver decreased respiratory resistance and increased lung compliance during mechanical ventilation. TRIAL REGISTRATION: Name of registry: Japan Medical Association Center for Clinical Trials. TRIAL REGISTRATION NUMBER: reference JMA-IIA00136. Date of registration: 2 September 2013. URL of trial registry record: https://dbcentre3.jmacct.med.or.jp/JMACTR/App/JMACTRE02_04/JMACTRE02_04.aspx?kbn=3&seqno=3582.
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Resistência das Vias Respiratórias/fisiologia , Anestesia Geral/métodos , Respiração com Pressão Positiva , Alvéolos Pulmonares/fisiologia , Idoso , Feminino , Humanos , Complacência Pulmonar , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Obstructive sleep apnea (OSA) is a condition of breathing pathology occurring during sleep, characterized by repeated episodes of upper airway obstruction. The aim of the study was to determine the occurrence of airway obstruction in smoking males with OSA in whom lung function tests had not been performed before. One hundred and four current smokers selected from 1241 patients were enrolled for the research. The subjects included in the study smoked minimum 20 cigarettes a day for at least 10 years. The diagnosis of OSA was confirmed by polysomnography (PSG) in the Sleep Laboratory and subjects were assigned to one of three groups, depending on the severity of OSA. The control group consisted of 30 age-matched male smokers in whom OSA was not confirmed in PSG. Patients from the study and control group scored ≥ 11points in the Epworth Sleepiness Scale. Spirometry, impulse oscillometry, and body plethysmography were used to assess pulmonary function. Airflow limitation in subjects of the control group and OSA patients was confirmed. There were no significant differences in the incidence of bronchial obstruction between the control and study groups, and among the patients of various OSA severity. We conclude that the severity of OSA in smokers does not associate with the presence of airway obstruction. However, the increased peripheral respiratory resistance found in oscillometry did relate to a longer smoking time in OSA patients.
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Obstrução das Vias Respiratórias/diagnóstico , Apneia Obstrutiva do Sono/diagnóstico , Fumantes , Estudos de Casos e Controles , Humanos , Masculino , Pletismografia , Polissonografia , EspirometriaRESUMO
The mechanisms whereby anticholinergics improve asthma outcomes, such as lung function, symptoms, and rate of exacerbation, can be numerous. The most obvious is by affecting the contraction of airway smooth muscle (ASM). The acetylcholine released from the cholinergic nerves is the most important bronchoconstrictor that sets the baseline degree of contractile activation of ASM in healthy individuals. Although the degree of ASM's contractile activation can also be fine-tuned by a plethora of other bronchoconstrictors and bronchodilators in asthma, blocking the ceaseless effect of acetylcholine on ASM by anticholinergics reduces, at any given moment, the overall degree of contractile activation. Because the relationships that exist between the degree of contractile activation, ASM force, ASM shortening, airway narrowing, airflow resistance, and respiratory resistance are not linear, small decreases in the contractile activation of ASM can be greatly amplified and thus translate into important benefits to a patient's well-being. Plus, many inflammatory and remodeling features that are often found in asthmatic lungs synergize with the contractile activation of ASM to increase respiratory resistance. This review recalls that the proven effectiveness of anticholinergics in the treatment of asthma could be merely attributed to a small reduction in the contractile activation of ASM.
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Asma/tratamento farmacológico , Antagonistas Colinérgicos/farmacologia , Animais , Asma/fisiopatologia , Antagonistas Colinérgicos/uso terapêutico , Humanos , Contração Muscular/efeitos dos fármacos , Respiração/efeitos dos fármacosRESUMO
OBJECTIVES: International guidelines recommend the use of long-acting bronchodilators for the treatment of chronic obstructive pulmonary disease (COPD), but the usefulness of short-acting bronchodilator assist use for stable COPD remains uncertain. The purpose of the present study was to objectively demonstrate the effects of assist use of procaterol, a short-acting ß2-agonist, on the respiratory mechanics of stable COPD patients treated with a long-acting bronchodilator using forced oscillation technique (FOT) and conventional spirometry. We also confirmed the length of time for which procaterol assist could significantly improve the pulmonary function. METHODS: We enrolled 28 outpatients with mild to severe COPD (Global Initiative for Obstructive Lung Disease stages I-III), who had used the same long-acting bronchodilator for longer than 3 months and who were in stable condition. All measures were performed using both FOT and spirometry sequentially from 15 min to 2 h after inhalation. RESULTS: Compared to baseline, inhaled procaterol assist use modestly but significantly improved spirometric and FOT measurements within 2 h after inhalation. These significant effects continued for at least 2 h. -Significant correlations were found between parameters -measured by spirometry and those measured by FOT. CONCLUSIONS: Procaterol assist use modestly but significantly improved pulmonary function determined by spirometry and respiratory mechanics in patients with stable COPD treated with long-acting bronchodilators. Thus, inhaled procaterol has the potential for assist use for COPD.
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Agonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Procaterol/uso terapêutico , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Administração por Inalação , Agonistas de Receptores Adrenérgicos beta 2/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Volume Expiratório Forçado/efeitos dos fármacos , Humanos , Japão , Pulmão/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Procaterol/administração & dosagem , Testes de Função Respiratória , EspirometriaRESUMO
OBJECTIVE: To compare the pulmonary function, measured at birth and at hospital discharge, of infants whose mothers had been randomized to a single rescue course of antenatal steroids versus those whose mothers had been randomized to placebo. STUDY DESIGN: This study involved follow-up at hospital discharge of subjects of a randomized, double-blinded trial. In the original trial, pregnant women at ≥14 days after their initial course of antenatal steroids and <34 weeks' gestation were randomized to rescue antenatal steroids (44 mothers, 56 infants) or placebo (41 mothers, 57 infants). Passive respiratory compliance (Crs), passive respiratory resistance, and functional residual capacity were measured in all infants at birth and again at discharge to evaluate changes in pulmonary mechanics over time. Statistical analyses were based on intention to treat. RESULTS: We previously reported that compared with infants in the placebo group, infants in the rescue antenatal steroids group had a higher mean Crs value measured within 72 hours of birth (1.21 vs 1.01 mL/cm H2O/kg; P < .05). Here we show that the Crs benefit in the antenatal steroids group was sustained until discharge. Infants in the placebo group demonstrated improvement in Crs such that by discharge, there was no difference in mean Crs between the rescue antenatal steroids and placebo groups (1.18 vs 1.22 mL/cm H2O/kg). CONCLUSIONS: Rescue antenatal steroids significantly increased Crs measured within 72 hours of birth, and this increase was sustained until hospital discharge. Preterm infants in the placebo group demonstrated a decreased initial Crs compared with the rescue antenatal steroids group, but achieved a comparable Crs by the time of discharge. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00669383.
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Betametasona/administração & dosagem , Recém-Nascido Prematuro , Complacência Pulmonar/efeitos dos fármacos , Síndrome do Desconforto Respiratório do Recém-Nascido/tratamento farmacológico , Adulto , Feminino , Seguimentos , Capacidade Residual Funcional/efeitos dos fármacos , Idade Gestacional , Glucocorticoides/administração & dosagem , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Alta do Paciente , Gravidez , Cuidado Pré-Natal/métodos , Estudos Prospectivos , Valores de Referência , Testes de Função Respiratória , Medição de Risco , Resultado do TratamentoRESUMO
The Douglas bag technique is reviewed as one in a series of articles looking at historical insights into measurement of whole body metabolic rate. Consideration of all articles looking at Douglas bag technique and chemical gas analysis has here focused on the growing appreciation of errors in measuring expired volumes and gas composition, and subjective reactions to airflow resistance and dead space. Multiple small sources of error have been identified and appropriate remedies proposed over a century of use of the methodology. Changes in the bag lining have limited gas diffusion, laboratories conducting gas analyses have undergone validation, and WHO guidelines on airflow resistance have minimized reactive effects. One remaining difficulty is a contamination of expirate by dead space air, minimized by keeping the dead space <70 mL. Care must also be taken to ensure a steady state, and formal validation of the Douglas bag method still needs to be carried out. We may conclude that the Douglas bag method has helped to define key concepts in exercise physiology. Although now superceded in many applications, the errors in a meticulously completed measurement are sufficiently low to warrant retention of the Douglas bag as the gold standard when evaluating newer open-circuit methodology.
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Fisiologia/história , Troca Gasosa Pulmonar , Ventilação Pulmonar , Animais , História do Século XX , Humanos , Fisiologia/instrumentação , Fisiologia/métodos , Espirometria/história , Espirometria/instrumentação , Espirometria/métodosRESUMO
The impulse oscillometry (IOS) is recognized as a complementary method to spirometry in the diagnostics of obstructive pulmonary disorders. The IOS enables to measure total respiratory resistance (R5) and proximal respiratory resistance (R20), with the R5-R20 difference reflecting small airway resistance. This study seeks to evaluate the usefulness of R5-R20, maximal mid-expiratory flow (MMEF), and forced expiratory volume in 3 s/forced vital capacity ratio (FEV3/FVC), in the assessment of small airway obstruction in chronic obstructive pulmonary disease (COPD). One hundred and six COPD patients and 43 control subjects, aged over 55, were investigated. Spirometry and IOS were used to assess pulmonary function. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were evaluated. The findings demonstrate significant reductions in FEV3/FVC and MMEF, and an increase in R5-R20 difference in COPD patients; the changes that depended on the severity of airway obstruction. The sensitivity of R5-R20 in reflecting the MMEF was 84%, specificity 44.2%, PPV 72.4%, and NPV 61.3%. We conclude that the R5-R20 difference is superior to spirometry in the assessment of small bronchi obstruction. A high sensitivity of R5-R20 in reflecting the MMEF makes the IOS method particularly useful for detection of mild lung injury, while a high specificity of the spirometric FEV3/FVC ratio makes it useful to exclude obstruction of small airways. Both methods are thus complimentary.
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Obstrução das Vias Respiratórias/diagnóstico , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Idoso , Obstrução das Vias Respiratórias/fisiopatologia , Resistência das Vias Respiratórias/fisiologia , Feminino , Volume Expiratório Forçado/fisiologia , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Oscilometria/métodos , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Sensibilidade e Especificidade , Espirometria/métodos , Volume de Ventilação Pulmonar/fisiologiaRESUMO
Vocal cord dysfunction induced by exercise in children with uncontrolled asthma was identified by laryngoscopy. The paradoxical adduction of the vocal cords was also indicated by the breathing-related changes of the forced oscillation respiratory resistance showing prominent increase during inspiration and a large positive difference between inspiration and expiration. The breathing-related changes of respiratory resistance offer thus a useful first-line technique to diagnose vocal cord dysfunction.
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Asma Induzida por Exercício , Respiração , Disfunção da Prega Vocal , Asma Induzida por Exercício/diagnóstico , Asma Induzida por Exercício/fisiopatologia , Criança , Diagnóstico Diferencial , Feminino , Humanos , Doenças da Laringe/fisiopatologia , Laringoscopia/métodos , Masculino , Disfunção da Prega Vocal/diagnóstico , Disfunção da Prega Vocal/fisiopatologia , Prega Vocal/fisiopatologiaRESUMO
BACKGROUND AND OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is characterized by a mixture of emphysema and airway disease. The forced oscillation technique (FOT) has been applied to COPD patients to clarify changes in respiratory mechanics; dynamic changes in respiratory resistance (Rrs) during breathing (within-breath changes in Rrs, ΔRrs) are characteristic of COPD. However, the pathophysiological significance of these changes is unknown. The aim of this study was to assess how emphysema and airway disease influence ΔRrs in COPD patients. METHODS: In this cross-sectional study, stable COPD patients were recruited and underwent respiratory impedance measurements with a commercially available FOT device. Rrs was recorded during tidal breathing and then analyzed as whole-breath Rrs (Rrs at 5 Hz, R5; Rrs at 20 Hz, R20; and their difference, R5-R20) or as ΔRrs, the difference between the expiratory and inspiratory Rrs (ΔR5, ΔR20 and ΔR5-R20). The percentage of the low attenuation area (LAA%) and airway wall area (WA%) was quantified by computed tomography analysis, and their contributions to ΔRrs were examined. RESULTS: Seventy-five COPD patients were recruited. LAA% was negatively correlated with ΔR5 and ΔR5-R20 (P = 0.0002 and P = 0.0033, respectively); meanwhile, WA% in B(10) was positively correlated with ΔR5 and ΔR5-R20 (P = 0.0057 and P < 0.0001, respectively). Multivariate analysis revealed that the contribution of both LAA% and WA% in B(10) to ΔRrs was independent of the severity of airflow limitations. CONCLUSION: This study shows that emphysema suppresses ΔRrs in COPD patients, while airway disease increases ΔRrs in these patients.
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Resistência das Vias Respiratórias , Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar/fisiopatologia , Mecânica Respiratória/fisiologia , Idoso , Estudos Transversais , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Testes de Função Respiratória/métodos , Sistema Respiratório/fisiopatologia , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND AND OBJECTIVE: Non-invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been used in infants. The study aims to assess the use of the forced oscillation technique to measure the influence of antenatal exposures on respiratory mechanics in unsedated infants enrolled in a birth cohort study in Cape Town, South Africa. METHODS: Healthy term infants were studied at 6-10 weeks of age using the forced oscillation technique. Respiratory impedance was measured in the frequency range 8-48 Hz via a face mask during natural sleep. Respiratory system resistance, compliance and inertance were calculated from the impedance spectra. RESULTS: Of 177 infants tested, successful measurements were obtained in 164 (93%). Median (25-75%) values for resistance, compliance and inertance were 50.2 (39.5-60.6) cmH2 O.s.L(-1), 0.78 (0.61-0.99) mL.cmH2 O(-1) and 0.062 (0.050-0.086) cmH2 O.s(2) .L(-1), respectively. As a group, male infants had 16% higher resistance (P = 0.006) and 18% lower compliance (P = 0.02) than females. Infants whose mothers smoked during pregnancy had a 19% lower compliance than infants not exposed to tobacco smoke during pregnancy (P = 0.005). Neither maternal HIV infection nor ethnicity had a significant effect on respiratory mechanics. CONCLUSIONS: The forced oscillation technique is sensitive enough to demonstrate the effects of tobacco smoke exposure and sex in respiratory mechanics in healthy infants. This technique will facilitate assessing perinatal influences of lung function in infancy.
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Exposição Materna/efeitos adversos , Testes de Função Respiratória/métodos , Fenômenos Fisiológicos Respiratórios , Fumar/efeitos adversos , Impedância Elétrica , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Valores de Referência , Sistema Respiratório , África do SulRESUMO
AIM: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive condition with unknown aetiology that causes the lung parenchyma to scar incessantly, lowering the quality of life and hastening death. In this investigation, we studied the anti-fibrotic activity of Geneticin (a derivative of gentamycin) using in vitro and in vivo models. MAIN METHODS: The TGF-ß-mediated differentiation model was adopted to investigate (fibrotic marker's levels/expression) the anti-fibrotic activity of geneticin (GNC) in in-vitro scenarios (LL29 and DHLF cells). In vivo, the bleomycin (BLM)-induced pulmonary fibrosis model was employed by administering BLM intratracheally. Post 14 days of BLM administration, animals were treated with geneticin (6.25, 12.5, and 25 mg·kg-1) for another 14 days, and their therapeutic effect was investigated using a spectrum of techniques. KEY FINDINGS: RTqPCR and western-blot results revealed that geneticin treatment significantly attenuated the TGF-ß/BLM mediated fibrotic cascade of markers in both in-vitro and in-vivo models respectively. Further, the BLM-induced pulmonary fibrosis model revealed, that geneticin dose-dependently reduced the BLM-induced inflammatory cell infiltrations, and thickness of the alveoli walls, improved the structural distortion of the lung, and aided in improving the survival rate of the rats. Picrosirus and Masson's trichrome staining indicated that geneticin therapy reduced collagen deposition and, as a result, lung functional characteristics were improved as assessed by flexivent. Mechanistic studies have shown that geneticin reduced fibrosis by attenuating the TGF-ß/Smad through modulating the AMPK/SIRT1 signaling. SIGNIFICANCE: These findings suggest that geneticin may be a promising therapeutic agent for the treatment of pulmonary fibrosis in clinical settings.
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Proteínas Quinases Ativadas por AMP , Bleomicina , Fibrose Pulmonar , Transdução de Sinais , Sirtuína 1 , Fator de Crescimento Transformador beta , Animais , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/tratamento farmacológico , Fibrose Pulmonar/patologia , Fibrose Pulmonar/induzido quimicamente , Ratos , Sirtuína 1/metabolismo , Sirtuína 1/genética , Masculino , Bleomicina/toxicidade , Proteínas Quinases Ativadas por AMP/metabolismo , Proteínas Smad/metabolismo , Ratos Sprague-Dawley , Modelos Animais de DoençasRESUMO
Objective: To compare early pulmonary function tests (PFTs) in neonates with critical congenital heart disease (CHD) compared to a historical reference group. Design: Infants > 37 weeks gestation with critical CHD were studied within the first few days of life and prior to cardiac surgery and compared to data from a published reference group. Passive respiratory resistance (Rrs) and compliance (Crs) were measured with the single breath occlusion technique following specific acceptance criteria. The study was powered for a 30% difference in Rrs. Results: PFTs in 24 infants with CHD were compared to 31 historical reference infants. There was no difference in the Rrs between the groups. The infants with CHD had a significantly decreased Crs (1.02 ± 0.26 mL/cmH2O/kg versus 1.32 ± 0.36; (p < 0.05; mean ± SD)). Conclusions: Further prospective studies are required to quantify early PFTs in infants with CHD of different phenotypes.
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PURPOSE: To compare the effects of 9 weeks of training with a concurrent flow resistance (CFR) device versus a concurrent pressure threshold resistance (CPTR) device on health-related quality of life (HRQoL) in wheelchair rugby (WR) athletes. METHOD: Twenty-four male WR athletes (22 with tetraplegia, 1 with a spastic cerebral palsy, and 1 with congenital upper and lower limb deformities) were matched by lesion level, completeness of injury, and rugby classification prior to being randomly assigned to 1 of 3 groups: (1) CPTR (n=8), (2) CFR (n=8), or (3) controls (CON, n=8). Pre/post testing included assessment of HRQoL as measured by the Short-Form Health Survey Version 2.0 (SF-36v2). Manufacturer protocol guidelines for the CFR and CPTR groups were followed for breathing exercises. RESULTS: Sixteen participants completed the study (CPTR=4, CFR=5, CON=7). The Mann-Whitney U rank order revealed significantly greater reductions in bodily pain (P = .038) and improvements in vitality (P = .028) for CFR versus CON. CONCLUSION: Results from this study suggest that training with a CFR device improves some aspects of HRQoL (eg, vitality and bodily pain) in WR athletes. Further research with a larger sample size is needed to examine the impact of these devices on improving HRQoL for wheelchair athletes.
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OBJECTIVE: To analyze the impact of repeated forced spirometry maneuvers on oscillometry parameters of healthy children. METHODS: This is a cross-sectional study with healthy children (6-12 y old) from schools in Florianopolis-SC/Brazil. Good health condition was confirmed through questionnaires, health history, and normal spirometry. Spirometry maneuvers and impulse oscillometry were conducted according to the American Thoracic Society guidelines. The school children were grouped according to the number of spirometry maneuvers performed: 1) 3 maneuvers; 2) 4 maneuvers and 3) 5 to 8 maneuvers. The following oscillometry values were considered: at rest (T0); after the first spirometry maneuver (T1); and after the last maneuver (T2), according to the groups' allocation. The mixed model ANOVA was applied to verify the interaction of oscillometry parameters in all 3 moments and groups. The Friedman test was used for analysis of Fres (p < 0.05). RESULTS: In 149 school children (mean age: 9.13 y old ± 1.98), there was a significant increase in Z5, R5, R20, and X5 values at rest and after the first spirometry maneuver, and values at rest and after the last maneuver in all groups. The effects on analyzed variables were significant in Z5 (F: 12.35; gl: 2; p < 0.001), R5 (F: 11.14; df: 2, p < 0.001), R20 (F: 7.53; df: 2, p < 0.001), and X5 (F: 4.30; df: 2, p = 0.014). CONCLUSION: There were changes in respiratory mechanics after spirometry, like the increase in baseline Z5, R5, R20, and X5 after the first forced spirometry maneuver, and in comparison to the last maneuver obtained.