Normative reference equations of airway dynamics assessed by whole-body plethysmography during spontaneous breathing evaluated in infants, children, and adults.

Effective specific airway resistance (sReff ), its reciprocal the effective specific airway conductance (sGeff ) are computed as ratios between the integral of the resistive aerodynamic work of breathing (sWOB) and the integral of the tidal flow/volume loop, the reciprocal, respectively. Unfortunately, reference equations to obtain normative values for sReff , sGeff , and sWOB are not yet available. To assess reference equations for sWOB, sReff , and sGeff during tidal breathing at resting level in healthy infants, children, and adults by a multidimensional model. Retrospectively exported data were collected from databases of five Swiss lung function centers, in which plethysmography (Jaeger Würzburg, Germany) was performed for the assessment of airway dynamics, static lung volumes, and forced breathing flow-volume loops, in a collective of 28 healthy infants, 47 children, and 273 adults. From this cohort, reference equations were computed based on anthropometric measures, lung volumes, indices of the breathing pattern, and timing of breathing. By multi-linear modeling reference equations of sReff , sGeff , and sWOB could be defined taking as independent parameters apart from anthropometric parameters, also parameters given by the ratio between the tidal volume and functional residual capacity (FRCpleth /VT ), and the ratio between VT and inspiratory time (VT /TI ). An alternative statistical approach to define reference equations of airway dynamics reveals that apart from the subject's anthropometric measurements, parameters of the magnitude of static lung volumes, the breathing pattern, and the timing of breathing are co-variants of reference equations of airway dynamics over a large age range.

Cardiac autonomic modulation response and functional capacity in older women / Respuesta de la modulación autonómica cardíaca y capacidad funcional en mujeres mayores / Resposta da modulação autonômica cardíaca e capacidade funcional em mulheres idosas

ABSTRACT Objective: To analyze cardiac autonomic modulation response and functional capacity in physically active older women. Methods: Seventy-five older women (60-70 years) from the community were divided into the following groups: sedentary (n=19), hydro-gymnastics (n=18), pilates (n=19), and dance (n=19). Blood pressure, body composition, heart rate variability, and functional capacity were assessed for the characterization of the groups at rest and 48 hours after the last physical exercise session. Results: The sedentary group presented higher waist-to-hip ratio, diastolic blood pressure, and resting heart rate compared to the other groups (p<0.05). It was also observed that the dance group presented better functional capacity and VO2peak scores (all p<0.05). Regarding cardiac autonomic modulation, both dance and pilates groups demonstrated better RMSSD (26.71 ± 9.07 and 29.82 ± 7.16, respectively; p<0.05), LF (45.79 ± 14.81 and 45.95 ± 15.16 n.u., respectively; p<0.05), and LF/HF (0.92 ± 0.56 and 0.58 ± 0.26, respectively; p<0.05) scores. In the symbolic analysis, the dance group had a greater predominance of parasympathetic autonomic modulation than the other groups (p<0.05). Conclusion: These results conclude that physically active elderly women, practicing hydro-gymnastics, pilates or dance, presented physiological benefits, such as better functional capacity and improvements in hemodynamic variables and autonomic cardiac modulation. In addition, the group that practiced dance presented greater parasympathetic modulation, as well as greater functional capacity, when compared to the other modalities. Level of evidence: I; STARD: studies of diagnostic accuracy.

RESUMEN Objetivo: Analizar la respuesta de la modulación autonómica cardíaca y la capacidad funcional en mujeres mayores físicamente activas. Métodos: Setenta y cinco mujeres mayores (60 a 70 años) de la comunidad fueron divididas en los siguientes grupos: sedentaria (n = 19), hidrogimnasia (n = 18), pilates (n = 19) y danza (n = 19). La presión arterial, la composición corporal, la variabilidad de la frecuencia cardíaca y la capacidad funcional fueron evaluadas para la caracterización de los grupos en reposo y 48 horas después de la última sesión de ejercicio físico. Resultados: El grupo sedentario presentó mayor relación cintura-cadera, presión arterial diastólica y frecuencia cardíaca en reposo cuando comparado a los otros grupos (p <0,05). Se observó que el grupo de danza presentó mejores puntajes de capacidad funcional y VO2Pico (todos p <0,05). Con relación a la modulación autonómica cardíaca, los grupos de danza y pilates demostraron mejores puntajes para RMSSD (26,71 ± 9,07 y 29,82 ± 7,16, respectivamente; p <0,05), LF (45,79 ± 14,81 y 45,95 ± 15,16 nu, respectivamente; p <0,05), y LF/HF (0,92 ± 0,56 y 0,58 ± 0,26, respectivamente; p <0,05). En el análisis simbólico, el grupo de danza presentó mayor predominancia de la modulación autonómica parasimpática que los demás grupos (p <0,05). Conclusión: Esos resultados concluyen que las mujeres mayores físicamente activas, practicantes de hidrogimnasia, pilates o danza, tienen beneficios fisiológicos, como mejor capacidad funcional y mejora de las variables hemodinámicas y de la modulación cardíaca autonómica. Además, el grupo que practicaba danza tuvo mayor modulación parasimpática y mayor capacidad funcional cuando comparado con las otras modalidades. Nivel de evidencia: I; STARD: estudios de precisión diagnóstica.

RESUMO Objetivo: Analisar a resposta da modulação autonômica cardíaca e a capacidade funcional em idosas fisicamente ativas. Métodos: Setenta e cinco mulheres idosas (60 a 70 anos) da comunidade foram divididas nos seguintes grupos: sedentária (n = 19), hidroginástica (n = 18), pilates (n = 19) e dança (n = 19). A pressão arterial, a composição corporal, a variabilidade da frequência cardíaca e a capacidade funcional foram avaliadas para a caracterização dos grupos em repouso e 48 horas depois da última sessão de exercício físico. Resultados: O grupo sedentário apresentou maior relação cintura-quadril, pressão arterial diastólica e frequência cardíaca em repouso quando comparado aos outros grupos (p <0,05). Observou-se também que o grupo da dança apresentou melhores escores de capacidade funcional e VO2pico (todos p < 0,05). Com relação à modulação autonômica cardíaca, os grupos de dança e pilates demonstraram melhores escores para RMSSD (26,71 ± 9,07 e 29,82 ± 7,16, respectivamente; p < 0,05), LF (45,79 ± 14,81 e 45,95 ± 15,16 nu, respectivamente; p<0,05) e LF/HF (0,92 ± 0,56 e 0,58 ± 0,26, respectivamente; p < 0,05). Na análise simbólica, o grupo da dança apresentou maior predominância da modulação autonômica parassimpática do que os demais grupos (p < 0,05). Conclusão: Esses resultados concluem que idosas fisicamente ativas praticantes de hidroginástica, pilates ou dança, têm benefícios fisiológicos, como melhor capacidade funcional e melhora das variáveis hemodinâmicas e da modulação cardíaca autonômica. Além disso, o grupo que praticava dança teve maior modulação parassimpática e maior capacidade funcional quando comparado com outras modalidades. Nível de evidência: I; STARD: estudos de precisão diagnóstica.

Effect of Predicted Versus Measured Thoracic Gas Volume on Body Fat Percentage in Young Adults.

The BodPod® (COSMED, Concord, CA) uses predicted (pTGV) or measured thoracic gas volume (mTGV) during estimations of percentage body fat (%BF). In young adults, there is inconsistent evidence on the variation between pTGV and mTGV, and the effect of sex as a potential covariate on this relationship is unknown. This study examined the difference between TGV assessments and its effect on %BF and potential sex differences that may impact this relationship. A retrospective analysis of BodPod® pTGV and mTGV for 95 men and 86 women ages 18-30 years was performed. Predicted TGV was lower than mTGV for men (-0.49 ± 0.7 L; p < .0001). For men, %BF derived by pTGV was lower than that by mTGV (-1.3 ± 1.8%; p < .0001). For women, no differences were found between pTGV and mTGV (-0.08 ± 0.6 L; p > .05) or %BF (-0.03 ± 0.2%; p > .05). The two-predictor model of sex and height was able to account for 57.9% of the variance in mTGV, F(2, 178) = 122.5, p < .0001. Sex corrected for the effect of height was a significant predictor of mTGV (ß = 0.483 L, p < .0001). There is bias for pTGV to underestimate mTGV in individuals with a large mTGV, which can lead to significant underestimations of %BF in young adults; this was especially evident for men in this study. Sex is an important covariate that should be considered when deciding to use pTGV. The results indicate that TGV should be measured whenever possible for both men and women ages 18-30 years.

Comparación de variables clínicas, capacidad funcional, ansiedad/depresión y calidad de vida en pacientes con EPOC de acuerdo a la clasificación GOLD 2018 / Comparison of clinical variables, functional capacity, anxiety/depression and quality of life in patients with COPD according to the GOLD 2018 classification

INTRODUCCIÓN: La Global Obstructive Lung Disease (GOLD) anualmente actualiza la guía para manejo de la EPOC, introduciendo cambios en la clasificación por letras, evaluación de síntomas o severidad de la obstrucción. Esto ha motivado el interés en indagar sobre las diferencias entre grupos en variables clínicas, calidad de vida relacionada con la salud (CVRS) y capacidad funcional. OBJETIVO: Determinar las diferencias en variables clínicas, supervivencia, de capacidad funcional, de ansiedad/depresión y CVRS en pacientes con enfermedad pulmonar obstructiva crónica (EPOC) de acuerdo a la clasificación GOLD 2018 en una clínica de Cali. MÉTODOS: Estudio observacional, analítico y transversal; se incluyeron 128 pacientes con diagnóstico de EPOC divididos en 3 grupos: GOLD-B, GOLD-C y GOLD-D. RESULTADOS: La edad media de los grupos fue 71 años y el 61% eran hombres. Las hospitalizaciones fueron más prevalentes en el grupo GOLD-C y GOLD-D, con 100% y 86% respectivamente, valor p < 0,001, con diferencias significativas en la supervivencia p < 0,001. La capacidad funcional evidenció una mayor distancia en el grupo GOLD-C con 344m y la menor distancia para el grupo GOLD-B con 271m, encontrando diferencia estadísticamente significativa. No se encontraron diferencias estadísticamente significativas en la ansiedad y la depresión. Al comparar los 3 grupos los pacientes GOLD-C tenían mejor CVRS en el cuestionario SGRQ; media de 37±15, GOLD-B de 45±16 y GOLD-D 55±15, con valor p = 0,002. CONCLUSIÓN: El grupo GOLD-C presentó mayor superviviencia, capacidad funcional y calidad de vida; por otra parte el grupo GOLD-D tuvo peor condición clínica, capacidad funcional y calidad de vida

INTRODUCTION: The Global Obstructive Lung Disease (GOLD) annually updates the COPD management guide, introducing changes in letter classification, symptom assessment, or severity of obstruction. This has motivated interest in investigating differences among groups in clinical variables, quality of life related to health (QOLRH) and functional capacity. OBJECTIVE: To determine the differences in clinical variables, survival, functional capacity, anxiety/depression and QOLRH in patients with chronic obstructive pulmonary disease (COPD) according to the GOLD 2018 classification in a Clinic in Cali (Colombia). METHODS: An observational, analytical and cross-sectional study including 128 patients (61% men) with a mean age of 71 years and diagnosis of COPD divided into three groups; GOLD-B, GOLD-C and GOLD-D. RESULTS: Hospitalizations were more prevalent in the GOLD-C and GOLD-D groups at 100% and 86% respectively, p value <.001, with significant differences in survival P<.001. Group GOLD-C showed greater functional capacity at 344 meters with a shorter distance for group GOLD-B at 271m, a statistically significant difference was found. No statistically significant differences were found in anxiety and depression. When comparing the three groups the GOLD- C patients had better QOLRH in the SGRQ questionnaire; mean of 37±15, (GOLD-B) of 45±16 and GOLD-D 55±15 with a P value=.002. CONCLUSION: Group GOLD-C showed greater survival, functional capacity and quality of life and GOLD-D had worse clinical condition, functional capacity and quality of life

Comparison of inspiratory and expiratory lung and lobe volumes among supine, standing, and sitting positions using conventional and upright CT.

Currently, no clinical studies have compared the inspiratory and expiratory volumes of unilateral lung or of each lobe among supine, standing, and sitting positions. In this prospective study, 100 asymptomatic volunteers underwent both low-radiation-dose conventional (supine position, with arms raised) and upright computed tomography (CT) (standing and sitting positions, with arms down) during inspiration and expiration breath-holds and pulmonary function test (PFT) on the same day. We compared the inspiratory/expiratory lung/lobe volumes on CT in the three positions. The inspiratory and expiratory bilateral upper and lower lobe and lung volumes were significantly higher in the standing/sitting positions than in the supine position (5.3-14.7% increases, all P < 0.001). However, the inspiratory right middle lobe volume remained similar in the three positions (all P > 0.15); the expiratory right middle lobe volume was significantly lower in the standing/sitting positions (16.3/14.1% decrease) than in the supine position (both P < 0.0001). The Pearson's correlation coefficients (r) used to compare the total lung volumes on inspiratory CT in the supine/standing/sitting positions and the total lung capacity on PFT were 0.83/0.93/0.95, respectively. The r values comparing the total lung volumes on expiratory CT in the supine/standing/sitting positions and the functional residual capacity on PFT were 0.83/0.85/0.82, respectively. The r values comparing the total lung volume changes from expiration to inspiration on CT in the supine/standing/sitting positions and the inspiratory capacity on PFT were 0.53/0.62/0.65, respectively. The study results could impact preoperative CT volumetry of the lung in lung cancer patients (before lobectomy) for the prediction of postoperative residual pulmonary function, and could be used as the basis for elucidating undetermined pathological mechanisms. Furthermore, in addition to morphological evaluation of the chest, inspiratory and expiratory upright CT may be used as an alternative tool to predict lung volumes such as total lung capacity, functional residual capacity, and inspiratory capacity in situation in which PFT cannot be performed such as during an infectious disease pandemic, with relatively more accurate predictability compared with conventional supine CT.

Effect of positive end-expiratory pressure on functional residual capacity in two experimental models of acute respiratory distress syndrome.

OBJECTIVE: Measurement of positive end-expiratory pressure (PEEP)-induced recruitment lung volume using passive spirometry is based on the assumption that the functional residual capacity (FRC) is not modified by the PEEP changes. We aimed to investigate the influence of PEEP on FRC in different models of acute respiratory distress syndrome (ARDS). METHODS: A randomized crossover study was performed in 12 pigs. Pulmonary (n = 6) and extra-pulmonary (n = 6) ARDS models were established using an alveolar instillation of hydrochloric acid and a right atrium injection of oleic acid, respectively. Low (5 cmH2O) and high (15 cmH2O) PEEP were randomly applied in each animal. FRC and recruitment volume were determined using the nitrogen wash-in/wash-out technique and release maneuver. RESULTS: FRC was not significantly different between the two PEEP levels in either pulmonary ARDS (299 ± 92 mL and 309 ± 130 mL at 5 and 15 cmH2O, respectively) or extra-pulmonary ARDS (305 ± 143 mL and 328 ± 197 mL at 5 and 15 cmH2O, respectively). The recruitment volume was not significantly different between the two models (pulmonary, 341 ± 100 mL; extra-pulmonary, 351 ± 170 mL). CONCLUSIONS: PEEP did not influence FRC in either the pulmonary or extra-pulmonary ARDS pig model.

Enfermedad tromboembólica crónica pulmonar / Chronic Pulmonary Thromboembolic Disease

Es frecuente observar lesiones trombóticas persistentes en los pacientes que sufren una embolia pulmonar. Estas lesiones pueden cursar con un espectro clínico amplio, desde un curso asintomático con recuperación funcional completa hasta la hipertensión pulmonar tromboembólica crónica. En los últimos años ha emergido el concepto de enfermedad tromboembólica crónica pulmonar para designar al subgrupo de pacientes con lesiones trombóticas persistentes que presentan síntomas con el esfuerzo y disfunción vascular pulmonar, pero que no muestran hipertensión pulmonar en reposo. La prevalencia de esta entidad es desconocida y los criterios para diagnosticarla no están definidos. El objetivo del presente artículo es analizar las secuelas que se producen tras una embolia pulmonar y revisar la información disponible sobre la enfermedad tromboembólica crónica, con especial énfasis en su diagnóstico y abordaje terapéutico

Persistent thrombotic lesions are common in patients with pulmonary embolism. These lesions occur on a clinical spectrum, ranging from an asymptomatic course with complete functional recovery to chronic thromboembolic pulmonary hypertension. The concept of chronic thromboembolic disease has emerged in recent years to describe a subgroup of patients with persistent thrombotic lesions who have symptoms on exertion and pulmonary vascular dysfunction, but no pulmonary hypertension at rest. The prevalence of this entity is unknown and the criteria for diagnosing it are not defined. The aim of this article is to analyze post- pulmonary embolism sequelae and review existing evidence on chronic thromboembolic disease, with special emphasis on its diagnosis and therapeutic approach

Diaphragm thickening assessed by ultrasonography is lower than healthy adults in patients with chronic obstructive pulmonary disease.

BACKGROUND: Ultrasound imaging has been widely used for imaging of the diaphragm thickness (Tdi) and thickening. Few studies assessed the Tdi using ultrasonography in patients with chronic obstructive pulmonary disease (COPD). We measured the Tdi and thickening in patients with COPD compared with healthy younger and healthy older adults to reveal the influence of ageing and/or COPD. METHODS: Thirty-eight male patients with COPD (age 72 ± 8 years), 15 healthy younger (age 22 ± 1 years) and 15 healthy older (age 72 ± 5 years) male volunteers were recruited. We measured Tdi at total lung capacity (TdiTLC ), functional residual capacity (TdiFRC ) and residual volume (TdiRV ) using B-mode ultrasonography. We calculated the change ratio of TdiTLC and TdiRV (ΔTdi%). We used a one-way analysis of variance and multiple comparison test for the comparison analysis. RESULTS: The TdiTLC and the ΔTdi% were significantly lower in patients with COPD compared to the healthy adults. There was no significant difference in these values with age. There was no between group difference in the TdiFRC or TdiRV . CONCLUSIONS: Our results indicate significant differences in TdiTLC and ΔTdi% between patients with COPD and healthy adults. Therefore, diaphragm ultrasonography can assess diaphragm dysfunction associated with COPD. We suggest that it is better to use TdiTLC and ΔTdi% (not only Tdi at rest) to assess diaphragm function.

Lung clearance index in healthy volunteers, measured using a novel portable system with a closed circuit wash-in.

INTRODUCTION: Lung clearance index (LCI) is a sensitive measure of early lung disease, but adoption into clinical practice has been slow. Challenges include the time taken to perform each test. We recently described a closed-circuit inert gas wash-in method that reduces overall testing time by decreasing the time to equilibration. The aim of this study was to define a normative range of LCI in healthy adults and children derived using this method. We were also interested in the feasibility of using this system to measure LCI in a community setting. METHODS: LCI was assessed in healthy volunteers at three hospital sites and in two local primary schools. Volunteers completed three washout repeats at a single visit using the closed circuit wash-in method (0.2% SF6 wash-in tracer gas to equilibrium, room air washout). RESULTS: 160 adult and paediatric subjects successfully completed LCI assessment (95%) (100 in hospital, 60 in primary schools). Median coefficient of variation was 3.4% for LCI repeats and 4.3% for FRC. Mean (SD) LCI for the analysis cohort (n = 53, age 5-39 years) was 6.10 (0.42), making the upper limit of normal LCI 6.8. There was no relationship between LCI and multiple demographic variables. Median (interquartile range) total test time was 18.7 (16.0-22.5) minutes. CONCLUSION: The closed circuit method of LCI measurement can be successfully and reproducibly measured in healthy volunteers, including in out-of-hospital settings. Normal range appears stable up to 39 years. With few subjects older than 40 years, further work is required to define the normal limits above this age.

Efectos fisiológicos de las terapias de soporte respiratorio no invasivo y su potencial rol postextubación / Physiological effects of non-invasive respiratory support therapies and their potential post-extubation role

Posterior a una extubación programada existe un porcentaje de pacientes que fracasa y requiere reintubación (~20%), este evento es conocido como fracaso de extubación, el cual se asocia con mayor morbimortalidad. Para prevenir el fracaso de extubación se han propuesto terapias como la ventilación no invasiva (VNI) y la cánula nasal de alto flujo (CNAF). Estas terapias son capaces de entregar soporte respiratorio postextubación y justifican su uso en los efectos fisiológicos que son capaces de inducir, en dónde el impacto sobre el esfuerzo respiratorio e intercambio de gases sería fundamental. Con esta racionalidad fisiológica se han desarrollado diversos estudios en diferentes contextos clínicos, esto con el fin de dilucidar cuál terapia es la mejor alternativa. En esta revisión narrativa pretendemos describir y analizar los diversos efectos fisiológicos que induce la VNI y la CNAF

1D network simulations for evaluating regional flow and pressure distributions in healthy and asthmatic human lungs.

This study aimed to introduce a one-dimensional (1D) computational fluid dynamics (CFD) model for airway resistance and lung compliance to examine the relationship between airway resistance, pressure, and regional flow distribution. We employed five healthy and five asthmatic subjects who had dynamic computed tomography (CT) scans (4D CT) along with two static scans at total lung capacity and functional residual capacity. Fractional air-volume change ( ΔVairf ) from 4D CT was used for a validation of the 1D CFD model. We extracted the diameter ratio from existing data sets of 61 healthy subjects for computing mean and standard deviation (SD) of airway constriction/dilation in CT-resolved airways. The lobar mean (SD) of airway constriction/dilation was used to determine diameters of CT-unresolved airways. A 1D isothermal energy balance equation was solved, and pressure boundary conditions were imposed at the acinar region (model A) or at the pleural region (model B). A static compliance model was only applied for model B to link acinar and pleural regions. The values of 1D CFD-derived ΔVairf for model B demonstrated better correlation with 4D CT-derived ΔVairf than model A. In both inspiration and expiration, asthmatic subjects with airway constriction show much greater pressure drop than healthy subjects without airway constriction. This increased transpulmonary pressures in the asthmatic subjects, leading to an increased workload (hysteresis). The 1D CFD model was found to be useful in investigating flow structure, lung hysteresis, and pressure distribution for healthy and asthmatic subjects. The derived flow distribution could be used for imposing boundary conditions of 3D CFD. NEW & NOTEWORTHY A one-dimensional (1D) computational fluid dynamics (CFD) model for airway resistance and lung compliance was introduced to examine the relationship between airway resistance, pressure, and regional flow distribution. The 1D CFD model investigated differences of flow structure, lung hysteresis, and pressure distribution for healthy and asthmatic subjects. The derived flow distribution could be used for imposing boundary conditions of three-dimensional CFD.

Influence of obesity in pulmonary function and exercise tolerance in obese women with obstructive sleep apnea.

OBJECTIVE: To evaluate the influence of obesity on pulmonary function and exercise tolerance in women with obstructive sleep apnea (OSA). SUBJECTS AND METHODS: A descriptive analytic cross- sectional study was carried out. Thirty-nine (39) sedentary climacteric women, aged 45 to 60 years, were evaluated and submitted to polysomnography. The participants were divided into 4 groups: a) 'eutrophic non-OSA' (n = 13); b) 'eutrophic OSA' (n = 5); c) 'obese non-OSA' (n = 6); d) 'obese OSA' (n = 15). All subjects underwent clinical and anthropometric evaluation, followed by pulmonary function tests and 6-minute walk test (6MWT). RESULTS: There was a significant difference in the predicted percentage values of FEV1/FVC when comparing 'eutrophic OSA' and 'obese OSA' (97.6% ± 6.1% vs. 105.7% ± 5.7%, respectively; p = 0.025). The other spirometric variables did not show any differences between the studied groups. There was no significant difference in the maximum distance walked when the 'eutrophic non-OSA', 'eutrophic OSA', 'obese non-OSA' and 'obese OSA' groups were compared. CONCLUSION: Considering the results of this study, OSA itself did not influence pulmonary function or functional capacity parameters compared to eutrophic women. However, not only isolated obesity but also obesity associated with OSA can negatively impact sleep quality and lung function.

Effects of inspiratory muscle training on postural stability, pulmonary function and functional capacity in children with cystic fibrosis: A randomised controlled trial.

BACKGROUND: Previous research has found conflictive results regarding the benefits of inspiratory muscle training (IMT) for cystic fibrosis (CF) patients. Also, involvement of postural stability is a rising concern in chronic lung diseases but its role in CF patients is poorly understood. Our aim was to investigate the effects of IMT in CF patients as well as analysing the factors which may be related to postural stability. METHODS: Thirty-six children aged between 8 and 18 years with CF were randomly allocated to either "comprehensive chest PT" group (PT) or "IMT alongside comprehensive chest PT" group (PT+IMT). Both groups trained for 8 weeks. Dynamic and static postural stability tests on Biodex Balance system®, spirometry, respiratory muscle strength and 6-min walk distance (6MWD) was assessed at baseline and after 8 weeks of training. Determinants of postural stability was also analysed on baseline values. RESULTS: Maximum expiratory pressure (MEP) was found to be an independent predictor for overall limits of stability (LOS) score explaining %26 of variance (R = 0.514, p = 0.003). Overall LOS score, FVC, FEV1, peak expiratory flow, MEP and 6MWD significantly improved in both groups, with no significant differences between groups. Maximum inspiratory pressure (MIP) also improved in both groups but the magnitude of improvement in MIP was greater in PT+IMT group (38 cmH2O vs 13 cmH2O; p < 0.001). CONCLUSIONS: Combining IMT with chest PT failed to provide further improvements, except for MIP, suggesting that a comprehensive chest PT program may be individually effective in improving overall LOS score, spirometry, respiratory muscle strength and 6MWD. TRIAL REGISTRATION: www.ClinicalTrials.gov; registration number: NCT03375684.

Respiratory system reactance reflects communicating lung volume in chronic obstructive pulmonary disease.

Respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) is theoretically and experimentally related to lung volume. In chronic obstructive pulmonary disease (COPD), the absolute volume measured by body plethysmography includes a proportion that is inaccessible to pressure oscillations applied via the mouth, that is, a "noncommunicating" lung volume. We hypothesized that in COPD the presence of noncommunicating lung would disrupt the expected Xrs-volume relationship compared with plethysmographic functional residual capacity (FRCpleth). Instead, Xrs would relate to estimates of communicating volume, namely, expiratory reserve volume (ERV) and single-breath alveolar volume (VaSB). We examined FOT and lung function data from people with COPD (n = 51) and from healthy volunteers (n = 40). In healthy volunteers, we observed an expected inverse relationship between reactance at 5 Hz (X5) and FRCpleth. In contrast, there was no such relationship between X5 and FRCpleth in COPD subjects. However, there was an inverse relationship between X5 and both ERV and VaSB. Hence the theoretical Xrs-volume relationship is present in COPD but only when considering the communicating volume rather than the absolute lung volume. These findings confirm the role of reduced communicating lung volume as an important determinant of Xrs and therefore advance our understanding and interpretation of FOT measurements in COPD. NEW & NOTEWORTHY To investigate the determinants of respiratory system reactance (Xrs) measured by the forced oscillation technique (FOT) in chronic obstructive pulmonary disease (COPD), we examine the relationship between Xrs and lung volume. We show that Xrs does not relate to absolute lung volume (functional residual capacity) in COPD but instead relates only to the volume of lung in communication with the airway opening. This communicating volume may therefore be fundamental to our interpretation of FOT measurements in COPD and other pulmonary diseases.

Tidal breathing flow volume profiles during sleep in wheezing infants measured by impedance pneumography.

Overnight analysis of tidal breathing flow volume (TBFV) loops, recorded by impedance pneumography (IP), has been successfully applied in the home monitoring of children with wheezing disorders. However, little is known on how sleep physiology modifies the relationship between TBFV profiles and wheeze. We studied such interactions in wheezing infants. Forty-three infants recruited because of recurrent lower airway symptoms were divided into three groups based on their risk of asthma: high (HR), intermediate (IR), or low (LR). Sedated patients underwent infant lung function testing including assessment of airway responsiveness to methacholine at the hospital and a full-night recording of TBFV profiles at home with IP during natural sleep. Overnight TBFV indexes were estimated from periods of higher and lower respiration variability, presumably belonging to active [rapid eye movement (REM)] and quiet [non-REM (NREM)] sleep, respectively. From 35 valid recordings, absolute time indexes showed intrasubject sleep phase differences. Peak flow relative to time and volume was lower in HR compared with LR only during REM, suggesting altered expiratory control. Indexes estimating the concavity/convexity of flow decrease during exhalation suggested limited flow during passive exhale in HR compared with IR and LR, similarly during NREM and REM. Moreover, during REM convexity was negatively correlated with maximal flow at functional residual capacity and methacholine responsiveness. We conclude that TBFV profiles determined from overnight IP recordings vary because of sleep phase and asthma risk. Physiological changes during REM, most likely decrease in respiratory muscle tone, accentuate the changes in TBFV profiles caused by airway obstruction. NEW & NOTEWORTHY Impedance pneumography was used to investigate overnight tidal breathing flow volume (TBFV) indexes and their interactions with sleep phase [rapid eye movement (REM) vs. non-REM] at home in wheezing infants. The study shows that TBFV indexes vary significantly because of sleep phase and asthma risk of the infant and that during REM the changes in TBFV indexes caused by airway obstruction are accentuated and better associated with lung function of the infant.

Influence of obesity in pulmonary function and exercise tolerance in obese women with obstructive sleep apnea

ABSTRACT Objective: To evaluate the influence of obesity on pulmonary function and exercise tolerance in women with obstructive sleep apnea (OSA). Subjects and methods: A descriptive analytic cross- sectional study was carried out. Thirty-nine (39) sedentary climacteric women, aged 45 to 60 years, were evaluated and submitted to polysomnography. The participants were divided into 4 groups: a) 'eutrophic non-OSA' (n = 13); b) 'eutrophic OSA' (n = 5); c) 'obese non-OSA' (n = 6); d) 'obese OSA' (n = 15). All subjects underwent clinical and anthropometric evaluation, followed by pulmonary function tests and 6-minute walk test (6MWT). Results: There was a significant difference in the predicted percentage values of FEV1/FVC when comparing 'eutrophic OSA' and 'obese OSA' (97.6% ± 6.1% vs. 105.7% ± 5.7%, respectively; p = 0.025). The other spirometric variables did not show any differences between the studied groups. There was no significant difference in the maximum distance walked when the 'eutrophic non-OSA', 'eutrophic OSA', 'obese non-OSA' and 'obese OSA' groups were compared. Conclusion: Considering the results of this study, OSA itself did not influence pulmonary function or functional capacity parameters compared to eutrophic women. However, not only isolated obesity but also obesity associated with OSA can negatively impact sleep quality and lung function.

Lung Function in Infants with Sickle Cell Anemia.

Lung volumes and forced expiratory flows were evaluated in 22 infants with sickle cell anemia and compared with a control group. Forced expiratory flows showed significantly lower values in the sickle cell group. The majority of infants had normal lung function, and obstruction was the most common pattern of abnormality.

Influence of body mass on predicted values of static hyperinflation in COPD.

Introduction: For interpretation of body plethysmographic static hyperinflation, reference values are of crucial importance. Earliest reference values have been published by the European Coal and Steel Community (ECSC) and are based on sex, body height and age as predictors. As obesity can lead to a reduction of functional residual capacity (FRC) in lung-healthy subjects, more recent approaches included body weight or body surface area. This raises the question whether these models are appropriate in patients with COPD-induced hyperinflation. Method: Several FRC prediction models and their relation to body weight were analyzed in 1513 patients with stable COPD (mean [SD] age: 64.5 [8.2] years; GOLD grades 1-4: 219/722/484/88), a subset of the multicenter COPD and Systemic Consequences - Comorbidities Network cohort. Results: Absolute values of FRC were inversely related to body mass index (p<0.001). Applying the ECSC equations to calculate predicted values, this pattern was maintained (p<0.001). By contrast, an inverted, ie, positive, relation occurred when using equations that include body weight or surface area (p<0.001). The present analysis confirmed the inverse relation of body mass and FRC in COPD, resulting from a restrictive ventilatory pattern by diaphragm elevation and decreased chest wall compliance in obesity. The weight influence in the prediction models, as obtained from lung-healthy controls, appears to lead to an overcorrection and consequently to an inappropriate overestimation of hyperinflation as indicated by FRC %predicted in COPD. Conclusion: It is concluded that models not including body weight as predictor, like the classical ECSC equations, could be superior in the interpretation of FRC in COPD.