New reference values for maximum respiratory pressures in healthy Brazilian children following guidelines recommendations: A regional study.

OBJECTIVE: To determine reference values for maximum static respiratory pressures in healthy children from a Brazilian region, following recommendations of the European Respiratory Society (ERS) and the Brazilian Society of Pneumology and Tisiology (SBPT). METHODS: A cross-sectional observational study was conducted with healthy children (6 to 11 years) of both sexes. The maximum inspiratory and expiratory pressures (PImax and PEmax, respectively) were measured using a digital manometer. Each child performed a minimum of three and a maximum of five maneuvers; three acceptable and reproducible maneuvers were considered for analysis. Minimum time for each maneuver was 1.5 seconds, with a one-second plateau, and one minute of rest between them. A stepwise multiple linear regression analysis was conducted for PImax and PEmax, considering correlations between independent variables: age, weight, and sex. RESULTS: We included 121 children (62 girls [51%]). Boys reached higher values for maximum respiratory pressures than girls. Respiratory pressures increased with age showing moderate effect sizes (PImax: f = 0.36; PEmax: f = 0.30) between the stratified age groups (6-7, 8-9, and 10-11 years). Age and sex were included in the PImax equation (PImax = 24.630 + 7.044 x age (years) + 13.161 x sex; R2 = 0.189). PEmax equations were built considering age for girls and weight for boys [PEmax (girls) = 55.623 + 4.698 x age (years) and PEmax (boys) = 82.617 + 0.612 x weight (kg); R2 = 0.068]. CONCLUSIONS: This study determined new reference equations for maximal respiratory pressures in healthy Brazilian children, following ERS and SBPT recommendations.

Non-invasive assessment of fatigue and recovery of inspiratory rib cage muscles during endurance test in healthy individuals.

INTRODUCTION: Fatigue is defined as loss of capacity to develop muscle force and/or velocity that is reversible at rest. We assessed non-invasively the fatigue and recovery of inspiratory rib cage muscles during two respiratory endurance tests in healthy individuals. METHODS: The sniff nasal inspiratory pressure (SNIP) was assessed before and after two respiratory endurance tests: normocapnic hyperpnea (NH) and inspiratory pressure threshold loading (IPTL). Contractile (maximum rate of pressure development and time to peak pressure) and relaxation parameters (maximum relaxation rate [MRR], time constant of pressure decay [τ], and half relaxation time) obtained from sniff curves and shortening velocity and mechanical power estimated using optoelectronic plethysmography were analyzed during SNIP maneuvers. Respiratory muscle activity (electromyography) and tissue oxygenation (near-infrared spectroscopy-NIRS) were obtained during endurance tests and SNIP maneuvers. Fatigue development of inspiratory rib cage muscles was assessed according to the slope of decay of median frequency. RESULTS: Peak pressure during SNIP decreased after both protocols (p <0.05). MRR, shortening velocity, and mechanical power decreased (p <0.05), whereas τ increased after IPTL (p <0.05). The median frequency of inspiratory rib cage muscles (i.e., sum of sternocleidomastoid, scalene, and parasternal) decreased linearly during IPTL and exponentially during NH, mainly due to the sternocleidomastoid. CONCLUSION: Fatigue development behaved differently between protocols and relaxation properties (MRR and τ), shortening velocity, and mechanical power changed only in the IPTL.

Remote versus face-to-face home-based exercise programme in people with amyotrophic lateral sclerosis: protocol for a randomised clinical trial.

INTRODUCTION: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease with variable and complex clinical manifestations that requires a multidisciplinary approach. However, face-to-face treatment in this population may experience barriers, such as difficulty accessing physical therapists or other professionals. As a result, strategies (eg, telerehabilitation) emerged to facilitate treatment and physical therapy monitoring. This study aims to evaluate the effects of remote versus face-to-face home-based exercise programmes on clinical outcomes and treatment adherence of people with ALS. METHODS AND ANALYSIS: This is a single-blind randomised clinical trial protocol that will include 44 people with clinical diagnosis of ALS at any clinical stage and aged between 18 and 80 years. Participants will be randomised into two groups after face-to-face evaluation and perform a home-based exercise programme three times a week for 6 months. A physical therapist will monitor the exercise programme once a week remotely (phone calls-experimental group) or face-to-face (home visits-control group). The primary outcome measure will be functional capacity (Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised). Secondary outcomes will include disease severity (Amyotrophic Lateral Sclerosis Severity Scale), fatigue (Fatigue Severity Scale), pain (Visual Analogue Scale and body pain diagram), adverse events and adherence rate. Outcomes will be initially evaluated face-to-face and revaluated remotely every 2 months and 1 month after interventions. Linear mixed models will compare outcome measures between groups and evaluations (α=5%). ETHICS AND DISSEMINATION: This study was approved by the research ethics committee of Hospital Universitário Onofre Lopes/Universidade Federal do Rio Grande do Norte (no. 3735479). We expect to identify the effects of an exercise programme developed according to ALS stages and associated with remote or face-to-face monitoring on clinical outcomes using revaluations and follow-up after interventions. TRIAL REGISTRATION NUMBER: Brazilian Registry Clinical Trials (RBR-10z9pgfv).

Breathing pattern and muscle activity using different inspiratory resistance devices in children with mouth breathing syndrome.

Aim: The aim of this study was to evaluate the acute effects of different inspiratory resistance devices and intensity of loads via nasal airway on the breathing pattern and activity of respiratory muscles in children with mouth breathing syndrome (MBS). Methods: Children with MBS were randomised into two groups based on inspiratory load intensity (20% and 40% of the maximal inspiratory pressure). These subjects were assessed during quiet breathing, breathing against inspiratory load via nasal airway and recovery. The measurements were repeated using two different devices (pressure threshold and flow resistance). Chest wall volumes and respiratory muscle activity were evaluated by optoelectronic plethysmography and surface electromyography, respectively. Results: During the application of inspiratory load, there was a significant reduction in respiratory rate (p<0.04) and an increase in inspiratory time (p<0.02), total time of respiratory cycle (p<0.02), minute ventilation (p<0.03), tidal volume (p<0.01) and scalene and sternocleidomastoid muscles activity (root mean square values, p<0.01) when compared to quiet spontaneous breathing and recovery, regardless of load level or device applied. The application of inspiratory load using the flow resistance device showed an increase in the tidal volume (p<0.02) and end-inspiratory volume (p<0.02). Conclusion: For both devices, the addition of inspiratory loads using a nasal interface had a positive effect on the breathing pattern. However, the flow resistance device was more effective in generating volume and, therefore, has advantages compared to pressure threshold.

Association between performance on the Glittre ADL-test and the functional capacity of patients with HF: A cross-sectional study.

Background: The Weber classification based on peak VO2 is a well-established method for categorizing patients with heart failure (HF) regarding severity. However, other submaximal tests such as the Glittre ADL-Test have been gaining prominence in practice due to a coherent and more comprehensive correlation with limitations for performing activities of daily living in patients with heart failure.Objective: To investigate the correlation between the time required to perform the Glittre ADL-Test and the peak VO2 in patients with HF.Methods: A cross-sectional study conducted with 40 adult individuals (21 to 65 years) diagnosed with HF of all etiologies, with LVEF<50% and NYHA II and III.Results: The average time for performing the Glittre ADL-Test was 284.9 seconds, and a significant difference was found between Weber classification classes A and C (p = .01). Significant correlations with peak VO2 were also found (r = -0.424 - p < .01). Thirty (30) patients performed a second test, and the ICC found in the reproducibility analysis was 0.75 (95% CI 0.14-0.91) and p < .01.Conclusion: The Glittre ADL-Test was able to reflect the functional performance of individuals with HF, suggesting that it represents an evaluation tool which can be safely used in clinical practice.

Thoracoabdominal asynchrony and paradoxical motion in Duchenne muscular dystrophy and healthy subjects during cough: A case control study.

OBJECTIVE: To assess thoracoabdominal asynchrony (TAA) and inspiratory paradoxical motion at different positionings in subjects with Duchenne muscular dystrophy (DMD) versus healthy subjects during quiet spontaneous breathing (QB) and cough. METHODS: This is a case control study with a matched-pair design. We assessed 14 DMD subjects and 12 controls using optoelectronic plethysmography (OEP) during QB and spontaneous cough in 3 positions: supine, supine with headrest raised at 45°, and sitting with back support at 80°. The TAA was assessed using phase angle (θ) between upper (RCp) and lower rib cage (RCa) and abdomen (AB), as well as the percentage of inspiratory time the RCp (IPRCp ), RCa (IPRCa ), and AB (IPAB ) moved in opposite directions. RESULTS: During cough, DMD group showed higher RCp and RCa θ (p < .05), RCp and AB θ (p < .05) in supine and 45° positions, and higher RCp and Rca θ (p = .006) only in supine position compared with controls. Regarding the intragroup analysis, during cough, DMD group presented higher RCp and AB θ (p = .02) and RCa and AB θ (p = .002) in supine and higher RCa and AB θ (p = .002) in 45° position when compared to 80°. Receiver operating characteristic curve analyzes were able to discriminate TAA between controls and DMD in RCa supine position (area under the curve: 0.81, sensibility: 78.6% and specificity: 91.7%, p = .001). CONCLUSION: Subjects with DMD yields TAA with insufficient deflation of chest wall compartments and rib cage distortion during cough, by noninvasive assessment.

Effects of Inspiratory Load on Chest Wall Kinematics, Breathing Pattern, and Respiratory Muscle Activity of Mouth-Breathing Children.

BACKGROUND: We sought to evaluate the acute effects of different inspiratory loads using nasal and oral interfaces on the volumes of the chest wall and its compartments, breathing pattern, and respiratory muscle activation in children with mouth-breathing syndrome. METHODS: Children with mouth-breathing syndrome were randomized into 2 groups, one with an inspiratory load intensity 20% of maximum inspiratory pressure (n = 14), and the other with an inspiratory load intensity 40% of maximum inspiratory pressure (n = 15). The chest wall volumes and electromyography of sternocleidomastoid, rectus abdominis, scalene, and internal intercostal muscles were used to analyze respiration against the 2 load intensities and using 2 interfaces (ie, nasal and oral). RESULTS: A total of 72 children with mouth-breathing syndrome were recruited, and 29 were evaluated in this study. The use of inspiratory load promoted improvement in the components of the breathing pattern: breathing frequency (P = .039), inspiratory time (P = .03), and total respiratory time (P = .043); and increases in tidal volume (P < .001), end-inspiratory volume (P < .001), and electrical activity of scalene muscles and sternocleidomastoid muscles (P < .001) when compared to quiet breathing. The load imposed via a nasal interface versus an oral interface provided an increase in tidal volume (P = .030), end-inspiratory volume (P = .02), and electrical activity of scalene muscles (P < .001) and sternocleidomastoid muscles (P = .02). CONCLUSIONS: The use of acute inspiratory loads improved the breathing pattern and increased lung volume and electrical activity of inspiratory muscles. This work brings new perspective to the investigation of using nasal interfaces during the application of inspiratory loads. The nasal interface was more effective compared to the oral interface commonly used in clinical practice.

Effects of Positioning on Cough Peak Flow and Muscular Electromyographic Activation in Duchenne Muscular Dystrophy.

BACKGROUND: Advanced stages of Duchenne muscular dystrophy (DMD) result in muscle weakness and the inability to generate an effective cough. Several factors influence the effectiveness of cough in patients with DMD. The aim of this study was to assess whether differences in positioning affect cough peak flow (CPF) and muscular electromyographic activation in subjects with DMD compared with paired healthy subjects. METHODS: Optoelectronic plethysmography and surface electromyography were used to assess chest wall volumes, chest wall inspiratory capacity, CPF, breathing pattern, and electromyographic activity of sternocleidomastoid, scalene, rectus abdominis, and external oblique muscles during inspiratory and expiratory cough phases in the supine position, supine position with headrest raised at 45°, and sitting with back support at 80° in 12 subjects with DMD and 12 healthy subjects. RESULTS: Subjects with DMD had lower CPF (P < .01) in comparison to control subjects in all positions; the DMD group also exhibited lower CPF (P = .045) in the supine position versus 80°. Moreover, the relative volume contributions of the rib cage and abdominal compartments to tidal volume modified significantly with posture. The electromyographic activity during inspiratory and expiratory cough phases was lower in subjects with DMD compared to healthy subjects for all evaluated muscles (P < .05), but no significant differences were observed with posture change. CONCLUSIONS: In subjects with DMD, posture influenced CPF and the relative contribution of the rib cage and abdominal compartments to tidal volume. However, muscular electromyographic activation was not influenced by posture in subjects with DMD and healthy subjects.

Maximal Voluntary Ventilation Should Not Be Estimated From the Forced Expiratory Volume in the First Second in Healthy People and COPD Patients.

PURPOSE: To evaluate the concordance between the value of the actual maximum voluntary ventilation (MVV) and the estimated value by multiplying the forced expiratory volume in the first second (FEV1) and a different value established in the literature. METHODS: A retrospective study was conducted with healthy subjects and patients with stable chronic obstructive pulmonary disease (COPD). Five prediction formulas MVV were used for the comparison with the MVV values. Agreement between MVV measured and MVV obtained from five prediction equations were studied. FEV1 values were used to estimate MVV. Correlation and agreement analysis of the values was performed in two groups using the Pearson test and the Bland-Altman method; these groups were one group with 207 healthy subjects and the second group with 83 patients diagnosed with COPD, respectively. RESULTS: We recruited 207 healthy subjects (105 women, age 47 ± 17 years) and 83 COPD patients (age 66 ± 6 years; 29 GOLD II, 30 GOLD III, and 24 GOLD IV) for the study. All prediction equations presented a significant correlation with the MVV value (from 0.38 to 0.86, p < 0.05) except for the GOLD II subgroup, which had a poor agreement with measured MVV. In healthy subjects, the mean difference of the value of bias (and limits of agreement) varied between -3.9% (-32.8 to 24.9%), and 27% (-1.4 to 55.3%). In COPD patients, the mean difference of value of bias (and limits of agreement) varied between -4.4% (-49.4 to 40.6%), and 26.3% (-18.3 to 70.9%). The results were similar in the subgroup analysis. CONCLUSION: The equations to estimate the value of MVV present a good degree of correlation with the real value of MVV, but they also show a poor concordance. For this reason, we should not use the estimated results as a replacement for the real value of MVV.

Acute Effects of Inspiratory Loads and Interfaces on Breathing Pattern and Activity of Respiratory Muscles in Healthy Subjects.

OBJECTIVES: The aim of this study was to evaluate the acute effects of different inspiratory loads and different interfaces on the breathing pattern and activity of the respiratory muscles. METHODS: Twenty healthy adults were recruited and assigned to two groups (20 and 40% of the Maximal Inspiratory Pressure) by way of randomized crossover allocation. Subjects were evaluated during quiet breathing, breathing against inspiratory load, and recovery. The measurements were repeated using two different interfaces (nasal and oral). Chest wall volumes and respiratory muscle activity were assessed with optoelectronic plethysmography and surface electromyography, respectively. RESULTS: During the application of inspiratory load, significant changes were observed in the respiratory rate (p < 0.04), inspiratory time (p < 0.02), minute ventilation (p < 0.04), tidal volume (p < 0.01), end-inspiratory volume (p < 0.04), end-expiratory volume (p < 0.03), and in the activity of the scalene, sternocleiomastoid, and parasternal portion of the intercostal muscles (RMS values, p < 0.01) when compared to quiet breathing, regardless of the load level or the interface applied. Inspiratory load application yielded significant differences between using nasal and oral interfaces with an increase in the tidal volume (p < 0.01), end-inspiratory volume (p < 0.01), and electrical activity of the scalene and sternocleiomastoid muscles (p < 0.01) seen with using the nasal interface. CONCLUSION: The addition of an inspiratory load has a significant effect on the breathing pattern and respiratory muscle electrical activity, and the effects are greater when the nasal interface is applied.

Acute effects of three pulmonary reexpansion modalities on thoracoabdominal motion of healthy subjects: Randomized crossover study.

BACKGROUND: Chest physiotherapy can be an alternative to increase lung volumes through pulmonary expansion therapies, but there is still inconsistency in the literature in order to determine which device can promote a greater volume increase at the expense of a better ventilatory pattern. Therefore, the aim of this study was to evaluate and compare the chest wall kinematics of healthy subjects submitted to the use of three different devices for pulmonary reexpansion. METHODS: Chest wall compartmental and operational volumes, breathing pattern and thoracoabdominal asynchrony were evaluated in 12 healthy individuals through optoelectronic plethysmography during quiet breathing, pulmonary reexpansion and recovery. Three different devices (volume-oriented incentive spirometer-IS-v; positive expiratory pressure-PEP; and incentive spirometer volume and pressure oriented-IS-vp) were administered in a random order with at least 48h between the devices. RESULTS: A greater volume variation in the chest wall and its compartments was observed when the IS-vp was used in comparison with the other devices (p<0.05). Furthermore, the IS-vp mobilizes a greater amount of volume accompanied by greater synchronism between the compartments when compared to IS-v (p <0.05). CONCLUSION: The IS-vp may be able to increase total and compartmental chest wall volumes, as well as improve synchrony among compartments when compared to IS-v and PEP devices, thus constituting an important tool for treating patients with restrictive ventilatory pattern.

Chest wall volume and asynchrony in stroke and Parkinson's disease subjects: A case-control study.

BACKGROUND: The expansion of the rib cage and abdomen occurs in a synchronic way during a coordinated contraction of the diaphragm and the abdominal and intercostal muscles under normal conditions and healthy. The presence of restrictive respiratory disease may lead to uncoordinated action of the respiratory muscles which affects breathing pattern and chest wall volumes. The aim of this study was to evaluate chest wall volumes, chest wall asynchrony and inspiratory paradoxical movement of breathing, as well as the influence of the time of disease diagnosis in subjects with Parkinson's disease and post-Stroke in comparison to healthy individuals. METHODS: Total and compartmental chest wall volumes, chest wall asynchrony and paradoxical movement were measured at rest in a seated position by Optoelectronic Plethysmography in 76 individuals (29 healthy individuals, 20 post-Stroke and 27 Parkinson's disease subjects). Post-stroke and Parkinson's disease subjects were also grouped according to the length of diagnosis. RESULTS: In both groups with restrictive respiratory disease we observed that pulmonary rib cage compartment (VRCp) volume is reduced when compared to healthy subjects (p <0.05). This same pattern was observed when analyzing post-stroke subjects with more than three years of diagnosis and Parkinson's subjects with less than three years of diagnosis (p<0.05). Furthermore, post-stroke subjects with inspiratory paradoxical movement showed decreased total and compartmental chest wall volumes (p<0.05), while individuals with Parkinson's disease with inspiratory paradoxical movement only presented a decrease in pulmonary rib cage compartment volume (p<0.05). CONCLUSION: Our study presents new findings for better understanding of chest wall volumes and chest wall asynchrony in post-stroke and Parkinson's disease individuals. Half of the subjects with post-Stroke and Parkinson's disease presented inspiratory paradox movement, but changes in breathing pattern was especially observed in post-stroke subjects with more than three years of diagnosis.

[Domiciliary respiratory muscle training in myotonic dystrophy]. / Entrenamiento muscular respiratorio domiciliario en la distrofia muscular miotónica.

A 42-year-old man diagnosed with myotonic dystrophy experienced loss of respiratory muscle strength over a period of 6 months. We report the application of a domiciliary training program targeting both inspiratory and expiratory muscles. Maximal inspiratory and expiratory pressures, forced vital capacity, and forced midexpiratory flow rate were measured 6 months before start of training, just before commencement of the program, and immediately after 12 weeks of training. Adherence to the program was satisfactory. Inspiratory muscle training was efficacious in increasing respiratory muscle strength. Expiratory muscle training, which made use of the Threshold PEP bronchial hygiene device incorporating an adapted flutter valve, was not efficacious in increasing maximal expiratory pressure or halting its loss. However, decreased obstruction of medium-caliber airways was observed with use of the device.

Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals.

OBJECTIVE:: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. METHODS:: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. RESULTS:: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. CONCLUSIONS:: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects. OBJETIVO:: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. MÉTODOS:: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. RESULTADOS:: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. CONCLUSÕES:: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.

Effects of 8-week, interval-based inspiratory muscle training and breathing retraining in patients with generalized myasthenia gravis.

STUDY OBJECTIVE: To assess the effect of interval-based inspiratory muscle training (IMT) combined with breathing retraining (BR) in patients with generalized myasthenia gravis (MG) in a partial home program. DESIGN: A randomized controlled trial with blinding of outcome assessment. SETTING: A secondary-care respiratory clinic. PATIENTS: Twenty-seven patients with generalized MG were randomized to a control group or a training group. INTERVENTIONS: The training group underwent interval-based IMT associated with BR (diaphragmatic breathing [DB] and pursed-lips breathing [PLB]) three times a week for 8 weeks. The sessions included 10 min each of DB, interval-based IMT, and PLB. Interval-based IMT consisted of training series interspersed with recovery time. The threshold load was increased from 20 to 60% of maximal inspiratory pressure (P(Imax)) over the 8 weeks. MEASUREMENTS AND RESULTS: Lung function, respiratory pattern, respiratory muscle strength, respiratory endurance, and thoracic mobility were measured before and after the 8 weeks. The training group improved significantly compared to control group in P(Imax) (p = 0.001), maximal expiratory pressure (P(Emax)) [p = 0.01], respiratory rate (RR)/tidal volume (V(T)) ratio (p = 0.05), and upper chest wall expansion (p = 0.02) and reduction (p = 0.04). Significant differences were seen in the training group compared to baseline P(Imax) (p = 0.001), P(Emax) (p = 0.01), maximal voluntary ventilation (p = 0.02), RR/V(T) ratio (p = 0.003), Vt (p = 0.02), RR (p = 0.01), total time of RR (p = 0.01), and upper chest wall expansion (p = 0.005) and reduction (p = 0.005). No significant improvement was seen in lower chest wall or lung function. CONCLUSIONS: The partial home program of interval-based IMT associated with BR is feasible and effective in patients with generalized MG. Improvements in respiratory muscle strength, chest wall mobility, respiratory pattern, and respiratory endurance were observed.

Monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of pulmonary function evaluation in amyotrophic lateral sclerosis.

OBJECTIVE: It was study the relationship between respiratory muscle strength and forced vital capacity (FVC) in patients with amyotrophic lateral sclerosis (ALS) versus healthy subjects. METHODS: Pulmonary function and respiratory muscle strength [maximal inspiratory (PImax), maximal expiratory (PEmax) and sniff nasal inspiratory pressure (SNIP)] were assessed in patients with ALS and healthy subjects, matched using cutoffs established in the literature for impaired pulmonary function and respiratory muscle weakness. RESULTS: Twenty-eight ALS patients and 28 healthy subjects were studied. We found sensitivity and specificity for PImax, PEmax and SNIP of 75/58%, 81/67% and 75/67%. The Receiver Operating Characteristic curve (ROC curve) indicated that the variables PImax, PEmax and SNIP can identify differences in respiratory muscle strength between ALS and healthy individuals at 0.89, 0.9 and 0.82, respectively. A positive correlation was recorded between FVC (%) versus SNIP, PImax and PEmax. CONCLUSION: In ALS, monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of FVC.

Diurnal variations in the parameters of pulmonary function and respiratory muscle strength in patients with COPD.

OBJECTIVE: To evaluate the magnitude of diurnal changes in the parameters of pulmonary function and respiratory muscle strength/endurance in a sample of patients with COPD. METHODS: A group of 7 patients underwent spirometry, together with determination of MIP and MEP, at two distinct times (between 8:00 and 8:30 a.m. and between 4:30 and 5:00 p.m.) on a single day. Between assessments, the patients remained at rest in the laboratory. RESULTS: In accordance with the Global Initiative for Chronic Obstructive Pulmonary Disease staging system, COPD was classified as moderate, severe, and very severe in 1, 3, and 3 of the patients, respectively. From the first to the second assessment, there were significant decreases in FVC, FEV1, and MEP (of 13%, 15%, and 10%, respectively), as well as (less than significant) decreases in PEF, MIP, and maximal voluntary ventilation (of 9%, 3%, and 11%, respectively). CONCLUSIONS: In this sample of COPD patients, there were diurnal variations in the parameters of pulmonary function and respiratory muscle strength. The values of FEV1, FVC, and MEP were significantly lower in the afternoon than in the morning.

Comparison of different levels of positive expiratory pressure on chest wall volumes in healthy children and patients with fibrosis / Comparação de diferentes níveis de pressão expiratória positiva em volumes de parede torácica em crianças saudáveis e pacientes com fibrose / Comparación de los diferentes niveles de la presión espiratoria positiva en los volúmenes de la pared torácica en niños saludables y pacientes con fibrosis

ABSTRACT Positive Expiratory Pressure (PEP) improves lung function, however, PEP-induced changes are not fully established. The aim of this study was to assess the acute effects of different PEP levels on chest wall volumes and the breathing pattern in children with Cystic Fibrosis (CF). Anthropometric data, lung function values, and respiratory muscle strength were collected. Chest wall volumes were assessed by Optoelectronic plethysmography at rest and during the use of different PEP levels (10 and 20 cm H2O), randomly chosen. Eight subjects with CF (5M, 11.5±3.2 years, 32±9.5 kilograms) and seven control subjects (4M, 10.7±1.5 years, 38.2±7.8 kilograms) were recruited. The CF group showed significantly lower FEF values 25-75% (CF: 1.8±0.8 vs. CG: 2.3±0.6) and FEV1/FVC ratio (CF: 0.8±0.1 vs. CG: 1±0.1) compared with the control group (p<0.05). Different PEP levels increased the usual volume in chest wall and its compartments in both groups; however, this volume was significantly higher in the control group compared with the CF group during PEP20 (CW: 0.77±0.25 L vs. 0.44±0.16 L; RCp: 0.3±0.13 L vs. 0.18±0.1 L; RCa: 0.21±0.1 L vs. 0.12±0.1 L; AB: 0.25±0.1 L vs. 0.15±0.1 L; p<0.05 for all variables). Minute ventilation was significantly higher during PEP compared with breathing at rest in both groups (p<0.005). End-expiratory volume was also higher during PEP compared with breathing at rest for chest wall and pulmonary rib cage in both groups (p<0.05). Different PEP levels may increase chest wall volumes in CF patients.

RESUMO Pressão Expiratória Positiva (PEwP) melhora a função pulmonar, entretanto, as mudanças induzidas pela PEP não estão totalmente estabelecidas. O objetivo do estudo foi avaliar os efeitos agudos de diferentes intensidades de PEP nos volumes da parede torácica (PT) e padrão respiratório em crianças com Fibrose Cística (FC). Dados antropométricos, função pulmonar e força da musculatura respiratória. Os volumes da PT foram avaliados através da Pletismografia Optoeletrônica (POE) em repouso e durante o uso de diferentes intensidades de PEP (10 e 20 cm H2O). Foram recrutados 8 sujeitos com FC (5H; 11,5 ± 3,2 anos; 32 ± 9,5 kg) e 7 sujeitos (4H; 10,7 ± 1,5 anos; 38,2 ± 7,8 kg). Grupo FC mostrou valores significativamente menores para FEF 25-75% (FC: 1,8 ± 0,8 vs. GC: 2,3 ± 0,6) e relação VEF1/CVF (FC: 0,8 ± 0,1 vs. GC: 1 ± 0,1) comparado ao grupo controle (p>0,05). Diferentes intensidades de PEP levaram a um aumento do volume corrente da PT e seus compartimentos em ambos os grupos, entretanto, este volume aumentou de forma significativa no grupo controle quando comparado ao grupo FC durante PEP20 (CW: 0,77 ± 0,25 L vs. 0,44 ± 0,16 L; RCp: 0,3 ± 0,13 L vs. 0,18 ± 0,1 L; RCa: 0,21 ± 0,1 L vs. 0,12 ± 0,1 L; AB: 0,25 ± 0,1 L vs. 0,15 ± 0,1 L; p>0,05 para todas as variáveis). A ventilação minuto aumentou de forma significativa durante a PEP em comparação a respiração em repouso para ambos os grupos (p>0,005). Volume expiratório final também foi maior durante a PEP em comparação a respiração em repouso para PT e caixa torácica pulmonar em ambos os grupos (p>0,05). Diferentes intensidades de PEP podem induzir aumentos nos volumes da parede torácica em pacientes com FC.

RESUMEN La Presión Espiratoria Positiva (PEP) mejora la función pulmonar, mientras tanto, los cambios inducidos por la PEP no están totalmente establecidos. El objetivo del estudio fue evaluar los efectos agudos de distintas intensidades de PEP en los volúmenes de la pared torácica (PT) y patrón respiratorio en niños con Fibrosis Cística (FC). Datos antropométricos, función pulmonar y fuerza de la musculatura respiratoria. Los volúmenes de la PT fueron evaluados a través de la Pletismografía Optoelectrónica (POE) en reposo y durante el uso de distintas intensidades de PEP (10 y 20 cm H2O). Fueron reclutados 8 sujetos con FC (5H; 11,5 ± 3,2 años; 32 ± 9,5 kg) y 7 sujetos (4H; 10,7 ± 1,5 años; 38,2 ± 7,8 kg). Grupo FC mostró valores significativamente menores para FEF 25-75% (FC: 1,8 ± 0,8 vs. GC: 2,3 ± 0,6) y relación VEF1/CVF (FC: 0,8 ± 0,1 vs. GC: 1 ± 0,1) comparado al grupo control (p>0,05). Distintas intensidades de PEP conllevaron a un incremento del volumen corriente de la PT y sus compartimentos en ambos los grupos, mientras tanto, este volumen incrementó de manera significativa en el grupo control cuando comparado al grupo FC durante PEP20 (CW: 0,77 ± 0,25 L vs. 0,44 ± 0,16 L; RCp: 0,3 ± 0,13 L vs. 0,18 ± 0,1 L; RCa: 0,21 ± 0,1 L vs. 0,12 ± 0,1 L; AB: 0,25 ± 0,1 L vs. 0,15 ± 0,1 L; p>0,05 para todas las variables). La ventilación minuto incrementó de manera significativa durante la PEP en comparación a la respiración en reposo para ambos grupos (p>0,005). El volumen espiratorio final también fue más grande durante la PEP en comparación a la respiración en reposo para PT y la caja torácica pulmonar en ambos los grupos (p>0,05). Las distintas intensidades de PEP pueden inducir incrementos en los volúmenes de la pared torácica en pacientes con FC.

Reference values for sniff nasal inspiratory pressure in healthy subjects in Brazil: a multicenter study.

OBJECTIVE: The objectives of this study were to determine reference values for sniff nasal inspiratory pressure (SNIP) and to propose reference equations for the population of Brazil. METHODS: We evaluated 243 healthy individuals (111 males and 132 females), between 20 and 80 years of age, with an FVC and FEV1/FVC ratio > 80% and > 85% of the predicted value, respectively. All of the subjects underwent respiratory muscle strength tests to determine MIP, MEP, and SNIP. RESULTS: We found that SNIP values were higher in males than in females (p < 0.05) and that SNIP correlated negatively with age, for males (r = -0.29; p < 0.001) and for females (r = -0.33; p < 0.0001). Linear regression also revealed that age influenced the predicted SNIP, for males (R² = 0.09) and females (R² = 0.10). We obtained predicted SNIP values that were higher than those obtained for other populations. CONCLUSIONS: We have devised predictive equations for SNIP to be used in adults (20-80 years of age) in Brazil. These equations could help minimize diagnostic discrepancies among individuals.

Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals / Efeitos da pressão expiratória positiva na depuração pulmonar do ácido dietilenotriaminopentacético marcado com tecnécio-99m em aerossol em indivíduos saudáveis

ABSTRACT Objective: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.

RESUMO Objetivo: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. Métodos: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. Resultados: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. Conclusões: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.