Respiratory muscles: structure, function and relationship with the ACE gene: a brief morphofunctional communication / Músculos respiratorios: estructura, función y relación con el gen de la ECA: una breve comunicación morfofuncional

SUMMARY: Pulmonary ventilation is a mechanical process in which the respiratory muscles act in coordination to maintain the oxygenation of the organism. Any alteration in the performance of these muscles may reduce the effectiveness of the process. The respiratory muscles differ from the other skeletal muscles in the vital support that they provide through rhythmiccontractions. The structure and energy system of the muscles are specially adapted to perform this function. The composition of the respiratory muscles is exceptional; they are small, and present an abundant capillary network, endowing them with a high aerobic level and resistance to fatigue. Coordinated regulation of the local renin-angiotensin system provides proper blood flow and energy supply in the myofibrils of the skeletal muscle tissue. Specifically, this performance will depend to a large extent on blood flow and glucose consumption, regulated by the renin-angiotensin system. The angiotensin converting enzyme is responsible for degrading kinins, which finally regulate muscle bioenergy and glucose between the blood vessel and the skeletal muscle. The objective of this review is to describe the structure of the respiratory muscles and their association with the angiotensin converting enzyme gene.

La ventilación pulmonar es un proceso mecánico en el que los músculos respiratorios actúan coordinadamente para mantener la oxigenación en el organismo. Así, cualquier alteración en el desempeño de estos músculos puede reducir la efectividad del proceso. Los músculos respiratorios se diferencian de otros músculos esqueléticos, debido al apoyo vital que brindan a través de sus contracciones rítmicas. La estructura y el sistema energético de estos músculos están especialmente adaptados para realizar esta función. La composición de los músculos respiratorios es especial; son pequeñas y presentan una abundante red capilar, lo que les otorga un alto nivel aeróbico y resistencia a la fatiga. La regulación coordinada del sistema renina-angiotensina local, proporciona un adecuado flujo sanguíneo y suministro de energía a las miofibrillas del músculo esquelético. En concreto, este rendimiento dependerá en gran medida del flujo sanguíneo y del consumo de glucosa, regulado por el sistema renina-angiotensina. Aquí, la enzima convertidora de angiotensina es responsable de degradar las kininas, que finalmente regulan la bioenergía muscular y la glucosa entre el vaso sanguíneo y el músculo esquelético. El objetivo de esta breve comunicación es describir la estructura de los músculos respiratorios y su asociación con el gen de la enzima convertidora de angiotensina.

Evaluation of pulmonary function in patients of non-specific low back pain / Avaliação da função pulmonar em pacientes com dor lombar inespecífica

INTRODUCTION: Diaphragm is the primary inspiratory muscle and it plays an essential role in controlling the spine during postural control. In nonspecific low back pain, the diaphragm muscle becomes weak, due to which the pulmonary functions may decrease. To the best of our knowledge there is a scarcity of literature in regard to the effect of low back pain on pulmonary parameters. Thus, the study is aimed to evaluate the pulmonary function in patients with non-specific low back pain. METHODS: One hundred and thirteen patients with non-specific low back pain and 113 BMI matched normal individuals as a comparison group aged 18-40 years of male and female genders were recruited by purposive sampling method for this prospective cross-sectional study. The non-specific back pain group included participants diagnosed with non-specific low back pain with pain intensity > 3 on VAS scale and duration > 3 months. After initial screening and assessment, anthropometric characteristics were recorded. Then, the pulmonary function test (FEV1, FVC, FEV1/ FVC, PEFR, SVC, MVV) were recorded in both groups. RESULT: Kolmogorov-Smirnov test was used for normality assessment and data was found to be not normally distributed. Non parametric data was represented as median and IQR (Inter Quartile Range). Between groups data analysis was performed by using MannWhitney U test and the effect size was computed for the study variables. P < 0.05 was considered as statistically significant. There was a significant difference in pulmonary function values of FEV1, FEV1/FVC, PEFR, SVC, MVV. There was no significant difference in age and BMI of the participants of both groups. CONCLUSION: There exist significant differences in pulmonary function in patients with non-specific low back pain.

INTRODUÇÃO: O diafragma é o principal músculo inspiratório e desempenha um papel essencial no controle da coluna durante o controle postural. Na dor lombar inespecífica, o músculo diafragma torna-se fraco, podendo as funções pulmonares diminuir. Até onde sabemos, há escassez de literatura a respeito do efeito da dor lombar nos parâmetros pulmonares. Assim, o estudo tem como objetivo avaliar a função pulmonar em pacientes com dor lombar inespecífica. MÉTODOS: Cento e treze pacientes com dor lombar inespecífica e 113 indivíduos normais pareados com IMC como grupo de comparação com idades entre 18 e 40 anos, dos gêneros masculino e feminino, foram recrutados por método de amostragem proposital para este estudo transversal prospectivo. O grupo de dor nas costas inespecífica incluiu participantes com diagnóstico de dor lombar inespecífica com intensidade de dor > 3 na escala VAS e duração > 3 meses. Após triagem e avaliação inicial, as características antropométricas foram registradas. Em seguida, foram registrados os testes de função pulmonar (VEF1, CVF, VEF1/CVF, PFE, CVL, VVM) em ambos os grupos. RESULTADO: O teste de Kolmogorov-Smirnov foi utilizado para avaliação da normalidade e os dados não apresentaram distribuição normal. Os dados não paramétricos foram representados como mediana e IQR (intervalo interquartil). A análise dos dados entre grupos foi realizada pelo teste U de Mann-Whitney e o tamanho do efeito foi calculado para as variáveis do estudo. < 0,05 foi considerado estatisticamente significativo. Houve diferença significativa nos valores de função pulmonar de VEF1, VEF1/CVF, PFE, CVL, VVM. Não houve diferença significativa na idade e no IMC dos participantes de ambos os grupos. CONCLUSÃO: Existem diferenças significativas na função pulmonar em pacientes com dor lombar inespecífica.

Respiratory muscle strength should be continuously monitored for patients on mechanical ventilation / 中华危重病急救医学

Mechanical ventilation (MV) is an effective treatment for respiratory failure. In recent years, it has been found that MV can not only cause ventilation-associated lung injury (VALI), but also cause ventilation-induced diaphragmatic dysfunction (VIDD). Although the injury site and etiology are not the same, they are interrelated and mutually causal, and eventually lead to weaning failure. Studies have indicated that diaphragmatic function protection strategy should be implemented in patients on MV. That is, the entire process from assessing the ability of spontaneous breathing before MV, to the initiation of spontaneous breathing and to weaning during MV. For patients on MV, continuous monitoring of respiratory muscle strength should be conducted. Early prevention, early intervention and timely detection of VIDD may reduce the occurrence of difficult weaning, resulting in improved prognosis. This study mainly discussed the risk factors and pathogenesis of VIDD.

Comparison of Effects of Liuzijue Exercise and Conventional Respiratory Training on Patients after Cardiac Surgery: A Randomized Controlled Trial / 中国结合医学杂志

OBJECTIVE@#To evaluate the feasibility and safety of Liuzijue exercise (LE) for the clinical effect in patients after cardiac surgery.@*METHODS@#Totally 120 patients who underwent cardiac surgery and were admitted to the Cardiothoracic Intensive Care Unit of Nanjing Drum Tower Hospital between July and Oclober, 2022 were allocated to the LE group, the conventional respiratory training (CRT) group, and the control group by a random number table at a ratio of 1:1:1; 40 patients in each group. All patients received routine treatment and cardiac rehabilitation. LE group and CRT group respectively performed LE and CRT once a day for 30 min for 7 days. Control group did not receive specialized respiratory training. The forced vital capacity, forced expiratory volume in 1 s, peak inspiratory flow rate, peak expiratory flow rate, maximum inspiratory pressure, maximum expiratory pressure, modified Barthel index (MBI), and Hamilton Rating Scale for Anxiety (HAM-A) were evaluated before, after 3 and 7 days of intervention. In addition, the postoperative length of hospital stay (LOS) and the adverse events that occurred during the intervention period were compared.@*RESULTS@#A total of 107 patients completed the study, 120 patients were included in the analysis. After 3 days of intervention, the pulmonary function, respiratory muscle strength, MBI and HAM-A of all 3 groups improved compared with that before the intervention (P<0.05 or P<0.01). Compared with the control group, pulmonary function and respiratory muscle strength were significantly improved in the CRT and LE groups (P<0.05 or P<0.01). MBI and HAM-A were significantly improved in the LE group compared with the control and CRT groups (P<0.05 or P<0.01). On the 7th day after intervention, the difference was still statistically significant (P<0.01), and was significantly different from that on the 3rd day (P<0.05 or P<0.01). In addition, on the 7th day of intervention, the pulmonary function and respiratory muscle strength in the LE group were significantly improved compared with those in the CRT group (P<0.01). MBI and HAM-A were significantly improved in the CRT group compared with the control group (P<0.01). There were no significant differences in postoperative LOS among the 3 groups (P>0.05). No training-related adverse events occurred during the intervention period.@*CONCLUSIONS@#LE is safe and feasible for improving pulmonary function, respiratory muscle strength, the ability to complete activities of daily living and for relieving anxiety of patients after cardiac surgery (Registration No. ChiCTR2200062964).

Respiratory muscle sequelae in young university students infected by coronavirus disease 2019: an observational study

SUMMARY BACKGROUND: The infection caused by coronavirus disease 2019 can lead to respiratory sequelae in individuals who have experienced severe or mild symptoms. METHODS: An observational, cross-sectional study was developed, following the STROBE guidelines. Maximal inspiratory and expiratory mouth pressures were assessed in 50 healthy young students (26 women, 24 men; age 22.20±2.41 years). The inclusion criteria were as follows: aged between 18 and 35 years; control group: not diagnosed with coronavirus disease 2019; and coronavirus disease 2019 group: diagnosed with coronavirus disease 2019, at least 6 months ago. The exclusion criteria were as follows: obese/overweight; infected with coronavirus disease 2019 or coronavirus disease 2019 symptoms in the last 6 months; smokers; and asthmatics. RESULTS: When comparing with groups, the coronavirus disease 2019 group presented statistically significant lower maximal inspiratory pressure values compared with the control group (88.32±16.62 vs. 101.01±17.42 cm H2O; p=0.01). Regarding the maximal expiratory pressure, no significant differences were found. Similar results were found when performing a subgroup analysis by sex and group. CONCLUSIONS: Young students who suffered from coronavirus disease 2019 asymptomatically or mildly at least 6 months ago presented a significant decrease in the inspiratory muscle strength as a sequel, so we believe that patients affected by this disease should have a brief postinfection assessment of this musculature to detect the indication for cardiorespiratory rehabilitation.

Fisiología respiratoria: el control de la respiración / Respiratory fisiology: the breath control

El control de la respiración comprende un componente automático involuntario y un componente voluntario, con centros de control en el tronco encefálico, principalmente en la médula oblonga y en el puente, y en la corteza cerebral. Estos centros reciben aferencias provenientes de sensores que detectan señales químicas y no químicas, interactúan entre sí y generan respuestas que llegan a las neuronas motoras inferiores a nivel de médula espinal. Estos procesos determinan el funcionamiento de los músculos implicados en la respiración, y de ese modo permite garantizar que los niveles de pO2 p CO2 y pH en la sangre arterial se mantengan en forma óptima, frente a diferentes situaciones y demandas metabólicas. Se hace una revisión actualizada del tema que permita comprender estos procesos.

The control of breathing comprises an involuntary automatic component and a voluntary component, with control centers in the brain stem, mainly in the medulla oblongata and in the bridge, and in the cerebral cortex. These centers receive afferences from sensors that detect chemical and non-chemical signals, interact with each other and generate responses that reach the lower motor neurons at the spinal cord level. These processes determine the functioning of the muscles involved in breathing, and thus ensure that the levels of pO2 p CO2 and pH in arterial blood are optimally maintained, in the face of different situations and metabolic demands. An up-to-date review of the subject is carried out to understand these processes.

Correlação entre capacidade funcional, força muscular respiratória e força de preensão palmar em candidatos a transplante de fígado / Correlation of functional capacity, respiratory muscle strength, and hand grip strength in liver transplant candidates

Introdução: O transplante de fígado (TxF) é o procedimento padrão recomendado para pacientes com doença hepática terminal. Muitos, enquanto aguardam o TxF apresentam como deterioração funcional a diminuição da força muscular respiratória, força de preensão palmar e capacidade funcional. O objetivo deste estudo foi correlacionar a capacidade funcional, força muscular respiratória e força de preensão palmar em candidatos a transplante de fígado. Métodos: Trata-se de um estudo observacional, prospectivo, quantitativo. Participaram do estudo pacientes candidatos ao TxF que estavam em tratamento na unidade de transplante de fígado em um hospital de referência no noroeste paulista. Os pacientes foram avaliados por meio de: teste de caminhada de seis minutos, manovacuometria e dinamometria. Para análise dos dados foi utilizado o teste de correlação linear de Pearson. Valores de p ≤ 0,05 foram considerados significantes. Resultados: Foram avaliados 38 pacientes cirróticos no pré-operatório de TxF. A média de idade dos pacientes foi de 54,34 ± 8,18 anos, com predominância do gênero masculino (68%), a média do MELD e do IMC foram de 20,84 ± 6,26 pontos e 27,75 ± 5,0 kg/m2, respectivamente. Na força muscular respiratória verificou-se que os pacientes apresentaram média de pressão inspiratória máxima (PImáx) 75,89% e pressão expiratória máxima (PEmáx) 76,82% do predito. Nas análises de correlações entre as variáveis do estudo verificou-se correlação diretamente proporcional, significativa (p ≤ 0,0001) e forte entre preensão manual vs força muscular respiratória, moderada entre preensão manual vs capacidade funcional e moderada entre força muscular respiratória vs capacidade funcional. Conclusão: Os pacientes candidatos a TxF apresentaram correlação positiva entre capacidade funcional, força muscular respiratória e força de preensão palmar. Alterações na força muscular respiratória e de preensão palmar se correlacionaram a redução na capacidade funcional nestes pacientes.

Introduction: Liver transplantation (TxF) is the standard procedure recommended for patients with terminal liver disease. Many, while waiting for the TxF present as functional deterioration the decrease in respiratory muscle strength, hand grip strength, and functional capacity. The aim of this study was correlate functional capacity, respiratory muscle strength, and hand grip strength in liver transplant candidates. Methods: This is an observational, prospective, quantitative study. Candidates for TxF who were being treated at the liver transplant unit in a referral hospital in northwest São Paulo participated in the study. The patients were evaluated using: six- minute walk test, manovacuometry, and dynamometry. Pearson's linear correlation test was used for data analysis. Values of p ≤ 0.05 were considered significant. Results: A total of 38 cirrhotic patients were evaluated in the preoperative period of TxF. The mean age of the patients was 54.34 ± 8.18 years, with a predominance of males (68%), the mean MELD and BMI were 20.84 ± 6.26 points and 27.75 ± 5.0 kg/m2, respectively. Regarding respiratory muscle strength, it was found that patients had a mean maximum inspiratory pressure (PImax) 75.89% and maximum expiratory pressure (PEmax) 76.82% of the predicted. In the analysis of correlations between the study variables, there was a directly proportional, significant (p ≤ 0.0001) and strong correlation between hand grip vs respiratory muscle strength, moderate between hand grip vs functional capacity and moderate between respiratory muscle strength vs functional capacity. Conclusion: Candidate patients for TxF showed a positive correlation between functional capacity, respiratory muscle strength, and hand grip strength. Changes in respiratory muscle strength and hand grip was correlated with the reduction in functional capacity in these patients.

Treinamento cardiorrespiratório e força dos músculos ventilatórios de idosas: ensaio controlado randomizado duplo cego / Cardiorespiratory training and ventilatory muscle strength in elderly women: double blind randomized controlled trial

A dinapenia da musculatura ventilatória relaciona-se com as complicações respiratórias pós-operatórias e aos óbitos de idosos submetidos a procedimentos cirúrgicos de etiologia toracoabdominal. Objetivo: Verificar o efeito crônico do treinamento cardiorrespiratório sobre a força dos músculos ventilatórios de idosas. Métodos: Amostra (n = 24) randomizada nos grupos: controle (n = 8), treinamento ventilatório (n = 7) e treinamento cardiorrespiratório (n = 9). O desfecho primário (PImáx e PEmáx) foi medido por um manovacuômetro digital MDV®300 (MDI/Brasil). Rodou-se a estatística descritiva (média e desvio padrão), seguida de uma ANOVA 3x3 e o testes post-hoc de Bonferroni, todos com significância de (P ≤ 0,05). Resultados: O teste Post Hoc atestou diferença estatisticamente significativa do grupo treinamento cardiorrespiratório no reteste 1 e 2 quando comparados ao teste inicial (PImáx; P = 0,000001 e P = 0,0000001 respectivamente) e (PEmáx; P = 0,000000 em ambas as comparações). Conclusão: O treinamento cardiorrespiratório proposto foi capaz de aumentar significativamente a PImáx, PEmáx, resistência aeróbica e a força de membros inferiores das participantes deste ECR. (AU)

Lung age and respiratory muscle strength in female volleyball players

SUMMARY OBJECTIVE: Lung age estimation is a useful approach to determine pulmonary pathologies. In literature, no studies have evaluated and compared lung age in athletes with healthy volunteers. This study aims to compare lung age and respiratory muscle strength in female volleyball players and age-matched healthy volunteers. METHODS: A total of 18 female volleyball players (22.39±4.97 years) and 20 female healthy volunteers (24.85±3.33 years) were included. Pulmonary functions and respiratory muscle strength were assessed using a spirometer and mouth pressure device, respectively. The lung age was calculated using reference equations associated with gender, height, and forced expiratory volume in 1 second. RESULTS: Lung age was significantly lower, and forced expiratory volume in 1 L, forced vital capacity, and maximal inspiratory and expiratory pressure (cmH2O, %) were higher in female volleyball players compared with healthy volunteers (p≤0.05). CONCLUSION: The lung age and respiratory muscle strength of female volleyball players were better than healthy volunteers. Regular training in female volleyball players may improve respiratory functions and lung age.

Resistência muscular periférica e inspiratória reduzida em pacientes com cirrose hepática: um estudo transversal / Reduced peripheral and inspiratory muscle endurance in patients with liver cirrhosis: a cross-sectional study

ABSTRACT BACKGROUND: Liver cirrhosis (LC) causes several musculoskeletal changes. OBJECTIVE: To test the hypothesis that the peripheral and inspiratory muscle endurance are reduced in patients with liver cirrhosis. METHODS: Twenty-one patients with LC (LC group; 61±14 years) and 18 age-matched subjects (control group; 56±17 years) had accepted to participate in this cross-sectional observational study. To assess peripheral muscle endurance, all volunteers performed a rhythmic handgrip exercise at 45% of their maximum voluntary contraction. A metronome was used to control the contraction-relaxation cycles at 60/min. The inspiratory muscle endurance was assessed using PowerBreath®. Participants underwent inspiratory muscle exercise at 60% of their maximal inspiratory muscle strength. The time until failure characterized the muscle endurance for both handgrip and inspiratory muscle exercises. Additionally, the quality of life of the participants was assessed. RESULTS: The muscle endurance was lower in the LC group when compared to the control group for both handgrip (67 vs 130 s, P<0.001) and inspiratory muscle exercises (40 vs 114 s, P<0.001). The peripheral muscle endurance was directly correlated with the total quality of life score (r=0.439, P=0.01) and to the following domains: fatigue (r=0.378 e P=0.030), activity (r=0.583, P=0.001), systemic symptoms (r=0.316, P=0.073) and preoccupation (r=0.370, P=0.034). The inspiratory muscle endurance was inversely correlated with the total quality of life score (r=0.573, P=0.001) and the following domains: fatigue (r=0.503, P=0.002), activity (r=0.464, P=0.004), systemic symptoms (r=0.472, P=0.004), abdominal symptoms (r=0.461, P=0.005), emotional function (r=0.387, P=0.02) and preoccupation (r=0.519, P=0.001). CONCLUSION: Both peripheral and inspiratory muscle endurance were lower in LC patients when compared to the control group.

RESUMO CONTEXTO: A cirrose hepática (CH) causa várias alterações musculoesqueléticas. OBJETIVO: Testar a hipótese de que as resistências dos músculos periféricos e inspiratórios estão reduzidas em pacientes com CH. MÉTODOS: Vinte e um pacientes com CH (grupo CH; 61±14 anos) e 18 indivíduos pareados por idade (grupo controle; 56±17 anos) aceitaram participar deste estudo observacional transversal. Para avaliar a resistência muscular periférica, todos os voluntários realizaram um exercício de preensão manual rítmica a 45% de sua contração voluntária máxima. Um metrônomo foi usado para controlar os ciclos de contração-relaxamento a 60/min. A resistência muscular inspiratória foi avaliada com o PowerBreath®. Os participantes foram submetidos a exercícios musculares inspiratórios a 60% de sua força muscular inspiratória máxima. O tempo até a falha caracterizou a resistência muscular para os exercícios de preensão manual e de músculos inspiratórios. Além disso, foi avaliada a qualidade de vida dos participantes. RESULTADOS: A resistência muscular foi menor no grupo CH quando comparada ao grupo controle tanto para os exercícios de preensão manual (67 vs 130 s, P<0,001) quanto para os músculos inspiratórios (40 vs 114 s, P<0,001). A resistência muscular periférica foi diretamente correlacionada com o escore total de qualidade de vida (r=0,439, P=0,01) e com os seguintes domínios: fadiga (r=0,030, P=0,378), atividade (r=0,378 e P=0,030), sintomas sistêmicos (r=0,316, P=0,073) e preocupação (r=0,370, P=0,034). A resistência muscular inspiratória foi inversamente correlacionada com o escore total de qualidade de vida (r=0,573, P=0,001) e com os seguintes domínios: fadiga (r=0,503, P=0,002), atividade (r=0,464, P=0,004), sintomas sistêmicos (r=0,472, P=0,004), sintomas abdominais (r=0,461, P=0,005), função emocional (r=0,387, P=0,02) e preocupação (r=0,519, P=0,001). CONCLUSÃO: As resistências musculares periférica e inspiratória foram menores nos pacientes com CH quando comparados ao grupo controle.

Alterações posturais associadas a distúrbios respiratórios e sua correlação com as desordens temporomandibulares: uma revisão de literatura / Postural changes associated with respiratory disorders and their correlation with temporomandibular disorders: a literature review

Objetivo: a presente revisão almeja fornecer à prática clínico-odontológica e ao meio científico uma compreensão atualizada acerca da correlação entre as alterações posturais geradas pela presença de distúrbios respiratórios e as desordens temporomandibulares (DTMs). Revisão de literatura: foi realizada uma busca entre o período de 2005 a 2021 nas seguintes bases de dados: Medline (via PubMed), Portal de Periódicos Capes e Scopus, utilizando-se dos termos "temporomandibular joint; temporomandibular disorders; posture control; postural control; breathing". Como resultado, foram encontrados 4.384 documentos, que foram analisados por títulos, resumos, texto completo e critérios de elegibilidade, até se chegar ao total de 5 estudos a serem incluídos nesta revisão. Considerações finais: os principais fatores observados foram a associação das DTMs com condições como padrão de respiração do tipo bucal, postura anterior da cabeça, hiperatividade de músculos acessórios da respiração, rotação posterior da mandíbula e apneia obstrutiva do sono. Os estudos ressaltaram a necessidade da abordagem completa desses pacientes, visto que os papéis dos distúrbios respiratórios e das alterações posturais podem representar desafios no diagnóstico e no tratamento das DTMs.(AU)

Objective: this review aims to provide to the clinical dental practice and the scientific community an updated understanding of the correlation between postural changes generated by the presence of respiratory disorders and temporomandibular joint disorders (TMD). Literature review: a search was carried out covering the period from 2005 to 2021 in the following databases: Medline (via PubMed), Portal de Periódicos Capes and Scopus using the terms temporomandibular joint; temporomandibular disorders; posture control; postural control; breathing. As a result, 4,384 documents were obtained and shortlisted by title, abstracts, full text and eligibility criteria, resulting in the five studies included in this review. Final considerations: the main factors observed were the association of TMD with conditions as mouth breathing, anterior head posture, hyperactivity of accessory breathing muscles, posterior rotation of the jaw and obstructive sleep apnea. The studies underscored the need for a complete approach to these patients, given that the role of respiratory disorders and postural changes may represent a challenge in the diagnosis and treatment of TMD.(AU)

Inspiratory Muscle Weakness is Related to Poor Short-Term Outcomes for Heart Transplantation

Abstract Introduction: In heart transplantation (HT) recipients, several factors are critical to promptly adopting appropriate rehabilitation strategies and may be important to predict outcomes way after surgery. This study aimed to determine preoperative patient-related risk factors that could adversely affect the postoperative clinical course of patients undergoing HT. Methods: Twenty-one hospitalized patients with heart failure undergoing HT were evaluated according to respiratory muscle strength and functional capacity before HT. Mechanical ventilation (MV) time, reintubation rate, and intensive care unit (ICU) length of stay were recorded, and assessed postoperatively. Results: Inspiratory muscle strength as absolute and percentpredicted values were strongly correlated with MV time (r=-0.61 and r=-0.70, respectively, at P<0.001). Concerning ICU length of stay, only maximal inspiratory pressure (MIP) absolute and percent-predicted values were significantly associated. The absolute -MIP- was significantly negatively correlated with ICU length of stay (r=-0.58 at P=0.006) and the percent-predicted MIP was also significantly negatively correlated with ICU length of stay (r=-0.68 at P=0.0007). No associations were observed between preoperative functional capacity, age, sex, and clinical characteristics and MV time and ICU length of stay in the cohort included in this study. Patients with respiratory muscle weakness had a higher prevalence of prolonged MV, reintubation, and delayed ICU length of stay. Conclusion: An impairment of preoperative MIP was associated with poorer short-term outcomes following HT. As such, inspiratory muscle strength is an important clinical preoperative marker in patients undergoing HT.

Pressões respiratórias máximas em indivíduos obesos antes e após cirurgia bariátrica / Maximum respiratory pressure in obese individuals before and after bariatric surgery

A obesidade é uma doença crônica e multifatorial que leva a alterações sistêmicas e é considerada um problema de saúde pública mundial. Entre as alterações respiratórias decorrentes da obesidade se discute como o ganho de peso ou a perda deste pode interferir nas pressões respiratórias máximas (PRM), não existindo consenso na literatura. Objetivo: Analisar o poder preditivo das equações de referência para PMR em obesos antes e após perda de peso. Métodos: Estudo transversal no qual foram incluídos vinte pacientes obesos dos Programas de Cirurgia Bariátrica de hospitais de referência em Manaus/Amazonas, que tiveram as PRM avaliadas por meio de manuvacuometria antes e aproximadamente um ano e meio após a cirurgia bariátrica. Resultados: O peso médio diminuiu de 138,5 ± 21,7 kg para 82,7 ± 8,2 kg após a cirurgia. As PRM foram supranormais antes da cirurgia e reduzidas após a cirurgia. Entre as equações analisadas, apenas as propostas por Sanchez et al. foram capazes de predizer os valores medidos. Conclusão: As PRM foram aumentadas nos obesos mórbidos avaliados e reduzidas após a cirurgia. As equações mais utilizadas na prática clínica brasileira parecem não ser capazes de predizer valores de PRM nessa população, sendo as mais adequadas as propostas por Sanchez et al. (AU)

Obesity is a chronic and multifactorial disease and is considered a global public health problem. Among the respiratory changes due to obesity, weight gain or loss of body weight can interfere with maximal respiratory pressures, and there is no consensus in the literature. Objective: To analyze the predictive power of the reference equations for maximal respiratory pressures in obese before and after weight loss. Methods: A crosssectional study was carried out in which 20 obese patients were included in the Bariatric Surgery Programs of reference hospitals in Manaus/Amazonas. The maximal respiratory pressures were assessed by manuvacuometry before and approximately one year after bariatric surgery. Results: The mean weight decreased from 138.5 ± 21.7 kg to 82.7 ± 8.2 kg after surgery. The maximal respiratory pressures were supranormal before surgery and reduced after surgery. Among the analyzed equations, only those proposed by Sanchez et al. were able to predict the measured values. Conclusion: The maximal respiratory pressures were increased in the morbidly obese evaluated and reduced after the surgery. The most used equations in Brazilian clinical practice seem not to be able to predict maximal respiratory pressures values in this population, being the most adequate those proposed by Sanchez et al. (AU)

Uso da eletromiografia de superfície na resultância do treinamento muscular inspiratório com carga linear em portadores do vírus linfotrópico humano tipo 1 / Use of surface electromyography in results of inspiratory muscle training with linear load in patients with type 1 human lymphotropic virus

Este estudo visa avaliar por eletromiografia de superfície o comportamento dos músculos inspiratórios no treinamento muscular em voluntários com vírus linfotrópico de célula T humana do tipo 1. Trata-se de um ensaio clínico. Sete voluntários, com idade 58,85 ± 7,2) anos, realizaram treinamento muscular inspiratório domiciliar por 4 semanas, 3 vezes por semana, 30 minutos diários por meio de incentivador de carga linear. Para avaliação utilizou-se os dados de pressão inspiratória máxima e os dados da eletromiografia de superfície nas fases pré (T0), segunda semana (T2) e após a quarta semana (T4) de treinamento. Observou-se aumento progressivo da força muscular inspiratória de T0 a T4 (p = 0,007), assim como, aumento do recrutamento das unidades motoras pela análise da amplitude do sinal eletromiográfico, sendo mais evidente para o músculo esternocleidomastóideo (p = 0,12) em comparação ao músculo diafragma (p = 0,6). Verificou-se que no decurso do treinamento muscular ocorreu melhora significativa da força muscular inspiratória com maior recrutamento das fibras musculares dos músculos analisados na amostra. (AU)

This study aimed to evaluate by surface electromyography the behavior of inspiratory muscles in the muscle training of volunteers with human T-cell lymphotropic virus type 1. This was a clinical trial. Seven volunteers, 58,85 ± 7.21 years old, underwent inspiratory muscle training at home for 4 weeks, 3 times a week, 30 minutes daily by means of a linear load stimulator. The maximum inspiratory pressure data and the surface electromyography data were used for evaluation in the pre (T0), second week (T2) and after the fourth week (T4) training phases. There was a progressive increase in inspiratory muscle strength from T0 to T4 (p = 0.007), as well as an increase in the recruitment of motor units by analyzing the amplitude of the electromyographic signal, being more evident for the sternocleidomastoid muscle (p = 0.12) in comparison to the diaphragm muscle (p = 0.6). During the muscle training inspiratory muscle strength improves with greater recruitment of muscle fibers from the muscles analyzed in the sample. (AU)

Oxigenación de músculos respiratorios y locomotores durante el test cardiopulmonar en pacientes con circulación de fontan: serie de casos / Patients with fontan: oxygen consumption in respiratory and Locomotor muscles during excersie testing

Resumen: Antecedentes: Los pacientes con circulación de Fontan (PCF) presentan limitación cardíaca durante el esfuerzo máximo lo que repercute en menor capacidad de ejercicio (VO2-peak). La rehabilitación cardiovascular (RC) revierte este desacondicionamiento, al aumentar el gasto cardíaco y diferencia arteriovenosa de oxígeno, aspectos evaluados con monitorización invasiva y gases exhalados. La valoración no invasiva de la saturación muscular de oxígeno (SmO2) es un método de reciente aplicación para evaluar la limitación muscular al ejercicio. En PCF esta limitación puede atribuirse a la mayor acción de músculos respiratorios (cambios ventilatorios) y/o locomotores (carga periférica). Objetivo: Evaluar el trabajo de músculos respiratorios y locomotores durante el ejercicio físico máximo e incremental mediante los cambios en la SmO2. Métodos: A seis PCF (5 hombres; 13.8±2.9 años; 158±9cm; 49.8±13.3 kg) se les valoró el VO2-peak (23.0±4.5mL·kg-1·min-1) mediante ciclo-ergoespirometría sincrónicamente con SmO2 en músculos respiratorios (SmO2-m.Intercostales) y locomotores (SmO2-m.Vastus-Laterallis) mediante espectroscopía cercana al rango infrarrojo durante el test cardiopulmonar. Resultados: SmO2-m.Intercostales disminuyó desde el 60% del VO2-peak (p<0.05), mientras que SmO2-m.Vastus-Laterallis no cambió. La ventilación pulmonar (VE) aumentó progresivamente, siendo significativo a partir del 60% VO2-peak (p<0.05). La mayor desoxigenación de SmO2-m.Intercostales (∆SmO2) se asoció con los máximos cambios en ventilación pulmonar (∆VE) en ejercicio (rho=0.80; p=0.05). Conclusiones: Durante un protocolo de esfuerzo, los pacientes con circulación de Fontan presentan mayor trabajo muscular respiratorio que locomotor. Los cambios en la ventilación pulmonar se asocian a mayor extracción de oxígeno en la musculatura respiratoria, reforzando la necesidad de incorporar el entrenamiento respiratorio en la rehabilitación cardiovascular.

Abstract: Background: During a maximum incremental exercise patients with Fontan circulation (PFC) show cardiac limitation reducing aerobic exercise capacity (VO2-peak). Cardiovascular rehabilitation (CR) reverses this deconditioning by increasing cardiac output and arteriovenous oxygen difference, aspects that can be evaluated by invasive methods and analyzing the exhaled gases. Non-invasive assessment of muscle oxygen saturation (SmO2) is a novel method for recording local oxygen levels. By this technology, it is possible to evaluate the muscle limitation to exercise. In PFC, that limitation could be attributed to higher contractions of respiratory (ventilatory changes) and/ or locomotor muscles (peripheral load). Objective: To evaluate in PFC the changes at SmO2 of respiratory and locomotor muscles during a maximum and incremental exercise protocol (cardiopulmonary test, VO2-peak). Methods: Six PFC (5 men; 13.8±2.9 years; 158±9 cm; 49.8±13.3 kg) were assessed during the VO2peak test (23.0±4.5mL·kg-1·min-1) by cyclo-ergospirometry synchronously with SmO2 at respiratory (SmO2-m.Intercostales) and locomotor (SmO2-m. Vastus-Laterallis) muscles by Near-Infrared Spectroscopy (NIRS). Results: SmO2-m.Intercostales decreased from 60% of VO2-peak (p<0.05), while SmO2-m.Vastus-Laterallis did not change. Minute ventilation (VE) increased progressively, showing changes to rest at 60% of VO2-peak (p<0.05). The higher deoxygenation of SmO2-m.Intercostales (∆SmO2) correlated to maximum changes of lung ventilation (∆VE) (rho=0.80; p=0.05). Conclusions: During an incremental and maximum exercise protocol, patients with Fontan circulation have more work at respiratory than locomotor muscles. Changes in VE are direct associated with greater extraction of oxygen at respiratory muscles, reinforcing the incorporation of respiratory muscle training in cardiovascular rehabilitation.

Avaliação da capacidade funcional, força muscular respiratória e pico de fluxo expiratório em pacientes com apneia obstrutiva do sono / Evaluation of functional capacity, respiratory muscular strength and expiratory flow peak in patients with obstructive sleep apnea

Introdução: A síndrome da apneia obstrutiva do sono (SAOS) é caracterizada pela obstrução das vias aéreas superiores durante o sono, o que causa efeitos sistêmicos durante a vigília. Objetivo: O objetivo deste estudo é avaliar a capacidade funcional, a força da musculatura respiratória e o pico de fluxo expiratório (PFE) de pacientes com SAOS. Métodos: Trata-se de um estudo transversal realizado na cidade de Patos de Minas/MG no ano de 2019, no qual foram incluídos 14 indivíduos que possuíam SAOS moderada e grave. Primeiramente os pacientes responderam a um questionário sociodemográfico elaborado pelos autores. Em seguida, foi realizada a manovacuometria, a mensuração do PFE e o teste de caminhada de seis minutos (TC6M). Resultados: A maioria dos pacientes eram homens (71,4%), obesos (78,6%) e hipertensos (57,1%). Como resultados dos testes obtivemos - PImáx obtida vs predita = 86,4 vs 102,8 (p = 0,004), PEmáx obtida vs predita = 98,5 vs 113,5 (p = 0,05), PFE obtido vs predito = 381,3 vs 495,8 (p < 0,001) e TC6M obtido vs predito = 485,3m vs 536,6m (p = 0,03). Conclusão: Nessa amostra de indivíduos com SAOS grave e moderada houve redução da força muscular respiratória, do PFE, e da capacidade funcional. (AU)

Introduction: Obstructive sleep apnea syndrome (OSAS) is characterized by upper airway obstruction during sleep, which causes systemic effects during wakefulness. Objective: The objective of this study is to assess functional capacity, respiratory muscle strength and peak expiratory flow (PEF) in patients with OSAS. Methods: This is a cross-sectional study held in the city of Patos de Minas/MG in the year of 2019, that included 14 individuals who had severe and moderate sleep apnea. First, the patients answered to a sociodemographic questionnaire prepared by the authors. Then, manovacuometry, PEF and six-minute walk test (6MWT) were performed. Results: Most patients were men (71.4%), obese (78.6%) and hypertensive (57.1%). As results of the tests we obtained - MIP obtained vs predicted = 86.4 vs 102.8 (p = 0.004), MPE obtained vs predicted = 98.5 vs 113.5 (p = 0.05), PEF obtained vs predicted = 381.3 vs 495.8 (p <0.001) and 6MWT obtained vs predicted = 485.3m vs 536.6m (p = 0.03). Conclusion: In this sample of individuals with severe and moderate OSAS, we observed a reduction in respiratory muscle strength, PEF, and functional capacity. (AU)

Efeito do treinamento muscular respiratório em pacientes com doença de Huntington: relato de casos / Effect of muscular respiratory training in Huntington disease's patients: study cases

Introdução: A doença de Huntington (DH) é uma doença neurodegenerativa progressiva, caracterizada pela tríade: alterações motoras, distúrbios psiquiátricos e disfunção cognitiva. Os pacientes com DH apresentarão restrição da mobilidade, que, futuramente, irá ocasionar fraqueza muscular generalizada. Objetivo: Avaliar os efeitos do treinamento da musculatura respiratória com o uso do Threshold em pacientes diagnosticados com DH atendidos na clínica escola de Fisioterapia do Centro Universitário Unieuro. Métodos: Os participantes foram submetidos ao programa de treinamento da musculatura respiratória com o uso do Threshold® IMT. O programa consiste em 3 séries com 5 repetições ao dia, por 3 semanas. Ao final do treinamento os pacientes foram reavaliados, e os resultados obtidos foram comparados com os resultados obtidos na avaliação inicial. Resultados: Após 3 semanas de treinamento, o paciente 1 apresentou como melhor resultado da pressão inspiratória máxima e da pressão expiratória máxima igual a 50 cmH2O e no teste de caminhada de 6 minutos percorreu 261 metros. Já o paciente 2 apresentou como melhor resultado da pressão inspiratória máxima 70 cmH2O e da pressão expiratória máxima 60 cmH2O, e no teste de caminhada de 6 minutos percorreu 146 metros. Conclusão: Conclui-se que o treinamento muscular respiratório pode ser benéfico para os pacientes com doença de Huntington, porém são necessários mais estudos para determinar o melhor protocolo para os mesmos. (AU)

Introduction: Huntington's disease (DH) is a progressive neurodegenerative disease, characterized by the triad: motor alterations, psychiatric disorders and cognitive dysfunction. Patients with HD will exhibit mobility restriction, which in the future will lead to generalized muscle weakness. Objective: To evaluate the effects of respiratory muscle training with the use of Threshold in patients diagnosed with DH treated at the Clinical School of Physical therapy of Unieuro University Center. Methods: Participants underwent respiratory muscle training with Threshold® IMT. The program consists of 3 sets with 5 replicates per day, for 3 weeks. At the end of the training the patients were reassessed, and the results obtained were compared with the results obtained in the initial evaluation. Results: After 3 weeks of training, patient 1 presented the best result of maximal inspiratory pressure and maximal expiratory pressure equal to 50 cmH20 and walked in the 6-minute walk test 261 meters. Already, patient 2 presented the best inspiratory pressure result 70 cmH2O and the maximum expiratory pressure 60 cmH2O, and in the 6-minute walk test it ran 146 meters. Conclusion: We concluded that respiratory muscle training may be beneficial for patients with Huntington's disease, but further studies are needed to determine the best protocol for them. (AU)

Respiratory muscle impairment evaluated with mep/mip ratio in children and adolescents with chronic respiratory disease / Fraqueza muscular respiratória avaliada por meio da relação pemax/pimax em crianças com doença respiratória crônica

ABSTRACT Objective: To evaluate the strength of respiratory muscles and to compare maximum inspiratory (MIP) and expiratory (MEP) pressure and MEP/MIP ratio between patients with chronic respiratory diseases and healthy individuals. Methods: Case-control study. Individuals with neuromuscular disease and post-infectious bronchiolitis obliterans were considered. In addition, they were also matched according to anthropometric and demographic characteristics with healthy children and adolescents. MIP, MEP in the three groups, and pulmonary function only in patients with chronic respiratory diseases were recorded. Results: A total of 52 subjects with CRD (25 with neuromuscular disease, and 27 with post-infectious bronchiolitis obliterans) and 85 healthy individuals were included, with an average age of 11.3±2.1 years. Patients with neuromuscular disease and post-infectious bronchiolitis obliterans presented lower MIP and MEP when compared with healthy individuals, although MEP/MIP ratio was lower in patients with neuromuscular disease (0.87±0.3) and higher in patients with post-infectious bronchiolitis obliterans (1.1±0.3) compared to the healthy group (0.97±0.2). Only in patients with neuromuscular disease a negative correlation was observed between MEP/MIP ratio and age (r=-0.50; p=0.01). Conclusions: Differences in the pattern of muscular weakness between patients with chronic respiratory diseases were observed. In patients with neuromuscular disease, a decrease in the MEP/MIP ratio depending on MIP was verified; and in those patients with post-infectious bronchiolitis obliterans, an increase in the MEP/MIP ratio depending on MIP was also observed.

RESUMO Objetivo: Avaliar a força dos músculos respiratórios e comparar a relação entre a pressão expiratória máxima (PEmáx) e a pressão inspiratória máxima (PImáx) em pacientes com doença respiratória crônica (DRC) e crianças saudáveis. Métodos: Estudo caso-controle. Foram selecionados indivíduos com doença neuromuscular e bronquiolite obliterante pós-infecciosa. Ademais, os grupos foram pareados com crianças e adolescentes saudáveis, considerando características antropométricas e demográficas. Foram registradas a PImáx e a PEmáx nos três grupos e a função pulmonar apenas em pacientes com doença respiratória crônica. Resultados: Foram incluídos 52 indivíduos com DRC (25 com doença neuromuscular e 27 com bronquiolite obliterante pós-infecciosa) e 85 indivíduos saudáveis, com idade média de 11,3±2,1 anos. Pacientes com doença neuromuscular e bronquiolite obliterante pós-infecciosa apresentaram menor PImáx e PEmáx em comparação aos indivíduos saudáveis, embora a relação PEmáx/PImáx tenha sido menor nos pacientes com doença neuromuscular (0,87±0,3) e maior nos pacientes com bronquiolite obliterante pós-infecciosa (1,1±0,3) em comparação ao grupo saudável (0,97±0,2). Somente em pacientes com doença neuromuscular foi observada uma correlação negativa entre a razão PEmáx/PImáx e a idade (r=-0,50; p=0,01). Conclusões: Foram observadas diferenças no padrão de fraqueza muscular em pacientes com doença respiratória crônica. Nos pacientes com doença neuromuscular, verificou-se diminuição na relação PEmáx/PImáx dependendo da PImáx; em pacientes com bronquiolite obliterante pós-infecciosa, foi observado aumento na relação dependendo da PImáx.

Effects of respiratory muscle training on parasympathetic activity in diabetes mellitus

This study verified the effects of respiratory muscle training (RMT) on hemodynamics, heart rate (HR) variability, and muscle morphology in rats with streptozotocin-induced diabetes mellitus (DM). Thirty-six male Wistar rats were randomized into 4 groups and 34 completed the study: i) sham-sedentary (Sham-ST; n=9); ii) sham-RMT (Sham-RMT; n=9); iii) DM-sedentary (DM-ST; n=8); and iv) DM-RMT (DM-RMT; n=8). Hemodynamics were assessed by central cannulation, and R-R intervals were measured by electrocardiogram. In addition, the effects of RMT on the cross-sectional area of the diaphragm, anterior tibial, and soleus muscles were analyzed. The induction of DM by streptozotocin resulted in weight loss, hyperglycemia, reduced blood pressure, and attenuated left ventricular contraction and relaxation (P<0.05). We also observed a decrease in root mean square of successive differences between adjacent RR intervals (RMSSD) index and in the cross-sectional area of the muscles assessed, specifically the diaphragm, soleus, and anterior tibial muscles in diabetic rats (P<0.05). Interestingly, RMT led to an increase in RMSSD in rats with DM (P<0.05). The induction of DM produced profound deleterious changes in the diaphragmatic and peripheral muscles, as well as impairments in cardiovascular hemodynamics and autonomic control. Nevertheless, RMT may beneficially attenuate autonomic changes and improve parasympathetic modulation.