Lower Respiratory Muscle Strength Research Articles

The Influence of Lung Function and Respiratory Muscle Strength on Quadriceps Muscle Fatigability in COPD Patients Under Long-term Oxygen Therapy

BackgroundThis research investigates quadriceps muscle fatigability (MF) in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure (CRF) at different levels of lung obstruction [severe obstruction (SO)=FEV1 <50% and >30% versus very severe obstruction (VSO)=FEV1 ≤30%]. It explores the relationships between quadriceps MF and lung function, respiratory muscles, and oxygenation status. MethodsA post hoc cross-over analysis in 45 COPD patients (20 SO and 25 VSO) undergoing long-term oxygen therapy was performed. Delta change in quadriceps maximum voluntary contraction (MVC) (absolute value and percentage) before and after a constant workload was calculated. Associations between quadriceps MF and lung function, respiratory muscles, and gas exchange were examined using Pearson's correlation and multivariate linear regression analysis. ResultsSO patients experience a more substantial reduction in MVC compared to VSO (−15.15±9.13% vs −9.29±8.90%, p=0.0357), despite comparable resting MVC. Dyspnea is more pronounced in VSO at the beginning and end of the exercise. Correlations were found between MF and maximal inspiratory pressure (MIP) (r=−0.4412, p=0.0056), maximal expiratory pressure (MEP) (r=−0.3561, p=0.0282), and a tendency for FEV1% (r=−0.2931, p=0.0507). The regression model (R2=0.4719) indicates that lower MIP and FEV1 and high total lung capacity are significant factors in reducing quadriceps muscle fatigability after a fatiguing task. ConclusionCOPD patients with more severe pulmonary obstruction and hyperinflation and lower respiratory muscle strength have lower quadriceps MF but higher dyspnea both at rest and during exercise.

Patterns of Changes in Respiratory Muscle Strength over 1 Year in Non-Sarcopenia, Sarcopenia, and Severe Sarcopenia

In this prospective longitudinal cohort study, we explored the characteristics of older people with lower respiratory muscle strength, according to sarcopenia severity, over the course of 1 year. The maximum expiratory pressure (MEP), grip strength, walking speed, and skeletal muscle mass index of 58 participants (28 men, 30 women; mean age, 76.9 ± 7.7 years) were measured at baseline and at the 1-year follow-up. Participants were classified into a decreased MEP group (n = 29; MEP decreased by ≥10% after 1 year) and a non-decreased MEP group (n = 29; MEP decreased by <10%). Sarcopenia status in the mild direction at baseline was significantly associated with MEP decline after one year. Repeated two-way analysis of variance showed significant main effects of measurement time (p < 0.001) and severity of sarcopenia (p = 0.026), as well as a significant interaction effect (p = 0.006). Surprisingly, MEP decreased significantly in the non-sarcopenia and sarcopenia groups, but not in the severe sarcopenia group. Thus, individuals without sarcopenia and those with moderate sarcopenia at baseline are predisposed to MEP decline and should be closely monitored for signs of such decline and associated adverse events.

Exercise Capacity Is Independent of Respiratory Muscle Strength in Patients with Chronic Heart Failure.

Background: Exercise intolerance in patients with chronic heart failure (CHF) is associated with a number of factors, including breathlessness and respiratory muscle weakness. However, many studies reported controversial results, and as yet there is no study on Arabic patients with CHF. This study aimed to examine the impact of breathlessness and respiratory muscle strength on exercise capacity in Arabic patients with CHF. Methods: This was a cross-sectional study, involving 42 stable adult male patients with CHF with a reduced ejection fraction and 42 controls who were free from cardiorespiratory and neuromuscular diseases. Patients with CHF and the controls underwent respiratory muscle strength tests and a six-minute walk test (6MWT), and the measurements were taken. Dyspnea was recorded using the modified Medical Research Council (mMRC) scale, along with the number of comorbidities. Results: Patients with CHF and controls were similar in age and sex. Patients with CHF had a greater number of comorbidities, a higher dyspnea score, a lower 6MWT score, and lower respiratory muscle strength (p < 0.001). Only 7% of patients with CHF had weak inspiratory muscle strength (<60% of that predicted) and 40% terminated the 6MWT due to dyspnea. The 6MWT was associated with mMRC (rs = −0.548, p < 0.001) but not with respiratory muscle strength (p > 0.05). Conclusions: Exercise intolerance in patients with CHF was associated with dyspnea and was independent of respiratory muscle strength.

Mild Cognitive Impairment Is Associated With Markers of Muscle Weakness and Reduced Bone Density, and Specific Metabolic Alterations Despite Preserved Physical Activity

ObjectivesBone loss and frailty commonly occur in people with dementia residing in nursing homes and lead to increased risk of disabilities and poor health outcomes. Whether these systemic manifestations and related metabolic disturbances are present in older adults with Mild Cognitive impairment (MCI), who are still physically active, remains unclear. MethodsCommunity dwelling older adults without confounding comorbidities were divided, using the Montreal Cognitive Assessment (MoCA) score cut-off of 26, into two groups: non-MCI (n = 18; age: 67.3 [63.3, 71.2 y]) and MCI (n = 20; age: 71.3 [66.9, 75.7 y]). Body composition (by DXA), respiratory strength (by mouth pressure), and extremity strength (by dynamometer) were assessed. Stable isotope techniques were used to measure production and plasma concentrations of amino acids involved in muscle, bone, and brain health (tau-methylhistidine, hydroxyproline, glycine, tryptophan). Plasma enrichments were analyzed by LC-MS/MS. Statistics performed by ANCOVA with age, gender, and BMI as covariates. Significance set at P < 0.05. Results expressed as means [95% CI]. ResultsMCI participants (MoCA score: 22.5 [21.3, 23.6]) had lower respiratory muscle strength (p = 0.007) than the non-MCI group (MoCA score: 28.2 [27.5, 28.8]) but muscle mass and daily physical activity were not different. Bone density of the spine (p = 0.02) and hip (p = 0.07) were lowest in those with the lowest MoCA scores. The MCI group had lower concentrations of glycine (p = 0.0045), tryptophan corrected for large neutral amino acids (p = 0.0017), and productions of glycine (p = 0.0085), tau-methylhistidine (p = 0.05), and tryptophan (p = 0.06). MoCA score was negatively associated with plasma triglyceride (p = 0.02) and liver enzyme (AST) level (p = 0.01), but not with glucose or CRP levels. ConclusionsOlder adults with MCI are prone to low bone density and respiratory muscle weakness despite preserved physical activity. Whether these systemic manifestations are causally related to the observed metabolic alterations in MCI deserves further investigation. Funding SourcesNone

Long COVID Syndrome Following Infection with SARS-CoV-2- A Devastating Influence on Health Status in Some Affected Individuals

Almost a year since the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) began causing COVID-19, our knowledge about its manifestations continues to expand. As more people become fatally ill with COVID-19, it is now clear that many patients who developed a mild illness, recovered from a serious illness, or had an asymptomatic infection are also beginning to suffer from a newly described entity called Long COVID. Studies show that show COVID-19 influences the cardiovascular framework, yet the general effects stay obscured. Impaired diffusion capacity, lower respiratory muscle strength, and lung imaging abnormalities are seen in COVID-19 patients in the early recovery stage. As compared to non-severe cases, severe patients had a higher incidence of Diffusion capacity of lung for carbon monoxide (DLCO) impairment and are more prone to total lung capacity decrease and 6-Minute Walk Test (6MWT) decline. The degree and seriousness of long-term well-being outcomes remain unclear, yet increasing information points in the direction of poorer physiological outcomes. Long-term sequelae of COVID-19 will have enduring implications on those afflicted’s physical, mental, and social health while having a substantial monetary impact on society.

Impact of coronavirus disease 2019 on pulmonary function in early convalescence phase

ObjectiveThis study investigated the influence of Coronavirus Disease 2019 (COVID-19) on lung function in early convalescence phase.MethodsA retrospective study of COVID-19 patients at the Fifth Affiliated Hospital of Sun Yat-sen University were conducted, with serial assessments including lung volumes (TLC), spirometry (FVC, FEV1), lung diffusing capacity for carbon monoxide (DLCO),respiratory muscle strength, 6-min walking distance (6MWD) and high resolution CT being collected at 30 days after discharged.ResultsFifty-seven patients completed the serial assessments. There were 40 non-severe cases and 17 severe cases. Thirty-one patients (54.3%) had abnormal CT findings. Abnormalities were detected in the pulmonary function tests in 43 (75.4%) of the patients. Six (10.5%), 5(8.7%), 25(43.8%) 7(12.3%), and 30 (52.6%) patients had FVC, FEV1, FEV1/FVC ratio, TLC, and DLCO values less than 80% of predicted values, respectively. 28 (49.1%) and 13 (22.8%) patients had PImax and PEmax values less than 80% of the corresponding predicted values. Compared with non-severe cases, severe patients showed higher incidence of DLCO impairment (75.6%vs42.5%, p = 0.019), higher lung total severity score (TSS) and R20, and significantly lower percentage of predicted TLC and 6MWD. No significant correlation between TSS and pulmonary function parameters was found during follow-up visit.ConclusionImpaired diffusing-capacity, lower respiratory muscle strength, and lung imaging abnormalities were detected in more than half of the COVID-19 patients in early convalescence phase. Compared with non-severe cases, severe patients had a higher incidence of DLCO impairment and encountered more TLC decrease and 6MWD decline.

Impairment of respiratory muscle strength in Berardinelli-Seip congenital lipodystrophy subjects

BackgroundBerardinelli-Seip Congenital Generalized Lipodystrophy (BSCL) is an ultra-rare metabolic disease characterized by hypertriglyceridemia, hyperinsulinemia, hyperglycemia, hypoleptinemia, and diabetes mellitus. Although cardiovascular disturbances have been observed in BSCL patients, there are no studies regarding the Respiratory Muscle Strength (RMS) in this type of lipodystrophy. This study aimed to evaluate RMS in BSCL subjects compared with healthy subjects.MethodsEleven individuals with BSCL and 11 healthy subjects matched for age and gender were included in this study. The Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure (MEP), and Peripheral Muscle Strength (PMS) were measured for three consecutive years. BSCL subjects were compared to healthy individuals for MIP, MEP, and PMS. Correlations between PMS and MIP were also analyzed. The genetic diagnosis was performed, and sociodemographic and anthropometric data were also collected.ResultsBSCL subjects showed significantly lower values for MIP and MEP (p < 0.0001 and p = 0.0002, respectively) in comparison to healthy subjects, but no changes in handgrip strength (p = 0.15). Additionally, we did not observe changes in MIP, MEP, and PMS two years after the first analysis, showing maintenance of respiratory dysfunction in BSCL subjects (p = 0.05; p = 0.45; p = 0.99). PMS and MIP were not correlated in these subjects (r = 0.56; p = 0.18).ConclusionBSCL subjects showed lower respiratory muscle strength when compared with healthy subjects; however, PMS was not altered. These findings were maintained at similar levels during the two years of evaluation. Our data reveal the first association of BSCL with the development of respiratory muscle weakness.

Respiratory muscle strength in children with mild bronchial asthma disease

Background: Respiratory muscle strength can be decreased in patients with asthma; however, it is not well-documented whether a mild bronchial asthma disease can affect respiratory muscle strength in children and can be associated with higher presence of breathing difficulties. Objective: The main aim of the present study was to compare respiratory muscle strength between children with asthma and age-matched healthy children. The next aim of this study was to assess the incidence of decreased respiratory muscle strength in children with asthma and healthy children and assess the effect of decreased respiratory muscle strength on the incidence of breathing difficulties. Methods: Children with mild bronchial asthma (n = 167) and age-matched, healthy children (n = 100) were recruited into this study. Pulmonary function tests, maximal inspiratory (PImax) and expiratory (PEmax) mouth pressures and the incidence of breathing difficulty were evaluated in children with asthma and healthy controls. Results: The inspiratory muscle strength was similar between children with asthma and healthy children. Conversely, the expiratory muscle strength was lower in asthmatic children. There was a statistically significant difference between girls with asthma and healthy girls (PEmax = 81.7 ± 29.8% vs. 100.1 ± 23.7% of predicted, p < .001). PEmax was significantly higher in boys with asthma than in girls with asthma (PEmax = 92.9 ± 26.4 % vs. 81.7 ± 29.8% of predicted, p = .03). A higher incidence of breathing difficulties during physical activity (uphill walking, running, swimming) was confirmed in children with asthma with lower respiratory muscle strength. Conclusions: There was a higher prevalence of decreased expiratory muscle strength in children with asthma; therefore, respiratory muscle strength should be tested in these children, especially in those who are symptomatic.

Muscle function and quality of life in the Crohn’s disease

Abstract Introduction: Crohn’s disease (CD) is an inflammatory bowel disease, marked by exacerbations and remissions periods. Peripheral manifestations in CD may be present with the syndrome of skeletal muscle dysfunction (SMD), which is characterized by loss of muscle strength, fatigue complain, limited exercise capacity and impaired quality of life of these patients. Objective: Evaluate muscle strength, physical capacity and quality of life of patients with CD and compare them with healthy controls. Methods: 18 patients CD and 12 healthy controls matched for age and sex were involved. Peripheral muscle strength evaluated by handgrip strength of the dominant hand and respiratory muscle strength by measures of respiratory muscle strength (maximal inspiratory/expiratory pressure - MIP and MEP). Exercise capacity evaluated by Shuttle test (ST) and the quality of life by the Short-form 36 (SF-36) and by the Inflammatory Bowel Disease Questionnaire (IBDQ). Results: Patients with CD presented a lower respiratory muscle strength (MIP = -68.93 ± 26.61 vs 29.63 ± -100 cmH2O, p = 0.0013 and MEP = 81.07 ± 30.26 vs 108 ± 25.30 cmH2O, p = 0.032) and a tendency the lower peripheral muscle strength (31.72 ± 8.55 vs 39.00 ± 13.37 kgf, p = 0.09). In addition, CD patients presented worse physical capacity on the ST compared to the control group (513.7 ± 237m vs 983.0 ± 263m, p &lt; 0.05) and worse quality of life in 7 of 8 domains of the SF-36 and in all dimensions of the IBDQ. Conclusion: Patients with CD showed muscle functional impairment and poorer quality of life compared to healthy control group. These findings suggest that the assessment and maybe interventions in the muscle function must be used in clinical practice.

Avaliação da força muscular respiratória em indivíduos com síndrome de down

As a result of muscle changes caused by the generalized hypotonia found in individuals with Down syndrome (DS), these subjects develop changes in respiratory muscle strength. The objective of the study was to assess respiratory muscle strength (RMS) of individuals having DS. Thus, the objective of the study was to evaluate the respiratory muscle strength (RMS) in individuals with DS. It was cross-sectional study, conducted at the Association of Parents and Friends of Exceptional (APFE) of countryside of Sao Paulo. 20 volunteers were evaluated, divided into two groups, 10 non-syndromic individuals and 10 individuals diagnosed with DS, aged between 18 and 35 years, of both genders. The evaluation of RMS was performed by an analog manometer through which were measured maximal inspiratory pressures (MIP) and maximum expiratory pressures (MEP). For data analysis, were used the BioEstat version 5.3. Data normality was verified by the Shapiro-Wilk test. After, comparison tests were used for two independent samples (Student’s t and Mann-Whitney tests), adopting a significance level of 5%. When comparing both groups, we can find a significant difference in MIP (p= 0.0011) and MEP (p= 0.0002), and lower RMS values were obtained in the group of individuals with DS. SD (MIP: -109±49.49 x -29.50±9.07) and (MEP: 127±44.06 x 45.50±10.11) Therefore, individuals with Down syndrome have decreased RMS. It is believed that these individuals would benefit from a rehabilitation program, including physiotherapy, thus minimizing possible respira-tory complications.

Childhood mouth-breathing consequences at adult age: ventilatory function and quality of life

Introduction Mouth breathing can affect the functions of the respiratory systems and quality of life. For this reason, children who grow up with this stimulus may have implications on physical and psychological aspects at adult age.Objective To evaluate childhood mouth-breathing consequences for the ventilatory function and quality of life at adult age.Materials and methods Prospective, observational and cross-sectional study with 24 adults, between 18 and 30 years old, mouth breathers during childhood, comprised the childhood mouth-breathing group (CMB). The childhood nasal-breathing (CNB) group was composed of 20 adults of the same age, without history of respiratory disease during all their lives. Measurements of maximal respiratory pressures, peak expiratory flow and 6-minute walk test were assessed. In addition, all the volunteers answered the Short Form-36 questionnaire (SF-36).Results The maximal inspiratory (p = 0.001) and expiratory (p = 0.000) pressures as well as the distance in the walk test (p = 0.003) were lower in the COB. The COB also presented lower score in the General Health domain of the SF-36 Questionnaire (p = 0.002).Conclusion Childhood mouth-breathing yields consequences for the ventilatory function at adult age, with lower respiratory muscle strength and functional exercise capacity. Conversely, the quality of life was little affected by the mouth breathing in this study.

Effects of inspiratory muscle training on lung volumes, respiratory muscle strength, and quality of life in patients with ataxia telangiectasia

Ataxia telangiectasia (AT) is a genetic syndrome caused by a mutation of chromosome 11. The clinical features are cerebellar ataxia, telangiectasia, and progressive loss of muscular coordination, including an inefficient cough secondary to progression of neurological disease. To evaluate the effects of inspiratory muscle training (IMT) on ventilation, lung volume, dyspnoea, respiratory muscle strength, and quality of life in patients with AT. A longitudinal study was conducted with 11 AT patients and nine healthy volunteers. Ventilometry, subjective sensation of dyspnoea, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and quality of life were assessed before and after a 24-week IMT program. The IMT load used was set at 60% of the MIP, and the training was performed for 20 min daily. Patients with AT had lower height and weight and also had lower respiratory muscle strength and lung volume compared with healthy volunteers. Furthermore, patients with AT showed a significant improvement when pre- and post-IMT were compared for ventilatory pattern: Vt (476.5 ± 135 ml vs. 583.3 ± 66 ml, P = 0.015) and f (23.3 ± 6 rpm vs. 20.4 ± 4 rpm, P = 0.018), and VC (1,664 ± 463 ml/kg vs. 2,145 ± 750 ml/kg, P = 0.002). IMT also significantly improved the sensation of dyspnoea (median 0.5; minimum 0; maximum 1.0; P = 0.022) and respiratory muscle strength: MIP (-22.2 ± 2 cmH2O vs. -38 ± 9 cmH2O, P < 0.001) and MEP (29 ± 7 cmH2O vs. 40 ± 8 cmH2O, P = 0.001). The health and vitality domains of the SF-36 also showed significant improvement (P = 0.009 and P = 0.014, respectively) post-IMT. IMT was effective in improving ventilatory pattern, lung volume, respiratory muscle strength, and the health and vitality domains for quality of life in patients with AT. IMT may be an effective adjunct therapy to drug treatment for patients with AT.

Association of body mass index with exercise cardiopulmonary responses in lung function-matched patients with chronic obstructive pulmonary disease

Background and ObjectivesLung function is traditionally used to define the severity of chronic obstructive pulmonary disease (COPD). However, this does not exclude other factors. This study investigated the influence of body mass index (BMI) on exercise responses and quality of life in patients with COPD matched for values of forced expiratory volume in 1 second (FEV1). MethodsUnderweight, normal-weight, and overweight patients with COPD, matched for FEV1, were studied. All patients were evaluated by spirometry, a cardiopulmonary exercise test, respiratory muscle strength, and, St. George's Respiratory Questionnaire (SGRQ). ResultsThe baseline characteristics and mean FEV1 of the 3 groups were similar (P > .05). Respiratory muscle strengths and SGRQ scores were lowest in underweight patients (P < .05). In terms of exercise response, the lowest oxygen uptake at anaerobic threshold and peak exercise, the highest ventilatory equivalent, and the lowest oxygen pulse were evident in underweight patients (P < .05). ConclusionsUnderweight patients with COPD had lower respiratory muscle strength, impaired exercise capacity, earlier anaerobic metabolism, ineffective ventilation, and poorer quality of life.

Position and ventilatory response to added dead space in prematurely born infants

Prematurely born infants are at increased risk of sudden infant death syndrome (SIDS) if slept prone. Prematurely born infants would have an impaired response to an added dead space and lower respiratory muscle strength in the prone compared to the supine position. Prospective study. PATIENT-SUBJECT SELECTION: Twenty-five infants, median gestational age of 30 (range 26-32) weeks. The infants were studied supine and prone at a median of 36 weeks postmenstrual age. Breath by breath minute volume was measured at baseline and after a dead space was incorporated into the breathing circuit; the time constant of the response was calculated. The maximum inspiratory occlusion pressure generated (MIOP) and the pressure generated over the first 100 msec (P(0.1)) during airway occlusion were assessed. The median time constant was longer (26 (range 8-106) sec vs. 22 (range 6-92) sec (P = 0.045)) and the median MIOP (P = 0.001) and P(0.1) (P = 0.003) were lower in the prone compared to the supine position. Prematurely born infants have a dampened response to tube breathing and reduced respiratory muscle strength in the prone compared to the supine position, which may contribute to their increased vulnerability to SIDS in the prone position.

Mechanics of Respiratory Muscles in Single-Lung Transplant Recipients

Background: Emphysema and pulmonary fibrosis force the patients to breathe at an abnormal lung volume, which alters the lengths of the respiratory muscles and thereby their work capability is reduced. After single-lung transplantation, muscle function is restored on the side of the transplant but it may be asymmetric to that on the side of the native diseased lung. Objective: Investigating the hypothesis that single-lung transplantation induces mechanical asymmetry of the respiratory muscles on the two sides. Methods: Simultaneously noninvasive measurements of inspiratory and expiratory mouth pressure, airflow rate and electromyography signals from the sternomastoid, external intercostal, rectus abdominis and external oblique muscles were acquired during different breathing maneuvers. The study group included 10 single-lung transplant recipients (5 with pulmonary fibrosis and 5 with emphysema) and 10 healthy controls. Results: Analysis of the finding shows a significant lower global strength of the respiratory muscles of single-lung transplant recipients compared to that of healthy subjects. No significant difference in the EMG signals of respiratory muscles was found either between the different groups or between the sides of the transplant and the native lung in the patient groups. Both single-lung transplant recipients and healthy subjects demonstrated high EMG activity of the inspiratory muscles during inspiration at different breathing efforts. Conclusion: Patients after single-lung transplantation have lower respiratory muscle strength than healthy subjects, but apparently normal electrical activity. The lower global respiratory muscle strength emphasizes the importance of their rehabilitation before and after single-lung transplantation.