Muscle function in COPD: a complex interplay

Effect of low-moderate intensity traditional Chinese exercises combined with acupuncture on patients with stable chronic obstructive pulmonary disease: study protocol for a randomized controlled trial

Background

Traditional Chinese exercises (TCEs), as a new technology for pulmonary rehabilitation, have been proven to be effective in patients with chronic obstructive pulmonary disease (COPD). However, further aggravation of dynamic hyperinflation manifested as exertional dyspnea during exercises may limit the partial therapeutic efficacy of TCEs on patients with COPD. Acupuncture therapy, internationally recognized as a complementary and alternative therapy, can effectively improve the degree of dyspnea, and it is expected to serve as an adjuvant therapy for exercise training in patients with COPD to fully realize the therapeutic efficacy of exercise training. Therefore, this study aims to explore the multidimensional and multi-system effects of the combination of pulmonary-based Qigong (PQ) exercise and acupuncture therapy on patients with COPD.

Methods

This protocol describes an assessor-blinded, data analyst-blinded, four-arm randomized controlled trial that aims to recruit 132 participants with stable COPD and randomly allocate them into pulmonary-based Qigong exercise group, acupuncture group, pulmonary-based Qigong exercise and acupuncture combined group, or control group at a 1:1:1:1 ratio. All participants will receive usual medical care and health education; those in the intervention groups will receive PQ exercise, acupuncture treatment, or a combination of both treatments three times per week for 8 weeks. The primary outcome will be the exercise endurance as assessed by a 6-min walk test. Secondary outcomes will include lung function, degree of dyspnea, diaphragmatic function, respiratory muscle strength, skeletal muscle structure, skeletal muscle function, psychological states, and quality of life. Exploratory outcomes will include the levels of inflammatory mediators. The frequency and severity of acute exacerbations of COPD will be recorded at baseline and 1 year after intervention.

Discussion

The findings of this study will clarify the effects of the combination of PQ exercise and acupuncture therapy on the multi-system function of patients with stable COPD to provide evidence for acupuncture as an adjuvant therapy for pulmonary rehabilitation.

Clinical trial registration

https://www.chictr.org.cn, ChiCTR2300076255.

The effects of sex hormones on BDNF secretion in airway smooth muscle of patients with obstructive pulmonary disease

Obstructive pulmonary diseases, including asthma and chronic obstructive pulmonary disease, present significant global public health challenges and substantially impair patients' quality of life. Research indicates that sex hormones and brain-derived neurotrophic factor (BDNF) are pivotal in regulating airway function and inflammatory responses. Specifically, sex hormones modulate the expression and function of BDNF through their receptors, namely estrogen receptors and androgen receptors. Conversely, BDNF enhances cell survival and exerts anti-inflammatory and antioxidant effects, influencing the functionality of sex hormone receptors. This review elucidates the interactions between sex hormones and BDNF in obstructive pulmonary disease, emphasizing their synergistic roles in managing airway inflammation, facilitating tissue repair, and mitigating oxidative stress. Through a thorough examination of these mechanisms, this review aims to foster a more profound comprehension of the potential therapeutic implications for the management of these diseases.

Exercise Attenuate Diaphragm Atrophy in COPD Mice via Inhibiting the RhoA/ROCK Signaling

Background

Exercise is an indispensable component of pulmonary rehabilitation with strong anti-inflammatory effects. However, the mechanisms by which exercise prevents diaphragmatic atrophy in COPD (chronic obstructive pulmonary disease) remain unclear.

Methods

Forty male C57BL/6 mice were assigned to the control (n=16) and smoke (n=24) groups. Mice in the smoke group were exposed to the cigarette smoke (CS) for six months. They were then divided into model and exercise training groups for 2 months. Histological changes were observed in lung and diaphragms. Subsequently, agonist U46639 and antagonist Y27632 of RhoA/ROCK were subjected to mechanical stretching in LPS-treated C2C12 myoblasts. The expression levels of Atrogin-1, MuRF-1, MyoD, Myf5, IL-1β, TNF-α, and RhoA/ROCK were determined by Western blotting.

Results

Diaphragmatic atrophy and increased RhoA/ROCK expression were observed in COPD mice. Exercise training attenuated diaphragmatic atrophy, decreased the expression of MuRF-1, and increased MyoD expression in COPD diaphragms. Exercise also affects the upregulation of RhoA/ROCK and inflammation-related proteins. In in vitro experiments with C2C12 myoblasts, LPS remarkably increased the level of inflammation and protein degradation, whereas Y27632 or combined with mechanical stretching prevented this phenomenon considerably.

Conclusion

RhoA/ROCK plays an important role in the prevention of diaphragmatic atrophy in COPD.

Lung Hyperinflation as Treatable Trait in Chronic Obstructive Pulmonary Disease: A Narrative Review

Lung hyperinflation (LH) is a common clinical feature in patients with chronic obstructive pulmonary disease (COPD). It results from a combination of reduced elastic lung recoil as a consequence of irreversible destruction of lung parenchyma and expiratory airflow limitation. LH is an important determinant of morbidity and mortality in COPD, partially independent of the degree of airflow limitation. Therefore, reducing LH has become a major target in the treatment of COPD over the last decades. Advances were made in the diagnostics of LH and several effective interventions became available. Moreover, there is increasing evidence suggesting that LH is not only an isolated feature in COPD but rather part of a distinct clinical phenotype that may require a more integrated management. This narrative review focuses on the pathophysiology and adverse consequences of LH, the assessment of LH with lung function measurements and imaging techniques and highlights LH as a treatable trait in COPD. Finally, several suggestions regarding future studies in this field are made.

Effects of pulmonary-based Qigong exercise in stable patients with chronic obstructive pulmonary disease: a randomized controlled trial

BACKGROUND

Physical exercise training is the central component of pulmonary rehabilitation. This study aimed to further investigate the rehabilitative effects of pulmonary-based Qigong exercise (PQE) in stable patients with chronic obstructive pulmonary disease (COPD).

METHODS

In this randomized, assessor-blinded clinical trial, 44 participants with stable COPD were randomly assigned to 2 groups in a 1:1 ratio. Participants in the control group received usual care for 3 months. Participants in the intervention group received usual care combined with PQE (60 min each time, 2 times per day, 7 days per week, for 3 months). The outcome included exercise capacity, lung function test, skeletal muscle strength, dyspnea, and quality of life were measured before and after intervention.

RESULTS

A total of 37 participants completed the trial. Compared to the control group, after 3 months of PQE, the mean change in exercise capacity, skeletal muscle strength, and quality of life were statistically significant (P < 0.05, for each), but no significant differences were observed in lung function (except for the forced expiratory volume in one second) and dyspnea (P > 0.05, for each).

CONCLUSION

The findings of study suggest that the proposed program of 3 months of PQE intervention has significant improvement in exercise capacity, skeletal muscle strength, and quality of life of COPD-stable patients.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (Trial ID: ChiCTR-1800017405 on 28 July 2018; available at https://www.chictr.org.cn/showproj.html?proj=28343 ).

Impaired Skeletal Muscle in Patients with Stable Chronic Obstructive Pulmonary Disease (COPD) Compared with Non-COPD Patients

Purpose

This study was designed to investigate the differences in skeletal-muscle atrophy between patients with stable chronic obstructive pulmonary disease (COPD) and healthy controls; associated factors were also considered. The study comprised selected residents of communities near the First Affiliated Hospital of Soochow University in Suzhou City, East China.

Patients and Methods

Included in this study were 123 COPD patients and 60 controls. All patients completed spirometry as well as examinations to determine their functional exercise capacity, body composition, and handgrip strength (HGS).

Results

COPD patients had less fat-free mass (FFM), a lower FFM index (FFMI), and a lower 6-min walking distance (6MWD) compared with controls (P = 0.007, P = 0.020, and P < 0.001, respectively) (FFMI: 17.59 ± 1.83 vs 18.34 ± 1.64). The HGS of these patients was also lower compared with that of controls (32.88 ± 7.84 vs 35.48 ± 7.42), and HGS tended toward statistical significance (P = 0.064, respectively). In multivariate analysis, age (β = -0.107, P < 0.001), gender (β = 0.212, P < 0.001), body mass index (BMI) (β = 0.462, P < 0.001), FEV1% (β = 0.108, P = 0.009), and calf circumference (CC) (β = 0.457, P < 0.001) were significantly associated with FFMI.

Conclusion

Impaired skeletal muscle mass was more common in COPD patients than in controls. Multiple regression analysis showed that CC may be used to detect the degree of impairment, particularly by health-care providers working outside of the hospital.

Associations Between Muscle Weakness and Clinical Outcomes in Current and Former Smokers

Introduction

Smokers with chronic obstructive pulmonary disease (COPD) are at increased risk of muscle weakness. There are limited data describing weakness in smokers with normal spirometry and preserved ratio-impaired spirometry (PRISm), 2 subgroups at risk of respiratory symptom burden and activity limitations. In this study, we evaluated the associations of 2 weakness measures, sit-to-stand (STS) and handgrip strength (HGS), with clinical outcomes in smokers with COPD, normal spirometry, and PRISm.

Methods

We evaluated 1972 current and former smokers from the COPD Genetic Epidemiology (COPDGene®) cohort with STS and HGS measurements at their 10-year study visit. Multivariable regression modeling was used to assess associations between weakness measures and the 6-minute walk distance (6MWD) test, the St George's Respiratory Questionnaire (SGRQ), the Short-Form-36 (SF-36), severe exacerbations, and prospective mortality, reported as standardized coefficients (β), odds ratios (ORs), or hazard ratios (HRs).

Results

Compared with HGS, STS was more strongly associated with the 6MWD (β=0.45, p<0.001 versus. β=0.25, p<0.001), SGRQ (β=-0.24, p<0.001 versus β=-0.18, p<0.001), SF-36 Physical Functioning (β=0.36, p<0.001 versus β=0.25, p<0.001), severe exacerbations (OR 0.95, p=0.04 versus OR 0.97, p=0.01), and prospective mortality (HR 0.83, p=0.001 versus HR 0.94, p=0.03). Correlations remained after stratification by spirometric subgroups. Compared with males, females had larger magnitude effect sizes between STS and clinical outcomes.

Conclusions

STS and HGS are easy to perform weakness measures that provide important information about functional performance, health-related quality of life, severe exacerbations, and survival in smokers, regardless of spirometric subgroup. This iterates the importance of screening current and former smokers for weakness in the outpatient setting.

Effects of eccentric, concentric and eccentric/concentric training on muscle function and mass, functional performance, cardiometabolic health, quality of life and molecular adaptations of skeletal muscle in COPD patients: a multicentre randomised trial

Background

Chronic obstructive pulmonary disease (COPD) is the third cause of death worldwide. COPD is characterised by dyspnoea, limited exercise tolerance, and muscle dysfunction. Muscle dysfunction has been linked to dysregulation between muscle protein synthesis, myogenesis and degradation mechanisms. Conventional concentric cycling has been shown to improve several clinical outcomes and reduce muscle wasting in COPD patients. Eccentric cycling is a less explored exercise modality that allows higher training workloads imposing lower cardio-metabolic demand during exercise, which has shown to induce greater muscle mass and strength gains after training. Interestingly, the combination of eccentric and concentric cycling training has scarcely been explored. The molecular adaptations of skeletal muscle after exercise interventions in COPD have shown equivocal results. The mechanisms of muscle wasting in COPD and whether it can be reversed by exercise training are unclear. Therefore, this study aims two-fold: (1) to compare the effects of 12 weeks of eccentric (ECC), concentric (CONC), and combined eccentric/concentric (ECC/CONC) cycling training on muscle mass and function, cardiometabolic health, physical activity levels and quality of life in severe COPD patients; and (2) to examine the molecular adaptations regulating muscle growth after training, and whether they occur similarly in specific muscle fibres (i.e., I, IIa and IIx).

Methods

Study 1 will compare the effects of 12 weeks of CONC, ECC, versus ECC/CONC training on muscle mass and function, cardiometabolic health, levels of physical activity and quality of life of severe COPD patients using a multicentre randomised trial. Study 2 will investigate the effects of these training modalities on the molecular adaptations regulating muscle protein synthesis, myogenesis and muscle degradation in a subgroup of patients from Study 1. Changes in muscle fibres morphology, protein content, genes, and microRNA expression involved in skeletal muscle growth will be analysed in specific fibre-type pools.

Discussion

We aim to demonstrate that a combination of eccentric and concentric exercise could maximise the improvements in clinical outcomes and may be ideal for COPD patients. We also expect to unravel the molecular mechanisms underpinning muscle mass regulation after training in severe COPD patients.

Trial Registry: Deutshches Register Klinischer Studien; Trial registration: DRKS00027331; Date of registration: 12 January 2022. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00027331.

Efficacy of Acupuncture on Quality of Life, Functional Performance, Dyspnea, and Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease: Protocol for a Randomized Clinical Trial

Chronic obstructive pulmonary disease (COPD) is a respiratory disease characterized by the presence of chronic airflow obstruction. Previous studies have evaluated the effect of acupuncture treatment (AT) in patients with COPD. Nevertheless, these studies show a great deal of heterogeneity in treatment protocols, having sample sizes that are too small to estimate and clarify effect size and heterogeneity in patients’ baseline. The aim of this study is to evaluate the effectiveness of acupuncture on quality of life, functional performance, dyspnea, and pulmonary function in patients with COPD. As such, patients will go through the following three phases: Phase I–pretreatment: period of subject selection and inclusion in the protocol, with an interview and performance of exams and tests as follows: Mini-Cog, dual-energy X-ray absorptiometry, spirometry, the Patient-Generated Index, Saint George’s Respiratory Questionnaire, the six-minute walk test, the London Chest Activity of Daily Living, and the COPD Assessment Test. Phase II–8 weeks of treatment, with AT 3 times a week, with two parallel groups: Group I–with 50 subjects–AT according to the recommended technical standards; Group II–with 50 subjects–Control, without acupuncture. Phase III–Continuation of AT for 8 weeks, maintaining the subjects in the previously allocated groups and following the same methodology.

Growth differentiation factor 11 induces skeletal muscle atrophy via a STAT3-dependent mechanism in pulmonary arterial hypertension

Skeletal muscle wasting is a clinically remarkable phenotypic feature of pulmonary arterial hypertension (PAH) that increases the risk of mortality. Growth differentiation factor 11 (GDF11), centrally involved in PAH pathogenesis, has an inhibitory effect on skeletal muscle growth in other conditions. However, whether GDF11 is involved in the pathogenesis of skeletal muscle wasting in PAH remains unknown. We showed that serum GDF11 levels in patients were increased following PAH. Skeletal muscle wasting in the MCT-treated PAH model is accompanied by an increase in circulating GDF11 levels and local catabolic markers (Fbx32, Trim63, Foxo1, and protease activity). In vitro GDF11 activated phosphorylation of STAT3. Antagonizing STAT3, with Stattic, in vitro and in vivo, could partially reverse proteolytic pathways including STAT3/socs3 and iNOS/NO in GDF11-meditated muscle wasting. Our findings demonstrate that GDF11 contributes to muscle wasting and the inhibition of its downstream molecule STAT3 shows promise as a therapeutic intervention by which muscle atrophy may be directly prevented in PAH.

Diaphragm Dysfunction and Rehabilitation Strategy in Patients With Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) affects the whole body and causes many extrapulmonary adverse effects, amongst which diaphragm dysfunction is one of the prominent manifestations. Diaphragm dysfunction in patients with COPD is manifested as structural changes, such as diaphragm atrophy, single-fibre dysfunction, sarcomere injury and fibre type transformation, and functional changes such as muscle strength decline, endurance change, diaphragm fatigue, decreased diaphragm mobility, etc. Diaphragm dysfunction directly affects the respiratory efficiency of patients and is one of the important pathological mechanisms leading to progressive exacerbation of COPD and respiratory failure, which is closely related to disease mortality. At present, the possible mechanisms of diaphragm dysfunction in patients with COPD include systemic inflammation, oxidative stress, hyperinflation, chronic hypoxia and malnutrition. However, the specific mechanism of diaphragm dysfunction in COPD is still unclear, which, to some extent, increases the difficulty of treatment and rehabilitation. Therefore, on the basis of the review of changes in the structure and function of COPD diaphragm, the potential mechanism of diaphragm dysfunction in COPD was discussed, the current effective rehabilitation methods were also summarised in this paper. In order to provide direction reference and new ideas for the mechanism research and rehabilitation treatment of diaphragm dysfunction in COPD.

Prolonged Mechanical Ventilation: Outcomes and Management

The number of patients requiring prolonged mechanical ventilation (PMV) is increasing worldwide, placing a burden on healthcare systems. Therefore, investigating the pathophysiology, risk factors, and treatment for PMV is crucial. Various underlying comorbidities have been associated with PMV. The pathophysiology of PMV includes the presence of an abnormal respiratory drive or ventilator-induced diaphragm dysfunction. Numerous studies have demonstrated that ventilator-induced diaphragm dysfunction is related to increases in in-hospital deaths, nosocomial pneumonia, oxidative stress, lung tissue hypoxia, ventilator dependence, and costs. Thus far, the pathophysiologic evidence for PMV has been derived from clinical human studies and experimental studies in animals. Moreover, recent studies have demonstrated the outcome benefits of pharmacological agents and rehabilitative programs for patients requiring PMV. However, methodological limitations affected these studies. Controlled prospective studies with an adequate number of participants are necessary to provide evidence of the mechanism, prognosis, and treatment of PMV. The great epidemiologic impact of PMV and the potential development of treatment make this a key research field.

Effects of pulmonary rehabilitation on diaphragm thickness and contractility in patients with chronic obstructive pulmonary disease

BACKGROUND

Studies are showing that pulmonary rehabilitation (PR) increases diaphragmatic excursion by decreasing hyperinflation in patients with chronic obstructive pulmonary disease (COPD). However, there is a lack of knowledge about its effects on the diaphragm thickness (dt) and contractility. This study aims to evaluate the dt and contractility before and after PR in patients with COPD.

METHODS

All subjects participated in an out-patient PR of 6 weeks and 3 sessions per week prospectively. Dyspnea severity, the disease-specific quality of life (St. Georges Respiratory Questionnaire-SGRQ), pulmonary function tests (PFT), exercise capacity, the dt at the end of the expiration and at maximal inspiration (B-mode ultrasound) were evaluated at baseline and after PR.

RESULTS

A total of 34 patients with a mean age and FEV1 61.05 ± 8.22 years and 57.9 ± 20.4% predicted respectively showed improvements in exercise capacity and some items of PFT and SGRQ. Diaphragmatic thickness at the end of the expiration also significantly improved regardless of the disease severity and was positively correlated with functional performance. The 6-weeks of PR didn't result in a significant difference in diaphragm contractility.

Reflexive thematic analysis exploring stakeholder experiences of virtual pulmonary rehabilitation (VIPAR)

Introduction

To enable greater availability of pulmonary rehabilitation (PR), video-conferencing technology was employed to link a community site to a standard outpatient PR service to deliver the programme closer to those with chronic respiratory disease. The service was called virtual pulmonary rehabilitation (VIPAR). To understand the experiences of those involved in this service, this study aimed to answer the question: How do the different stakeholders that interact with VIPAR experience the programme?

Methods

Focus groups were conducted with people with chronic lung disease attending either the community or outpatient PR site, in addition to the staff involved in the running of the PR groups. A total of five focus groups were conducted. Reflexive thematic analysis was used to analyse the transcripts.

Results

Participants who received VIPAR were positive regarding the programme and described the benefits of the service. Additionally, participants discussed the trade-off between convenience and relatedness. Staff described barriers to the service and solutions that could be employed to mitigate these, including greater training, organisation and understanding of risk.

Discussion

Using technology to increase the availability of PR is acceptable to the stakeholders involved, providing problems and organisational issues are resolved with training.

Intramuscular and Intermuscular Abdominal Fat Infiltration in COPD: A Propensity Score Matched Study

Purpose

Low-attenuation muscle area (LAMA) and normal-attenuation muscle area (NAMA) indicate lipid-rich and lipid-poor skeletal muscle areas, respectively. Additionally, intermuscular adipose tissue (IMAT) indicates localized fat between muscle groups. In this study, we aimed to evaluate the intramuscular and intermuscular fat infiltration in individuals with chronic obstructive pulmonary disease (COPD) by performing quantitative assessment of the LAMA, NAMA, and IMAT observed on abdominopelvic computed tomography (APCT) images.

Patients and Methods

We performed a cross-sectional study using data of subjects who underwent a general health examination with APCT at Ulsan University Hospital between March 2014 and June 2019. We classified the subjects into control and COPD groups based on age, smoking history, and pulmonary function results. We compared the attenuation and body mass index adjusted area of intra-abdominal components between the two groups using propensity score matching. We also evaluated these outcomes in COPD subgroups (mild and moderate stage subjects).

Results

Overall, 6,965 subjects were initially enrolled, and 250 pairs of control and COPD subjects were selected after propensity score matching. The NAMA attenuation (unstandardized β=−1.168, P<0.001) was lower, and the IMAT (unstandardized β=0.042, P=0.006) and LAMA (unstandardized β=0.120, P<0.001) indexes were greater in the COPD group than in the control group. In subgroup analysis, those with mild and moderate COPD also had high IMAT (unstandardized β=0.037, P=0.009 and unstandardized β=0.045, P<0.001) and LAMA (unstandardized β=0.089, P=0.002 and unstandardized β=0.147, P<0.001) indexes compared to the control subjects. However, the NAMA attenuation (unstandardized β=−1.075, P<0.001) and NAMA index (unstandardized β=−0.133, P=0.015) were significantly lower in moderate COPD subjects only.

Conclusion

Our study showed that intramuscular and intermuscular abdominal fat infiltration could be present in subjects with mild COPD, and it might be exacerbated in those with moderate COPD.

Effect of Oxidative Stress on Diaphragm Dysfunction and Exercise Intervention in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) can cause extrapulmonary injury such as diaphragm dysfunction. Oxidative stress is one of the main factors causing diaphragm dysfunction in COPD. Exercise plays a positive role in the prevention and treatment of diaphragm dysfunction in COPD, and the changes in diaphragm structure and function induced by exercise are closely related to the regulation of oxidative stress. Therefore, on the basis of the review of oxidative stress and the changes in diaphragm structure and function in COPD, this article analyzed the effects of exercise on oxidative stress and diaphragm dysfunction in COPD and explored the possible mechanism by which exercise improves oxidative stress. Studies have found that diaphragm dysfunction in COPD includes the decline of muscle strength, endurance, and activity. Oxidative stress mainly affects the structure and function of the diaphragm in COPD through protein oxidation, protease activation and calcium sensitivity reduction. The effects of exercise on oxidative stress level and diaphragm dysfunction may differ depending on the intensity, duration, and style of exercise. The mechanism of exercise on oxidative stress in the diaphragm of COPD may include improving antioxidant capacity, reducing oxidase activity and improving mitochondrial function.

ERS International Congress 2020 Virtual: highlights from the Allied Respiratory Professionals Assembly

This article provides an overview of outstanding sessions that were (co)organised by the Allied Respiratory Professionals Assembly during the European Respiratory Society International Congress 2020, which this year assumed a virtual format. The content of the sessions was mainly targeted at allied respiratory professionals, including respiratory function technologists and scientists, physiotherapists, and nurses. Short take-home messages related to spirometry and exercise testing are provided, highlighting the importance of quality control. The need for quality improvement in sleep interventions is underlined as it may enhance patient outcomes and the working capacity of healthcare services. The promising role of digital health in chronic disease management is discussed, with emphasis on the value of end-user participation in the development of these technologies. Evidence on the effectiveness of airway clearance techniques in chronic respiratory conditions is provided along with the rationale for its use and challenges to be addressed in future research. The importance of assessing, preventing and reversing frailty in respiratory patients is discussed, with a clear focus on exercise-based interventions. Research on the impact of disease-specific fear and anxiety on patient outcomes draws attention to the need for early assessment and intervention. Finally, advances in nursing care related to treatment adherence, self-management and patients' perspectives in asthma and chronic obstructive pulmonary disease are provided, highlighting the need for patient engagement and shared decision making. This highlights article provides readers with valuable insight into the latest scientific data and emerging areas affecting clinical practice of allied respiratory professionals.

Bronchoscopic lung volume reduction: status quo

Emphysema is associated with irreversible loss of lung compliance leading to gas trapping and hyperinflation. Surgical lung volume reduction has proven to improve lung function, exercise capacity, cardiac health and survival in patients with advanced emphysema; however, this procedure is associated with significant morbidity and mortality. Bronchoscopic lung volume reduction (BLVR) has emerged as an alternative approach for these patients. In this article, we review the different techniques used for the purpose of this procedure, its advantages and disadvantages. In addition, we discuss in length valve therapy and the studies that led to its recent FDA approval. Finally, we provide thought-provoking challenges that may be topics for further future investigation to enhance the efficacy and benefit of this technique.

Intolerance to and limitations of inspiratory muscle training in patients with advanced chronic obstructive pulmonary disease: A report of two cases

Inspiratory muscle training (IMT) has been attracting attention as one of the useful treatments in patients with chronic obstructive pulmonary disease (COPD). IMT is reportedly effective in most patients with COPD. However, little is known about the benefits of IMT, especially in patients with advanced COPD. We reported two cases of COPD that received 12-week IMT to explore intolerance to and the limitations of IMT in advanced COPD. The effectiveness of IMT was evaluated using cardiopulmonary exercise testing (CPET), spirometry, and respiratory muscle strength testing before and after the training. A 75-year-old man with normal body mass index (BMI) and forced expiratory volume in 1 s (FEV₁) of 1.63 L responded well to IMT, but a 78-year-old man with low BMI and FEV₁ of 0.83 L did not. In the responder, IMT resulted in increased minute ventilation (V' _E) and oxygen uptake at peak exercise in incremental load testing. Moreover, IMT increased endurance time in constant load testing and maximal inspiratory pressure. In both patients, breathing frequency (f _R) increased, but tidal volume and the inspiratory-expiratory ratio were not improved during exercise. Despite the high f _R obtained after IMT, V' _E at peak exercise did not increase and endurance time shortened in the non-responder. In underweight patients with advanced COPD, IMT might lead to tachypnea and ventilatory inefficiency, which in turn might decrease exercise performance. Therefore, underweight patients with advanced COPD might be unable to tolerate IMT and should avoid receiving the training.

Frailty transitions and associated clinical outcomes in patients with stable COPD: A longitudinal study

BACKGROUND

Although frailty is a frequent occurrence in chronic obstructive pulmonary disease (COPD) patients, evidence on the frequency of frailty transition is scarce.

AIMS

The present study aimed to describe the frailty status transition rates over a 2-year period and their associated clinical outcomes in stable COPD patients, and to determine predictors of improvement in frailty status.

METHODS

We prospectively included 119 patients with stable COPD (mean age ± SD, 66.9 ± 7.9 years) over a follow-up period of 2 years. Frailty was assessed using the Fried criteria (unintentional weight loss, weakness, exhaustion, low activity level, and slow walking speed). Several demographic, clinical, and health-related variables were measured. We calculated the rates for each of the frailty transitions (no change, improvement, or worsening) between baseline and 2 years. Outcomes were compared using one-way analysis of variance and predictors of improvement were identified in multivariate logistic regression.

RESULTS

After 2 years of follow-up, 21 (17.6%) patients had an improved frailty status, 14 (11.7%) had worsened, and 84 (70.5%) had maintained the same frailty status. The worsening group (vs no change group) had greater dyspnea (p = 0.013) and disability (p = 0.036) and lower handgrip strength (p = 0.001). In contrast, the improved group (vs no change group) had greater handgrip (p<0.001) and quadriceps strength (p = 0.032). Furthermore, the improved group had greater handgrip strength (p<0.001), quadriceps strength (p = 0.003), physical activity (p = 0.008), and lower disability (p = 0.019) than the worsening group. Additionally, we determined that the 5STS test (≤ 13.6s) and exacerbations (≥ 2) were independent predictors for improvement in frailty status [adjusted OR 9.46, p = 0.058 and adjusted OR 0.12, p = 0.026, respectively].

CONCLUSIONS

Frailty is a dynamic process for approximately one-third of patients with stable COPD and transitions in frailty status are associated with significant changes in clinical outcomes. The 5STS and exacerbations were independent predictors of improvement in frailty status.

Exercise intolerance and fatigue in chronic heart failure: is there a role for group III/IV afferent feedback?

Exercise intolerance and early fatiguability are hallmark symptoms of chronic heart failure. While the malfunction of the heart is certainly the leading cause of chronic heart failure, the patho-physiological mechanisms of exercise intolerance in these patients are more complex, multifactorial and only partially understood. Some evidence points towards a potential role of an exaggerated afferent feedback from group III/IV muscle afferents in the genesis of these symptoms. Overactivity of feedback from these muscle afferents may cause exercise intolerance with a double action: by inducing cardiovascular dysregulation, by reducing motor output and by facilitating the development of central and peripheral fatigue during exercise. Importantly, physical inactivity appears to affect the progression of the syndrome negatively, while physical training can partially counteract this condition. In the present review, the role played by group III/IV afferent feedback in cardiovascular regulation during exercise and exercise-induced muscle fatigue of healthy people and their potential role in inducing exercise intolerance in chronic heart failure patients will be summarised.

Relationships Between Forced Oscillatory Impedance and 6-minute Walk Distance After Pulmonary Rehabilitation in COPD

Rationale

Pulmonary rehabilitation for chronic obstructive pulmonary disease (COPD) reduces dyspnoea and improves exercise capacity and quality of life. The improvement in exercise capacity is variable and unpredictable, however. Respiratory system impedance obtained by forced oscillation technique (FOT) as a measure of ventilatory impairment in COPD may relate to improvement in exercise capacity with pulmonary rehabilitation. We aimed to determine if baseline FOT parameters relate to changes in exercise capacity following pulmonary rehabilitation.

Methods

At the start of rehabilitation, 15 COPD subjects (mean(SD) 75.2(6.1) years, FEV1 z-score −2.61(0.84)) had measurements by FOT, spirometry, plethysmographic lung volumes and 6-minute walk distance (6MWD). Respiratory system resistance (Rrs) and reactance (Xrs) parameters as the mean over all breaths (R_mean, X_mean), during inspiration only (R_insp, X_insp), and expiratory flow limitation (DeltaXrs = X_insp−X_exp), were calculated. FOT and 6MWD measurements were repeated at completion of rehabilitation and 3 months after completion.

Results

At baseline, Xrs measures were unrelated to 6MWD. X_insp improved significantly with rehabilitation (from mean(SD) −2.35(1.02) to −2.04(0.85) cmH₂O.s.L⁻¹, p=0.008), while other FOT parameters did not. No FOT parameters related to the change in 6MWD at program completion. Baseline X_mean, DeltaXrs, and FVC z-score correlated with the change in 6MWD between completion and 3 months after completion of rehabilitation (r_s=0.62, p=0.03; r_s=−0.65, p=0.02; and r_s=0.62, p=0.03, respectively); with worse ventilatory impairment predicting loss of 6MWD. There were no relationships between Rrs parameters, FEV1 or FEV1/FVC z-scores and changes in 6MWD.

Conclusion

Baseline reactance parameters may be helpful in predicting those patients with COPD at most risk of loss of exercise capacity following completion of pulmonary rehabilitation.

Mobility impact and methods of diaphragm monitoring in patients with chronic obstructive pulmonary disease: a systematic review

The objectives of the study were to identify the factors that limit diaphragmatic mobility and evaluate the therapeutic results of the monitoring methods previously used in patients with chronic obstructive pulmonary disease. The PubMed, Web of Science, Scopus, and LILACS databases were used. A gray literature search was conducted with Google scholar. PRISMA was used, and the bias risk analysis adapted from the Cochrane Handbook for clinical trials and, for other studies, the Downs and Black checklist were used. Twenty-five articles were included in the qualitative synthesis analysis on physiotherapeutic techniques and diaphragmatic mobility. Eight clinical trials indicated satisfactory domains, and on the Downs and Black scale, 17 cohort studies were evaluated to have an acceptable score. Different conditions must be observed; for example, for postoperative assessments the supine position is suggested to be the most appropriate position to verify diaphragm excursion, although it has been shown to be associated with difficulty of restriction and matching in samples. Therefore, we identified the need for contemporary adjustments and strategies that used imaging instruments, preferably in the dorsal position. Therapeutic evidence on the association between the instrumental method and diaphragmatic mobility can be controversial. The ultrasound measurements indicated some relevance for different analyses, for pulmonary hyperinflation as well as diaphragm thickness and mobilization, in COPD patients. In particular, the study suggests that the ultrasound technique with B-mode for analysis and M-mode for diaphragmatic excursion be used with a 2 - 5 MHz with the patient in the supine position. However, the methods used to monitor diaphragm excursion should be adapted to the conditions of the patients, and additional investigations of their characteristics should be performed. More selective inclusion criteria and better matching in the samples are very important. In addition, more narrow age, sex and weight categories are important, especially in patients with chronic obstructive pulmonary disease.

Subjects With COPD Walk With Less Consistent Organization of Movement Patterns of the Lower Extremity

BACKGROUND

The inherent stride-to-stride fluctuations during walking are altered in the aging population and could provide insight into gait impairments and falls in patients with COPD. Stride-to-stride fluctuations are quantified two ways: variability of the fluctuations (eg, standard deviation), and movement patterns within the fluctuations. Our objective was to investigate stride-to-stride fluctuations by evaluating the variability and movement patterns of lower limb joints in subjects with COPD compared to subjects without COPD as control subjects.

METHODS

In this cross-sectional study, 22 subjects with COPD (age 63 ± 9 y; FEV₁ 54 ± 19% predicted) and 22 control subjects (age 62 ± 9 y; FEV₁ 95 ± 18% predicted) walked for 3 min on a treadmill while their gait was recorded. The amount of variability (ie, standard deviation and coefficient of variation) and movement patterns (ie, predictability and consistency in organization) were quantified for the range of motion and joint angle of the hip, knee, and ankle, at 3 walking speeds (ie, self-selected, fast, and slow). General linear mixed models were used for analysis.

RESULTS

Control subjects had more consistent organization of the hip and knee joint movement patterns compared to subjects with COPD (P = .02 and P = .02, respectively). Further, control subjects adapted to speed changes by demonstrating more consistent organization of movement patterns with faster speeds, whereas subjects with COPD did not. At the fast walking speed, subjects with COPD demonstrated less consistent organization of knee and hip joint movement patterns as compared to control subjects without COPD (P = .03 and P = .005, respectively). The amount of variability did not differ between groups.

CONCLUSIONS

Although subjects with COPD did not demonstrate decreased amount of variability, their hip and knee joint movement patterns were less consistent in organization during walking. Reduced consistency in organization of movement patterns may be a contributing factor to falls and mobility problems experienced by patients with COPD.

The Role of Manual Therapy in Patients with COPD

Chronic obstructive pulmonary disease (COPD) is a respiratory condition associated with altered chest wall mechanics and musculoskeletal changes. In this narrative review, we describe the underlying musculoskeletal abnormalities in COPD, the reasons for applying manual therapy techniques, their method of application and clinical effects. A variety of manual therapy techniques have been applied in individuals with COPD, including soft tissue therapy, spinal and joint manipulation and mobilisation, and diaphragmatic release techniques. These have been prescribed in isolation and in conjunction with other treatments, including exercise therapy. When applied in isolation, transient benefits in respiratory rate, heart rate and symptoms have been reported. Combined with exercise therapy, including within pulmonary rehabilitation, benefits and their corresponding clinical relevance have been mixed, the extent to which may be dependent on the type of technique applied. The current practical considerations of applying these techniques, including intense therapist–patient contact and the unclear effects in the long term, may limit the broad use of manual therapy in the COPD population. Further high quality research, with adequate sample sizes, that identifies the characteristic features of those with COPD who will most benefit, the optimal choice of treatment approach and the longevity of effects of manual therapy is required.

Growth/differentiation factor 15 causes TGFβ-activated kinase 1-dependent muscle atrophy in pulmonary arterial hypertension

INTRODUCTION

Skeletal muscle dysfunction is a clinically important complication of pulmonary arterial hypertension (PAH). Growth/differentiation factor 15 (GDF-15), a prognostic marker in PAH, has been associated with muscle loss in other conditions. We aimed to define the associations of GDF-15 and muscle wasting in PAH, to assess its utility as a biomarker of muscle loss and to investigate its downstream signalling pathway as a therapeutic target.

METHODS

GDF-15 levels and measures of muscle size and strength were analysed in the monocrotaline (MCT) rat, Sugen/hypoxia mouse and in 30 patients with PAH. In C2C12 myotubes the downstream targets of GDF-15 were identified. The pathway elucidated was then antagonised in vivo.

RESULTS

Circulating GDF-15 levels correlated with tibialis anterior (TA) muscle fibre diameter in the MCT rat (Pearson r=-0.61, p=0.003). In patients with PAH, plasma GDF-15 levels of <564 pg/L predicted those with preserved muscle strength with a sensitivity and specificity of ≥80%. In vitro GDF-15 stimulated an increase in phosphorylation of TGFβ-activated kinase 1 (TAK1). Antagonising TAK1, with 5(Z)-7-oxozeaenol, in vitro and in vivo led to an increase in fibre diameter and a reduction in mRNA expression of atrogin-1 in both C2C12 cells and in the TA of animals who continued to grow. Circulating GDF-15 levels were also reduced in those animals which responded to treatment.

CONCLUSIONS

Circulating GDF-15 is a biomarker of muscle loss in PAH that is responsive to treatment. TAK1 inhibition shows promise as a method by which muscle atrophy may be directly prevented in PAH.

TRIAL REGISTRATION NUMBER

NCT01847716; Results.

Ultrasound evaluation of diaphragmatic mobility in patients with idiopathic lung fibrosis: a pilot study

Background

Some previous works have tested LUS use in diagnosing and monitoring interstitial lung diseases. B-lines are main sonographic signs for interstitial diseases. Increasing evidences suggest that dyspnea and impaired exercise capacity in IPF patients can be related, at least in part, to respiratory muscle dysfunction, in particular to diaphragm functionality. Both B-mode and M-mode ultrasound techniques have been employed to assess diaphragm excursion (DE), which measures the distance that the diaphragm is able to move during the respiratory cycle.

Methods

The main objective of this case-control study was to evaluate if differences exist between diaphragmatic excursions in IPF patients and in a control group of healthy subjects. Secondary objectives were to evaluate possible correlations among respiratory excursions, anthropometric parameters and respiratory function parameters. All patients performed spirometry and body plethysmography (PC). Diaphragm was examined by ultrasound imaging in B-MODE, and respiratory excursions were evaluated in M-MODE. Examination consisted of 3 measurements of the inspiratory phase at rest and after deep inspiration.

Results

Twelve patients with IPF and 12 healthy subjects were enrolled. There were no significant differences between respiratory excursions in patients and controls during spontaneous breathing, while there was a statistically significant difference between the mean values of the deep respiratory excursion in the two groups (p value < 0.001). There was a positive correlation between respiratory excursion with normal breath and chest circumference in controls (p = 0.034; R = 0.614) and in patients (p = 0.032; R = 0.37), but this relationship was not found even in subjects in deep breathing. A positive correlation was found between FVC values and diaphragmatic motility both at rest and in deep breathing in fibrotic patients.

Conclusions

Diaphragmatic mobility is lower in IPF patients than in healthy controls, especially during deep inspiration. The correlation between reduced FVC and diaphragmatic excursion values in IPF patients can be of interest, since it could represent an index of functional respiratory function performed by a non-invasive, low-cost, simple and reliable imaging technique, such as LUS.

Spatiotemporal gait characteristics in patients with COPD during the Gait Real-time Analysis Interactive Lab-based 6-minute walk test

Background and aim

Overground gait assessment is limited by the analysis of multiple strides or both spatiotemporal gait characteristics, while fixed speed treadmill walking restricts natural gait speed variations. The Gait Real-time Analysis Interactive Lab (GRAIL)-based 6-minute walk test (6MWT) enables 3D motion analysis and self-paced treadmill walking, and could provide insight in gait alterations in patients with chronic obstructive pulmonary disease (COPD). The aim of this study is to compare spatiotemporal gait characteristics between patients with COPD and healthy elderly during the GRAIL-based 6MWT.

Materials and methods

Eighty COPD patients (60% male; 62±7 years; FEV₁:56±19% predicted) and 38 healthy elderly (63% male; 62±6 years; FEV₁:119±17% predicted) performed two GRAIL-based 6MWTs. Mean differences and coefficient of variation of spatiotemporal gait characteristics were calculated using the trial with the largest walk distance. Sub-analyses were conducted to account for walking speed differences between groups, and muscle strength and COPD severity within the patient group.

Results

COPD patients showed increased temporal gait characteristics, decreased stride and step lengths, and increased gait variability compared to healthy elderly (p<0.01). Stride length variability remained increased in COPD after correction for walking speed (MD:0.98%, CI:0.36–1.61, p = 0.003). Reduced quadriceps strength did not translate into altered gait characteristics, while COPD severity is associated with stride time (left MD:-0.02s, CI:-0.04–0.01, p = 0.003; right MD:-0.02s, CI:-0.04–0.01, p = 0.003).

Discussion

COPD patients performed the GRAIL-based 6MWT differently compared to healthy elderly. Further research should use other variability measures to investigate gait characteristics in COPD, to assess subtle alterations in gait and to enable development of rehabilitation strategies to improve gait, and possibly balance and fall risk in COPD. Other lower limb muscle groups should be considered when investigating gait alterations in COPD.

Conclusion

COPD patients have different gait characteristics compared to healthy elderly. Independent of walking speed, COPD patients demonstrate increased stride length variability during the GRAIL-based 6MWT compared to healthy elderly.

Effects of neurally adjusted ventilatory assist on air distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease

Background

Neurally adjusted ventilatory assist (NAVA) could improve patient-ventilator interaction; its effects on ventilation distribution and dead space are still unknown. The aim of this study was to evaluate the effects of varying levels of assist during NAVA and pressure support ventilation (PSV) on ventilation distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

Methods

Fifteen mechanically ventilated patients with AECOPD were included in the study. The initial PSV levels were set to 10 cmH₂O for 10 min. Thereafter, the ventilator mode was changed to NAVA for another 10 min with the same electrical activity of the diaphragm as during PSV. Furthermore, the ventilation mode was switched between PSV and NAVA every 10 min in the following order: PSV 5 cmH₂O; NAVA 50%; PSV 15 cmH₂O; and NAVA 150% (relative to the initial NAVA support level). Ventilation distribution in the lung was evaluated in percentages in regions of interest (ROI) of four anteroposterior segments of equal height (ROI1 to ROI4 represents ventral, mid-ventral, mid-dorsal, and dorsal, respectively). Blood gases, ventilation distribution (electrical impedance tomography), diaphragm activity (B-mode ultrasonography), and dead space fraction (PeCO₂ and PaCO₂) were measured.

Results

The trigger and cycle delays were lower during NAVA than during PSV. The work of trigger was significantly lower during NAVA compared to PSV. The diaphragm activities based on ultrasonography were higher during NAVA compared to the same support level during PSV. The ventilation distribution in ROI4 increased significantly (P < 0.05) during NAVA compared to PSV (except for a support level of 50%). Similar results were found in ROI3 + 4. NAVA reduced dead space fraction compared to the corresponding support level of PSV.

Conclusions

NAVA was superior to PSV in AECOPD for increasing ventilation distribution in ROI4 and reducing dead space.

Trial registration

Clinicaltrials.gov, NCT02289573. Registered on 12 November 2014.

Panoramic ultrasound: a novel and valid tool for monitoring change in muscle mass

BACKGROUND

The strong link between reduced muscle mass and morbidity and mortality highlights the urgent need for simple techniques that can monitor change in skeletal muscle cross-sectional area (CSA). Our objective was to examine the validity of panoramic ultrasound to detect change in quadriceps and gastrocnemius size in comparison with magnetic resonance imaging (MRI) in subjects randomized to 70 days of bed rest (BR) with or without exercise.

METHODS

Panoramic ultrasound and MRI images of the quadriceps and gastrocnemius muscles were acquired on the right leg of 27 subjects (26 male, 1 female; age: 34.6 ± 7.8 years; body mass: 77.5 ± 10.0 kg; body mass index: 24.2 ± 2.8 kg/m² ; height: 179.1 ± 6.9 cm) before (BR-6), during (BR3, 7, 11, 15, 22, 29, 36, 53, 69), and after (BR+3, +6, +10) BR. Validity of panoramic ultrasound to detect change in muscle CSA was assessed by Bland-Altman plots, Lin's concordance correlation coefficient (CCC), sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

Six hundred ninety-eight panoramic ultrasound CSA and 698 MRI CSA measurements were assessed. Concordance between ultrasound and MRI was excellent in the quadriceps (CCC: 0.78; P < 0.0001), whereas there was poor concordance in the gastrocnemius (CCC: 0.37; P < 0.0006). Compared with MRI, panoramic ultrasound demonstrated high accuracy in detecting quadriceps atrophy and hypertrophy (sensitivity: 73.7%; specificity: 74.2%) and gastrocnemius atrophy (sensitivity: 83.1%) and low accuracy in detecting gastrocnemius hypertrophy (specificity: 33.0%).

CONCLUSIONS

Panoramic ultrasound imaging is a valid tool for monitoring quadriceps muscle atrophy and hypertrophy and for detecting gastrocnemius atrophy.

Sarcopenia and frailty in chronic respiratory disease

Sarcopenia and frailty are geriatric syndromes characterized by multisystem decline, which are related to and reflected by markers of skeletal muscle dysfunction. In older people, sarcopenia and frailty have been used for risk stratification, to predict adverse outcomes and to prompt intervention aimed at preventing decline in those at greatest risk. In this review, we examine sarcopenia and frailty in the context of chronic respiratory disease, providing an overview of the common assessments tools and studies to date in the field. We contrast assessments of sarcopenia, which consider muscle mass and function, with assessments of frailty, which often additionally consider social, cognitive and psychological domains. Frailty is emerging as an important syndrome in respiratory disease, being strongly associated with poor outcome. We also unpick the relationship between sarcopenia, frailty and skeletal muscle dysfunction in chronic respiratory disease and reveal these as interlinked but distinct clinical phenotypes. Suggested areas for future work include the application of sarcopenia and frailty models to restrictive diseases and population-based samples, prospective prognostic assessments of sarcopenia and frailty in relation to common multidimensional indices, plus the investigation of exercise, nutritional and pharmacological strategies to prevent or treat sarcopenia and frailty in chronic respiratory disease.

Oxidative stress and skeletal muscle dysfunction are present in healthy smokers

Chronic exposure to cigarette smoke seems to be related to an increase of pro-inflammatory cytokines, oxidative stress and changes in muscular and physical performances of healthy smokers. However, these parameters have not yet been evaluated simultaneously in previous studies. The participants of this study were healthy males divided into two groups: smokers (n=20) and non-smokers (n=20). Inflammation was evaluated by measuring plasma levels of the cytokines IL-10, IL-6 e TNF-α, and of the soluble receptors sTNFR1 and sTNFR2. Oxidative stress was evaluated by determination of thiobarbituric acid reactive substances (TBARS) plasma levels, total antioxidant capacity of plasma and erythrocytes activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase. Muscular performance was evaluated by measuring the peak torque of knee flexors and extensors, and by determining the total work of the knee extensors. Physical performance was assessed by measuring the peak oxygen uptake (VO2 peak), the maximum heart rate (HRmax) and the walking distance in the shuttle walking test. Smokers showed an increase in the levels of the sTNFR1 and TBARS and a decrease in the total antioxidant capacity of plasma, in the catalase activity and in the total work (P<0.05). IL-6, IL-10, sTNFR2, SOD, peak torque, VO2 peak, HRmax and walking distance were similar between groups. Smokers presented increased oxidative stress and skeletal muscle dysfunction, demonstrating that the changes in molecular and muscular parameters occur simultaneously in healthy smokers.

Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews Issue 1, 2013 on Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease.Patients with advanced progressive disease often experience muscle weakness, which can impact adversely on their ability to be independent and their quality of life. In those patients who are unable or unwilling to undertake whole-body exercise, neuromuscular electrical stimulation (NMES) may be an alternative treatment to enhance lower limb muscle strength. Programmes of NMES appear to be acceptable to patients and have led to improvements in muscle function, exercise capacity, and quality of life. However, estimates regarding the effectiveness of NMES based on individual studies lack power and precision.

OBJECTIVES

Primary objective: to evaluate the effectiveness of NMES on quadriceps muscle strength in adults with advanced disease. Secondary objectives: to examine the safety and acceptability of NMES, and its effect on peripheral muscle function (strength or endurance), muscle mass, exercise capacity, breathlessness, and health-related quality of life.

SEARCH METHODS

We identified studies from searches of the Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), and Database of Abstracts of Reviews of Effects (DARE) (the Cochrane Library), MEDLINE (OVID), Embase (OVID), CINAHL (EBSCO), and PsycINFO (OVID) databases to January 2016; citation searches, conference proceedings, and previous systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials in adults with advanced chronic respiratory disease, chronic heart failure, cancer, or HIV/AIDS comparing a programme of NMES as a sole or adjunct intervention to no treatment, placebo NMES, or an active control. We imposed no language restriction.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on study design, participants, interventions, and outcomes. We assessed risk of bias using the Cochrane 'Risk of bias' tool. We calculated mean differences (MD) or standardised mean differences (SMD) between intervention and control groups for outcomes with sufficient data; for other outcomes we described findings from individual studies. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Eighteen studies (20 reports) involving a total of 933 participants with COPD, chronic respiratory disease, chronic heart failure, and/or thoracic cancer met the inclusion criteria for this update, an additional seven studies since the previous version of this review. All but one study that compared NMES to resistance training compared a programme of NMES to no treatment or placebo NMES. Most studies were conducted in a single centre and had a risk of bias arising from a lack of participant or assessor blinding and small study size. The quality of the evidence using GRADE comparing NMES to control was low for quadriceps muscle strength, moderate for occurrence of adverse events, and very low to low for all other secondary outcomes. We downgraded the quality of evidence ratings predominantly due to inconsistency among study findings and imprecision regarding estimates of effect. The included studies reported no serious adverse events and a low incidence of muscle soreness following NMES.NMES led to a statistically significant improvement in quadriceps muscle strength as compared to the control (12 studies; 781 participants; SMD 0.53, 95% confidence interval (CI) 0.19 to 0.87), equating to a difference of approximately 1.1 kg. An increase in muscle mass was also observed following NMES, though the observable effect appeared dependent on the assessment modality used (eight studies, 314 participants). Across tests of exercise performance, mean differences compared to control were statistically significant for the 6-minute walk test (seven studies; 317 participants; 35 m, 95% CI 14 to 56), but not for the incremental shuttle walk test (three studies; 434 participants; 9 m, 95% CI -35 to 52), endurance shuttle walk test (four studies; 452 participants; 64 m, 95% CI -18 to 146), or for cardiopulmonary exercise testing with cycle ergometry (six studies; 141 participants; 45 mL/minute, 95% CI -7 to 97). Limited data were available for other secondary outcomes, and we could not determine the most beneficial type of NMES programme.

AUTHORS' CONCLUSIONS

The overall conclusions have not changed from the last publication of this review, although we have included more data, new analyses, and an assessment of the quality of the evidence using the GRADE approach. NMES may be an effective treatment for muscle weakness in adults with advanced progressive disease, and could be considered as an exercise treatment for use within rehabilitation programmes. Further research is very likely to have an important impact on our confidence in the estimate of effect and may change the estimate. We recommend further research to understand the role of NMES as a component of, and in relation to, existing rehabilitation approaches. For example, studies may consider examining NMES as an adjuvant treatment to enhance the strengthening effect of programmes, or support patients with muscle weakness who have difficulty engaging with existing services.

Hand grip strength is associated with forced expiratory volume in 1 second among subjects with COPD: report from a population-based cohort study

Background

Cardiovascular diseases and skeletal muscle dysfunction are common comorbidities in COPD. Hand grip strength (HGS) is related to general muscle strength and is associated with cardiovascular disease and all-cause mortality, while the results from small selected COPD populations are contradictory. The aim of this population-based study was to compare HGS among the subjects with and without COPD, to evaluate HGS in relation to COPD severity, and to evaluate the impact of heart disease.

Subjects and methods

Data were collected from the Obstructive Lung disease in Northern Sweden COPD study, where the subjects with and without COPD have been invited to annual examinations since 2005. In 2009–2010, 441 subjects with COPD (postbronchodilator forced expiratory volume in 1 second [FEV₁]/vital capacity <0.70) and 570 without COPD participated in structured interviews, spirometry, and measurements of HGS.

Results

The mean HGS was similar when comparing subjects with and without COPD, but those with heart disease had lower HGS than those without. When compared by Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, the subjects with GOLD 3–4 had lower HGS than those without COPD in both sexes (females 21.4 kg vs 26.9 kg, P=0.010; males 41.5 kg vs 46.3 kg, P=0.038), and the difference persisted also when adjusted for confounders. Among the subjects with COPD, HGS was associated with FEV₁% of predicted value but not heart disease when adjusted for height, age, sex, and smoking habits, and the pattern was similar among males and females.

Conclusion

In this population-based study, the subjects with GOLD 3–4 had lower HGS than the subjects without COPD. Among those with COPD, HGS was associated with FEV₁% of predicted value but not heart disease, and the pattern was similar in both sexes.

Physical frailty and pulmonary rehabilitation in COPD: a prospective cohort study

Background

Frailty is an important clinical syndrome that is consistently associated with adverse outcomes in older people. The relevance of frailty to chronic respiratory disease and its management is unknown.

Objectives

To determine the prevalence of frailty among patients with stable COPD and examine whether frailty affects completion and outcomes of pulmonary rehabilitation.

Methods

816 outpatients with COPD (mean (SD) age 70 (10) years, FEV₁% predicted 48.9 (21.0)) were recruited between November 2011 and January 2015. Frailty was assessed using the Fried criteria (weight loss, exhaustion, low physical activity, slowness and weakness) before and after pulmonary rehabilitation. Predictors of programme non-completion were identified using multivariate logistic regression, and outcomes were compared using analysis of covariance, adjusting for age and sex.

Results

209/816 patients (25.6%, 95% CI 22.7 to 28.7) were frail. Prevalence of frailty increased with age, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, Medical Research Council (MRC) score and age-adjusted comorbidity burden (all p≤0.01). Patients who were frail had double the odds of programme non-completion (adjusted OR 2.20, 95% CI 1.39 to 3.46, p=0.001), often due to exacerbation and/or hospital admission. However, rehabilitation outcomes favoured frail completers, with consistently better responses in MRC score, exercise performance, physical activity level and health status (all p<0.001). After rehabilitation, 71/115 (61.3%) previously frail patients no longer met case criteria for frailty.

Conclusions

Frailty affects one in four patients with COPD referred for pulmonary rehabilitation and is an independent predictor of programme non-completion. However, patients who are frail respond favourably to rehabilitation and their frailty can be reversed in the short term.

Down-Regulation of Soluble α-Klotho is Associated with Reduction in Serum Irisin Levels in Chronic Obstructive Pulmonary Disease

PURPOSE

The klotho gene was originally identified as a putative aging-suppressor gene. Klotho-depleted mice display a shortened life span and exhibit a variety of premature aging-related phenotypes such as pulmonary emphysema and sarcopenia. This study was designed to determine the roles of secreted-type klotho protein on lung and skeletal muscle in chronic obstructive pulmonary disease (COPD).

METHODS

Serum α-klotho and irisin levels were assayed in 16 non-smokers, 13 smokers without COPD, and 24 smokers with COPD. Moreover, we examined correlations between soluble α-klotho levels and the results of lung function test, cardiopulmonary exercise test (CPET), and skeletal muscle function in smokers with COPD.

RESULTS

Soluble α-klotho levels were significantly lower in smokers with COPD compared to non-smokers and smokers without COPD. In smokers with COPD, those levels did not significantly correlate with any parameters of lung function test. In CPET, peak VO2 significantly correlated with FEV1 (% predicted) (r = 0.76, p = 0.0003) and DLCO (% predicted) (r = 0.62, p = 0.003). In contrast, soluble α-klotho levels did not significantly correlate with peak VO2. Irisin levels were also significantly lower in smokers with COPD. Moreover, there was a significant correlation between soluble α-klotho and serum irisin levels (r = 0.61, p = 0.004).

CONCLUSIONS

Our findings could provide a critical first step to understanding the impacts of soluble α-klotho on skeletal muscle in COPD and may lead to the identification of new molecular targets for the treatment of COPD.

Increased breathing resistance compromises the time course of rhythmical forearm movements-a pilot study

BACKGROUND AND OBJECTIVES

Skeletal muscle dysfunction is a major problem among the co-morbidities associated with chronic obstructive pulmonary disease (COPD). However, muscle weakness and increased fatigability are not the only limitations of skeletal muscle function. Motor-respiratory coordination (MRC) may occur even during movements at lowest workloads. MRC modifies the temporal pattern of motor actions, thus probably impairing motor performance and movement precision. Little attention has been paid to the question of whether motor functions may be compromised in COPD patients independent of workload and required muscle strength and endurance. The present pilot study was designed to investigate the effects of a simulated obstruction (SO) in healthy subjects on their breathing pattern and the timing of a rhythmical forearm movement.

METHODS

Twenty-one subjects performed flexion- extension movements with their right forearm at a self-chosen rate within a range between 0.2 and 0.4 Hz. After a control experiment with normal breathing, a plug with a narrow hole was inserted between face mask and pneumotachograph to simulate obstruction. Subjects were required to repeat the rhythmical forearm movement at the same rate as in the control experiment.

RESULTS

The condition of SO significantly prolonged breath duration but reduced tidal volume and ventilation. In addition, period duration of the forearm movement increased significantly under this condition while the movement-to-breathing frequency ratio remained almost constant. Increased breathing resistance was considered to cause prolonged breath duration accompanied by an increase in movement period duration. The constant near-integer ratio between movement and breathing rates indicates that the change in movement period duration resulted from MRC.

CONCLUSIONS

The findings of this pilot study demonstrate that increased breathing resistance may compromise motor performance even at lower workloads. This means that in COPD patients, not only muscle strength and endurance are reduced but, moreover, fine motor skills may be impaired. This aspect has particular importance for many everyday activities as reduced fine motor performance substantially contributes to a progressive inability of the patients to manage their daily life.

Prevalence of quadriceps muscle weakness in patients with COPD and its association with disease severity

INTRODUCTION

COPD presents with an array of extra-pulmonary symptoms of which skeletal muscle dysfunction, particularly of the quadriceps, is well recognized. This contributes to impaired quality of life and increased health care utilization. Work on the quadriceps originated from the observation that a good proportion of COPD patients stop exercise due to the feeling of leg fatigue rather than breathlessness. This study was carried out with the aim of finding the prevalence of quadriceps weakness in a population set and correlate it with severity of COPD.

METHODOLOGY

This cross-sectional study was conducted in 75 subjects suffering from COPD aged 45 years or above. COPD severity in the subjects was graded based on the GOLD staging system. A digital hand held dynamometer (HHD) was used to measure quadriceps muscle strength. Descriptive statistics were done, and Pearson's Correlation Coefficient and ANOVA analysis was used for expressing the results.

RESULTS

Ninety two percent of subjects were suffering from quadriceps muscle weakness. Quadriceps weakness was present in significantly high proportions even in those suffering from mild disease and belonging to a younger age group. The mean quadriceps muscle force value decreased with disease severity and this relation was found to be significant (P<0.01).

CONCLUSION

Majority of the COPD patients were found to be suffering from quadriceps weakness, which was also present in significant proportions in subjects belonging to younger age groups and suffering from mild disease. These findings indicate that onset of muscle weakness in COPD may precede the onset of symptoms. These findings suggest need for early remedial measure to prevent occurrence of associated systemic diseases.

Diaphragmatic motion studied by M-mode ultrasonography in combined pulmonary fibrosis and emphysema

BACKGROUND

The coexistence of emphysema and pulmonary fibrosis is known as combined pulmonary fibrosis and emphysema (CPFE). The aim of this study was to compare diaphragmatic motion measured by M-mode ultrasonography of patients with CPFE, idiopathic pulmonary fibrosis (IPF), and chronic obstructive pulmonary disease (COPD).

METHODS

Pulmonary function, high-resolution computed tomography (HRCT), and diaphragmatic motion were examined in patients with CPFE (n = 25), IPF (n = 18), and COPD (n = 60), and in healthy controls (n = 21). Diaphragmatic motions were measured on M-mode ultrasonographic images during quiet breathing and deep breathing.

RESULTS

There were no significant differences in right or left diaphragmatic motion during quiet breathing among the four groups, whereas differences were significant in right and left motion during deep breathing. Diaphragmatic motion in CPFE patients was the lowest among the four groups. COPD patients, especially those with severe COPD, showed significantly lower diaphragmatic motion than IPF patients or healthy controls. There were no differences in diaphragmatic motion between IPF patients and healthy controls. Right diaphragmatic motions during deep breathing were negatively correlated with emphysema scores (r = -0.606, p < 0.001), but were not correlated with fibrosis scores on HRCT.

CONCLUSIONS

Diaphragmatic weakness was found in CPFE patients. Emphysema but not fibrosis may be one cause of limited diaphragmatic motion in patients with CPFE. M-mode ultrasonographic evaluation of diaphragmatic motion during deep breathing may be a useful tool in diagnosing CPFE and in discriminating CPFE patients from IPF or COPD patients.

Musculoskeletal disorders in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction and inflammation but also accompanied by several extrapulmonary consequences, such as skeletal muscle weakness and osteoporosis. Skeletal muscle weakness is of major concern, since it leads to poor functional capacity, impaired health status, increased healthcare utilization, and even mortality, independently of lung function. Osteoporosis leads to fractures and is associated with increased mortality, functional decline, loss of quality of life, and need for institutionalization. Therefore, the presence of the combination of these comorbidities will have a negative impact on daily life in patients with COPD. In this review, we will focus on these two comorbidities, their prevalence in COPD, combined risk factors, and pathogenesis. We will try to prove the clustering of these comorbidities and discuss possible preventive or therapeutic strategies.

Factors associated with impairment of quadriceps muscle function in Chinese patients with chronic obstructive pulmonary disease

Background

Quadriceps muscle dysfunction is well confirmed in chronic obstructive pulmonary disease (COPD) and reported to be related to a higher risk of mortality. Factors contributing to quadriceps dysfunction have been postulated, while not one alone could fully explain it and there are few reports on it in China. This study was aimed to investigate the severity of quadriceps dysfunction in patients with COPD, and to compare quadriceps muscle function in COPD and the healthy elderly.

Methods

Quadriceps strength and endurance capabilities were investigated in 71 COPD patients and 60 age-matched controls; predicted values for quadriceps strength and endurance were calculated using regression equations (incorporating age, gender, anthropometric measurements and physical activities), based on the data from controls. Potential parameters related to quadriceps dysfunction in COPD were identified by stepwise regression analysis.

Results

Mean values of quadriceps strength was 46% and endurance was 38% lower, in patients with COPD relative to controls. Gender, physical activities and anthropometric measurements were predictors to quadriceps function in the controls. While in COPD, forced expiratory volume in 1 second percentage of predicted value (FEV₁% pred), nutritional depletion, gender and physical inactivity were identified as independent factors to quadriceps strength (R² = 0.72); FEV₁%pred, thigh muscle mass, serum levels of tumor necrosis factor-alpha (TNF-α) and gender were correlated to quadriceps endurance variance, with each p<0.05.

Conclusion

Quadriceps strength and endurance capabilities are both substantially impaired in Chinese COPD patients, with strength most affected. For the controls, physical activity is most important for quadriceps function. While for COPD patients, quadriceps dysfunction is related to multiple factors, with airflow limitation, malnutrition and muscle disuse being the main ones.

The skeletal muscle arachidonic acid cascade in health and inflammatory disease

Muscle atrophy and weakness are often observed in patients with chronic inflammatory diseases, and are the major clinical features of the autoimmune myopathies, polymyositis and dermatomyositis. A general understanding of the pathogenesis of muscle atrophy and the impaired muscle function associated with chronic inflammatory diseases has not been clarified. In this context, arachidonic acid metabolites, such as the prostaglandin and leukotriene subfamilies, are of interest because they contribute to immune and nonimmune processes. Accumulating evidence suggests that prostaglandins and leukotrienes are involved in causing muscular pain and inflammation, and also in myogenesis and the repair of muscles. In this Review, we summarize novel findings that implicate prostaglandins and leukotrienes in the muscle atrophy and weakness that occur in inflammatory diseases of the muscles, with a focus on inflammatory myopathies. We discuss the role of the arachidonic acid cascade in skeletal muscle growth and function, and individual metabolites as potential therapeutic targets for the treatment of inflammatory muscle diseases.

A comparison of muscle strength and endurance, exercise capacity, fatigue perception and quality of life in patients with chronic obstructive pulmonary disease and healthy subjects: a cross-sectional study

Background

Chronic obstructive pulmonary disease (COPD) has significant systemic effects that substantially impact quality of life and survival. The purpose of this study was to assess and compare peripheral muscle strength and endurance, exercise capacity, fatigue perception and quality of life between patients with COPD and healthy subjects.

Methods

Twenty COPD patients (mean FEV₁ 49.3 ± 19.2%) and 20 healthy subjects were included in the study. Pulmonary function testing and six-minute walk test (6MWT) were performed. Peripheral muscle strength was measured with a hand-held dynamometer, peripheral muscle endurance was evaluated with sit-ups, squats and modified push-ups tests. Fatigue perception was assessed using the Fatigue Impact Scale (FIS) and Fatigue Severity Scale (FSS). General quality of life was determined with the Nottingham Health Profile (NHP), and cough-specific quality of life was evaluated with the Leicester Cough Questionnaire (LCQ).

Results

Pulmonary functions, strength of shoulder abductor and flexor muscles, numbers of sit-ups and squats, 6MWT distance and 6MWT% were significantly lower in COPD patients than in healthy subjects (p < 0.05). FIS psychosocial sub-dimension and total scores, NHP scores for all sub-dimensions except pain sub-dimension of the COPD group were significantly higher than those of healthy subjects (p < 0.05). The LCQ physical, psychological and social sub-dimensions and total scores were significantly lower in COPD patients than in healthy subjects (p < 0.05).

Conclusions

Pulmonary functions, peripheral muscle strength and endurance, exercise capacity and quality of life were adversely affected in patients with COPD. There are greater effect of fatigue on psychosocial functioning and general daily life activities and effect of cough on the quality of life in patients with COPD. This study supports the idea that COPD patients must be evaluated in a comprehensive manner for planning pulmonary rehabilitation programs.

Physical Activity and Lung Function Growth in a Cohort of Chinese School Children: A Prospective Study

BACKGROUNDS/OBJECTIVES

Evidence on the association between physical activity and lung function in children is sparse. The aim of this study was to evaluate children's lung function growth in relation to their physical activity level in Chinese children.

METHODS

A total of 1713 school children aged 9.89±0.86 years who were asthma-free at baseline were followed-up for 18 months from 2006 to 2008 in Guangzhou, China. Information on physical activity and other socio-economic status were obtained from self-administered questionnaires. Lung function tests were performed with a standard procedure.

RESULTS

At the baseline survey, physically active girls had significantly higher forced vital capacity (FVC) than inactive girls (1.79 l vs. 1.75 l, p<0.05). The growth rates for lung function indices were significantly higher for girls who were physically active at either or both follow-up surveys than those inactive at both surveys during the follow-up period forced expiratory flows at 25% (FEF25) difference per year (dpy) (0.20 l/s vs. 0.15 l/s), forced expiratory flows at 75% (FEF75) dpy (0.57 l/s vs. 0.45 l/s) and forced expiratory flows between 25% and 75% (FEF25-75) dpy (0.36 l/s vs. 0.28 l/s) (all p<0.05).

CONCLUSIONS

Physical activity is positively associated with lung function growth among Chinese school-aged girls. Promotion of physical activity among children is of great importance.