Measuring and monitoring skeletal muscle function in COPD: current perspectives

Assessing Functional Capacity in Directly and Remotely Monitored Home-Based Settings in Individuals With Chronic Respiratory Diseases: Protocol for a Multinational Validation Study

BACKGROUND

Pulmonary rehabilitation is widely recommended to improve functional status and as secondary and tertiary prevention in individuals with chronic pulmonary diseases. Unfortunately, access to timely and appropriate rehabilitation remains limited. To help close this inaccessibility gap, telerehabilitation has been proposed. However, exercise testing is necessary for effective and safe exercise prescription. Current gold-standard tests, such as maximal cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT), are poorly adapted to home-based or telerehabilitation settings. This was an obstacle to the continuity of services during the COVID-19 pandemic. It is essential to validate tests adapted to these new realities, such as the 6-minute stepper test (6MST). This test, strongly inspired by 6MWT, consists of taking as many steps as possible on a "stepper" for 6 minutes.

OBJECTIVE

This study aims to evaluate the metrological qualities of 6MST by (1) establishing concurrent validity and agreement between the 6MST and CPET, as well as with the 6MWT; (2) determining test-retest reliability in a home-based setting with direct and remote (videoconferencing) monitoring; and (3) documenting adverse events and participant perspectives when performing the 6MST in home-based settings.

METHODS

Three centers (Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec in Québec, Groupement des Hôpitaux de l'Institut Catholique de Lille in France, and FormAction Santé in France) will be involved in this multinational project, which is divided into 2 studies. For study 1 (objective 1), 30 participants (Québec, n=15; France, n=15) will be recruited. Two laboratory visits will be performed to assess anthropometric data, pulmonary function, and the 3 exercise tolerance tests (CPET, 6MWT, and 6MST). Concurrent validity (paired sample t tests and Pearson correlations) and agreement (Bland-Altman plots with 95% agreement limits) will be evaluated. For study 2 (objectives 2 and 3), 52 participants (Québec, n=26; France, n=26) will be recruited. Following a familiarization trial (trial 1), the 6MST will be conducted on 2 separate occasions (trials 2 and 3), once under direct supervision and once under remote supervision, in a randomized order. Paired sample t test, Bland-Altman plots, and intraclass correlations will be used to compare trials 2 and 3. A semistructured interview will be conducted after the third trial to collect participants' perspectives.

RESULTS

Ethical approval was received for this project (October 12, 2023, in Québec and September 25, 2023, in France) and the first participant was recruited in February 2024.

CONCLUSIONS

This study innovates by validating a new clinical test necessary for the development and implementation of new models of rehabilitation adapted to home and telerehabilitation contexts. This study also aligns with the United Nations Sustainable Development Goals by contributing to augmenting health care service delivery (goal 3) and reducing health care access inequalities (goal 11).

TRIAL REGISTRATION

ClinicalTrials.gov NCT06447831; https://clinicaltrials.gov/study/NCT06447831.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57404.

Haemodynamic compensations for exercise tissue oxygenation in early stages of COPD: an integrated cardiorespiratory assessment study

BACKGROUND

Cardiovascular comorbidities are increasingly being recognised in early stages of chronic obstructive pulmonary disease (COPD) yet complete cardiorespiratory functional assessments of individuals with mild COPD or presenting with COPD risk factors are lacking. This paper reports on the effectiveness of the cardiocirculatory-limb muscles oxygen delivery and utilisation axis in smokers exhibiting no, or mild to moderate degrees of airflow obstruction using standardised cardiopulmonary exercise testing (CPET).

METHODS

Post-bronchodilator spirometry was used to classify participants as 'ever smokers without' (n=88), with 'mild' (n=63) or 'mild-moderate' COPD (n=56). All underwent CPET with continuous concurrent monitoring of oxygen uptake (V'O2) and of bioimpedance cardiac output (Qc) enabling computation of arteriovenous differences (a-vO2). Mean values of Qc and a-vO2 were mapped across set ranges of V'O2 and Qc isolines to allow for meaningful group comparisons, at same metabolic and circulatory requirements.

RESULTS

Peak exercise capacity was significantly reduced in the 'mild-moderate COPD' as compared with the two other groups who showed similar pulmonary function and exercise capacity. Self-reported cardiovascular and skeletal muscle comorbidities were not different between groups, yet disease impact and exercise intolerance scores were three times higher in the 'mild-moderate COPD' compared with the other groups. Mapping of exercise Qc and a-vO2 also showed a leftward shift of values in this group, indicative of a deficit in peripheral O2 extraction even for submaximal exercise demands. Concurrent with lung hyperinflation, a distinctive blunting of exercise stroke volume expansion was also observed in this group.

CONCLUSION

Contrary to the traditional view that cardiovascular complications were the hallmark of advanced disease, this study of early COPD spectrum showed a reduced exercise O2 delivery and utilisation in individuals meeting spirometry criteria for stage II COPD. These findings reinforce the preventive clinical management approach to preserve peripheral muscle circulatory and oxidative capacities.

Relationship between Volitional and Non-Volitional Quadriceps Muscle Endurance in Patients with Chronic Obstructive Pulmonary Disease

Volitional assessment of quadriceps muscle endurance is clinically relevant in patients with chronic obstructive pulmonary disease (COPD). However, studies that determine the construct validity of volitional tests by comparing them to non-volitional measures are lacking. Therefore, the aim of the current study is to evaluate the correlation between volitional and non-volitional quadriceps muscle endurance in patients with COPD. Quadriceps muscle endurance was evaluated in twenty-six patients with COPD. A volitional isometric and a volitional isokinetic protocol were performed on a computerised dynamometer to determine the isometric time and isokinetic work fatigue index, respectively. Non-volitional assessment of quadriceps muscle endurance was evaluated using repetitive electrical stimulations to establish the isometric muscle force decline. Sixteen patients (61 ± 8 years, 63% male, FEV1 47 (32-53)%) performed all three quadriceps endurance tests conforming to pre-defined test criteria. Both volitional isometric time and isokinetic work fatigue index did not significantly correlate with non-volitional muscle force decline (both p > 0.05). There was a strong correlation between volitional isometric time and isokinetic work fatigue index (rho = -0.716, p = 0.002). To conclude, this study suggests that volitional measures evaluate partly different aspects of quadriceps muscle endurance compared to non-volitional measures. Accordingly, these outcome measures cannot be used interchangeably.

Core outcome set for pulmonary rehabilitation of patients with COPD: results of a modified Delphi survey

INTRODUCTION

There is high heterogeneity of outcomes and measures reported in pulmonary rehabilitation (PR) trials of people with chronic obstructive pulmonary disease (COPD). This hinders study comparability and benchmarking of PR. We have developed a core outcome set (COS) to overcome these challenges.

METHODS

This study was informed by a systematic review and two qualitative studies and had patient involvement since its inception. A two-round Delphi survey was available in seven languages. Outcomes (n=63) scored 7-9 (crucial) by ≥70% of the participants and 1-3 (not that important) by ≤15% of participants from both groups in the Likert scale were automatically included in the COS, while outcomes that were considered crucial by only one of the groups were further discussed by the authors in a meeting.

RESULTS

A total of 299 people (n=229 healthcare professionals/researchers/policy-makers; n=70 people with COPD and informal caregivers) participated in the survey (83% retention), which covered 29 countries/five continents. After the second round, six outcomes were included and three were added in the meeting. The final COS contains dyspnoea, fatigue, functional exercise capacity, health-related quality of life, health behaviours/lifestyle, knowledge about the disease, lower limb muscle function, personal goals and problematic activities of daily living.

CONCLUSION

A COS for PR of people with COPD is now available and can be used by different stakeholders to improve consistency and comparability of studies, benchmark PR and improve the quality of care provided. Future research should establish the core measures and investigate the uptake of this COS.

Body Composition, Physical Function and Exercise Capacity in Chronic Obstructive Pulmonary Disease

Current literature yields unequivocal results regarding the effect of body composition on physical function in patients with chronic obstructive pulmonary disease and disproportionately includes a majority of males. The purpose of this study was to determine whether specific body composition measures are significantly associated with physical function and exercise capacity in patients with chronic obstructive pulmonary disease with equal representation of males and females. Independent variables included sex, total body mass, total body lean and fat mass, appendicular total mass, and appendicular lean and fat mass. Dependent variables included peak oxygen consumption, 6-minute walk distance and self-reported physical function. Patients (n = 170) with dual-energy X-ray absorptiometry data, 6-minute walk distance, and self-reported physical function were used for these analyses. A sub-set of 145 of these patients with peak oxygen consumption data were also analysed. Hierarchical multiple regression analysis was used to determine if sex and body composition measures correlated with physical function and exercise capacity and if they explained additional variance after controlling for disease severity. After controlling for disease severity, appendicular lean mass, total body fat mass, and sex explained an additional 16.5% of the variance in peak oxygen consumption (p < 0.001). Appendicular lean mass explained an additional 8.9% of the variance in 6-minute walk distance (p < 0.001) and an additional 2.5% of the variance in self-reported physical function (p = 0.057). Body composition measures may further predict exercise capacity, 6-minute walk distance, and self-reported physical function in patients with chronic obstructive pulmonary disease.

RNA-Sequencing and Bioinformatics Analysis of Exosomal Long Noncoding RNAs Revealed a Novel ceRNA Network in Stable COPD

Purpose

Exosomes are able to exchange their bioactive RNA cargo to recipient cells. In COPD, exosomes can be controlled and engineered for its use as targeted diagnostic and therapeutic tool. Our study explored novel lncRNAs and mRNAs in plasma exosomes that could be involved in the pathogenesis of COPD.

Methods

High-throughput sequencing was conducted to detect the alterations in the expression of exosomal lncRNAs and mRNAs. Gene ontology (GO) functional analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to determine the significant functions and pathways associated with differentially expressed (DE) lncRNAs. The mRNA expression profile dataset, GSE76925, and microRNA expression profile dataset, GSE70080, were obtained from the GEO database. Venn diagrams were used to find common DE mRNAs between my mRNAs dataset and GSE76925. These common DEGs were subjected to PPI analyses to identify Hub genes. Subsequently, Venn diagrams were used to identify common genes between the target genes of DE-miRNAs and Hub genes as well as DE-miRNAs and my lncRNAs dataset. Finally, a lncRNA-miRNA-mRNA co-expression network was constructed by prediction using proprietary software. The lncRNA and mRNA expressions were then validated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR).

Results

We identified 1578 differentially regulated lncRNAs and 3071 differentially regulated mRNAs. GO and KEGG pathway analyses suggested that the DE lncRNAs are involved in the pathogenesis of COPD. A lncRNA-miRNA-mRNA meshwork was established to predict the potential interactions among these RNAs. RP3-329A5.8 and MRPS11 expression was then subjected to qRT-PCR for validation. Correlations between MRPS11 and clinic-pathological features were explored.

Conclusion

Our study provided a set of lncRNAs and mRNAs that may be involved in the pathogenesis of COPD, thereby highlighting the need for further research on both diagnostic biomarkers and molecular mechanisms.

The interplay of physical and cognitive function in rehabilitation of interstitial lung disease patients: a narrative review

Background and Objective

Interstitial lung disease (ILD) encompasses several diverse pulmonary pathologies that result in abnormal diffuse parenchymal changes. When prescribing rehabilitation, several additional factors need to be considered as a result of aging, polypharmacy, and comorbidities manifested in ILD patients. This review aims to discuss issues related to frailty, skeletal muscle and cognitive function that limit physical activities in ILD patients. It will also highlight exercise training and propose complementary strategies for pulmonary rehabilitation.

Methods

A literature search was performed in MEDLINE, CINAHL (inception to October 19th, 2022) using search terms based on concepts of: idiopathic pulmonary fibrosis or interstitial lung disease; frailty; muscular atrophy; skeletal muscle dysfunction; cognitive dysfunction; sleep quality; sleep disorders; anxiety disorders; or depressive disorders. After eligible texts were screened, additional references were included from references cited in the screened articles.

Key Content and Findings

Frailty and skeletal muscle dysfunction are common in ILD. Weight loss, exhaustion, and anti-fibrotic medications can impact frailty, whereas physical inactivity, aging, corticosteroids and hypoxemia can contribute to sarcopenia (loss of muscle mass and function). Frailty is associated with worse clinical status, exercise intolerance, skeletal muscle dysfunction, and decreased quality of life in ILD. Sarcopenia appears to influence wellbeing and can potentially affect overall physical conditioning, cognitive function and the progression of ILD. Optimal assessment tools and effective strategies to prevent and counter frailty and sarcopenia need to be determined in ILD patients. Even though cognitive impairment is evident in ILD, its prevalence and underlying neurobiological model of contributing factors (i.e., inflammation, disease severity, cardiopulmonary status) requires further investigation. How ILD affects cognitive interference, motor control and consequently physical daily activities is not well defined. Strategies such as pulmonary rehabilitation, which primarily focuses on strength and aerobic conditioning have demonstrated improvements in ILD patient outcomes. Future incorporation of interval training and the integration of motor learning could improve transfer of rehabilitation strategies to daily activities.

Conclusions

Numerous underlying etiologies of ILD contribute to frailty, skeletal muscle and cognitive function, but their respective neurobiologic mechanisms require further investigation. Exercise training increases physical measures, but complementary approaches may improve their applicability to improve daily activities.

High Prevalence of Non-Responders Based on Quadriceps Force after Pulmonary Rehabilitation in COPD

Pulmonary rehabilitation (PR) in patients with COPD improves quality of life, dyspnea, and exercise tolerance. However, 30 to 50% of patients are "non-responders" (NRs) according to considered variables. Surprisingly, peripheral muscle force is never taken into account to attest the efficacy of PR, despite its major importance. Thus, we aimed to estimate the prevalence of force in NRs, their characteristics, and predictors of non-response. In total, 62 COPD patients were included in this retrospective study (May 2019 to December 2020). They underwent inpatient PR, and their quadriceps isometric maximal force (Q_MVC) was assessed. The PR program followed international guidelines. Patients with a Q_MVC increase <7.5 N·m were classified as an NR. COPD patients showed a mean improvement in Q_MVC after PR (10.08 ± 12.97 N·m; p < 0.001). However, 50% of patients were NRs. NRs had lower pre-PR values for body mass, height, body mass index, PaO₂, and Q_MVC. Non-response can be predicted by low Q_MVC, high PaCO₂, and gender (when male). This model has a sensitivity of 74% and specificity of 81%. The study highlights the considerable number of NRs and potential risk factors for non-response. To systematize the effects, it may be interesting to implement blood gas correction and/or optimize the programs to enhance peripheral and central effects.

Urinary titin N-fragment as a predictor of decreased skeletal muscle mass in patients with interstitial lung diseases

This study aimed to examine the validity of urinary N-terminal titin fragment/creatinine (urinary N-titin/Cr) reflecting muscle damage biomarker in patients with interstitial lung disease. This retrospective study enrolled patients with interstitial lung disease. We measured urinary N-titin/Cr. Furthermore, we measured the cross-sectional areas of the pectoralis muscles above the aortic arch (PMCSA) and erector spinae muscles of the 12th thoracic vertebra muscles (ESMCSA) to assess muscle mass until 1 year. We examined the correlation between urinary N-titin/Cr and the change in muscle mass. We plotted receiver operating characteristic curves to estimate the cut-off points for urinary N-titin/Cr for distinguishing the greater-than-median and smaller-than-median reduction of muscle mass after 1 year. We enrolled 68 patients with interstitial lung disease. The median urinary N-titin/Cr value was 7.0 pmol/mg/dL. We observed significant negative correlations between urinary N-titin/Cr and changes in the PMCSA after 1 year (p < 0.001) and changes in the ESMCSA after 6 months (p < 0.001) and 1 year (p < 0.001). The cut-off points for urinary N-titin/Cr were 5.2 pmol/mg/dL and 10.4 pmol/mg/dL in the PMCSA and ESMCSA, respectively. In summary, urinary N-titin/Cr may predict muscle loss in the long-term and act as a clinically useful biomarker reflecting muscle damage.

Pectoralis muscle index might be a factor associated with frailty in older women with breast cancer

BACKGROUND

To investigate the possible relationship between pectoralis muscle (PM) measurement and frailty in older women with breast cancer (BC) (preoperatively defined as stage 1, 2, and 3 diseases).

METHODS

This retrospective, observational study was conducted at Konya Training and Research Hospital between June and December 2020. A total of 102 patients [median age 62.5 years, median follow-up period two years] were included in the study. PM measurements were obtained from thorax computerized tomography (CT). Pectoralis muscle index (PMI) was calculated by dividing the PM area by the height square of the patients (cm2/m2). Pectoralis muscle density (PMD) was evaluated using CT findings, including their Hounsfield Units (HU). Frailty status and sarcopenia-risk assessments were done by a telephone interview in September 2020 using the FRAIL index (categorized as robust or nonrobust) and SARC-F questionnaire (classified as no sarcopenia-risk or risk of sarcopenia), respectively. PM measurements were compared between robust and nonrobust patients and between patients with a risk of sarcopenia and no sarcopenia risk.

RESULTS

The nonrobust patients had lower pectoralis major muscle index (PMaMI) (p = 0.041) and pectoralis major muscle density(PMaD) (p = 0.020) levels than robust patients in the whole study sample. PMI (p = 0.017) and PMaMI (p = 0.010) levels were significantly lower in the nonrobust patients than in robust patients with early-stage BC. Frailty status was positively correlated with age (rho: 0.621; p < 0.001), BC stage (rho: 0.220; p = 0.026), and SARC-F score (rho: 0.747; p < 0.001), and negatively correlated with PMaMI (rho: -0.197; p = 0.047) and PMaD (rho: -0.237; p = 0.016). There were significant associations between PMaMI (OR: 0.467, 95% Confidence Interval (CI): 0.226-0.962 p = 0.039) and PMI (OR: 0.543, 95% CI: 0.299-0.986 p = 0.045) levels with frailty status (being nonrobust) in regression models.

DISCUSSION

In the study, it has been shown that pectoralis muscle assessment might be a related parameter to frailty in older women with breast cancer.

Muscle Power in Patients with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis

This study aimed to review the impact of training on muscle power in patients with chronic obstructive pulmonary disease (COPD). Randomized controlled trials evaluating the effects of exercise-based interventions on limbs muscle power and rate of force development in COPD patients were investigated. Five international databases were searched until October 2022. Meta-analyses were performed calculating the mean difference or standardized mean difference. Risk of bias in studies was assessed using Cochrane Risk of Bias tool 2.0. A total of nine studies were included in the analysis. There were concerns about risk of bias in seven out of nine studies. Comparison of exercising and non-exercising groups showed a significant effect of exercise in improving muscle power (P=0.0004) and rate of force development (P<0.001), in five and three trials, respectively. Four studies comparing different trainings showed no significant results on muscle power (P=0.45). Eight to 16 weeks of exercise-based intervention versus no intervention might be beneficial to enhance upper and lower limbs muscle power and rate of force development in people with COPD. In contrast, muscle power did not improve when different training modalities were compared. Future studies performing power training in COPD patients are encouraged.

Skeletal Muscle Mitochondrial Dysfunction in Chronic Obstructive Pulmonary Disease: Underlying Mechanisms and Physical Therapy Perspectives

Skeletal muscle dysfunction (SMD) is a prevalent extrapulmonary complication and a significant independent prognostic factor in patients with chronic obstructive pulmonary disease (COPD). Mitochondrial dysfunction is one of the core factors that damage structure and function in COPD skeletal muscle and is closely related to smoke exposure, hypoxia, and insufficient physical activity. The currently known phenotypes of mitochondrial dysfunction are reduced mitochondrial content and biogenesis, impaired activity of mitochondrial respiratory chain complexes, and increased mitochondrial reactive oxygen species production. Significant progress has been made in research on physical therapy (PT), which has broad prospects for treating the abovementioned potential mitochondrial-function changes in COPD skeletal muscle. In terms of specific types of PT, exercise therapy can directly act on mitochondria and improve COPD SMD by increasing mitochondrial density, regulating mitochondrial biogenesis, upregulating mitochondrial respiratory function, and reducing oxidative stress. However, improvements in mitochondrial-dysfunction phenotype in COPD skeletal muscle due to different exercise strategies are not entirely consistent. Therefore, based on the elucidation of this phenotype, in this study, we analyzed the effect of exercise on mitochondrial dysfunction in COPD skeletal muscle and the regulatory mechanism thereof. We also provided a theoretical basis for exercise programs to rehabilitate this condition.

Muscle Function in Moderate to Severe Asthma: Association With Clinical Outcomes and Inflammatory Markers

BACKGROUND

Patients with severe asthma have been shown to have low muscle mass, but the clinical consequences are unknown.

OBJECTIVE

In a clinical cohort of patients with moderate to severe asthma, we aimed to assess muscle mass and strength and their relation with functional and clinical outcomes, as well as with systemic inflammatory markers.

METHODS

Muscle mass and strength were assessed by the fat-free mass index (FFMI), creatinine excretion in a 24-hour urine sample, and handgrip strength test. Functional outcomes included pulmonary function tests and the 6-minute walking distance, whereas clinical outcomes were assessed with questionnaires on asthma control, quality of life, and health care use. Associations of muscle mass and strength with asthma outcomes were assessed with multivariable regression analyses.

RESULTS

A total of 114 patients participated (36% male; mean age, 51.9 ± 14.4 years; body mass index, 27.7 ± 5.7 kg/m²). According to predefined criteria, 16% had a low FFMI and 8% a low urinary creatinine excretion, which did not differ between categories of asthma severity. Both lower FFMI and urinary creatinine excretion were associated with lower values of FEV₁ and 6-minute walking distance, whereas a lower handgrip strength was related to worse asthma control, poorer quality of life, and a higher probability of emergency visits (all P < .05). Except for higher leukocytes in relation to lower FFMI, we did not find associations between systemic inflammatory markers and muscle function.

CONCLUSIONS

This study demonstrates that low muscle mass is prevalent in patients with moderate to severe asthma and, along with low muscle strength, is associated with poorer clinical and functional outcomes. Our results encourage longitudinal studies into muscle function as a potential target for treatment to improve asthma outcomes.

Performance fatigability during isometric vs. concentric quadriceps fatiguing tasks in men and women

In the present study, we aimed to provide a robust comparison of the fatigability of the knee extensors following isometric (ISO) and concentric (CON) tasks. Twenty young adults (25 ± 4 yr, 10 women) randomly performed the ISO and CON quadriceps intermittent fatigue test, consisting of ten (5 s on/5-s off, ISO) or one-hundred (0.5-s on/0.5-s off, CON) contractions with 10 % increments per stage until exhaustion. Performance fatigability was quantified as maximal isometric (MVIC) and concentric (MVCC) torque loss. Voluntary activation and contractile function (peak-twitch) were investigated using peripheral nerve stimulation. Number of stages (6.2 ± 0.7 vs. 4.9 ± 0.8; P < 0.001) and torque-time integral (20,166 ± 7,821 vs. 11,285 ± 4,933 Nm.s; P < 0.001) were greater for ISO than CON. MVIC, MVCC and voluntary activation decreased similarly between sessions (P > 0.05) whereas peak-twitch amplitude decreased more for CON (P < 0.001). The number of contractions was similar across sexes (ISO: men = 62 ± 8, women = 61 ± 5; CON: men = 521 ± 67, women = 458 ± 76, P > 0.05). MVCC was more reduced in women for both sessions (all P < 0.05), while MVIC loss was similar between sexes. We concluded that, despite greater torque-time integral and duration for ISO, both sessions induced a similar performance fatigability at exhaustion. Contractile function was more altered in CON. Finally, sex-related difference in fatigability depends on the contraction mode used during testing.

Efetividade de diferentes protocolos e cargas utilizadas no treinamento muscular inspiratório de indivíduos com DPOC: uma revisão sistemática

RESUMO A doença pulmonar obstrutiva crônica (DPOC) provoca alterações no sistema musculoesquelético, afetando inclusive os músculos respiratórios e levando ao aumento da dispneia e à redução da capacidade funcional. Nesse sentido, o treinamento muscular inspiratório (TMI) deve fazer parte do programa de reabilitação pulmonar. Diversos estudos já demonstraram sua eficácia, contudo, ainda é necessário investigar qual a melhor forma de realizá-lo. Assim, o objetivo deste estudo foi investigar por meio de uma revisão sistemática a efetividade de diferentes protocolos e cargas de TMI sobre os desfechos de força e resistência dos músculos inspiratórios, bem como de capacidade funcional e redução da dispneia. Trata-se de uma revisão sistemática realizada de acordo com o protocolo PRISMA. A busca foi realizada em fevereiro de 2021, nas seguintes bases de dados: PubMed, SciELO, PEDro. Para a busca dos artigos, os seguintes descritores foram empregados: “COPD”; e “breathing exercises, resistive training, respiratory muscle training”. Um total de 398 pacientes foram incluídos nos 10 estudos selecionados, todos previamente diagnosticados com DPOC. Foram utilizados diferentes dispositivos para o TMI, e os protocolos variaram em relação às cargas e progressão. O dispositivo mais utilizado entre os artigos foi o Threshold, com carga estabelecida de acordo com a porcentagem da pressão inspiratória máxima (30-80%), reajustada de acordo com novas medições a cada uma ou duas semanas. Houve semelhança de resultados positivos encontrados tanto em treinamentos com cargas baixas quanto com cargas altas, havendo uma melhora na força muscular inspiratória, capacidade funcional e dispneia. No entanto, mais estudos são necessários para definir o melhor protocolo de TMI para DPOC.

Effectiveness of different protocols and loads used in inspiratory muscle training of individuals with COPD: a systematic review

ABSTRACT Chronic obstructive pulmonary disease (COPD) changes the musculoskeletal system, including the respiratory muscles, which are responsible for increasing dyspnea and reducing functional capacity. Several studies have already showed the effectiveness of inspiratory muscle training (IMT); therefore, it should be part of the pulmonary rehabilitation program. However, assessing the best way to do it is still necessary. Thus, this study aimed to evaluate, by a systematic review, the effectiveness of different IMT protocols and loads on the outcomes of inspiratory muscle strength and endurance, functional capacity, and dyspnea reduction. This systematic review was performed in accordance with the PRISMA protocol. Studies were searched in February 2021 in the PubMed, SciELO, PEDro. For the search, the following keywords were used: “COPD” and “breathing exercises, resistive training, respiratory muscle training.” A total of 398 individuals previously diagnosed with COPD were included in the 10 selected studies. Different IMT devices were used and protocols varied in relation to loads and progression. Threshold was the most used IMT device. Its load was established according to the percentage of maximal inspiratory pressure (MIP) (30-80%) and readjusted according to new measurements taken every one or two weeks. Respiratory muscle training with both low loads and high loads presented positive results, however, establishing which is the best IMT protocol for individuals with COPD is not possible yet. Inspiratory muscle strength, functional capacity, and dyspnea get better with IMT.

Role of progression of training volume on intramuscular adaptations in patients with chronic obstructive pulmonary disease

Introduction: Quadriceps dysfunction is a common systemic manifestation of chronic obstructive pulmonary disease (COPD), for which treatment using resistance training is highly recommended. Even though training volume is suggested to be a key explanatory factor for intramuscular adaptation to resistance training in healthy older adults, knowledge is scarce on the role of progression of training volume for intramuscular adaptations in COPD.

Methods: This study was a sub-analysis of a parallel-group randomized controlled trial. Thirteen patients with severe to very severe COPD (median 66 yrs, forced expiratory volume in 1 s 44% predicted) performed 8 weeks of low-load resistance training. In a post hoc analysis, they were divided into two groups according to their training volume progression. Those in whom training volume continued to increase after the first 4 weeks of training outlined the continued progression group (n = 9), while those with limited increase (<5%) or even reduction in training volume after the initial 4 weeks composed the discontinued progression group (n = 4). Fiber-type distribution and oxidative muscle protein levels, i.e., citrate synthase (CS), hydroxyacyl-coenzyme A dehydrogenase (HADH), mitochondrial transcription factor A (TfAM) as well as quadriceps endurance measures (total work from elastic band and isokinetic knee extension tests), were assessed before and after the intervention period.

Results: The continued progression group sustained their training volume progression during weeks 5–8 compared to weeks 1–4 (median +25%), while the discontinued progression group did not (median -2%) (p = 0.007 between groups). Compared with baseline values, significant between-group differences in fiber type distribution and TfAM muscle protein levels (range ± 17–62%, p < 0.05) and in individual responses to change in Type I and Type IIa fiber type proportion, CS, HADH, and TfAM muscle protein levels outcomes (median 89 vs. 50%, p = 0.001) were seen in favor of the continued progression group. Moreover, only the continued progression group had a significant increase in HADH muscle protein levels (+24%, p = 0.004), elastic band (+56%, p = 0.004) and isokinetic (+7%, p = 0.004) quadriceps endurance, but the between-group differences did not reach statistical significance (range 14–29%, p = 0.330–1.000).

Discussion: The novel findings of the current study were that patients with COPD who had a continued progression of training volume across the 8-weeks intervention had an increased proportion of Type I fibers, and TfAM muscle protein levels and decreased proportion of Type II fibers compared to those that did not continue to progress their training volume after the initial weeks. Additionally, HADH muscle protein levels and quadriceps endurance measurements only improved in the continued progression group, although no significant between-group differences were seen. These findings highlight the importance of continued progression of training volume during resistive training to counteract quadriceps dysfunction within the COPD population. Still, considering the small sample size and the post hoc nature of our analyses, these results should be interpreted cautiously, and further research is necessary.

Influence of handgrip strength on pharyngeal transit time in individuals with chronic obstructive pulmonary disease

OBJECTIVE

To investigate the relationship between Handgrip Strength (HGS), dysphagia classification, nutritional aspects, and Pharyngeal Transit Time (PTT) in subjects with Chronic Obstructive Pulmonary Disease (COPD).

METHODS

Study based on the analysis of secondary data from a database. The sample comprised 15 COPD patients of both sexes and a mean age of 65.7 years. We collected information on HGS, videofluoroscopic swallowing study, Volume-Viscosity Swallow Test (V-VST), and Body Mass Index (BMI). We applied correlation, effect size, and logistic regression tests at the 5% significance level.

RESULTS

Most individuals had severe COPD (66.7%), mean dominant HGS of 28.2, and non-dominant HGS of 25.3. Five subjects were malnourished, five were well-nourished, and five were obese. Most of them had normal swallowing (40%), normal V-VST results (60%), and PTT of 0.89 s (liquid) and 0.81 s (pudding-thick). There was no significant correlation between the swallowing classification and the other variables. We obtained a significant correlation (p = 0.015), though weak (r = -0.611), between non-dominant HGS and PTT. Regarding the binary logistic regression, HGS variables and HGS asymmetry were not enough to be considered a risk to clinically abnormal swallowing (V-VST).

CONCLUSION

Subjects with COPD in this study had a longer PTT than reported in the literature for normal subjects and a weak correlation between PTT and non-dominant HGS. The variables related to muscle condition were not considered predictors for abnormal swallowing.

LEVEL OF EVIDENCE: 3

Leveraging deep phenotyping from health check-up cohort with 10,000 Korean individuals for phenome-wide association study of 136 traits

The expanding use of the phenome-wide association study (PheWAS) faces challenges in the context of using International Classification of Diseases billing codes for phenotype definition, imbalanced study population ethnicity, and constrained application of the results in research. We performed a PheWAS utilizing 136 deep phenotypes corroborated by comprehensive health check-ups in a Korean population, along with trans-ethnic comparisons through using the UK Biobank and Biobank Japan Project. Meta-analysis with Korean and Japanese population was done. The PheWAS associated 65 phenotypes with 14,101 significant variants (P < 4.92 × 10-10). Network analysis, visualization of cross-phenotype mapping, and causal inference mapping with Mendelian randomization were conducted. Among phenotype pairs from the genotype-driven cross-phenotype associations, we evaluated penetrance in correlation analysis using a clinical database. We focused on the application of PheWAS in order to make it robust and to aid the derivation of biological meaning post-PheWAS. This comprehensive analysis of PheWAS results based on a health check-up database will provide researchers and clinicians with a panoramic overview of the networks among multiple phenotypes and genetic variants, laying groundwork for the practical application of precision medicine.

Effects of neuromuscular electrical stimulation on exercise capacity, muscle strength and quality of life in COPD patients: A Systematic Review with Meta-Analysis

OBJECTIVE

To determine the effects of neuromuscular electrical stimulation on disabilities and activity limitation of individuals affected by chronic obstructive pulmonary disease.

DATA SOURCES

MEDLINE, PEDro database, Cochrane Controlled Trials Register, and SciELO, were searched from inception until October 2021.

REVIEW METHODS

Inclusion criteria were patients with COPD, randomized controlled trials comparing neuromuscular electrical stimulation alone or combined conventional pulmonary rehabilitation and neuromuscular electrical stimulation versus control or sham or pulmonary rehabilitation in disabilities and activity limitation in COPD. There were no mandatory language or publication date restrictions. Two reviewers selected studies independently. Weighted mean differences and 95% confidence intervals were calculated.

RESULTS

32 studies met the study criteria, including 1.269 participants. Neuromuscular electrical stimulation improved exercise capacity (MD 1.10, 95% CI: 0.33, 1.86, N = 147), and muscle strength (0.53, 95% CI: 0.20, 0.87, N = 147) compared to sham group. Combined neuromuscular electrical stimulation and conventional rehabilitation improved exercise capacity (MD 34.28 meters, 95% CI: 6.84, 61.73, N = 262) compared to conventional rehabilitation alone. No adverse events were reported.

CONCLUSIONS

Neuromuscular electrical stimulation resulted in small improvement in disabilities and activity limitation (below the MCID) in COPD. Thus, the inclusion of neuromuscular electrical stimulation in rehabilitation programs must consider the cost Because of inadequate methodological conduction and reporting of methods, some studies were of low quality.

Isokinetic testing of quadriceps function in COPD: feasibility, responsiveness, and minimal important differences in patients undergoing pulmonary rehabilitation

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Evaluation of isokinetic quadriceps testing in COPD is needed to assess its efficacy.

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Isokinetic testing was performed incorrectly in a quarter of patients with COPD.

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Quadriceps peak torque and total work improved following pulmonary rehabilitation.

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Minimal important differences for peak torque and total work were determined.

Background

Isokinetic testing of peripheral muscle function is valid and reliable in patients with chronic obstructive pulmonary disease (COPD).

Objective

To evaluate whether and to what extent isokinetic testing of quadriceps function meets pre-defined test criteria in patients with COPD; to determine the response to pulmonary rehabilitation (PR), and to calculate minimal important differences (MIDs) of isokinetic quadriceps function.

Methods

Retrospective analysis of 2033 patients with COPD (age: 65±9 years, body mass index: 26±6 kg/m², FEV₁: 49±22% predicted) who followed a comprehensive PR program. Pre and post PR isokinetic quadriceps function was assessed with 30 maximal extension-flexion contractions at an angular speed of 90°/s on a computerized dynamometer. The chosen anchors were 6-min walk test and COPD assessment test.

Results

Pre PR, 27% of the patients performed the isokinetic test incorrectly. In male and female patients with a correct pre and post PR isokinetic test, peak torque (Δ=10±13 Nm or 9% and Δ=7±9 Nm or 10%, respectively) and total work (Δ=263±270 J or 14% and Δ=198±190 J or 15%, respectively) improved significantly. There was no change in work fatigue index following PR. Using distribution-based calculations, MID estimates for peak torque and total work ranged between 6–7 Nm and 97–135 J in males and between 4–5 Nm and 62–99 J in females.

Conclusions

Based on the current test criteria, three in four patients with COPD performed the isokinetic quadriceps test correctly during baseline PR assessment. Furthermore, peak torque and total work, but not work fatigue index, were responsive to PR and sex-specific MIDs were established.

Clinical significance of pectoralis muscle strength in elderly patients with idiopathic pulmonary fibrosis

Introduction

Investigations of muscle dysfunction in patients with idiopathic pulmonary fibrosis (IPF) are limited to peripheral muscles. However, decreased thoracic muscle mass is known and deterioration of chest wall muscle strength is not clear.

Objective

The aims of the present study were to evaluate pectoralis muscle strength located on the chest wall and to investigate the relationship of spirometric measurements and respiratory muscle strength with pectoralis muscle strength.

Methods

Elderly patient with IPF (mean disease duration 7.47±7.04 years) and the age-and sex-matched healthy volunteers were recruited in this cross-sectional study. The pulmonary function test was performed by a portable spirometer for spirometric variables and a gas analyzer for diffusing capacity for carbon monoxide (DL_CO). Maximal inspiratory (MIP) and expiratory pressure (MEP) were measured with mouth pressure device. Modified Medical Research Council Dyspnea Scale (MMRC) was used to determined dyspnea severity. The pectoralis muscle strength was assessed isometrically during shoulder joint horizontal adduction movement with a handheld dynamometer.

Results

A total of 17 patients with IPF (9 males, mean age 69.06±3.94 years) and 19 healthy controls (10 males, mean age 70.95 ±4.99 years) were included. Patients with IPF had lower pectoralis muscle strength than healthy controls (p<0.001). Significant relationships were found between pectoralis muscle strength and MIP (r=0.79, p<0.001), MEP (r=0.81, p<0.001), FEV₁% (r=0.54, p=0.02), FVC% (r=0.68, p<0.003) and DL_CO (r=0.61, p=0.009). With multiple linear regression analysis, pectoralis muscle strength was the only independent predictor of FVC% (adjusted R²=0.37, p<0.05).

Conclusion

In patients with IPF, pectoralis muscle strength decreases and is associated with pulmonary function. In particular pectoralis muscle strength is likely to have an important impact on FVC%. Therefore, we consider that this test should be included routinely in chest diseases and rehabilitation clinics. The trial was registered U.S. National Library of Medicine clinical trial registry (https://clinicaltrials.gov, Trial ID: NCT04803617).

Association between Neurologic Outcomes and Changes of Muscle Mass Measured by Brain Computed Tomography in Neurocritically Ill Patients

This study aimed to investigate whether skeletal muscle mass estimated via brain computed tomography (CT) could predict neurological outcomes in neurocritically ill patients. This is a retrospective, single-center study. Adult patients admitted to the neurosurgical intensive care unit (ICU) from January 2010 to September 2019 were eligible. Cross-sectional areas of paravertebral muscles at the first cervical vertebra level (C1-CSA) and temporalis muscle thickness (TMT) on brain CT were measured to evaluate skeletal muscle mass. The primary outcome was the Glasgow Outcome Scale score at 3 months. Among 189 patients, 81 (42.9%) patients had favorable neurologic outcomes. Initial and follow-up TMT values were higher in patients with favorable neurologic outcomes compared to those with poor outcomes (p = 0.003 and p = 0.001, respectively). The initial C1-CSA/body surface area was greater in patients with poor neurological outcomes than in those with favorable outcomes (p = 0.029). In multivariable analysis, changes of C1-CSA and TMT were significantly associated with poor neurological outcomes. The risk of poor neurologic outcome was especially proportional to changes of C1-CSA and TMT. The follow-up skeletal muscle mass measured via brain CT at the first week from ICU admission may help predict poor neurological outcomes in neurocritically ill patients.

Effects of Exercise Intervention on Peripheral Skeletal Muscle in Stable Patients With COPD: A Systematic Review and Meta-Analysis

Objectives: Peripheral skeletal muscle dysfunction is an important extrapulmonary manifestation of chronic obstructive pulmonary disease (COPD) that can be counteracted by exercise training. This study aimed to review the effect of three major exercise training modalities, which are used in pulmonary rehabilitation to improve on skeletal muscle mass, function, and exercise capacity in COPD.

Methods: PubMed, Embase, EBSCO, Web of Science, and the PEDro database were searched on April 25, 2020. Only randomized controlled studies published in English evaluating the effects of exercise interventions on peripheral skeletal muscle mass, strength, and exercise capacity in stable COPD patients were included. The quality of included studies was evaluated using the PEDro scale. The mean difference (MD) or the standardized mean difference (SMD) with 95% CI was calculated to summarize the results. Subgroup meta-analysis was used to investigate the effects of different exercise training modalities and different outcome measures. The Grading of Recommendations Assessment, Development, and Evaluation guidelines were used to rate evidence quality.

Results: A total of 30 randomized controlled trials involving 1,317 participants were included. Data from trials investigating endurance exercise (EE), resistance exercise (RE), and combined aerobic and resistance exercise (CE) were pooled into a meta-analysis, and the differences compared with the non-exercising COPD control were improvement in the muscle strength and exercise capacity in stable COPD patients. Subgroup meta-analysis for different exercise training modalities showed that RE significantly improved muscle strength (SMD = 0.6, 95% CI 0.35–0.84, I² = 61%), EE and CE significantly increased VO_2peak (EE: MD = 3.5, 95% CI 1.1–5.91, I² = 92%; CE: MD = 1.66, 95% CI 0.22–3.1, I² = 1%). Subgroup meta-analysis for different outcome measures showed that only isotonic strength was improved after exercise interventions (SMD = 0.89, 95% CI 0.51–1.26, I² = 71%).

Conclusion: Moderate evidence supports that exercise training in stable COPD patients has meaningful and beneficial effects on peripheral skeletal muscle strength and exercise capacity. Peripheral skeletal muscle shows a higher response to RE, and the isotonic test is relatively sensitive in reflecting muscle strength changes. The proportion of aerobic and resistance exercise components in a combined exercise program still needs exploration.

Systematic Review Registration: The review was registered with the PROSPERO: (The website is https://www.crd.york.ac.uk/PROSPERO/, and the ID is CRD42020164868).

Isolated Resistance Training Programs to Improve Peripheral Muscle Function in Outpatients with Chronic Obstructive Pulmonary Diseases: A Systematic Review

This systematic review aims to establish which isolated resistance training (RT) programs have been used in outpatients with chronic obstructive pulmonary disease (COPD) and their impact on all aspects of peripheral skeletal muscle function. Electronic databases were systematically searched up to June 2021. The eligibility criteria were: (1) randomized controlled trials investigating the effects of supervised and isolated RT programs in outpatients with COPD and (2) RT programs lasting 8-12 weeks, (3) including at least one outcome measure related to trainable muscle characteristics. Initially, 6576 studies were identified, whereas 15 trials met the inclusion criteria. All the included trials reported that isolated RT improved both upper and lower limbs' maximal strength. Muscle endurance and power also increased after RT but received less attention in the analysis. Furthermore, few studies assessed the effect of RT on muscle mass and cross-sectional area, reporting only limited improvement. Isolated RT programs carried out 2-3 days a week for 8-12 weeks improved skeletal muscle function in individuals with COPD. The RT program should be specifically focused to the trainable muscle characteristic to be improved. For this reason, we further encourage the introduction of a detailed assessment of muscle function and structure during the pulmonary rehabilitation practice.

Impact of chronic obstructive pulmonary disease on passive viscoelastic components of the musculoarticular system

Chronic obstructive pulmonary disease (COPD) produces skeletal muscle atrophy and weakness, leading to impairments of exercise performance. The mechanical work needed for movement execution is also provided by the passive tension developed by musculoarticular connective tissue. To verify whether COPD affects this component, the passive viscoelastic properties of the knee joint were evaluated in 11 patients with COPD and in 11 healthy individuals. The levels of stiffness and viscosity were assessed by means of the pendulum test, consisting in a series of passive leg oscillations. In addition, to explore the contribution of passive tension in the mechanical output of a simple motor task, voluntary leg flexion-extension movements were performed. Patients with COPD showed a statistically significant reduction in stiffness and viscosity compared to controls. Voluntary execution of flexion-extension movements revealed that the electromyographic activity of the Rectus Femoris and Biceps Femoris was lower in patients than in controls, and the low viscoelastic tension in the patients conditioned the performance of active movements. These results provide novel insights on the mechanism responsible for the movement impairments associated with COPD.

Is the Power Spectrum of Electromyography Signal a Feasible Tool to Estimate Muscle Fiber Composition in Patients with COPD?

A greater proportion of glycolytic muscle fibers is a manifestation of skeletal muscle dysfunction in Chronic Obstructive Pulmonary Disease (COPD). Here, we propose to use the spectral analysis of the electromyographic signal as a non-invasive approach to investigate the fiber muscle composition in COPD. We recorded the electromyographic activity of Rectus Femoris (RF), Vastus Lateralis (VL), Vastus Medialis (VM) and Biceps Femoris (BF) muscles, in ten patients and ten healthy individuals, during non-fatiguing, flexion–extension leg movements. The mean (MNF) and median frequencies (MDF) were calculated, and the most common profiles of electromyographic power spectrum were characterized by using the principal component analysis. Frequency parameters showed higher values in patients with COPD than in the control group for the RF (+25% for MNF; +21% for MNF), VL (+16% for MNF; 16% for MNF) and VM (+22% for MNF; 22% for MNF) muscles during the extension movements and for the BF (+26% for MNF; 34% for MNF) muscle during flexion movements. Spectrum profiles of the COPD patients shifted towards the higher frequencies, and the changes in frequency parameters were correlated with the level of disease severity. This shift of frequencies may indicate an increase in glycolytic muscle fibers in patients with COPD. These results, along with the non-fatigable nature of the motor task and the adoption of a non-invasive method, encourage to use electromyographic spectral analysis for estimating muscle fiber composition in patients with COPD.

The correlation between quadriceps muscle strength and endurance and exercise performance in patients with COPD

To determine the association between quadriceps muscle strength (QMS) and endurance (QME) and exercise capacity in patients with COPD after stratification for sex and resting lung function (LF). Data were collected from 3,246 patients with COPD (60% men, 64 ± 9 yr), including measures of exercise capacity [peak aerobic capacity (peakV̇o₂), 6-min walk distance (6MWD)] and isokinetic QMS and QME. Patients were stratified for sex, forced expiratory volume in 1 s (>50/≤50% predicted), single breath carbon monoxide diffusing capacity (>50/≤50% predicted), and residual volume (>140/≤140% predicted). After stratification for resting LF, QMS and QME were significantly associated with peakV̇o₂ (r range: 0.47-0.61 and 0.49-0.65 for men and 0.53-0.66 and 0.48-0.67 for women, respectively) and 6MWD (r range: 0.29-0.42 and 0.44-0.55 for men and 0.25-0.54 and 0.34-0.55 for women, respectively) (P < 0.001). Regression models demonstrated that QMS and QME were significant determinants of peakV̇o₂ (explained variance R² range: 35.6%-48.8% for men and 36.8%-49.0% for women) and 6MWD (R² range: 24.3%-43.3% for men and 28.4%-40.3% for women), independent of age and fat-free mass. Quadriceps muscle function was significantly associated with peakV̇o₂ and 6MWD in male and female patients with COPD after stratification for resting LF, in which QME appear to be a more important determinant than QMS. This underlines the importance of systematically evaluating both quadriceps muscle strength and endurance in in all patients with COPD.NEW & NOTEWORTHY Our findings identified quadriceps muscle function as an important determinant of exercise capacity across a wide spectrum of lung function. Quadriceps muscle endurance appears to be a more important determinant than quadriceps muscle strength, underlining the importance of including both the measurement of quadriceps muscle strength and endurance in routine assessment for all patient with COPD.

Isotonic quadriceps endurance is better associated with daily physical activity than quadriceps strength and power in COPD: an international multicentre cross-sectional trial

Knowledge about modifiable determinants of daily physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) is crucial to design effective PA interventions. The present study aimed to determine the contribution of quadriceps strength, power and endurance to daily PA in COPD. Additionally, for quadriceps endurance, we also aimed to determine to what extent the association varies according to the mode of movement (isotonic, isometric, or isokinetic). Using a multicentre cross-sectional trial design we determined the contribution of quadriceps function to daily PA (steps, sedentary time and time spent doing moderate-to-very-vigorous physical activity [MVPA]) using bivariate and partial Pearson correlation analysis (r) and multiple linear regression models (ΔR²). Pre-determined controlling factors were sex, age, body mass index (BMI), COPD-assessment test, forced expiratory volume in one second in percent of the predicted value (FEV_1pred), and distance walked on the 6-minute walk test. Eighty-one patients with COPD (mean ± SD: age 67 ± 8 years, FEV_1pred 57 ± 19%, daily steps 4968 ± 3319, daily sedentary time 1016 ± 305 min, and MVPA time 83 ± 45 min) were included. Small to moderate bivariate correlations (r = .225 to .452, p < .05) were found between quadriceps function and measures of PA. The best multiple linear regression models explained 38–49% of the variance in the data. Isotonic endurance was the only muscle contributor that improved all PA models; daily steps (ΔR² = .04 [relative improvement 13%] p = .026), daily sedentary time (ΔR² = .07 [23%], p = .005) and MVPA-minutes (ΔR² = .08 [20%], p = .001). Isotonic endurance was also independently associated with most PA variables, even when controlling for strength, power or isometric-isokinetic endurance properties of the muscle (r = .246 to .384, p < .05). In contrast, neither strength, power, isometric-or isokinetic endurance properties of the muscle was independently associated with PA measures when controlling for isotonic endurance (r = .037 to .219, p > .05). To conclude, strength, power, and endurance properties of the quadriceps were low to moderately associated with PA in patients with COPD. Isotonic quadriceps endurance was the only quadriceps property that was independently associated with the different measures of PA after controlling for a basic set of known determinants of PA, quadriceps strength or power, or isometric or isokinetic quadriceps endurance. Future longitudinal studies should investigate its potential as a modifiable determinant of PA.

[Which physical tests for which objectives in pulmonary rehabilitation?]

Chronic respiratory disease is a major cause of morbidity and mortality worldwide and an important cause of disability including a reduction of exercise, functional and muscle capacity contributing to a decreased quality of life. In the context of pulmonary rehabilitation, a thorough patient-centered outcome assessment, including not only measures of lung function, but also exercise functional and muscle capacity, is imperative for a comprehensive disease management. Assessment of these impairments and dysfunctions with appropriate and change-sensitive procedures is thus necessary for personalizing the physical interventions and assessing the short- and long-term effectiveness of the intervention. The clinician currently has a wide variety of tests and measurements available to assess the physical and functional capacity of people with chronic respiratory disease. The aim of this review is to provide a pragmatic synthesis of the physical, functional and muscle capacity tests most commonly used in pulmonary rehabilitation. Ultimately, it should help the clinician to identify the relevant evaluations according to the objectives of the patients but also according to the available resources, the setting of pulmonary rehabilitation and the specific qualities of each test.

The CT pulmonary vascular parameters and disease severity in COPD patients on acute exacerbation: a correlation analysis

Background

It is necessary to analyze the CT pulmonary vascular parameters and disease severity in chronic obstructive pulmonary disease (COPD) patients to provide evidence support for the management of COPD.

Methods

COPD patients on acute exacerbation admitted to our hospital from COPD patients from January 2019 to March 2020 was selected. The characteristics and ratio of the cross-sectional area (CSA) of small pulmonary vessels to the total area of the lung field, and the ratio of pulmonary artery and aorta (PA/A) cross-sectional diameter in patients with COPD were analyzed.

Results

A total of 128 COPD patients were included. There were significant differences in the duration of COPD, smoking history, the PaO₂, PaCO₂, pH, and FEV1, FVC and FEV1/FVC among COPD patients with different severity (all p < 0.05). The duration of COPD, smoking, PaO₂, PaCO₂, CSA and PA/A were correlated with the COPD severity (all p < 0.05). Both CSA, PA/A were correlated with post BD FEV1 (all p < 0.05). The cutoff value of CSA and PA/A for the diagnosis of severe COPD was 0.61 and 0.87 respectively, and the AUC of CSA and PA/A for the diagnosis of severe COPD was 0.724 and 0.782 respectively.

Conclusions

Patients with CSA ≤ 0.61 and PA/A ≥ 0.87 may have higher risks for severe COPD, and more studies are needed in the future to further elucidate the management of COPD.

Towards Personalized Management of Sarcopenia in COPD

The awareness of the presence and consequences of sarcopenia has significantly increased over the past decade. Sarcopenia is defined as gradual loss of muscle mass and strength and ultimately loss of physical performance associated with aging and chronic disease. The prevalence of sarcopenia is higher in chronic obstructive pulmonary disease (COPD) compared to age-matched controls. Current literature suggests that next to physical inactivity, COPD-specific alterations in physiological processes contribute to accelerated development of sarcopenia. Sarcopenia in COPD can be assessed according to current guidelines, but during physical performance testing, ventilatory limitation should be considered. Treatment of muscle impairment can halt or even reverse sarcopenia, despite respiratory impairment. Exercise training and protein supplementation are currently at the basis of sarcopenia treatment. Furthermore, effective current and new interventions targeting the pulmonary system (eg, smoking cessation, bronchodilators and lung volume reduction surgery) may also facilitate muscle maintenance. Better understanding of disease-specific pathophysiological mechanisms involved in the accelerated development of sarcopenia in COPD will provide new leads to refine nutritional, exercise and physical activity interventions and develop pharmacological co-interventions.

Association between peak inspiratory flow rate and hand grip muscle strength in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease

Rationale

Ineffective peak inspiratory flow rate (PIFR) generation in patients using inhalers results in insufficient drug delivery to the lungs and poor clinical outcomes. Low inspiratory muscle strength is associated with suboptimal PIFR.

Objective

To examine in a prospective study the relationship between PIFR and skeletal muscle strength using hand grip strength (HGS) as a surrogate.

Methods

Adult patients admitted with acute exacerbation of chronic obstructive pulmonary disease (COPD) were enrolled. PIFR was measured within 48 hours before discharge. PIFR below 60L/min was considered suboptimal. HGS was measured using a handheld dynamometer. Any readmissions and emergency department visit data were collected. The associations between PIFR, HGS, 30 and 90-day COPD and all-cause readmissions were examined, without and with adjustment for age, race and gender.

Results

Of the 75 enrolled patients, 56% had suboptimal PIFR; they were older (63.9±9.7 vs. 58.2±7.7 years) and had significantly lower HGS (24.2±11.1 vs. 30.9±10.9 Kg) compared to those with optimal PIFR. There were no significant differences between the two PIFR groups by gender, race, history of coronary artery disease, congestive heart failure, hypertension or functional scores. Each kilogram increase in HGS was associated with 0.50 (95%CI 0.18–0.89, p = 0.003) L/min increase in PIFR. We did not observe an association between PIFR and 30 or 90-day readmission rates.

Conclusion

We found a significant association between HGS and PIFR in hospitalized patients with acute exacerbations of COPD. Whether interventions aimed at increasing skeletal muscle strength also result in improvement in PIFR remains unclear and need further study.