Influence of diaphragmatic mobility on exercise tolerance and dyspnea in patients with COPD

The Application of Diaphragm Ultrasound in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic Obstructive Pulmonary Disease (COPD) is a prevalent condition that poses a significant burden on individuals and society due to its high morbidity and mortality rates. The diaphragm is the main respiratory muscle, its function has a direct impact on the quality of life and prognosis of COPD patients. This article aims to review the structural measurement and functional evaluation methods through the use of diaphragmatic ultrasound and relevant research on its application in clinical practice for COPD patients. Thus, it serves to provide valuable insights for clinical monitoring of diaphragm function in COPD patients, facilitating early clinical intervention and aiding in the recovery of diaphragm function.

Ultrasound assessment of diaphragmatic dysfunction in non-critically ill patients: relevant indicators and update

Diaphragm dysfunction (DD) can be classified as mild, resulting in diaphragmatic weakness, or severe, resulting in diaphragmatic paralysis. Various factors such as prolonged mechanical ventilation, surgical trauma, and inflammation can cause diaphragmatic injury, leading to negative outcomes for patients, including extended bed rest and increased risk of pulmonary complications. Therefore, it is crucial to protect and monitor diaphragmatic function. Impaired diaphragmatic function directly impacts ventilation, as the diaphragm is the primary muscle involved in inhalation. Even unilateral DD can cause ventilation abnormalities, which in turn lead to impaired gas exchange, this makes weaning from mechanical ventilation challenging and contributes to a higher incidence of ventilator-induced diaphragm dysfunction and prolonged ICU stays. However, there is insufficient research on DD in non-ICU patients, and DD can occur in all phases of the perioperative period. Furthermore, the current literature lacks standardized ultrasound indicators and diagnostic criteria for assessing diaphragmatic dysfunction. As a result, the full potential of diaphragmatic ultrasound parameters in quickly and accurately assessing diaphragmatic function and guiding diagnostic and therapeutic decisions has not been realized.

Assessment of diaphragmatic function by ultrasonography in patients with systemic sclerosis and its relation to clinical parameters : A case-control study

BACKGROUND

Diaphragmatic function can be affected in many diseases and disorders. Although systemic sclerosis (SSc) is a serious connective tissue disease that affects not only the skin but also the pulmonary and musculoskeletal systems, there is insufficient information about diaphragm function.

AIMS

To compare the diaphragmatic parameters by ultrasonography (USG) in patients with SSc and healthy individuals and examine the relationship between these parameters and clinical features in patients with SSc.

METHODS

This study included 13 patients with SSc and 15 healthy individuals. Muscle thickness (in deep inspiration Tins and at the end of calm expiration Texp), changes in thickness (∆T), and thickening fraction at deep breathing were evaluated by USG. Skin thickness, pulmonary function tests, respiratory muscle strength, and the perception of dyspnea were measured as clinical features.

RESULTS

The results of Texp, Tins, and ∆T were similar in both groups (p > 0.05), albeit patients in the SSc group had less thickening fraction compared to the control group (79.9 ± 36.7 cm and 103.8 ± 20.6 cm, respectively, p < 0.05). The Tins, ∆T, and thickening fraction of the diaphragm were associated with skin thickness, pulmonary function test parameters, and respiratory muscle strength (p < 0.05). Besides, there was significant correlation between muscle thickening fraction and perception of dyspnea (p < 0.05).

CONCLUSION

These results confirm that diaphragm thickness and contractility can be affected in patients with SSc. Therefore, ultrasonographic evaluation of the diaphragm can play a complementary role to pulmonary function test and respiratory muscle strength measurement in the diagnosis and follow-up of patients with SSc.

Changes in diaphragm thickness and 6-min walking distance improvement after inspiratory muscle training in patients with chronic obstructive pulmonary disease: Clinical trial

Aim

Inspiratory muscle training (IMT) improves respiratory muscle function and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD), but the detailed mechanism is unclear. The purpose of this study is to elucidate the mechanism of functional improvement by IMT from P0.1, an index of respiratory central output, and thickness of diaphragm (Tdi), a noninvasive and reliable ultrasound examination.

Methods

This clinical trial study enrolled 13 elderly patients with COPD. IMT was performed using the POWER breathe® Medic Plus breathing trainer in combination with each participant's outpatient rehabilitation regimen. Starting at 20% of the maximal inspiratory pressure (PImax) and increasing to 50%, the participants performed 30 IMT repetitions twice a day for 2 months. P0.1 is the value of airway-occlusion pressure at 0.1 s after the start of inspiratory flow, and Tdi was measured at rest and maximal breathing.

Results

PImax and 6-min walking distance(6MWD) significantly increased after training. Tdi at resting inspiration and expiration, and maximal inspiration also significantly increased after training. In addition, the Borg Scale scores for dyspnea and leg fatigue and the respiratory rate of the 1-min recovery period after the 6MWD significantly decreased. There was no significant difference in P0.1.

Conclusions

These results suggest that the effects of IMT may be attributed to the improved peripheral factors rather than to the central factors in elderly COPD patients.

Prevalence of diaphragm dysfunction in patients with interstitial lung disease (ILD): The role of diaphragmatic ultrasound

BACKGROUND

Diaphragm ultrasound (DUS) has been extensively used in critically ill patients while data on outpatients with interstitial lung disease (ILD) are limited. We hypothesized that diaphragm function, assessed by ultrasound, could be impaired in patients with ILD, considering both Idiopathic Pulmonary Fibrosis (IPF) and Connective Tissue Disease (CTD-ILD), compared to healthy subjects. Moreover, this impairment could impact clinical and functional parameters.

METHODS

All consecutive CTD-ILD and IPF patients followed in our center (March-October 2020) were screened. Diaphragm displacement (DD), inspiratory thickness (Ti), expiratory thickness (Te), thickening fraction (TF), and respiratory functional parameters were collected. The prevalence of diaphragmatic dysfunction (TF <30%) was then recorded.

RESULTS

Eighty-two consecutive patients (41 CTD-ILD, 41 IPF) and 15 age- and sex-matched controls were enrolled. In the overall population, 24 out of 82 (29%) presented diaphragmatic dysfunction. In CTD-ILD, DD and Ti were lower as compared to IPF (p = 0.021 and p = 0.036, respectively); while diaphragmatic dysfunction was more prevalent compared to controls (37% vs 7%, p = 0.043). TF positively correlated to patients' functional parameters in the CTD-ILD group (FVC%pred: p = 0.003; r = 0.45), while not in the IPF group. Diaphragmatic dysfunction was associated with moderate/severe dyspnea in both CTD-ILD and IPF (p = 0.021).

CONCLUSION

The prevalence of diaphragmatic dysfunction was 29% in patients with ILD and was associated with moderate/severe dyspnea. CTD-ILD presented lower DD compared with IPF and a higher prevalence of diaphragmatic dysfunction (TF<30%) compared with controls. TF was associated with lung function only in CTD-ILD patients, suggesting its potential role in the comprehensive patient assessment.

Ultrasound assessment of the respiratory system using diaphragm motion-volume indices

Background

Although previous studies have determined limit values of normality for diaphragm excursion and thickening, it would be beneficial to determine the normal diaphragm motion-to-inspired volume ratio that integrates the activity of the diaphragm and the quality of the respiratory system.

Methods

To determine the normal values of selected ultrasound diaphragm motion-volume indices, subjects with normal pulmonary function testing were recruited. Ultrasound examination recorded diaphragm excursion on both sides during quiet breathing and deep inspiration. Diaphragm thickness was also measured. The inspired volumes of the corresponding cycles were systematically recorded using a spirometer. The indices were calculated using the ratio excursion, or percentage of thickening, divided by the corresponding breathing volume. From this corhort, normal values and limit values for normality were determined. These measurements were compared to those performed on the healthy side in patients with hemidiaphragm paralysis because an increase in hemidiaphragm activity has been previously demonstated in such circumstances.

Results

A total of 122 subjects (51 women, 71 men) with normal pulmonary function were included in the study. Statistical analysis revealed that the ratio of excursion, or percentage of thickening, to inspired volume ratio significantly differed between males and females. When the above-mentioned indices using excursion were normalized by body weight, no gender differences were found. The indices differed between normal respiratory function subjects and patients with hemidiaphragm paralysis (27 women, 41 men). On the paralyzed side, the average ratio of the excursion divided by the inspired volume was zero. On the healthy side, the indices using the excursion and the percentage of thickening during quiet breathing or deep inspiration were significantly increased comparedto patients with normal lung function. According to the logistic regression analysis, the most relevant indice appeared to be the ratio of the excursion measured during quiet breathing to the inspired volume.

Conclusion

The normal values of the diaphragm motion-volume indices could be useful to estimate the performance of the respiratory system. Proposed indices appear suitable in a context of hyperactivity.

Shear wave elastography of the diaphragm in acute exacerbation of chronic obstructive pulmonary disease: A prospective observational study

Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are prone to diaphragmatic dysfunction. However, dynamic assessment of diaphragmatic function is complex and difficult, and whether the assessment of diaphragmatic function can reflect clinical indicators such as lung function in AECOPD patients remains unclear. We studied diaphragm stiffness and diaphragm stiffening rate (DSR) in AECOPD patients with acute exacerbations ≥ 2 times within 1 year and their correlation with clinical data, the diaphragmatic thickening fraction (DTF), lung function, and blood gas values. In total, 112 AECOPD patients in group C and Group D who had acute exacerbations ≥ 2 times within 1 year in the Global Initiative for Chronic Obstructive Lung Disease Guideline A (low risk, few symptoms), B (low risk, many symptoms), C (High risk, few symptoms), D (High risk, many symptoms) grouping system were included in the study. Their general clinical data, chronic obstructive pulmonary disease assessment test (CAT), modified medical research council (mMRC), number of acute exacerbations in 1 year, DTF, lung function, and blood gas analysis were collected. The diaphragm shear wave elasticity at functional residual capacity (DsweFRC) and DSR were measured by ultrasound. The DsweFRC and DSR of Group D were higher than those of Group C (P < .05). DsweFRC, DSR were negatively correlated with DTF, forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC (r ranged from -0.293 to -0.697, all P < .05), and positively correlated with CAT score, mMRC score, and arterial carbon dioxide pressure (r ranged from 0.274 to 0.462, all P < .05) in both groups; the correlation coefficients of DsweFRC, DSR and DTF, FEV1/FVC in group D were greater than those in group C. There was no correlation between DsweFRC, DSR and arterial oxygen partial pressure in both groups (P > .05). The DsweFRC, DSR increased with the number of acute exacerbations per year in both groups. We found that diaphragmatic stiffness in AECOPD patients increased with the number of acute exacerbations within 1 year, correlated with DTF, CAT, mMRC, lung function, and arterial carbon dioxide pressure and provides a simple and practical method for dynamically assessing diaphragmatic function and disease severity in AECOPD patients.

Is manual therapy of the diaphragm effective for people with Obstructive Lung Diseases? A Systematic Review

BACKGROUND

Diaphragm dysfunction is common among people with obstructive lung disease (OLD). The effectiveness of manual therapy (MT) techniques specifically targeting this region remains unclear. The scope of this systematic review is to investigate the effectiveness of MT on the zone of apposition (ΖΟΑ) of the diaphragm in lung function, diaphragm excursion (DE), chest expansion, exercise capacity (EC), maximal inspiratory pressure (PImax) and dyspnea in people suffering from OLD.

METHODS

Key databases were systematically searched. Two independent reviewers screened the papers for inclusion. Methodological quality and the quality of evidence were assessed using the PEDro scale and the GRADE approach, respectively.

RESULTS

Two studies were included. One showed that diaphragmatic stretching and the manual diaphragm release technique (MDRT) improved DE and CE (p<0.001, p<0.05, respectively). The other showed that MDRT improved DE and EC (p<0.05, p<0.05, respectively).

CONCLUSION

This systematic review provides preliminary evidence on the effectiveness of MT on the ZOA of the diaphragm in people with COPD. Further research is needed in order for definitive conclusions to be drawn.

REGISTRATION NUMBER IN PROSPERO

CRD42022308595.

Home based pulmonary tele-rehabilitation under telemedicine system for COPD: a cohort study

Background

Pulmonary tele-rehabilitation can improve adherence to pulmonary rehabilitation. However, there are few reports on home based pulmonary tele-rehabilitation. We assessed the effectiveness of home based pulmonary tele-rehabilitation under telemedicine system in patients with chronic obstructive pulmonary disease (COPD).

Methods

This cohort study enrolled 174 patients with COPD who received home based pulmonary tele-rehabilitation under telemedicine system. The follow-up time was 12 weeks. Patients were grouped according to pulmonary rehabilitation weeks, number of rehabilitation times and total duration time, and when these three data were inconsistent, the two lowest values were grouped: control group (total rehabilitation weeks < 1 week, total number of rehabilitation times < 5, total duration time < 150 min, n = 46), pulmonary rehabilitation group 1 (PR-1) (1 week ≤ rehabilitation weeks < 4 weeks, 5 ≤ total number of rehabilitation times < 20, 150 min ≤ total duration time  < 1200 min, n = 31), pulmonary rehabilitation group 2 (PR-2) (4 weeks ≤ rehabilitation weeks < 8 weeks, 20 ≤ total number of rehabilitation times < 40, 600 min ≤ total duration time < 2400 min, n = 23), pulmonary rehabilitation group 3 (PR-3) (8 weeks ≤ rehabilitation weeks < 12 weeks, 40 ≤ total number of rehabilitation times < 60, 1200 min ≤ total duration time < 3600 min, n = 40) and pulmonary rehabilitation group 4 (PR-4) (rehabilitation weeks = 12 weeks, total number of rehabilitation times = 60, total duration time = 3600 min, n = 34). The clinical data before and after rehabilitation were collected and evaluated, including dyspnea symptoms, 6-min walk distance (6MWD), diaphragmatic mobility, anxiety and depression.

Results

There was no significance difference between control group and PR-1 group. PR-2 group after rehabilitation had significantly decreased CAT and HAMA scores than control (P < 0.05). Compared with control, PR-3 group and PR-4 group after rehabilitation had significantly higher 6MWD and diaphragmatic motility during deep breathing, but significantly lower CAT score, mMRC score, HAMA score, and HAMD score (P < 0.05). Compared with before pulmonary rehabilitation, in PR-3 and PR-4 groups, the 6MWD and the diaphragmatic motility during deep breathing were significantly higher, while CAT score, mMRC score, HAMA score, and HAMD score (for PR-4 only) were significantly lower after pulmonary rehabilitation (P < 0.05). There was no significant difference between PR-3 group and PR-4 group (P > 0.05). In the 12-week pulmonary rehabilitation program, patients who completed at least 8 weeks, namely those in the PR-3 and PR-4 groups, accounted for 42.5% of the total number. Education, income and response rate to telemedicine system reminders were the main risk factors associated with home based pulmonary tele-rehabilitation.

Conclusions

Home based pulmonary tele-rehabilitation under telemedicine system for more than 8 weeks can significantly improve the dyspnea symptoms, 6MWD, diaphragmatic mobility during deep breathing, and negative emotions of patients with moderate to severe stable COPD.

Trial registration: This study was registered at Chinese Clinical Trial Registry under registration number of ChiCTR2200056241CTR2200056241.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02077-w.

MRI-assessed diaphragmatic function can predict frequent acute exacerbation of COPD: a prospective observational study based on telehealth-based monitoring system

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have considerably high mortality and re-hospitalisation rate. Diaphragmatic dysfunction (DD) is common in COPD patients. However, whether diaphragmatic dysfunction is related to acute exacerbation is yet to be elucidated. This study aimed to evaluate the diaphragm function by magnetic resonance imaging (MRI) in COPD patients and assess whether the impact of DD may help predict AECOPD.

METHODS

20 healthy adult volunteers and 80 COPD patients were enrolled. The diaphragms function parameters were accessed by MRI. Patients were guided to start self-management by the Telehealth-based monitoring system following the enrolment. Events of acute exacerbation of COPD were recorded by the system and confirmed by healthcare providers. Binary univariate and multivariate logistic regression analyses were performed to investigate the factors associated with the frequency of AECOPD. Receiver operating characteristic (ROC) curves were further used to assess the value of prediction indexes.

RESULTS

Fifty-nine COPD patients completed a one-year follow-up based on the Telehealth-based monitoring system. The clinical outcomes showed that the diaphragm function parameters at the end of maximal breathing were lower in the COPD group than in the healthy control group (P < 0.05). ANOVA showed significant differences among Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages for diaphragm function parameters, including chest wall motion, lung area, upper-lower diameter, and the diaphragm thickening fraction at the end of maximal breathing (P < 0.05). Moreover, significant differences in diaphragm function parameters were observed between patients with infrequent AECOPD (n = 28) and frequent AECOPD (n = 31) based on the frequency of AECOPD (P < 0.05). The diaphragm thickening fraction and the chest wall motion were associated with AECOPD after adjusting for age, sex, BMI, and lung functions, and the combination of predictions showed better accuracy in predicting the frequency of AECOPD.

CONCLUSIONS

In COPD patients, diaphragm function parameters correlate with the severity of airflow limitation. The diaphragm thickening fraction and the chest wall motion were associated with the frequency of AECOPD and can predict it.

Diaphragmatic Movement at Rest and After Exertion: A Non-Invasive and Easy to Obtain Prognostic Marker in COPD

Introduction

Diaphragmatic dysfunction is common in patients with chronic obstructive pulmonary disease (COPD). This study aimed to assess the prognostic significance of impaired diaphragmatic movement at rest and after exercise.

Methods

This was a prospective study of patients with stable COPD. Diaphragmatic movements were examined at rest and after a 6-minute walking test (6MWT) with a convex transducer with a frequency of 3.5-5-7.5 MHz. Maximal movement of the diaphragm was measured in both right and left diaphragm, and the side with higher amplitude was selected for further analysis. Measurements obtained were evaluated for their prognostic value for a composite endpoint of moderate and severe COPD exacerbations and death in 1 year time period was assessed. In addition, postbronchodilator spirometry, symptoms, quality of life, and demographic and clinical information were collected.

Results

A total of 96 patients were analyzed (62.5% male, mean age 65.1 years (standard deviation (SD): 8.1), mean FEV1 (% predicted): 55.8%, SD: 18.3%, mean CAT: 15.6 units, SD: 9.2). Sixty-four patients (67%) presented the composite endpoint. In the multivariate Cox analysis, FVC (HR = 0.944, p = 0.005), CAT score (HR = 1.133, p = 0.011), previous severe exacerbations (HR = 5.446, p = 0.004) and diaphragmatic movement at rest (HR = 0.932, p = 0.033) were found to be predictors of the composite endpoint. This model correctly classified 86.5% (83/96) of the patients.

Conclusion

Non-invasive assessment of diaphragmatic movement by ultrasound measurement both at rest and after exercise could contribute to the assessment of disease severity and prognosis of COPD.

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.

Assessments and Targeted Rehabilitation Therapies for Diaphragmatic Dysfunction in Patients with Chronic Obstructive Pulmonary Disease: A Narrative Review

Purpose

This review summarizes the characteristics, assessment methods, and targeted rehabilitation therapies of diaphragm dysfunction in patients with chronic obstructive pulmonary disease (COPD).

Methods

Extensive literature was searched in PubMed, the Cochrane Library, Web of Science, Chinese National Knowledge Infrastructure Database, Wanfang, and SinoMed.

Results

Under the influence of oxidative stress, inflammation, and other factors, the diaphragm function of patients with COPD changes in mobility, muscle strength, thickness, and thickening. In patients with COPD, diaphragm mobility can be assessed using ultrasound, X-ray fluoroscopy, and magnetic resonance imaging. Diaphragmatic strength can be measured by transdiaphragmatic pressure and maximal inspiratory pressure. Diaphragmatic thickness and thickening can be assessed using ultrasound. Rehabilitation therapies targeting the diaphragm include diaphragmatic breathing, diaphragm-related manual therapy, and phrenic nerve electrical stimulation. Diaphragmatic breathing is safe, simple, and not limited by places. Diaphragmatic manual therapies, which require patient cooperation and one-on-one operation by a professional therapist, are effective. Phrenic nerve electrical stimulation is suitable for patients with severe conditions. These therapies improve the diaphragmatic function, lung function, dyspnea, and exercise capacity of patients with COPD.

Conclusion

The diaphragmatic function is commonly assessed in terms of mobility, strength, thickness, and thickening. Diaphragmatic targeted rehabilitation therapies have proven to be efficient, which are recommended to be included in the pulmonary rehabilitation strategy for patients with COPD.

Diaphragmatic excursion is correlated with the improvement in exercise tolerance after pulmonary rehabilitation in patients with chronic obstructive pulmonary disease

BACKGROUND

In patients with chronic obstructive pulmonary disease (COPD), the maximum level of diaphragm excursion (DEmax) is correlated with dynamic lung hyperinflation and exercise tolerance. This study aimed to elucidate the utility of DEmax to predict the improvement in exercise tolerance after pulmonary rehabilitation (PR) in patients with COPD.

METHODS

This was a prospective cohort study. Of the 62 patients with stable COPD who participated in the outpatient PR programme from April 2018 to February 2021, 50 completed the programme. Six-minute walk distance (6MWD) was performed to evaluate exercise tolerance, and ultrasonography was performed to measure DEmax. Responders to PR in exercise capacity were defined as patients who demonstrated an increase of > 30 m in 6MWD. The receiver operating characteristic (ROC) curve was used to determine the cut-off point of DEmax to predict responses to PR.

RESULTS

Baseline levels of forced expiratory volume in 1 s, 6MWD, maximum inspiratory pressure, DEmax and quadriceps muscle strength were significantly higher, and peak dyspnoea of modified Borg (mBorg) scale score was lower in responders (n = 30) than in non-responders (n = 20) to PR (p < 0.01). In multivariate analysis, DEmax was significantly correlated with an increase of > 30 m in 6MWD. The area under the ROC curve of DEmax to predict responders was 0.915, with a sensitivity and specificity of 83% and 95%, respectively, at a cut-off value of 44.9 mm of DEmax.

CONCLUSION

DEmax could adequately predict the improvement in exercise tolerance after PR in patients with COPD.

Ultrasound Evaluation of Diaphragm Force Reserve in Patients with Chronic Obstructive Pulmonary Disease

Rationale: Diaphragm function is a key determinant of dyspnea in chronic obstructive pulmonary disease (COPD); however, it is rarely assessed in clinical practice. Lung hyperinflation can also impair diaphragm function. Ultrasound can assess the activity, function, and force reserve of the diaphragm.Objectives: To compare diaphragm activity, function, and force reserve among patients with COPD and healthy control subjects.Methods: Patients with stable COPD (n = 80) and healthy control subjects (n = 20) were enrolled (97% of them were men). Ultrasound was used to measure the thickening fraction of the diaphragm during tidal breathing and maximum volitional effort. Outcome measures were as follows: 1) the difference in diaphragm force reserve, activity, and function between patients with COPD and control subjects; 2) the correlation between lung volumes and diaphragm force reserve, activity, and function; and 3) the relationship between diaphragm force reserve and the rate of moderate to severe exacerbation of COPD.Results: The tidal thickening fraction of the diaphragm during resting breathing (TFdi-tidal) was higher in patients with COPD than in control subjects (P = 0.002); it was approximately twice as high in patients with severe COPD than in control subjects. Patients with COPD had poorer diaphragm function than control subjects as assessed by the maximal thickening fraction of the diaphragm during Muller maneuver (P < 0.01). Diaphragm force reserve ratio assessed by 1-(tidal thickening fraction of the diagphragm during resting breathing/maximal thickening fraction of the diaphragm) was lower in patients with COPD than in control subjects, and it fell with increasing Global Initiative for Chronic Obstructive Lung Disease stages (P < 0.001); it correlated with inspiratory capacity (r = 0.46) and the body mass index, airflow obstruction, dyspnea, exercise capacity (BODE) index, a multidimensional scoring system (r = -0.49). Patients who developed exacerbation during the following 2 years had less force reserve than patients without exacerbation (P = 0.024).Conclusions: Male patients with COPD have increased diaphragm workload, impaired diaphragm function, and reduced force reserve compared with healthy subjects. Ultrasound assessment of the diaphragm in COPD provides important functional information.Clinical trial registered with the Thai Clinical Trials Registry (TCTR20160411001). Registered 31 April 5, 2016.

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.

Diaphragmatic Ultrasound in Non-Cystic Fibrosis Bronchiectasis: Relationship to Clinical Parameters

The aim of this study was to assess diaphragm thickness (DT) and mobility (DM) and to investigate their relationship to clinical parameters in patients with non-cystic fibrosis (non-CF) bronchiectasis. Thirty-eight patients with non-CF bronchiectasis were enrolled in this cross-sectional study. DT was measured using ultrasound at different lung volumes (at residual volume [DT_RV], functional residual capacity [DT_FRC] and total lung capacity [DT_TLC]). DM was measured using ultrasound during quiet breathing (DM_QB) and deep breathing (DM_DB). Disease severity, pulmonary function, respiratory muscle strength, exercise capacity and physical activity were assessed. DT_RV correlated with disease severity (ρ = 0.332, p = 0.042), FEV1% (r = 0.387, p = 0.016) and FVC% (r = 0.405, p = 0.012). DT_FRC correlated with FVC% (r = 0.331, p = 0.042). DT_TLC correlated with disease severity (r = 0.430, p = 0.007) and total physical activity time (r = 0.379, p = 0.019). DM_DB correlated with disease severity (ρ = -0.380, p = 0.019), FEV1% (r = 0.369, p = 0.023) and FVC% (r = 0.405, p = 0.012). DT is related to disease severity, pulmonary function and physical activity, while DM is related to disease severity and pulmonary function in patients with non-CF bronchiectasis.

Latent traits of lung tissue patterns in former smokers derived by dual channel deep learning in computed tomography images

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease and the traditional variables extracted from computed tomography (CT) images may not be sufficient to describe all the topological features of lung tissues in COPD patients. We employed an unsupervised three-dimensional (3D) convolutional autoencoder (CAE)-feature constructor (FC) deep learning network to learn from CT data and derive tissue pattern-clusters jointly. We then applied exploratory factor analysis (EFA) to discover the unobserved latent traits (factors) among pattern-clusters. CT images at total lung capacity (TLC) and residual volume (RV) of 541 former smokers and 59 healthy non-smokers from the cohort of the SubPopulations and Intermediate Outcome Measures in the COPD Study (SPIROMICS) were analyzed. TLC and RV images were registered to calculate the Jacobian (determinant) values for all the voxels in TLC images. 3D Regions of interest (ROIs) with two data channels of CT intensity and Jacobian value were randomly extracted from training images and were fed to the 3D CAE-FC model. 80 pattern-clusters and 7 factors were identified. Factor scores computed for individual subjects were able to predict spirometry-measured pulmonary functions. Two factors which correlated with various emphysema subtypes, parametric response mapping (PRM) metrics, airway variants, and airway tree to lung volume ratio were discriminants of patients across all severity stages. Our findings suggest the potential of developing factor-based surrogate markers for new COPD phenotypes.

Diaphragmatic excursion correlates with exercise capacity and dynamic hyperinflation in COPD patients

Background

Although the pathophysiological mechanisms involved in the development of dyspnoea and poor exercise tolerance in patients with COPD are complex, dynamic lung hyperinflation (DLH) plays a central role. Diaphragmatic excursions can be measured by ultrasonography (US) with high intra- and interobserver reliability. The objective of this study was to evaluate the effect of diaphragmatic excursions as assessed by US on exercise tolerance and DLH in patients with COPD.

Methods

Patients with COPD (n=20) and age-matched control subjects (n=20) underwent US, which was used to determine the maximum level of diaphragmatic excursion (DE_max). Ventilation parameters, including the change in inspiratory capacity (ΔIC), were measured in the subjects during cardiopulmonary exercise testing (CPET). We examined the correlations between DE_max and the ventilation parameters.

Results

The DE_max of patients with COPD was significantly lower than that of the controls (45.0±12.8 mm versus 64.6±6.3 mm, respectively; p<0.01). The perception of peak dyspnoea (Borg scale) was significantly negatively correlated with DE_max in patients with COPD. During CPET, oxygen uptake/weight (V′_O2/W) and minute ventilation (V′_E) were significantly positively correlated with DE_max, while V′_E/V′_O2 and V′_E/carbon dioxide output (V′_CO2) were significantly negatively correlated with DE_max in patients with COPD. DE_max was also significantly positively correlated with ΔIC, reflecting DLH, and with V′_O2/W, reflecting exercise capacity.

Conclusion

Reduced mobility of the diaphragm was related to decreased exercise capacity and increased dyspnoea due to dynamic lung hyperinflation in COPD patients.

Reduced diaphragmatic excursion, as measured on ultrasound images, might predict decreased exercise capacity and increased dyspnoea due to dynamic lung hyperinflation in COPD patientshttps://bit.ly/3jkERxZ

Diaphragmatic ultrasound: a review of its methodological aspects and clinical uses

The diaphragm is the main muscle of respiration, acting continuously and uninterruptedly to sustain the task of breathing. Diaphragmatic dysfunction can occur secondary to numerous pathological conditions and is usually underdiagnosed in clinical practice because of its nonspecific presentation. Although several techniques have been used in evaluating diaphragmatic function, the diagnosis of diaphragmatic dysfunction is still problematic. Diaphragmatic ultrasound has gained importance because of its many advantages, including the fact that it is noninvasive, does not expose patients to radiation, is widely available, provides immediate results, is highly accurate, and is repeatable at the bedside. Various authors have described ultrasound techniques to assess diaphragmatic excursion and diaphragm thickening in the zone of apposition. Recent studies have proposed standardization of the methods. This article reviews the usefulness of ultrasound for the evaluation of diaphragmatic function, addressing the details of the technique, the main findings, and the clinical applications.

The Use of Diaphragm Ultrasonography in Pulmonary Physiotherapy of COPD Patients: A Literature Review

There is potentially a broad range of patient populations in which ultrasound imaging (US) might be beneficial form of physiotherapy process support. Among them, the group of patients with chronic obstructive pulmonary disease (COPD) is of great importance, as in this individuals the diaphragm dysfunction is frequently observed. Pulmonary physiotherapy often includes techniques which are intended to influence the diaphragm muscle but its anatomy does not allow for variety of techniques to assess function. Lack of easily available and reliable measures complicates outcomes interpretation and makes decision-making process difficult. A review of the electronic literature was conducted to identify studies related to the US assessment of physiotherapy process and its outcome in COPD patients. As a consequence, seven papers were identified. Based on the results obtained, it can be concluded that the diaphragm excursion is US measure that is most often described in context of diaphragm-related physiotherapy in COPD patients. The methodology applied, however, varies greatly making it difficult to compare results. Thus, developing standards of outcome assessment methods and therapy monitoring systems which are supported by evidence should be of paramount importance. Future studies could also focus on identifying which components of physiotherapeutic diaphragm-targeted approach provide acceptable level of evidence.

Diagnostic and clinical values of non-cardiac ultrasound in COPD: A systematic review

BACKGROUND

Clinical and research utility of non-cardiac ultrasound (US) in chronic obstructive pulmonary disease (COPD) has been widely investigated. However, there is no systematic review assessing the clinical values of non-cardiac US techniques in COPD.

METHODS

We systematically searched electronic databases from inception to 24 June 2020. Two independent reviewers in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines extracted data. A narrative synthesis of the results was conducted considering non-cardiac US techniques that looked for diaphragm, muscles and bones in patients with COPD.

RESULTS

In total, 2573 abstracts were screened, and 94 full-text papers were reviewed. A total of 54 studies met the inclusion criteria. Thirty-five studies assessed the diaphragm, while 19 studies evaluated different muscles, including limb muscles and pulmonary lesions in COPD using US. Of the 54 included studies, 30% (16/54) evaluated the changes in either limb muscles or diaphragmatic features before and after physical interventions; 67% (36/54) assessed the correlations between sonographic features and COPD severity. Indeed, 14/15 and 9/13 studies reported a significant reduction in diaphragm excursion and thickness in COPD compared with healthy subjects, respectively; this was correlated significantly with the severity and prognosis of COPD. Three studies reported links between diaphragm length and COPD, where lower diaphragm length correlated with poorer prognosis and outcomes. Quadriceps (rectus femoris), ankle dorsiflexor (tibialis anterior) and vastus lateralis were the most common muscles in COPD assessed by US. More than 70% (12/17) of the studies reported a significant reduction in the cross-sectional area (CSA) of the rectus femoris, rectus femoris and vastus lateralis thickness in COPD compared with healthy subjects. Quadriceps CSA and thickness correlated positively with COPD prognosis, in which patients with reduced quadriceps CSA and thickness have higher risk of exacerbation, readmission and death.

CONCLUSION

US measurements of diaphragm excursion and thickness, as well as lower limb muscles strength, size and thickness, may provide a safe, portable and effective alternative to radiation-based techniques in diagnosis and prognosis as well as tracking improvement postintervention in patients with COPD.

Assessment of diaphragmatic function by ultrasonography: Current approach and perspectives

This article reports the various methods used to assess diaphragmatic function by ultrasonography. The excursions of the two hemidiaphragms can be measured using two-dimensional or M-mode ultrasonography, during respiratory maneuvers such as quiet breathing, voluntary sniffing and deep inspiration. On the zone of apposition to the rib cage for both hemidiaphragms, it is possible to measure the thickness on expiration and during deep breathing to assess the percentage of thickening during inspiration. These two approaches make it possible to assess the quality of the diaphragmatic function and the diagnosis of diaphragmatic paralysis or dysfunction. These methods are particularly useful in circumstances where there is a high risk of phrenic nerve injury or in diseases affecting the contractility or the motion of the diaphragm such as neuro-muscular diseases. Recent methods such as speckle tracking imaging and ultrasound shear wave elastography should provide more detailed information for better assessment of diaphragmatic function.

Ultrasonographic assessment of skeletal muscle mass and diaphragm function in patients with chronic obstructive pulmonary disease: A case-control study

BACKGROUND

Although muscle dysfunction is a major contributor to morbidity in chronic obstructive pulmonary disease (COPD), assessment of skeletal muscle, and diaphragm function is not routinely performed in COPD patients.

OBJECTIVES

(1) The aim is to assess muscle dysfunction in COPD by measuring the zone of apposition of diaphragm, diaphragm excursion, thickness of diaphragm, and rectus femoris cross-sectional area (RFCSA) with ultrasonography.(2) To correlate the above assessments with spirometric parameters; notably forced expiratory volume in 1 s (FEV₁).

METHODS

Twenty-four consecutive stable COPD patients and 18 controls were included after obtaining written informed consent. Demographic and clinical data, spirometric values, 6-min walk distance, and sonographic parameters mentioned above were compiled for the analysis.

RESULTS

All included participants were male with a mean age of 62.5 ± 8.4 years. The mean FEV₁in cases was 1.12 ± 0.4 L versus 2.41 ± 0.5 L in controls. The diaphragm thickness (1.8 ± 0.5 mm vs. 2.2 ± 0.6 mm;P = 0.005) and RFCSA was significantly lower in COPD patients (4.8 ± 1.3 cm^[2] vs. 6.12 ± 1.2 cm^[2];P = 0.02). However, diaphragm excursion (5.35 ± 2.8 cm vs. 7 ± 2.6 cm) although lower in COPD patients, was not significantly different between the groups. Correlation between FEV₁and ultrasound diaphragm measurements and RFCSA by Spearman's Rho correlation was poor (ρ= 0.2).

CONCLUSION

Ultrasonographic assessment of the diaphragm and rectus femoris can be used as markers to assess skeletal muscle dysfunction in COPD as diaphragmatic function and RFCSA were lower in COPD patients.

Dissociation between reduced diaphragm inspiratory motion and normal diaphragm thickening in acute chronic pulmonary obstructive disease exacerbation: a case report

INTRODUCTION

Patients with chronic pulmonary obstructive disease (COPD) are at risk of acute exacerbation. Diaphragm muscle is classically highly solicited in COPD exacerbation.

PATIENT CONCERNS

A COPD patient was admitted because of acute dyspnea with wheezing.

DIAGNOSIS

acute COPD exacerbation.

INTERVENTIONS

A diaphragm ultrasound and a Doppler echocardiography were performed at bedside.

OUTCOMES

We measured diaphragm thickening at the apposition zone and diaphragm inspiratory motion from the subcostal view, in addition with classical echocardiographic parameters.

CONCLUSION

Despite a normal diaphragm thickening, diaphragm motion during inspiration is reduced in acute COPD exacerbation. These apparently discrepant findings may be explained by the alterations of the respiratory mechanics during COPD exacerbations, which should be considered when evaluating the diaphragmatic function by imaging.

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.

Ultrasound Assessment Of Diaphragmatic Function During Acute Exacerbation Of Chronic Obstructive Pulmonary Disease: A Pilot Study

Purpose

Impairment of diaphragmatic function is one of the main pathophysiological mechanisms of chronic obstructive pulmonary disease (COPD) and is known to be related to acute exacerbation. Ultrasonography (US) allows for a simple, non-invasive assessment of diaphragm kinetics. The purpose of this study was to investigate the changes in diaphragmatic function during acute exacerbation of COPD, by US.

Methods

This single-center, prospective study included patients with acute exacerbation of COPD symptoms. US measurements were performed within 72 hrs after exacerbation and after improvement of symptoms. Diaphragmatic excursion and its thickening fraction (TF) were measured as markers of diaphragmatic function. TF was calculated as (thickness at end inspiration - thickness at end expiration)/thickness at end expiration.

Results

Ten patients were enrolled. All patients were male, and the mean age was 79.8 years. The TF of the right diaphragm showed a significant increase from the initial to the follow-up values (80.1 ± 104.9 mm vs. 159.5 ± 224.6 mm, p = 0.011); however, the diaphragmatic excursion did not vary significantly between the initial and follow-up values (22 ± 6 mm vs 23 ±12 mm). The change in excursion between the stable and exacerbation periods was positively correlated with time to the next exacerbation and negatively correlated with the time taken to recover from the exacerbation.

Conclusion

These data support the possibility that a defect in diaphragm thickening is related to acute exacerbation of COPD.

Diaphragmatic ultrasound findings correlate with dyspnea, exercise tolerance, health-related quality of life and lung function in patients with fibrotic interstitial lung disease

BACKGROUND

Fibrotic interstitial lung disease (FILD) patients are typically dyspneic and exercise-intolerant with consequent impairment of health-related quality of life (HRQoL). Respiratory muscle dysfunction is among the underlying mechanisms of dyspnea and exercise intolerance in FILD but may be difficult to diagnose. Using ultrasound, we compared diaphragmatic mobility and thickening in FILD cases and healthy controls and correlated these findings with dyspnea, exercise tolerance, HRQoL and lung function.

METHODS

We measured diaphragmatic mobility and thickness during quiet (QB) and deep breathing (DB) and calculated thickening fraction (TF) in 30 FILD cases and 30 healthy controls. We correlated FILD cases' diaphragmatic findings with dyspnea, exercise tolerance (six-minute walk test), lung function and HRQoL (St. George's Respiratory Questionnaire).

RESULTS

Diaphragmatic mobility was similar between groups during QB but was lower in FILD cases during DB when compared to healthy controls (3.99 cm vs 7.02 cm; p <  0.01). FILD cases showed higher diaphragm thickness during QB but TF was lower in FILD when compared to healthy controls (70% vs 188%, p <  0.01). During DB, diaphragmatic mobility and thickness correlated with lung function, exercise tolerance and HRQoL, but inversely correlated with dyspnea. Most FILD cases (70%) presented reduced TF, and these patients had higher dyspnea and exercise desaturation, lower HRQoL and lung function.

CONCLUSION

Compared to healthy controls, FILD cases present with lower diaphragmatic mobility and thickening during DB that correlate to increased dyspnea, decreased exercise tolerance, worse HRQoL and worse lung function. FILD cases with reduced diaphragmatic thickening are more dyspneic and exercise-intolerant, have lower HRQoL and lung function.

Diaphragmatic thickness in chronic obstructive lung disease and relationship with clinical severity parameters

Background/aim

Sonographic assessment of diaphragm structure and function would be a useful clinical tool in patients with chronic obstructive pulmonary disease (COPD). Our aim was to determine the muscle thickness of the diaphragm and the usefulness of clinical practice in patients with COPD.

Materials and methods

The diaphragmatic thickness of 34 COPD patients and 34 healthy subjects was measured during tidal volume (Tmin) and deep inspiration (Tmax) on both sides using a B-mode ultrasound. The body mass index and the modified Medical Research Council (mMRC) index values were reported.

Results

There was no correlation among TminR (P = 0.134), TminL (P = 0.647), TmaxR (P = 0.721), and TmaxL (P = 0.905) between the patients with COPD and the control group. There was also no significant difference between diaphragmatic thickness and COPD severity, respiratory function (P = 0.410), and frequency of exacerbations (P = 0.881) and mMRC (P = 0.667).

Conclusion

Diaphragmatic dysfunction in COPD is related to mobility restriction rather than muscle thickness.

Possibilities of ultrasound research of the diaphragm

The ultrasound method is a non-invasive and safe diagnostic method. Ultrasound examination (ultrasound) of the diaphragm allows you to conduct a direct study of its structure and function. Using stationary and portable ultrasound scanners, the study of the diaphragm can be carried out in specialized laboratories, in outpatient departments, in various departments of the clinic, including in intensive care units, in patients in different clinical conditions. Ultrasound of the diaphragm can be implemented on devices of different technical levels. Despite the fact that at present the diaphragm ultrasound method is not standardized, nevertheless, it provides clinically important information for solving various clinical studies, including when conducting dynamic observation.

Comparison of diaphragmatic mobility between COPD patients with and without thoracic hyperkyphosis: a cross-sectional study

Objective:

To compare diaphragmatic mobility, lung function, and respiratory muscle strength between COPD patients with and without thoracic hyperkyphosis; to determine the relationship of thoracic kyphosis angle with diaphragmatic mobility, lung function, and respiratory muscle strength in COPD patients; and to compare diaphragmatic mobility and thoracic kyphosis between male and female patients with COPD.

Methods:

Participants underwent anthropometry, spirometry, thoracic kyphosis measurement, and evaluation of diaphragmatic mobility.

Results:

A total of 34 patients with COPD participated in the study. Diaphragmatic mobility was significantly lower in the group of COPD patients with thoracic hyperkyphosis than in that of those without it (p = 0.002). There were no statistically significant differences between the two groups of COPD patients regarding lung function or respiratory muscle strength variables. There was a significant negative correlation between thoracic kyphosis angle and diaphragmatic mobility (r = −0.47; p = 0.005). In the sample as a whole, there were statistically significant differences between males and females regarding body weight (p = 0.011), height (p < 0.001), and thoracic kyphosis angle (p = 0.036); however, there were no significant differences in diaphragmatic mobility between males and females (p = 0.210).

Conclusions:

Diaphragmatic mobility is lower in COPD patients with thoracic hyperkyphosis than in those without it. There is a negative correlation between thoracic kyphosis angle and diaphragmatic mobility. In comparison with male patients with COPD, female patients with COPD have a significantly increased thoracic kyphosis angle.

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.

Meta-analysis of the Effect of a Pulmonary Rehabilitation Program on Respiratory Muscle Strength in Patients with Chronic Obstructive Pulmonary Disease

PURPOSE

Pulmonary rehabilitation (PR) programs are important in the treatment of patients with chronic obstructive pulmonary disease (COPD) but vary widely in type, duration, and efficacy. This meta-analysis investigated the effect of PR programs on respiratory muscle strength in patients with COPD.

METHODS

PubMed, Embase, and CINAHL were searched. The primary outcome variables were maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP). The secondary outcome variables were the modified Borg score after the 6-min walking test, percent predicted forced expiratory volume in 1 second (FEV₁%pred), and percent FEV₁/forced volume capacity (FVC). Comprehensive Meta-Analysis, version 3.0, was used to analyze the data. The effect size was calculated using the standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Twenty randomized controlled trials (with 992 participants) were included in the analysis. The PR programs had a significant effect on the MEP (SMD, 0.87; 95% CI, 0.42-1.32; p < .001), MIP (SMD, 0.53; 95% CI, 0.13-0.93; p = .009), and modified Borg score (SMD, -0.37; 95% CI, -0.52 to -0.22; p < .001) in patients with COPD. There was no effect on FEV₁%pred (SMD, 0.09; 95% CI, -0.12 to 0.30; p = .406) or FEV₁/FVC% (SMD, 0.04; 95% CI, -0.17 to 0.26; p = .702).

CONCLUSION

PR programs improve respiratory muscle strength in patients with COPD. Strategies for selecting a suitable PR program need to be developed, and future studies should evaluate the long-term effects of such programs on pulmonary function.

Utility of ultrasound assessment of diaphragmatic function before and after pulmonary rehabilitation in COPD patients

Background

Pulmonary rehabilitation (PR) may improve respiratory symptoms and skeletal muscle strength in patients with COPD. We aimed to evaluate changes in ultrasound (US) measurements of diaphragmatic mobility and thickness after PR in COPD patients and to test its correlation with PR outcomes.

Methods

Twenty-five COPD patients were enrolled and underwent a diaphragm US assessment before and after a 12-week PR program.

Results

We found a correlation between the intraindividual percentage of change in the diaphragmatic length of zone of apposition at functional residual capacity (ΔLzapp%) and the change in 6-minute walking distance (6MWD) after PR (rho=0.49, P=0.02). ΔLzapp% was significantly higher in patients with improved 6MWD and COPD Assessment Test (CAT) score (mean rank=12.03±2.57 vs 6.88±4.37; P=0.02). A ΔLzapp% of ≥10% was able to discriminate among patients with improved 6MWD, with a sensitivity of 83% and a specificity of 74%. The area under the receiver operating characteristic curve for ΔLzapp% was 0.83. A cutoff value of ≥9% of ΔLzapp% had a positive predictive value in discriminating a reduction in ≥2 points of CAT score after PR, with a sensitivity and a specificity of 80% and 62%, respectively.

Conclusion

Diaphragm US assessment represents a useful prognostic marker of PR outcomes in COPD patients.

Validity and reliability of assessing diaphragmatic mobility by area on X-rays of healthy subjects

OBJECTIVE

To investigate the concurrent validity, as well as the intra- and inter-rater reliability, of assessing diaphragmatic mobility by area (DMarea) on chest X-rays of healthy adults.

METHODS

We evaluated anthropometric parameters, pulmonary function, and diaphragmatic mobility in 43 participants. Two observers (rater A and rater B) determined diaphragmatic mobility at two time points. We used Pearson's correlation coefficient to evaluate the correlation between DMarea and the assessment of diaphragmatic mobility by distance (DMdist). To evaluate intra- and inter-rater reliability, we used the intraclass correlation coefficient (ICC [2,1]), 95% CI, and Bland-Altman analysis.

RESULTS

A significant correlation was found between the DMarea and DMdist methods (r = 0.743; p < 0.0001). For DMarea, the intra-rater reliability was found to be quite high for the right hemidiaphragm (RHD)-ICC (2,1) = 0.92 (95% CI: 0.86-0.95) for rater A and ICC (2,1) = 0.90 (95% CI: 0.84-0.94) for rater B-and the left hemidiaphragm (LHD)-ICC (2,1) = 0.96 (95% CI: 0.93-0.97) for rater A and ICC (2,1) = 0.91 (95% CI: 0.81-0.95) for rater B-(p < 0.0001 for all). Also for DMarea, the inter-rater reliability was found to be quite high for the first and second evaluations of the RHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.95 (95% CI: 0.86-0.97), respectively-and the LHD-ICC (2,1) = 0.99 (95% CI: 0.98-0.99) and ICC (2,1) = 0.94 (95% CI: 0.87-0.97)-(p < 0.0001 for both). The Bland-Altman analysis showed good agreement between the mobility of the RHD and that of the LHD.

CONCLUSIONS

The DMarea method proved to be a valid, reliable measure of diaphragmatic mobility.

Mobilidade diafragmática direita e esquerda em indivíduos saudáveis e na doença pulmonar obstrutiva crônica

RESUMO Avaliar o músculo diafragma é importante para verificar suas possíveis alterações ou disfunções. Existem várias formas de avaliar a mobilidade diafragmática, mas poucos estudos que comparam a mobilidade do hemidiafragma direito com o esquerdo. O objetivo deste estudo é avaliar se existem diferenças entre a mobilidade diafragmática das hemicúpulas direita e esquerda em indivíduos saudáveis e em indivíduos com Doença Pulmonar Obstrutiva Crônica (DOCP), bem como comparar a mobilidade diafragmática entre homens e mulheres, e entre pacientes saudáveis e com DPOC. Foram avaliados 40 indivíduos saudáveis e 40 indivíduos com diagnóstico clínico de DPOC. Utilizaram-se os parâmetros antropométricos, cardiopulmonares e avaliação da mobilidade diafragmática pelo método radiográfico. Os dados foram analisados estatisticamente e tratados com análise descritiva (média e desvio-padrão) e análise inferencial. Para comparar a mobilidade das hemicúpulas diafragmáticas direita e esquerda, utilizou-se o teste t pareado. O nível de significância adotado para o tratamento estatístico foi de 5% (p<0,05). Não houve diferença da mobilidade diafragmática tanto do lado direito quanto do lado esquerdo nos indivíduos saudáveis (p=0,45) e nos indivíduos com DPOC (p=0,77), assim como não houve diferenças quando os grupos foram separados por sexo. Foi encontrada uma diferença importante comparando tanto a mobilidade diafragmática do lado direito quanto do lado esquerdo entre indivíduos saudáveis e DPOC (p<0,001). Concluiu-se que a mobilidade diafragmática das hemicúpulas direita e esquerda em indivíduos saudáveis e em indivíduos com DPOC é a mesma. Não há diferença da mobilidade entre homens e mulheres. A mobilidade diafragmática é reduzida em paciente com DPOC.

Exercise Prevents Diaphragm Wasting Induced by Cigarette Smoke through Modulation of Antioxidant Genes and Metalloproteinases

Background

The present study aimed to analyze the effects of physical training on an antioxidant canonical pathway and metalloproteinases activity in diaphragm muscle in a model of cigarette smoke-induced chronic obstructive pulmonary disease (COPD).

Methods

Male mice were randomized into control, smoke, exercise, and exercise + smoke groups, which were maintained in trial period of 24 weeks. Gene expression of kelch-like ECH-associated protein 1; nuclear factor erythroid-2 like 2; and heme-oxygenase1 by polymerase chain reaction was performed. Metalloproteinases 2 and 9 activities were analyzed by zymography. Exercise capacity was evaluated by treadmill exercise test before and after the protocol.

Results

Aerobic training inhibited diaphragm muscle wasting induced by cigarette smoke exposure. This inhibition was associated with improved aerobic capacity in those animals that were submitted to 24 weeks of aerobic training, when compared to the control and smoke groups, which were not submitted to training. The aerobic training also downregulated the increase of matrix metalloproteinases (MMP-2 and MMP-9) and upregulated antioxidant genes, such as nuclear factor erythroid-2 like 2 (NRF2) and heme-oxygenase1 (HMOX1), in exercise + smoke group compared to smoke group.

Conclusions

Treadmill aerobic training protects diaphragm muscle wasting induced by cigarette smoke exposure involving upregulation of antioxidant genes and downregulation of matrix metalloproteinases.

Use of thoracic ultrasound by physiotherapists: a scoping review of the literature

BACKGROUND

Use of diagnostic thoracic ultrasound (TUS) in medical professions to examine the pleura, lung parenchyma and diaphragm is gaining in popularity, however the ways in which physiotherapists are using TUS is unclear.

OBJECTIVE

The aim of this scoping review is to gain an understanding of the emerging evidence base surrounding physiotherapy use of TUS to inform research and clinical practice.

DATA SOURCES

A systematic search was conducted of the following databases: Cochrane, EPPI centre, PROSPERO, Medline, CINAHL, AMED, EMBASE, HMIC, and BNI.

STUDY SELECTION

Inclusion criteria: primary research reporting the use of diagnostic TUS; a physiotherapist as part of the study design or as the chief investigator; published in English.

SYNTHESIS METHODS

Data regarding demographics, design, type of conditions and anatomical structures investigated and profession leading the TUS of included papers were compiled in a tabular format.

RESULTS

Of the 26 included papers, nine studied healthy participants, four studied COPD and four studied critical care patients. Most papers (n=23) involved scanning the diaphragm. In eight studies the physiotherapist operated the TUS.

LIMITATIONS

The paper selection process was performed by one author; with no cross-checking by another individual.

CONCLUSION

Use of TUS by physiotherapists is an emerging area in both diaphragm and lung diagnostics. A wide range of patient populations may benefit from physiotherapists using TUS. Papers in this review are heterogeneous making any generalisability difficult but does show its potential for varied uses. TUS is an innovative skill in the hands of physiotherapists, but more research is needed.

Relação entre a mobilidade diafragmática e as curvaturas da coluna vertebral em pacientes com doença pulmonar obstrutiva crônica

RESUMO Na doença pulmonar obstrutiva crônica (DPOC), os pacientes podem apresentar redução da mobilidade diafragmática e uma série de compensações na coluna torácica, nas cinturas escapular e pélvica. No entanto, não está clara a relação da mobilidade diafragmática com alterações posturais na coluna vertebral e na pelve desses indivíduos. Objetivou-se verificar se existe relação entre a mobilidade diafragmática com as curvaturas da coluna vertebral de pacientes com DPOC e em indivíduos aparentemente saudáveis. Foram avaliados 22 pacientes com DPOC e 22 indivíduos aparentemente saudáveis. As avaliações foram: antropometria, espirometria, mobilidade diafragmática e avaliação postural. Foram analisadas quatro alterações posturais: lordose cervical, cifose torácica, lordose lombar, posição pélvica. Não houve diferença estatisticamente significativa entre os grupos, em relação às variáveis idade, massa corporal, estatura e IMC, confirmando que os grupos foram pareados. Não houve diferença estatisticamente significante em nenhuma das variáveis referentes às curvaturas da coluna vertebral e à posição da pelve entre os grupos estudados. No grupo DPOC houve correlação da mobilidade diafragmática com a cifose torácica (r=-0,543; p=0,009). Já em relação ao grupo de indivíduos aparentemente saudáveis, não houve correlação da mobilidade quanto os indivíduos aparentemente saudáveis apresentaram os mesmos ângulos de curvatura da coluna vertebral e a mesma posição da pelve. Contudo, os pacientes com DPOC apresentaram relação entre a mobilidade diafragmática e o ângulo da curvatura torácica.

Comparison between the phase angle and phase shift parameters to assess thoracoabdominal asynchrony in COPD patients

Determining the presence of thoracoabdominal asynchrony in chronic obstructive pulmonary disease (COPD) patients is clinically relevant, but there is no consensus on the optimal parameters for performing this analysis. We assessed 22 COPD patients (FEV1 40 ± 10% predicted) and 13 healthy controls during rest and exercise with optoelectronic plethysmography (70% maximum workload) on a cycle ergometer. Thoracoabdominal asynchrony was calculated by using phase angle and phase shift parameters following a three-compartment model involving the upper and lower rib cages and abdomen. Patients were classified as having thoracoabdominal asynchrony (TAA+) or not (TAA−) based on control values (mean ± 2 SDs). The chest wall volume and compartmental contribution were also measured. Thoracoabdominal asynchrony was observed in the lower rib cage. The phase angle detected more TAA+ patients at rest (15 vs. 7 patients) and during exercise (14 vs. 8 patients) compared with the phase shift. TAA+ patients also presented a lower chest wall volume, lower rib cage contribution, and higher abdominal contribution to chest wall volume compared with the control and TAA− patients. Thoracoabdominal asynchrony was more detectable during rest and exercise using the phase angle parameter, and it was observed in the lower rib cage compartment, reducing the chest wall volume during exercise in patients with COPD.

NEW & NOTEWORTHY This study contributes to advance the knowledge over the previous lack of consensus on the assessment of thoracoabdominal asynchrony. We rigorously evaluated the related features that interfere in the measurement of the asynchrony (measurement tool, chest wall model and calculation parameter). Our results suggest that phase angle detects more suitably thoracoabdominal asynchrony that occurs on the lower ribcage and leads to a reduction in the chest wall volume during exercise in COPD patients.

Diaphragmatic mobility: relationship with lung function, respiratory muscle strength, dyspnea, and physical activity in daily life in patients with COPD

OBJECTIVE:

To evaluate diaphragmatic mobility in relation to lung function, respiratory muscle strength, dyspnea, and physical activity in daily life (PADL) in patients with COPD.

METHODS:

We included 25 patients with COPD, classified according to the Global Initiative for Chronic Obstructive Lung Disease criteria, and 25 healthy individuals. For all of the participants, the following were evaluated: anthropometric variables, spirometric parameters, respiratory muscle strength, diaphragmatic mobility (by X-ray), PADL, and the perception of dyspnea.

RESULTS:

In the COPD group, diaphragmatic mobility was found to correlate with lung function variables, inspiratory muscle strength, and the perception of dyspnea, whereas it did not correlate with expiratory muscle strength or PADL.

CONCLUSIONS:

In patients with COPD, diaphragmatic mobility seems to be associated with airway obstruction and lung hyperinflation, as well as with ventilatory capacity and the perception of dyspnea, although not with PADL.

OBJETIVO:

Avaliar a relação da mobilidade diafragmática com a função pulmonar, força muscular respiratória, dispneia e atividade física de vida diária (AFVD) em pacientes com DPOC.

MÉTODOS:

Foram avaliados 25 pacientes com diagnóstico de DPOC, classificados de acordo com critérios da Global Initiative for Chronic Obstructive Lung Disease, e 25 indivíduos saudáveis. Todos foram submetidos às seguintes avaliações: mensuração antropométrica, espirometria, força muscular respiratória, mobilidade diafragmática (por radiografia), AFVD e percepção de dispneia.

RESULTADOS:

No grupo DPOC, houve correlações da mobilidade diafragmática com variáveis de função pulmonar, força muscular inspiratória e percepção de dispneia. Não houve correlações da mobilidade diafragmática com força muscular expiratória e AFVD.

CONCLUSÕES:

A mobilidade diafragmática parece estar associada tanto com a obstrução das vias aéreas quanto com a hiperinsuflação pulmonar em pacientes com DPOC, assim como com a capacidade ventilatória e percepção de dispneia, mas não com AFVD.

Instantaneous changes in respiratory function induced by passive pelvic suspension in the supine position in relation to increased diaphragm excursion

[Purpose] This study aimed to introduce an approach of pelvic suspension (PS) using sling cords and to obtain evidence for changes in respiratory function of healthy subjects. [Subjects and Methods] Subjects were 25 healthy men. In the supine position, with hip and knee joints flexed at 90°, the subjects’ pelvises were suspended with sling belts. Diaphragm excursion, respiratory function, and respiratory comfort in these postures were measured using ultrasonography, respirometry, and visual analog scale (VAS), respectively. [Results] When the pelvis was passively suspended with sling cords, the diaphragm moved 5 mm cranially and diaphragm excursion showed an instantaneous increase compared with the control. The tidal volume (V_T) showed an increase and the respiration rate (RR) showed a decrease. The extent of diaphragm excursion was correlated with changes in V_T under the control and PS conditions. Independent measurements of pulmonary function revealed that PS reduced the expiratory reserve volume, being correlated positively and negatively to increases in vital and inspiratory capacities, respectively. Furthermore, VAS values for respiratory ease were greater with PS than with the control. [Conclusion] These results suggest that PS effectively changed diaphragm excursion and respiratory function, leading to ease of breathing (i.e., deep and slow respiration).

Brazilian studies on pulmonary function in COPD patients: what are the gaps?

BACKGROUND

COPD is a major cause of death and morbidity worldwide, and is characterized by persistent airflow obstruction. The evaluation of obstruction is critically dependent on sensitive methods for lung-function testing. A wide body of knowledge has been accumulated in recent years showing that these methods have been significantly refined and seems promising for detection of early disease.

OBJECTIVES

This review focuses on research on pulmonary function analysis in COPD performed in Brazil during this century.

MATERIALS AND METHODS

The literature was searched using a systematic search strategy limited to English language studies that were carried out in Brazil from the year 2000 onward, with study objectives that included a focus on lung function.

RESULTS

After we applied our inclusion and exclusion criteria, 94 articles addressed our stated objectives. Among the new methods reviewed are the forced-oscillation technique and the nitrogen-washout test, which may provide information on small-airway abnormalities. Studies investigating the respiratory muscles and thoracoabdominal motion are also discussed, as well as studies on automatic clinical decision-support systems and complexity measurements. We also examined important gaps in the present knowledge and suggested future directions for the cited research fields.

CONCLUSION

There is clear evidence that improvements in lung-function methods allowed us to obtain new pathophysiological information, contributing to improvement in our understanding of COPD. In addition, they may also assist in the diagnosis and prevention of COPD. Further investigations using prospective and longitudinal design may be of interest to elucidate the use of these new methods in the diagnosis and prevention of COPD.

B-mode ultrasound assessment of diaphragm structure and function in patients with COPD

BACKGROUND

Electromyographic evaluation of diaphragmatic neuromuscular disease in patients with COPD is technically difficult and potentially high risk. Defining standard values for diaphragm thickness and thickening ratio using B-mode ultrasound may provide a simpler, safer means of evaluating these patients.

METHODS

Fifty patients with a diagnosis of COPD and FEV₁ < 70% underwent B-mode ultrasound. Three images were captured both at end expiration (Tmin) and at maximal inspiration (Tmax). The thickening ratio was calculated as (Tmax/Tmin), and each set of values was averaged. Findings were compared with a database of 150 healthy control subjects.

RESULTS

There was no significant difference in diaphragm thickness or thickening ratio between sides within groups (control subjects or patients with COPD) or between groups, with the exception of the subgroup with severe air trapping (residual volume > 200%), in which the only difference was that the thickening ratio was higher on the left (P = .0045).

CONCLUSIONS

In patients with COPD presenting for evaluation of coexisting neuromuscular respiratory weakness, the same values established for healthy control subjects serve as the baseline for comparison. This knowledge expands the role of ultrasound in evaluating neuromuscular disease in patients with COPD.