Respiratory muscle training with normocapnic hyperpnea improves ventilatory pattern and thoracoabdominal coordination, and reduces oxygen desaturation during endurance exercise testing in COPD patients

Differential control of respiratory frequency and tidal volume during exercise

The lack of a testable model explaining how ventilation is regulated in different exercise conditions has been repeatedly acknowledged in the field of exercise physiology. Yet, this issue contrasts with the abundance of insightful findings produced over the last century and calls for the adoption of new integrative perspectives. In this review, we provide a methodological approach supporting the importance of producing a set of evidence by evaluating different studies together-especially those conducted in 'real' exercise conditions-instead of single studies separately. We show how the collective assessment of findings from three domains and three levels of observation support the development of a simple model of ventilatory control which proves to be effective in different exercise protocols, populations and experimental interventions. The main feature of the model is the differential control of respiratory frequency (f_R) and tidal volume (V_T); f_R is primarily modulated by central command (especially during high-intensity exercise) and muscle afferent feedback (especially during moderate exercise) whereas V_T by metabolic inputs. Furthermore, V_T appears to be fine-tuned based on f_R levels to match alveolar ventilation with metabolic requirements in different intensity domains, and even at a breath-by-breath level. This model reconciles the classical neuro-humoral theory with apparently contrasting findings by leveraging on the emerging control properties of the behavioural (i.e. f_R) and metabolic (i.e. V_T) components of minute ventilation. The integrative approach presented is expected to help in the design and interpretation of future studies on the control of f_R and V_T during exercise.

The use of time-of-flight camera to assess respiratory rates and thoracoabdominal depths in patients with chronic respiratory disease

INTRODUCTION

Over the last 5 years, the analysis of respiratory patterns presents a growing usage in clinical and research purposes, but there is still currently a lack of easy-to-use and affordable devices to perform such kind of evaluation.

OBJECTIVES

The aim of this study is to validate a new specifically developed method, based on Kinect sensor, to assess respiratory patterns against spirometry under various conditions.

METHODS

One hundred and one participants took parts in one of the three validations studies. Twenty-five chronic respiratory disease patients (14 with chronic obstructive pulmonary disease (COPD) [65 ± 10 years old, FEV₁  = 37 (15% predicted value), VC = 62 (20% predicted value)], and 11 with lung fibrosis (LF) [64 ± 14 years old, FEV₁  = 55 (19% predicted value), VC = 62 (20% predicted value)]) and 76 healthy controls (HC) were recruited. The correlations between the signal of the Kinect (depth and respiratory rate) and the spirometer (tidal volume and respiratory rate) were computed in part 1. We then included 66 HC to test the ability of the system to detect modifications of respiratory patterns induced by various conditions known to modify respiratory pattern (cognitive load, inspiratory load and combination) in parts 2 and 3.

RESULTS

There is a strong correlation between the depth recorded by the Kinect and the tidal volume recorded by the spirometer: r = 0.973 for COPD patients, r = 0.989 for LF patients and r = 0.984 for HC. The Kinect is able to detect changes in breathing patterns induced by different respiratory disturbance conditions, gender and oral task.

CONCLUSIONS

Measurements performed with the Kinect sensors are highly correlated with the spirometer in HC and patients with COPD and LF. Kinect is also able to assess respiratory patterns under various loads and disturbances. This method is affordable, easy to use, fully automated and could be used in the current clinical context. Respiratory patterns are important to assess in daily clinics. However, there is currently no affordable and easy-to-use tool to evaluate these parameters in clinics. We validated a new system to assess respiratory patterns using the Kinect sensor in patients with chronic respiratory diseases.

Mapping the global research landscape and hotspot of exercise therapy and chronic obstructive pulmonary disease: A bibliometric study based on the web of science database from 2011 to 2020

Background: The application of exercise therapy (ET) in chronic obstructive pulmonary disease (COPD) is generating increasing clinical efficacy and social-economic value. In this study, research trends, evolutionary processes and hot topics in this field are detailed, as well as predictions of future development directions.

Methods: Search for literature in the field of COPD and ET and analyze data to generate knowledge graphs using VOSiewer and CiteSpace software. The time frame for the search was from 2011 to January 2021. Then we extracted full-text key information (such as title, journal category, publication date, author, country and institution, abstract, and keyword) and obtained the co-citation analysis. Use hierarchal clustering analysis software developed by VOSviewer to map common citations, and use Citespace software to plot trend networks.

Results: The United States topped the list with 27.91% of the number of articles posted, followed by the UK at 25.44%. Imperial College London was the highest number of article publications in institutions, followed by Maastricht University and the University of Toronto. The Royal Brompton Harefield NHS Foundation Trust was one of many research institutions and currently holds the highest average citations per item (ACI) value, followed by Imperial College London and the University of Leuven. Judging from the number of publications related to ET and COPD, it is mainly published in cell biology, respiratory pulmonary diseases, and rehabilitation experiments study medicine. The European Respiration Journal is the most widely published in this field, followed by the International Journal of Chronic Obstructive Pulmonary Disease and Respiratory Medicine.

Conclusion: COPD combined with ET is widely used in clinical practice and is on the rise. A distinctive feature of the field is multidisciplinary integration. Rehabilitation research for COPD involves multidisciplinary collaboration, tissue engineering, and molecular biology mechanism studies to help patients remodel healthy breathing. Multidisciplinary rehabilitation measures provide a solid foundation for advancing clinical efficacy in the field of COPD.

Inspiratory Muscle Training in Patients with Chronic Obstructive Pulmonary Disease (COPD) as Part of a Respiratory Rehabilitation Program Implementation of Mechanical Devices: A Systematic Review

Chronic Obstructive Pulmonary Disease (COPD) is a complex and heterogeneous disease, with pulmonary and extrapulmonary manifestations, which leads to the need to personalize the assessment and treatment of these patients. The latest updates of national and international guidelines for the management of COPD reveal the importance of respiratory rehabilitation (RR) and its role in improving symptoms, quality of life, and psychosocial sphere of patients. Within RR, the inspiratory muscle training (IMT) has received special interest, showing benefits in maximum inspiratory pressure, perception of well-being, and health status in patients with chronic heart disease, respiratory diseases, and dyspnea during exercise. The aim of this review is to assess the efficacy of IMT in COPD patients through the use of inspiratory muscle training devices, compared with respiratory rehabilitation programs without inspiratory muscle training. In the last years, many mechanical devices focused on inspiratory muscle training have been developed, some of them, such as the AirOFit PRO™, PowerBreath®, or FeelBreathe®, have shown clear benefits. The active search for candidate patients to undergo the RR program with inspiratory muscle training using this type of device in COPD patients represents an advance in the treatment of this disease, with direct benefits on the quality of life of the patients. In this article, we review the available evidence on IMT in these patients and describe the different devices used for it.

Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running

Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called “Breath Tools” proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.

Application of pulmonary rehabilitation in patients with pulmonary embolism (Review)

As a common clinical emergency, pulmonary embolism (PE) is the third most fatal cardiovascular disease worldwide. Although current sophisticated medical technology has considerably improved the prognosis of patients with PE, they remain at risk of developing long-term complications such as post-PE syndrome. Pulmonary rehabilitation is of great value for patients with chronic lung diseases since it can improve their quality of life while also relieving clinical symptoms. Rehabilitation therapy has been demonstrated to improve recovery and prognosis of patients with PE. Due to short implementation time and the small number of studies, its effectiveness and safety in PE warrant further investigation. The present review focused on elucidating PE pathogenesis, post-PE syndrome and the clinical application of pulmonary rehabilitation in patients with PE.

Breathing exercises in people with COPD: A realist review

AIMS

To determine the theoretical framework that explains the mechanisms of the success of breathing exercise interventions in people with chronic obstructive pulmonary disease.

DESIGN

A realist review.

DATA SOURCES

Seven bibliographic databases and the grey literature were searched from 2015-January 2020 to identify the studies of breathing exercises.

REVIEW METHODS

The evaluation criteria of realist review and the mixed method appraisal tool were both used to evaluate the included studies. We extracted and integrated the context-mechanism-outcome strings of each study to form the theoretical framework.

RESULTS

Six theoretical mechanisms that affected the success of the intervention were articulated: Wide acceptance of training methods, Integration of the intervention with life, Self-management of the participants, Confidence in controlling symptoms, Participation and support of practitioners, Motivation for intervention. Conversely, the other two mechanisms including the gap between implementation and training and the duration of the intervention, had negative impacts on the implementation of breathing exercises.

CONCLUSION

This review updates and expands the previous literature review on the impact of breathing exercises in people and provides researchers and clinical practitioners with theoretical mechanisms to ensure that the interventions achieve expected effects.

IMPACT

When formulating or selecting breathing exercise interventions, our theoretical framework will guide researchers and clinical practitioners to ensure that the intervention will have practical effects.

Effects of inspiratory muscle training on resting breathing pattern in patients with advanced lung disease

AIM

The aim of this study was to evaluate the effects of interval high intensity inspiratory muscle training (IMT) on resting breathing pattern in patients with advanced lung disease.

METHODS

IMT was performed daily and training load set at 50 % of the maximal inspiratory pressure. Participants were evaluated at pre-IMT, post 8 weeks of IMT and follow-up (3 months after the end of IMT). Breathing pattern (volume and time variables as well as percentages of contribution to tidal volume) was evaluated by Optoelectronic Plethysmography at rest. Friedman test was used to verify the differences between the three time-points (p < 0.05).

RESULTS

Nineteen patients (54 ± 16 years old; 5 males) were evaluated at pre-IMT and post-IMT and fourteen were assessed at follow-up. There was no significant difference (p > 0.05) in any comparison for all evaluated breathing pattern variables at the three time-points.

CONCLUSION

Resting breathing pattern was not significantly changed after 8 weeks of IMT in patients with advanced lung disease.

A New Nasal Restriction Device Called FeelBreathe® Improves Breathing Patterns in Chronic Obstructive Pulmonary Disease Patients during Exercise

A device called FeelBreathe (FB)^® was designed, developed, and patented for inspiratory muscle training. The main aim was to determine the acute responses on lung ventilation, gas exchange, and heart rate during exercise in patients with chronic obstructive pulmonary disease (COPD) with and without the use of FB. In this study, a randomized cross-over trial was performed with 18 men diagnosed with COPD (FEV₁ between 30% and 70% of its predicted value). Each participant randomly conducted two trials with 30 min of rest between them with the same protocol on a treadmill for 10 min at a constant rate of 50% of VO_2peak. Each test was performed randomly and in a crossover randomized design in two different conditions: (1) oronasal breathing; and (2) nasal breathing with FB (nasal ventilatory flow restriction device). It was observed that FB had positive effects on dynamic hyperinflation, breathing pattern, and breathing efficiency, with higher expiratory and inspiratory time. Despite these differences, blood oxygen saturation percentage, oxygen uptake, and heart rate showed a similar response for both conditions during exercise. The results suggest that exercise performed with FB improved ventilatory responses compared to the oronasal mode in COPD patients. This new tool could be used during most daily tasks and exercise programs.

Effects of appropriate-intensity treadmill exercise on skeletal muscle and respiratory functions in a rat model of emphysema

The number of patients with chronic obstructive pulmonary disease (COPD), a typical respiratory disorder, is rapidly increasing globally. The purpose of this study was to determine the effects of appropriate-intensity treadmill exercise on skeletal muscle and respiratory functions in a rat model of emphysema. Twenty-one Wistar rats were randomly divided into three groups: the sham (SH) group, pulmonary emphysema (PE) group, and emphysema + exercise (EX) group. Cigarette smoke solution and lipopolysaccharide were intratracheally administered for 4 weeks in the PE and EX groups. The rats in the EX group were made to run on treadmills in the latter 2 weeks of the experiment. Lung tissue was stained with anti-macrophage antibodies; the specific force (contractile force per unit cross-sectional area) of the diaphragm and hind-limb muscles was measured, and blood was analyzed for serum cytokine levels. Many macrophages were observed in the lung tissue of the PE group. In the EX group, the population of macrophages was smaller, and the specific force of the diaphragm and extensor digitorum longus muscles was higher than in the PE group. Moreover, the degree of inflammation in the pulmonary tissue was reduced in the EX group. These results suggest that adaptive exercise may improve not only respiratory and muscle functions but also inflammation of the pulmonary tissue associated with emphysema.

Complementary therapeutic approaches in asthma

Asthma is defined by The Initiative for Asthma (GINA 2018) as a heterogeneous disease, which include chronic airway inflammation and a history of respiratory symptoms. In the last decades asthma had a rise in prevalence, becoming one of the most frequent diagnosed diseases in the world. The main goals of asthma management are to achieve good symptom control, minimize the risks of exacerbations, decrease rescue medication intake, improve the quality of life by decreasing respiratory system inflammation and ameliorating the patient’s lung function. Beside effective medications, asthma continues to impair quality of life for most patients. Due to the difficulty of controlling symptoms and exacerbations, the need of developing complementary options of treatment is increasing in order to achieve an optimum control and a lower risk of acute episodes or fatal events. Pulmonary rehabilitation is suggested for asthma patients when adequate medical therapy poorly control the symptoms and mental, physical or social consequences of illness persist during the daily life. The following non-drug therapy components are included in the rehabilitation program: physical training, comprehensive smoking cessation program, comprehensive patient education, respiratory physiotherapy, psychosocial support and comprehensive nutritional counseling. These complementary therapies have been proven to improve muscle strength, exercise capacity and symptomatology. Also, it has been associated to fewer exacerbations and a lower use of rescue medication, leading to a better quality of life. Key words: asthma, quality of life, symptomatology, rehabilitation, physiotherapy,

Effects of different modalities of inspiratory muscle training as an add-on to conventional treatment of patients with chronic obstructive pulmonary disease (COPD): study protocol for a randomized controlled trial

BACKGROUND

Chronic obstructive pulmonary disease (COPD) leads to peripheral and respiratory muscle dysfunctions. Nowadays, inspiratory muscle training can be geared toward strength or endurance gains. This study aims to investigate the effects of an inspiratory muscle training (IMT) protocol using different therapeutic modalities to be implemented in pulmonary rehabilitation programs. The effects of IMT on exercise capacity were considered as the primary endpoint, and the effects of IMT on inspiratory muscle function, health-related quality of life, and daily physical activity level were considered as the secondary outcomes.

METHODS

This study is a blinded-investigator randomized controlled clinical trial. Sixty subjects will be randomly allocated into three groups: (1) pulmonary rehabilitation (PR) associated with inspiratory muscle training without any load (PRWIMT), (2) PR associated with inspiratory muscle training with a linear load (PRIMTLL), and (3) PR associated with inspiratory muscle training with isocapnic voluntary hyperpnea (PRIMTIVH). The protocol will be performed 5 days a week (3 days with supervision) for 10 weeks. The study will assess anthropometric data, lung function, respiratory muscle strength, and functional capacity by the Incremental Shuttle Walking Test and the Six-Minute Walk Test, lung volumes during the submaximal endurance test, peripheral muscle strength of the upper and lower limbs, dyspnea, and quality of life related to health, before and after the training protocol. Normality will be tested using the Kolmogorov-Smirnov test, and variables will be compared by two-way analysis of variance. The significance level was set at p < 0.05. Ethics approval was obtained from the Institutional Ethics Committee in Research (1.663.411). The study results will be disseminated through presentation at specific scientific conferences and publication in peer-reviewed journals.

DISCUSSION

The different IMT protocols used in our study will be able to guide respiratory therapists to understand and to include in conventional PR programs the most effective respiratory muscle training type in subjects with COPD.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry, RBR-94v6kd . Registered on 11 March 2017.

The Effect of Breathing Retraining Using Metronome-Based Acoustic Feedback on Exercise Endurance in COPD: A Randomized Trial

BACKGROUND

During exercise-training patients with chronic obstructive pulmonary disease (COPD) can entrain their breathing pattern to visual-feedback cues as to achieve a slower respiratory rate and prolong exhalation. The result is an improvement in exercise tolerance and a reduction in dynamic hyperinflation. Acoustic stimuli, including metronome-generated acoustic stimuli, can entrain human movements. Accordingly, we hypothesized that exercise duration and dynamic hyperinflation would be less after exercise-training plus breathing-retraining using a metronome-based acoustic-feedback system than after exercise-training alone.

METHODS

Of 205 patients with COPD [FEV₁ = 44 ± 16% predicted (± SD)] recruited, 119 were randomly assigned to exercise-training plus breathing-retraining using acoustic feedback (n = 58) or exercise-training alone (n = 61). Patients exercised on a treadmill thrice-weekly for 12 weeks. Before and at completion of training, patients underwent constant-load treadmill testing with inspiratory capacity measures every 2 min.

RESULTS

At completion of training, improvements in exercise duration in the breathing-retraining plus exercise-training and exercise-training alone groups were similar (p = 0.35). At isotime, inspiratory capacity increased (less exercise-induced dynamic hyperinflation) by 3% (p = 0.001) in the breathing-retraining plus exercise-training group and remained unchanged in the exercise-alone group. The between-group change in inspiratory capacity, however, was not significant (p = 0.08).

CONCLUSIONS

In patients with COPD, breathing-retraining using a metronome-based acoustic feedback did not result in improved exercise endurance or decreased dynamic hyperinflation when compared to exercise-training alone.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT NCT01009099; URL: http://www.clinicaltrials.gov.

Observation of the curative effect of device-guided rehabilitation on respiratory function in stable patients with chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a serious lung disease for individuals in middle age and especially in old people. The study was aimed to observe the curative effect of device-guided rehabilitation on respiratory functions in stable COPD patients.

METHODS

Sixty-seven stable COPD patients were enrolled and assigned to the experiment group (n = 36) and the control group (n = 31). The conventional pulmonary rehabilitation treatments, including pursed lips breathing (PLB) and abdominal breathing training, were applied in the control group. Respiratory muscle training of the experiment group was performed using the respiratory endurance training device combined with traditional techniques. Both groups were assessed by 6-minute walk test (6MWT), COPD assessment test (CAT), body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index. Besides, the pulmonary function (FVC%, FEVl%) were measured at 6 months before and after treatment.

RESULTS

After treatment, the 6MWT, CAT, BODE index were significantly increased compared with pre-treatment in both groups (P < .01), but not FVC% and FEVl%. Compared with the control group, the combination therapy in the experiment group could significantly improve the 6MWT (P = .0094), CAT (P = .0071) and BODE index (P = .0064) as well as the changes of 6MWT (P < .01), CAT (P < .01), and BODE index (P < .01) before and after treatment.

CONCLUSIONS

The traditional respiratory training combined with device-guided pulmonary rehabilitation can improve the respiratory muscle function and athletic ability in stable COPD patients.

Home-Based, Moderate-Intensity Exercise Training Using a Metronome Improves the Breathing Pattern and Oxygen Saturation During Exercise in Patients With COPD

PURPOSE

One of the well-known but less-investigated effects of pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD) is the change in breathing pattern toward a more efficient one (higher tidal volume [VT], lower breathing frequency). Evidence suggests this change can be obtained only with supervised, high-intensity exercise training (ExTr). However, some patients either do not have such programs available or are unable to exercise at higher intensity. We evaluated the effects of a 12-wk, moderate-intensity, home-monitored ExTr program using a metronome on the breathing pattern, oxygen saturation (SpO2), and dyspnea during exercise in patients with COPD.

METHODS

Twenty-one patients with COPD (7 female, aged 64-85 yr) performed spirometry, incremental, and endurance walking tests (at 60% of maximal walking speed) on a treadmill before and after training. During the endurance test, patients were equipped with an instrument that continuously monitored ventilation ((Equation is included in full-text article.)E), breathing pattern, and SpO2. Patients trained at home for 12 wk, 30 min/d for at least 4 d/wk at moderate intensity. A metronome paced the walking speed.

RESULTS

Sixteen patients completed the program. After training, a significant change was observed in breathing pattern (lower (Equation is included in full-text article.)E and (Equation is included in full-text article.)E/VT ratio; P < .001), a higher SpO2 (P < .001), and a lower dyspnea perception at the same work intensity (P < .01). The (Equation is included in full-text article.)E/VT ratio and SpO2 during exercise were significantly related (r = 0.56, P = .001).

CONCLUSION

A change in breathing pattern towards more efficient ventilation can be obtained with a moderate, home-monitored ExTr program with a pace that is controlled by a metronome. Decreased (Equation is included in full-text article.)E/VT was associated with an improved SpO2 during exercise.

Respiratory muscle impairment in dialysis patients: can minimal dose of exercise limit the damage? A Preliminary study in a sample of patients enrolled in the EXCITE trial

AIM

Skeletal muscle atrophy and dysfunction with associated weakness may involve the respiratory muscles of dialysis patients. We evaluated the effect of moderate-intensity exercise on lung function and respiratory muscle strength.

METHODS

Fifty-nine patients (25 F, aged 65 ± 13 years) from two centers participating in the multicenter randomized clinical trial EXerCise Introduction To Enhance Performance in Dialysis (EXCITE) were studied. Subjects were randomized into a prescribed exercise group (E), wherein subjects performed two 10-min walking sessions every second day at an intensity below the self-selected speed, or a control group (C) with usual care. Physical performance was assessed by the 6-min walk test (6MWT). Patient lung function and respiratory muscle strength were evaluated by spirometry and maximal inspiratory pressure (MIP), respectively.

RESULTS

Forty-two patients (14 F) completed the study. At baseline, the groups did not differ in any parameters. In total, 7 patients (4 in E; 3 in C) showed an obstructive pattern. The pulmonary function parameters were significantly correlated with 6MWT but not with any biochemical measurements. Group E safely performed the exercise program. At follow-up, the spirometry parameters did not change in either group. A deterioration of MIP (-7 %; p = 0.008) was observed in group C, but not in group E (+3.3 %, p = ns). In E, an increase of 6MWT was also found (+12 vs. 0 % in C; p = 0.038).

CONCLUSION

In dialysis patients, a minimal dose of structured exercise improved physical capacity and maintained a stable respiratory muscle function, in contrast to the control group where it worsened.