Dyspnoea in COPD: can inspiratory muscle training help?

"Inspiratory muscle weakness in acutely hospitalized patients 75 years and over": a secondary analysis of a randomized controlled trial on the effectiveness of multicomponent exercise and inspiratory muscle training

PURPOSE

The impact of hospitalization for acute illness on inspiratory muscle strength in oldest-old patients is largely unknown, as are the potential benefits of exercise and inspiratory muscle training (IMT) during in-hospital stay.

DESIGN AND METHODS

This was a sub-study of a randomized clinical trial that evaluated the efficiency of a multicomponent exercise program in preventing hospitalization-associated disability. Patients were randomized into control (CG) and intervention (IG) groups. The intervention included two daily sessions of supervised walking, squat, balance, and IMT. Baseline and discharge maximal inspiratory pressure (MIP) and inspiratory muscle weakness (IMW) were determined. The effect of the intervention on inspiratory muscle strength was assessed by analyzing (1) the differences between groups in baseline and discharge MIP and IMW, (2) the association, patient by patient, between baseline and discharge MIP, and the improvement index (MIP discharge/baseline) in patients with or without IMW.

RESULTS

In total, 174 patients were assessed (mean age of 87), 57 in CG and 117 in IG. Baseline MIP was lower than predicted in both sexes (women 29.7 vs 44.3; men 36.7 vs 62.5 cmH2O, P < 0.001, baseline vs predicted, respectively). More than 65% of patients showed IMW at admission. In women in IG, the mean MIP was higher at discharge than at admission (P = 0.003) and was the only variable that reached expected reference levels at discharge (Measured MIP 39.2 vs predicted MIP 45 cmH2O, P = 0.883). Patients with IMW on admission showed a statistically significant improvement in MIP after the intervention.

CONCLUSION

IMW is very prevalent in oldest-old hospitalized with acute illness. Patients might benefit from a multicomponent exercise program including IMT, even during short-stay hospitalization.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NTC03604640. May 3, 2018.

Inspiratory muscle training for improving inspiratory muscle strength and functional capacity in older adults: a systematic review and meta-analysis

BACKGROUND

The ageing process can result in the decrease of respiratory muscle strength and consequently increased work of breathing and associated breathlessness during activities of daily living in older adults.

OBJECTIVE

This systematic review and meta-analysis aims to determine the effects of inspiratory muscle training (IMT) in healthy older adults.

METHODS

A systematic literature search was conducted across four databases (Medline/Pubmed, Web of Science, Cochrane Library CINAHL) using a search strategy consisting of both MeSH and text words including older adults, IMT and functional capacity. The eligibility criteria for selecting studies involved controlled trials investigating IMT via resistive or threshold loading in older adults (>60 years) without a long-term condition.

RESULTS

Seven studies provided mean change scores for inspiratory muscle pressure and three studies for functional capacity. A significant improvement was found for maximal inspiratory pressure (PImax) following training (n = 7, 3.03 [2.44, 3.61], P = <0.00001) but not for functional capacity (n = 3, 2.42 [-1.28, 6.12], P = 0.20). There was no significant correlation between baseline PImax and post-intervention change in PImax values (n = 7, r = 0.342, P = 0.453).

CONCLUSIONS

IMT can be beneficial in terms of improving inspiratory muscle strength in older adults regardless of their initial degree of inspiratory muscle weakness. Further research is required to investigate the effect of IMT on functional capacity and quality of life in older adults.

Effects of an Integrated Exercise Program Including "Functional" Inspiratory Muscle Training in Geriatric Individuals with and without Chronic Obstructive Pulmonary Disease

BACKGROUND

Inspiratory muscle training (IMT) is a commonly used exercise method for both patients with chronic obstructive pulmonary disease (COPD) and the older adult population. In addition to their primary function, respiratory muscles play an active role in core stabilization. However, no IMT program includes both of these functions (i.e., core stabilization and postural control functions as well as respiration). This study investigated the effects of a newly integrated exercise program, termed "functional IMT," in geriatric individuals with and without COPD.

METHODS

This prospective and experimental study included 45 geriatric individuals with COPD (n=22) and without COPD (n=23). The training program consisted of 4 weeks of conventional IMT followed by 4 weeks of functional IMT. Respiratory muscle strength, symptoms, exercise capacity, balance, postural control, physical activity, and quality of life were evaluated.

RESULTS

After training, respiratory muscle strength, symptoms, exercise capacity, balance, postural control, and quality of life improved in both groups (p&lt;0.05). In addition, physical activity was increased in the COPD group (p&lt;0.05). We observed no statistically significant difference in outcomes between the two groups before and after treatment (p&gt;0.05).

CONCLUSION

The gains were similar in both groups. Functional IMT, which is an integrated approach that includes all respiratory muscle functions, is a safe, effective, and innovative method for use in geriatric individuals with and without COPD.

Effect of inspiratory muscle training in hypercapnic chronic obstructive pulmonary disease patients during acute care: a randomised clinical trial

Weakness of respiratory muscles along with respiratory failure is a common finding in chronic obstructive pulmonary disease (COPD) patients which leads to dyspnoea and hence decreased functional capacity. Despite a sound theoretical rationale regarding the potential role of inspiratory muscles, the role of inspiratory muscle training (IMT) along with the conventional non-invasive ventilation (NIV) on important clinical outcomes has not been investigated in these patients during acute care. 34 hypercapnic stable COPD patients were randomly allocated to one of the interventions that lasted for 10 days: IMT with NIV (n=17), and NIV alone (n=17). IMT was administered 2 times in a day (15 min each time) by threshold loading at an intensity starting from 30% and progressed to 60% of their maximal inspiratory effort (PImax). NIV was given at an optimal pressure titrated for each patient for at least >8 h per day. Outcome measures (respiratory muscle strength, respiratory failure, dyspnoea, and functional capacity) were assessed before and after 10 days of intervention. Clinical characteristics and outcome variables of patients were similar between the groups at baseline. Addition of IMT led to a significantly greater increase in respiratory muscle strength (P=0.01), reduction in dyspnea (modified medical research council dyspnea scale, P=0.001); improved outcomes of respiratory failure (PaCO2, P=0.03; PaO2, P=0.002) and improved functional capacity (6 min walk distance, P=0.001) as compared to NIV alone. A short duration IMT program in addition to NIV was found to be effective in improving respiratory muscle strength, perception of dyspnoea, functional capacity and respiratory failure in hypercapnic COPD patients.

Exercise & Sports Science Australia (ESSA) position statement on exercise and chronic obstructive pulmonary disease

OBJECTIVES

Chronic obstructive pulmonary disease (COPD) results in airflow obstruction and a marked reduction in exercise capacity and health-related quality of life (HRQoL). Affecting over 1 in four Australians aged over 75 years, COPD remains one of the major causes of disability and death in the world. To date there have been over 80 randomised controlled trials examining the role of exercise training in a range of settings for individuals with COPD. This review will synthesise existing literature and provide health practitioners with broad evidence-based guidelines for exercise-training in this growing population.

DESIGN

Position stand.

METHODS

Synthesis of randomised controlled trials of exercise training and of existing guidelines for exercise in COPD. Systematic reviews of alternative modes of exercise training will also be reviewed.

RESULTS

There is convincing evidence that in adults with COPD, exercise-training improves exercise capacity, decreases symptoms such as dyspnoea and fatigue, and improves HRQoL. There is emerging evidence in this population that alternative modes of exercise training such as high intensity interval training (HIIT), aquatic based therapy, tai chi and neuromuscular electrical stimulation improve exercise outcomes when compared to no exercise.

CONCLUSIONS

For individuals with COPD, an exercise program of aerobic and strength exercises delivered over at least an 8-week period, that engages lower and upper body skeletal muscles, will deliver significant health improvements. Programs should be individualised, take into consideration relevant co-morbid conditions and be delivered appropriately qualified health practitioners experienced in clinical exercise prescription.

Predictive equations of maximum respiratory mouth pressures: A systematic review

BACKGROUND

Maximum inspiratory (Pimax) and expiratory (Pemax) mouth pressures are commonly used to detect respiratory muscle weakness resorting to predictive equations established for healthy people. There are several predictive equations, but they are widespread in the literature. This study aimed to review the existent predictive equations of maximum inspiratory (Pimax) and expiratory (Pemax) mouth pressures for adults. Additionally, we aimed to identify which ones were generated based on international standards.

METHODS

A systematic review of predictive equations of Pimax and Pemax for healthy adults was conducted. A comprehensive search was performed of Cochrane Library, EBSCO, PubMed, Scopus and Web of Science to identify studies that presented at least one equation for Pimax or Pemax developed for healthy adults. The quality of studies was assessed by two reviewers with the Quality Assessment of Diagnostic Accuracy Studies (Quadas-2).

RESULTS

Risk of bias was high in 8 of the 20 studies included. Forty-two Pimax and 34 Pemax equations were found, mostly using the variables age (n=39), weight (n=20) and height (n=8). These equations explained 3 to 96% of the Pimax/Pemax variance. They were developed with individuals from 11 countries (Portugal not included). Twelve Pimax and eight Pemax equations complied with international standards.

CONCLUSIONS

This review gathered the predictive equations that have been developed for both Pimax and Pemax, however most were generated from unstandardized procedures. Future studies should explore the suitability of these equations for populations for which specific ones are not available, such as the Portuguese population, and develop new equations if necessary.

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.

Effect of Respiratory Muscle Training on Pitch Range and Sound Duration in Brass Instrument Players and Singers

OBJECTIVE

Effective use of respiratory organs is important for musicians. Therefore, the impact of Respiratory Muscle Training (RMT) on phonation is open to research. The aim of this study was to investigate the measurable effects of RMT on blowing in brass instrumental and on voice performance in singers.

METHODS

Thirty musicians were recruited and separated into a four groups. The brass instrumental and singers groups were further subdivided into control and RMT groups for a 4 week RMT intervention giving a total four groups: singers experimental (SE; n:10), singers control (SC; n:10), brass instrument players experimental (BIPE; n:5), and BIPC (n:5). The groups selected from the musicians of Samsun State Opera and Ballet Directorate and Samsun Metropolitan Municipality Band Team participated in the study.

RESULTS

After 4 weeks of RMT application in the study groups, significant increase in all parameters except Forced vital capacity/Forced expiratory volume in 1 second was observed in the values of pulmonary function tests and respiratory muscle strength in subjects with SE and BIPE (P < 0.05). The most significant results of this study are that in addition to changes in the duration of phonation (SE 36%), high-pitch (SE 79%, BIPE 27%) and low-pitch sounds (BIPE 61% and SE 42%), the SE (15%) and BIPE (3%) groups reached higher pitches in the high-pitch notes.

CONCLUSIONS

It was determined that performance of the highest and lowest pitch sounds within a vocal register in a single breath and phonation times can be improved by RMT.

Respiratory muscle training in children and adults with neuromuscular disease

BACKGROUND

Neuromuscular diseases (NMDs) are a heterogeneous group of diseases affecting the anterior horn cell of spinal cord, neuromuscular junction, peripheral nerves and muscles. NMDs cause physical disability usually due to progressive loss of strength in limb muscles, and some NMDs also cause respiratory muscle weakness. Respiratory muscle training (RMT) might be expected to improve respiratory muscle weakness; however, the effects of RMT are still uncertain. This systematic review will synthesize the available trial evidence on the effectiveness and safety of RMT in people with NMD, to inform clinical practice.

OBJECTIVES

To assess the effects of respiratory muscle training (RMT) for neuromuscular disease (NMD) in adults and children, in comparison to sham training, no training, standard treatment, breathing exercises, or other intensities or types of RMT.

SEARCH METHODS

On 19 November 2018, we searched the Cochrane Neuromuscular Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase. On 23 December 2018, we searched the US National Institutes for Health Clinical Trials Registry (ClinicalTrials.gov), the World Health Organization International Clinical Trials Registry Platform, and reference lists of the included studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs, including cross-over trials, of RMT in adults and children with a diagnosis of NMD of any degree of severity, who were living in the community, and who did not need mechanical ventilation. We compared trials of RMT (inspiratory muscle training (IMT) or expiratory muscle training (EMT), or both), with sham training, no training, standard treatment, different intensities of RMT, different types of RMT, or breathing exercises.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodological procedures.

MAIN RESULTS

We included 11 studies involving 250 randomized participants with NMDs: three trials (N = 88) in people with amyotrophic lateral sclerosis (ALS; motor neuron disease), six trials (N = 112) in Duchenne muscular dystrophy (DMD), one trial (N = 23) in people with Becker muscular dystrophy (BMD) or limb-girdle muscular dystrophy, and one trial (N = 27) in people with myasthenia gravis.Nine of the trials were at high risk of bias in at least one domain and many reported insufficient information for accurate assessment of the risk of bias. Populations, interventions, control interventions, and outcome measures were often different, which largely ruled out meta-analysis. All included studies assessed lung capacity, our primary outcome, but four did not provide data for analysis (1 in people with ALS and three cross-over studies in DMD). None provided long-term data (over a year) and only one trial, in ALS, provided information on adverse events. Unscheduled hospitalisations for chest infection or acute exacerbation of chronic respiratory failure were not reported and physical function and quality of life were reported in one (ALS) trial.Amyotrophic lateral sclerosis (ALS)Three trials compared RMT versus sham training in ALS. Short-term (8 weeks) effects of RMT on lung capacity in ALS showed no clear difference in the change of the per cent predicted forced vital capacity (FVC%) between EMT and sham EMT groups (mean difference (MD) 0.70, 95% confidence interval (CI) -8.48 to 9.88; N = 46; low-certainty evidence). The mean difference (MD) in FVC% after four months' treatment was 10.86% in favour of IMT (95% CI -4.25 to 25.97; 1 trial, N = 24; low-certainty evidence), which is larger than the minimal clinically important difference (MCID, as estimated in people with idiopathic pulmonary fibrosis). There was no clear difference between IMT and sham IMT groups, measured on the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALFRS; range of possible scores 0 = best to 40 = worst) (MD 0.85, 95% CI -2.16 to 3.85; 1 trial, N = 24; low-certainty evidence) or quality of life, measured on the EuroQol-5D (0 = worst to 100 = best) (MD 0.77, 95% CI -17.09 to 18.62; 1 trial, N = 24; low-certainty evidence) over the medium term (4 months). One trial report stated that the IMT protocol had no adverse effect (very low-certainty evidence).Duchenne muscular dystrophy (DMD)Two DMD trials compared RMT versus sham training in young males with DMD. In one study, the mean post-intervention (6-week) total lung capacity (TLC) favoured RMT (MD 0.45 L, 95% CI -0.24 to 1.14; 1 trial, N = 16; low-certainty evidence). In the other trial there was no clear difference in post-intervention (18 days) FVC between RMT and sham RMT (MD 0.16 L, 95% CI -0.31 to 0.63; 1 trial, N = 20; low-certainty evidence). One RCT and three cross-over trials compared a form of RMT with no training in males with DMD; the cross-over trials did not provide suitable data. Post-intervention (6-month) values showed no clear difference between the RMT and no training groups in per cent predicted vital capacity (VC%) (MD 3.50, 95% CI -14.35 to 21.35; 1 trial, N = 30; low-certainty evidence).Becker or limb-girdle muscular dystrophyOne RCT (N = 21) compared 12 weeks of IMT with breathing exercises in people with Becker or limb-girdle muscular dystrophy. The evidence was of very low certainty and conclusions could not be drawn.Myasthenia gravisIn myasthenia gravis, there may be no clear difference between RMT and breathing exercises on measures of lung capacity, in the short term (TLC MD -0.20 L, 95% CI -1.07 to 0.67; 1 trial, N = 27; low-certainty evidence). Effects of RMT on quality of life are uncertain (1 trial; N = 27).Some trials reported effects of RMT on inspiratory and/or expiratory muscle strength; this evidence was also of low or very low certainty.

AUTHORS' CONCLUSIONS

RMT may improve lung capacity and respiratory muscle strength in some NMDs. In ALS there may not be any clinically meaningful effect of RMT on physical functioning or quality of life and it is uncertain whether it causes adverse effects. Due to clinical heterogeneity between the trials and the small number of participants included in the analysis, together with the risk of bias, these results must be interpreted very cautiously.

Inspiratory Muscle Training to Enhance Weaning from Mechanical Ventilation

This report describes the use of specific inspiratory muscle training to enhance weaning from mechanical ventilation in a patient who had failed conventional weaning strategies. A 79-year-old man remained ventilator-dependent 17 days following laparotomy. A program of daily inspiratory muscle training was initiated. The mean training threshold increased progressively during the program and simultaneously the periods of unassisted breathing achieved gradually increased. By day 27, mechanical ventilation was no longer required. Inspiratory muscle training can be implemented effectively in the difficult to wean patient and should be considered for patients who have failed conventional weaning strategies.

Combination of inspiratory and expiratory muscle training in same respiratory cycle versus different cycles in COPD patients: a randomized trial

Background

Difference between combined inspiratory and expiratory muscle training in same respiratory cycle or different cycles remained unclarified. We explored the difference between both patterns of combined trainings in patients with COPD.

Methods

In this randomized, open-label, controlled trial, stable COPD subjects trained for 48 minutes daily, for 8 weeks, using a monitoring device for quality control. Ninety-two subjects were randomly and equally assigned for sham training, inspiratory muscle training(IMT), combined inspiratory and expiratory muscle training in same cycle(CTSC) or combined inspiratory and expiratory muscle training in different cycles(CTDC). Respiratory muscle strength, as the primary endpoint, was measured before and after training. Registry: ClinicalTrials.gov (identifier: NCT02326181).

Results

Respiratory muscle training improved maximal inspiratory pressure(PImax), while no significant difference was found in PImax among IMT, CTSC and CTDC. Maximal expiratory pressure(PEmax) in CTSC and CTDC was greater than IMT(P = 0.026, and P=0.04, respectively) and sham training (P = 0.001). IMT, CTSC, and CTDC shortened inhalation and prolonged exhalation(P < 0.01). Subjects with respiratory muscle weakness in IMT and CTDC exhibited greater increase in PImax than those without. IMT, CTSC and CTDC showed no difference in symptoms and quality of life scales among themselves(P > 0.05).

Conclusion

Both patterns of CTSC and CTDC improved inspiratory and expiratory muscle strength, while IMT alone only raised PImax. Respiratory muscle training might change the respiratory cycles, and be more beneficial for COPD patients with inspiratory muscle weakness.

Effects of inspiratory muscle training on respiratory muscle electromyography and dyspnea during exercise in healthy men

Inspiratory muscle training (IMT) has consistently been shown to reduce exertional dyspnea in health and disease; however, the physiological mechanisms remain poorly understood. A growing body of literature suggests that dyspnea intensity can be explained largely by an awareness of increased neural respiratory drive, as measured indirectly using diaphragmatic electromyography (EMGdi). Accordingly, we sought to determine whether improvements in dyspnea following IMT can be explained by decreases in inspiratory muscle electromyography (EMG) activity. Twenty-five young, healthy, recreationally active men completed a detailed familiarization visit followed by two maximal incremental cycle exercise tests separated by 5 wk of randomly assigned pressure threshold IMT or sham control (SC) training. The IMT group (n = 12) performed 30 inspiratory efforts twice daily against a 30-repetition maximum intensity. The SC group (n = 13) performed a daily bout of 60 inspiratory efforts against 10% maximal inspiratory pressure (MIP), with no weekly adjustments. Dyspnea intensity was measured throughout exercise using the modified 0-10 Borg scale. Sternocleidomastoid and scalene EMG was measured using surface electrodes, whereas EMGdi was measured using a multipair esophageal electrode catheter. IMT significantly improved MIP (pre: -138 ± 45 vs. post: -160 ± 43 cmH₂O, P < 0.01), whereas the SC intervention did not. Dyspnea was significantly reduced at the highest equivalent work rate (pre: 7.6 ± 2.5 vs. post: 6.8 ± 2.9 Borg units, P < 0.05), but not in the SC group, with no between-group interaction effects. There were no significant differences in respiratory muscle EMG during exercise in either group. Improvements in dyspnea intensity ratings following IMT in healthy humans cannot be explained by changes in the electrical activity of the inspiratory muscles.NEW & NOTEWORTHY Exertional dyspnea intensity is thought to reflect an increased awareness of neural respiratory drive, which is measured indirectly using diaphragmatic electromyography (EMGdi). We examined the effects of inspiratory muscle training (IMT) on dyspnea, EMGdi, and EMG of accessory inspiratory muscles. IMT significantly reduced submaximal dyspnea intensity ratings but did not change EMG of any inspiratory muscles. Improvements in exertional dyspnea following IMT may be the result of nonphysiological factors or physiological adaptations unrelated to neural respiratory drive.

The effectiveness of specific exercise types on cardiopulmonary functions in patients with ankylosing spondylitis: a systematic review

The aim of this review was to assess the effectiveness of specific exercise types on pulmonary functions, aerobic and functional capacity in patients with ankylosing spondylitis (AS). A systematic search of Cochrane Database of Systematic Review, MEDLINE (EBSCO), Physiotherapy Evidence Database (PEDro), CINAHL (EBSCO), PUBMED, AMED, EMBASE (OVID) was conducted in January 2016. The outcome measures were spirometric measurements, chest expansion, 6 minute walk distance (6MWD), pVO₂, Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The search strategy was applied with limitation of date and language and this initial electronic search resulted in 143 relevant studies. After duplicates were removed, the titles and abstracts of 52 articles were screened. Of these, 14 full-text articles met initial criteria and were retrieved for review, with eight studies meeting final inclusion criteria. Both specific and conventional exercise groups showed significant improvements in BASDAI and BASFI scores (p < 0.05) in patients with AS, although there was no significant difference between two exercise groups. As for pulmonary functions, the specific exercise groups have greater improvements than conventional group in spirometric measurement, chest expansion (p < 0.05). However, there was no significant difference between specific conventional exercise types in 6MWD (p > 0.05). Specific exercises are an effective adjuvant therapy to enhance cardiopulmonary functions in patients with AS; therefore, it is assumed that in addition to the medical treatments, specific exercise therapy might reduce the cardiopulmonary complications related with AS.

Inspiratory muscle training during pulmonary rehabilitation in chronic obstructive pulmonary disease

Although recommended by international guidelines, the benefit of inspiratory muscle training (IMT) in addition to rehabilitation remains uncertain. The objective was to demonstrate the effectiveness of IMT on dyspnea using Borg scale and multidimensional dyspnea profile questionnaire at the end of a 6-minute walk test (6MWT) in patients with chronic obstructive pulmonary disease (COPD) with preserved average maximum inspiratory pressure (PImax) of 85 cm H2O (95% of predicted (pred.) value) and admitted for a rehabilitation program in a dedicated center. In a randomized trial, comparing IMT versus no IMT in 32 COPD patients without inspiratory muscle weakness (PImax >60 cm H2O) who were admitted for pulmonary rehabilitation (PR) for 3 weeks, we evaluated the effect of IMT on dyspnea, using both Borg scale and multidimensional dyspnea profile (MDP) at the end of the 6MWT, and on functional parameters included inspiratory muscle function (PImax) and 6MWT. All testings were performed at the start and the end of PR. In unadjusted analysis, IMT was not found to be associated with an improvement of either dyspnea or PImax. After adjustment on confounders (initial Borg score) and variables of interaction (forced expiratory volume in 1 second (FEV1)), we found a trend toward an improvement of “dyspnea sensory intensity”, items from MDP and a significant improvement on the variation in the 2 items of MDP (“tight or constricted” and “breathing a lot”). In the subgroup of patients with FEV1 < 50% pred., 5 items of MDP were significantly improved, whereas no benefit was observed in patients with FEV1 > 50% pred. IMT did not significantly improve dyspnea or functional parameter in COPD patients with PImax > 60 cm H2O. However, in the subgroup of patients with FEV1 < 50% pred., MDP was significantly improved.

Inspiratory muscle training for asthma

BACKGROUND

In some people with asthma, expiratory airflow limitation, premature closure of small airways, activity of inspiratory muscles at the end of expiration and reduced pulmonary compliance may lead to lung hyperinflation. With the increase in lung volume, chest wall geometry is modified, shortening the inspiratory muscles and leaving them at a sub-optimal position in their length-tension relationship. Thus, the capacity of these muscles to generate tension is reduced. An increase in cross-sectional area of the inspiratory muscles caused by hypertrophy could offset the functional weakening induced by hyperinflation. Previous studies have shown that inspiratory muscle training promotes diaphragm hypertrophy in healthy people and patients with chronic heart failure, and increases the proportion of type I fibres and the size of type II fibres of the external intercostal muscles in patients with chronic obstructive pulmonary disease. However, its effects on clinical outcomes in patients with asthma are unclear.

OBJECTIVES

To evaluate the efficacy of inspiratory muscle training with either an external resistive device or threshold loading in people with asthma.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register of trials, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov and reference lists of included studies. The latest search was performed in November 2012.

SELECTION CRITERIA

We included randomised controlled trials that involved the use of an external inspiratory muscle training device versus a control (sham or no inspiratory training device) in people with stable asthma.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We included five studies involving 113 adults. Participants in four studies had mild to moderate asthma and the fifth study included participants independent of their asthma severity. There were substantial differences between the studies, including the training protocol, duration of training sessions (10 to 30 minutes) and duration of the intervention (3 to 25 weeks). Three clinical trials were produced by the same research group. Risk of bias in the included studies was difficult to ascertain accurately due to poor reporting of methods.The included studies showed a statistically significant increase in inspiratory muscle strength, measured by maximal inspiratory pressure (PImax) (mean difference (MD) 13.34 cmH2O, 95% CI 4.70 to 21.98, 4 studies, 84 participants, low quality evidence). Our other primary outcome, exacerbations requiring a course of oral or inhaled corticosteroids or emergency department visits, was not reported. For the secondary outcomes, results from one trial showed no statistically significant difference between the inspiratory muscle training group and the control group for maximal expiratory pressure, peak expiratory flow rate, forced expiratory volume in one second, forced vital capacity, sensation of dyspnoea and use of beta2-agonist. There were no studies describing inspiratory muscle endurance, hospital admissions or days off work or school.

AUTHORS' CONCLUSIONS

There is no conclusive evidence in this review to support or refute inspiratory muscle training for asthma. The evidence was limited by the small number of trials with few participants together with the risk of bias. More well conducted randomised controlled trials are needed. Future trials should investigate the following outcomes: lung function, exacerbation rate, asthma symptoms, hospital admissions, use of medications and days off work or school. Inspiratory muscle training should also be assessed in people with more severe asthma and conducted in children with asthma.

Comparison of inspiratory muscle strength training effects between older subjects with and without chronic obstructive pulmonary disease

BACKGROUND/PURPOSE

Inspiratory muscle strength training (IMST) has been traditionally recommended for patients with chronic obstructive pulmonary disease (COPD) to improve respiratory strength. Respiratory strength is reduced as age increases. However, few studies have focused on the effects of IMST on older adults without COPD.

METHODS

Subjects were divided into training non-COPD (TNC, n = 24) and training COPD (TC, n = 12) according to their forced expiratory volume in 1 second (% predicted). Both groups received 6 weeks of IMST, with training at 75-80% of maximal inspiratory pressure using pressure threshold trainers. A second group of COPD subjects served as controls (CC, n = 24), which received no training. Dyspnea was measured using the basic dyspnea index. Health-related quality of life was measured using the SF-36. The SF-36 subcategories, physical component summary and mental component summary were compared. A 6-minute walk test was performed to determine functional status. Two-way repeated measures analysis of variance was used to compare group effects and training effects of IMST.

RESULTS

Maximal inspiratory pressure was increased in both training groups (TNC: 59.1 cmH(2)O pre-IMST to 82.5 cmH(2)O post-IMST; TC: 53.2 to 72.6), but not in the CC group. Therefore, the basic dyspnea index was improved in both training groups (TNC: 9.6 to 10.8; TC: 6.2 to 7.3). Functional status was improved in the TNC group (TNC: 392.1 m to 436.3 m), but not in the TC or CC groups. Quality of life was improved in the physical component summary in both training groups.

CONCLUSION

IMST increases maximal inspiratory pressure, relieves dyspnea and improves health-related quality of life in older adults. IMST especially improves functional status in subjects without COPD. IMST benefits subjects with COPD and those without COPD. Therefore, IMST as a treatment tool is not confined to patients with COPD.

Effects of high-intensity inspiratory muscle training following a near-fatal gunshot wound

BACKGROUND AND PURPOSE

Severe injuries sustained during combat may classify individuals as undeployable for active service. It is imperative that every effort is made to optimize physical function following such injuries.

CASE DESCRIPTION

A 38-year-old man sustained a gunshot wound during armed combat. The bullet entered via the left axilla and exited from the right side of the abdomen, resulting in severe thoracic and abdominal injuries. Five months later, he continued to describe severe dyspnea on exertion. During a cardiopulmonary exercise test on a cycle ergometer, he achieved a maximum rate of oxygen uptake of 2,898 mL·min(-1) (114% predicted) and maximum power of 230 W (114% predicted). His maximum forced inspiratory flow was 5.95 L·s(-1), and inspiratory reserve volume at test end was ∼80 mL. The test was terminated by the patient due to dyspnea that was too severe to tolerate. Video fluoroscopy demonstrated impaired right hemidiaphragm function. The main goals of therapy were to reduce dyspnea on exertion and to enable return to full work duties. A program of high-intensity, interval-based threshold inspiratory muscle training (IMT) was undertaken.

OUTCOMES

An average of 5 sessions of IMT were completed each week for 10 weeks. During a repeat cardiopulmonary exercise test, the patient achieved a similar power and maximum rate of oxygen uptake. His maximum forced inspiratory flow increased by 48% to 8.83 L·s(-1), and he was limited by leg fatigue.

DISCUSSION

High-intensity IMT was safe and well tolerated. It was associated with improvements in maximum forced inspiratory flow and changed the locus of symptom limitation during high-intensity exercise from dyspnea to leg fatigue.

Response of the respiratory muscles to rehabilitation in COPD

Respiratory rehabilitation is known to improve outcomes in patients with chronic obstructive pulmonary disease (COPD). The question addressed in the present review is whether these beneficial effects are related to improvements in inspiratory muscle function. Respiratory muscle fatigue often did not occur during exercise in patients with COPD, since exercise limitation usually occurred when significant force reserve in the inspiratory muscles was still present. Notwithstanding, a number of observations may provide indirect evidence that respiratory muscle fatigue may occur during exercise. Some evidence is present that, in normal humans, whole body exercise training improved inspiratory muscle endurance, but no studies are available in patients with COPD. Animal studies invariably demonstrated that exercise training increased the number of oxidative fibers and oxidative enzyme activity in inspiratory muscles. These effects, however, were considerably smaller than the effects found on peripheral muscles with similar fiber composition. Clear evidence indicated that inspiratory muscle training (IMT) improved inspiratory muscle function. Two large meta-analyses indicated that, if the training load was properly controlled, IMT alone or combined with general exercise reconditioning improved inspiratory muscle strength and endurance and dyspnea. The combination did not result in greater improvements in functional exercise capacity. Animal studies and one patient study confirmed the occurrence of structural remodeling of the inspiratory muscles in response to IMT. The final question is whether improvements in inspiratory muscle function produced by IMT lead to improved outcomes in COPD. In all five studies in which training load was adequately controlled, a significant reduction of dyspnea during activities of daily living was found. Eight randomized studies examined the effects of the combination. Greater improvements in exercise capacity were only found in three studies, and none showed a greater reduction in dyspnea.

Fifteen-count breathlessness score in adults with COPD

OBJECTIVE AND BACKGROUND

The Fifteen-Count Breathlessness Score (15CBS) has been reported to quantify breathlessness. The aim of this study was to determine the reliability and validity of the 15CBS in adults with COPD.

METHODS

Using an observational correlation design, subjects with clinical signs and symptoms of COPD were videotaped performing the 15CBS at a self-selected (task 1) and an 8-s counting pace (task 2), on two occasions with 5-min rest between attempts. Respiratory-related quality of life questionnaires, self-report shortness of breath measures and pulmonary function tests were completed by all subjects.

RESULTS

Thirty subjects completed the protocol. No significant differences and good linear relationships were calculated for the 15CBS within subjects (task 1 P = 0.32, r = 0.75 and task 2 P = 1.00, r = 0.86) and between assessors (task 1 P = 0.57, r = 0.99 and task 2 P = 0.21, r = 0.75). No significant relationships were evident between the 15CBS and shortness of breath or quality of life scores. Significant relationships existed between the 15CBS and FVC (litres and per cent predicted).

CONCLUSION

Most subjects completed the 15CBS using one breath, limiting discrimination between subjects with differing degrees of breathlessness. Although data from this study confirmed that the 15CBS is a reliable procedure within people with COPD, further modification is required to increase the validity and discriminative ability of this instrument.