Impact of inspiratory muscle training in patients with COPD: what is the evidence?

A meta-analysis including 32 randomised controlled trials on the effects of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD) patients was performed. Overall and subgroup analyses with respect to training modality (strength or endurance training, added to general exercise training) and patient characteristics were performed. Significant improvements were found in maximal inspiratory muscle strength (P(I,max); +13 cmH2O), endurance time (+261 s), 6- or 12-min walking distance (+32 and +85 m respectively) and quality of life (+3.8 units). Dyspnoea was significantly reduced (Borg score -0.9 point; Transitional Dyspnoea Index +2.8 units). Endurance exercise capacity tended to improve, while no effects on maximal exercise capacity were found. Respiratory muscle endurance training revealed no significant effect on P(I,max), functional exercise capacity and dyspnoea. IMT added to a general exercise programme improved P(I,max) significantly, while functional exercise capacity tended to increase in patients with inspiratory muscle weakness (P(I,max) <60 cmH2O). IMT improves inspiratory muscle strength and endurance, functional exercise capacity, dyspnoea and quality of life. Inspiratory muscle endurance training was shown to be less effective than respiratory muscle strength training. In patients with inspiratory muscle weakness, the addition of IMT to a general exercise training program improved P(I,max) and tended to improve exercise performance.

Exercise training and pulmonary rehabilitation: new insights and remaining challenges.

Pulmonary rehabilitation is now regarded as an evidence-based treatment for symptomatic patients with chronic obstructive pulmonary disease. It has been shown to enhance exercise tolerance, improve symptoms and health-related quality of life, and reduce exacerbations in patients with recurrent exacerbations. In this article we review the mechanisms through which exercise training results in beneficial effects. We also review three challenges that currently remain: 1) the fine tuning of exercise training and multidisciplinary programmes; 2) the timing of rehabilitation; and 3) efforts to enhance the accessibility and adherence to pulmonary rehabilitation programmes. Further research is needed in order to apply the now well-established principles of pulmonary rehabilitation to unusual patient populations, or patient populations that are unlikely to participate in conventional outpatient programmes.

A clinical practice guideline for physiotherapists treating patients with chronic obstructive pulmonary disease based on a systematic review of available evidence.

PURPOSE: Update of a clinical practice guideline for the physiotherapy management of patients with chronic obstructive pulmonary disease supporting the clinical decision-making process. METHODS: A systematic computerized literature search was performed on different modalities for improving physical exercise capacity, reducing exertional dyspnoea, improving airway clearance and encouraging changes in physical activity behaviour. Methodological quality was scored with the PEDro Scale. Scientific conclusions were graded according to the criteria of the; Dutch Evidence Based Guideline Development Platform'. These, together with practical considerations, were used to formulate recommendations for clinical practice. RESULTS: A total of 103 studies were included in the systematic review, consisting of five meta-analyses of randomized controlled trials, 84 randomized controlled trials and 14 uncontrolled studies. Twenty scientific conclusions supported six recommendations on physical exercise training. Nineteen scientific conclusions supported eight recommendations on interventions for reducing dyspnoea. Five scientific conclusions supported seven recommendations concerning treatment modalities to improve mucus clearance, and two scientific conclusions supported two recommendations on strategies for encouraging permanent changes in physical activity behaviour. CONCLUSIONS: Strong recommendations support the use of physical exercise training to improve health-related quality of life and functional exercise capacity. Future research should investigate whether additional interventions for reducing exertional dyspnoea have a place as adjuncts to physical exercise training in selected patients. In addition, treatment of impaired mucus clearance, especially during acute exacerbations, requires further research. With the advance of new technologies for objective measurements of physical activities in daily life more research is needed concerning interventions to initiate and maintain physical activity behaviour change during and after supervised physical exercise training programmes.

[Exercise effort training for COPD: physiological basis and results]. / Le réentraînement à l'effort des BPCO: bases physiologiques et résultats.

INTRODUCTION: In the last decade pulmonary rehabilitation has become a well accepted treatment for patients with chronic obstructive pulmonary disease (COPD) suffering from persistent dyspnea and fatigue, despite appropriate medical treatment. STATE OF ART: Patients with COPD frequently have muscular dysfunction that can be corrected by appropriate exercise training programmes. Muscle function as measured by strength and endurance tests exercise capacity and also the health status and quality of life are improved by exercise and endurance training. However, integration of exercise training in a multidisciplinary management programme is necessary to take account of all aspects of the illness. PERSPECTIVES: Methods of exercise training need to be adapted for patients with severe COPD who are unable to undertake endurance training and for patients who obtain little benefit. CONCLUSIONS: Pulmonary rehabilitation, thanks to its multidisciplinary nature, seems to be an effective modality of management for patients with COPD. However, the improvements in physical ability, quality of life and general health require an exercise training programme that is adapted for the individual patient.

Effects of controlled inspiratory muscle training in patients with COPD: a meta-analysis.

The purpose of this meta-analysis is to review studies investigating the efficacy of inspiratory muscle training (IMT) in chronic obstructive pulmonary disease (COPD) patients and to find out whether patient characteristics influence the efficacy of IMT. A systematic literature search was performed using the Medline and Embase databases. On the basis of a methodological framework, a critical review was performed and summary effect-sizes were calculated by applying fixed and random effects models. Both IMT alone and IMT as adjunct to general exercise reconditioning significantly increased inspiratory muscle strength and endurance. A significant effect was found for dyspnoea at rest and during exercise. Improved functional exercise capacity tended to be an additional effect of IMT alone and as an adjunct to general exercise reconditioning, but this trend did not reach statistical significance. No significant correlations were found for training effects with patient characteristics. However, subgroup analysis in IMT plus exercise training revealed that patients with inspiratory muscle weakness improved significantly more compared to patients without inspiratory muscle weakness. From this review it is concluded that inspiratory muscle training is an important addition to a pulmonary rehabilitation programme directed at chronic obstructive pulmonary disease patients with inspiratory muscle weakness. The effect on exercise performance is still to be determined.

Respiratory muscle weakness and respiratory muscle training in severely disabled multiple sclerosis patients.

OBJECTIVE: To evaluate the contribution of respiratory muscle weakness (part 1) and respiratory muscle training (part 2) to pulmonary function, cough efficacy, and functional status in patients with advanced multiple sclerosis (MS). DESIGN: Survey (part 1) and randomized controlled trial (part 2). SETTING: Rehabilitation center for MS. PATIENTS: Twenty-eight bedridden or wheelchair-bound MS patients (part 1); 18 patients were randomly assigned to a training group (n = 9) or a control group (n = 9) (part 2). INTERVENTION: The training group (part 2) performed three series of 15 contractions against an expiratory resistance (60% maximum expiratory pressure [PEmax]) two times a day, whereas the control group performed breathing exercises to enhance maximal inspirations. MAIN OUTCOME MEASURES: Forced vital capacity (FVC), inspiratory, and expiratory muscle strength (PImax and PEmax), neck flexion force (NFF), cough efficacy by means of the Pulmonary Index (PI), and functional status by means of the Extended Disability Status Scale (EDSS). RESULTS: Part 1 revealed a significantly reduced FVC (43% +/- 26% predicted), PEmax (18% +/- 8% predicted), and PImax (27% +/- 11% predicted), whereas NFF was only mildly reduced (93% +/- 26% predicted). The PI (median score, 10) and EDSS (median score, 8.5) were severely reduced. PEmax was significantly correlated to FVC, EDSS, and PI (r = .77, -.79, and -.47, respectively). In stepwise multiple regression analysis. PEmax was the only factor contributing to the explained variance in FVC (R2 = .60), whereas body weight (R2 = .41) was the only factor for the PI. In part 2, changes in PImax and PEmax tended to be higher in the training group (p = .06 and p = .07, respectively). The PI was significantly improved after 3 months of training compared with the control group (p < .05). After 6 months, the PI remained significantly better in the training group. CONCLUSIONS: Expiratory muscle strength was significantly reduced and related to FVC, cough efficacy, and functional status. Expiratory muscle training tended to enhance inspiratory and expiratory muscle strength. In addition, subjectively and objectively rated cough efficacy improved significantly and lasted for 3 months after training cessation.

Incentive spirometry does not enhance recovery after thoracic surgery.

OBJECTIVE: To investigate the additional effect of incentive spirometry to chest physiotherapy to prevent postoperative pulmonary complications after thoracic surgery for lung and esophageal resections. DESIGN: Randomized controlled trial. SETTING: University hospital, intensive care unit, and surgical department. PATIENTS: Sixty-seven patients (age, 59 +/- 13 yrs; forced expiratory volume in 1 sec, 93% +/- 22% predicted) undergoing elective thoracic surgery for lung (n = 40) or esophagus (n = 27) resection. INTERVENTIONS: Physiotherapy (breathing exercises, huffing, and coughing) (PT) plus incentive spirometry (IS) was compared with PT alone. MEASUREMENTS AND MAIN RESULTS: Lung function, body temperature, chest radiograph, white blood cell count, and number of hospital and intensive care unit days were all measured. Pulmonary function was significantly reduced after surgery (55% of the initial value) and improved significantly in the postoperative period in both groups. However, no differences were observed in the recovery of pulmonary function between the groups. The overall score of the chest radiograph, based on the presence of atelectasis, was similar in both treatment groups. Eight patients (12%) (three patients with lobectomy and five with esophagus resection) developed a pulmonary complication (abnormal chest radiograph, elevated body temperature and white blood cell count), four in each treatment group. Adding IS to regular PT did not reduce hospital or intensive care unit stay. CONCLUSIONS: Pulmonary complications after lung and esophagus surgery were relatively low. The addition of IS to PT did not further reduce pulmonary complications or hospital stay. Although we cannot rule out beneficial effects in a subgroup of high-risk patients, routine use of IS after thoracic surgery seems to be ineffective.

Low load inspiratory muscle training increases diaphragmatic fiber dimensions in rats.

The effects of 8 wk of inspiratory resistive loading (30 min/d, 3 x/wk) on diaphragm mass, contractile properties, fatigue, and fiber dimensions were studied in 10 male Wistar rats. They were conditioned to breathe through a Hans-Rudolph device. Half of them had to overcome a moderate inspiratory resistance (MR; n = 5), whereas the others only had to overcome the small resistance (SR; n = 5) of the inspiratory valve of the device. Results were compared with control rats (C; n = 5) moving and breathing freely. At the end of training, animals submitted to MR and SR generated mean inspiratory pressures of -2.5 +/- 1.1 and -0.2 +/- 0.05 cm H2O, respectively. TI/Ttot was 0.60 +/- 0.06 and 0.57 +/- 0.05, respectively. Body and diaphragm weight were unaffected by loading. Little or no change in in vitro diaphragmatic twitch kinetics, force generation, and fatigability was found between the three groups. Nevertheless, cross-sectional area of all fiber types increased in the two loaded groups compared with control animals. This increase reached statistical significance for type I fibers in the MR group (846 +/- 74 microm2) compared with the C and SR groups (589 +/- 32 and 683 +/- 96 microm2, respectively, p < 0.05). For IIa fibers both training groups were significantly different from the control group (SR: 768 +/- 99 and MR: 790 +/- 108 versus C: 592 +/- 37 microm2, p < 0.05). A hypertrophy of type IIx/b fibers was seen in MR compared with control animals (C: 1,555 +/- 136, SR: 1,845 +/- 338, MR: 2,053 +/- 326 microm2, p < 0.05). No differences were present in fiber type proportions between the three groups. We conclude that in our training setup, 8 wk of intermittent long-term inspiratory loading stressed the diaphragm already with a small resistance resulting in hypertrophy of predominantly type IIa fibers. A higher resistance resulted in hypertrophy of all fiber types.

Intermittent inspiratory muscle training induces fiber hypertrophy in rat diaphragm.

The effects of 8 wk of moderate load intermittent inspiratory resistive loading on diaphragm contractility, and histochemistry of the diaphragm, scalenes, and gastrocnemius were studied in rats. A resistance was placed in the inspiratory port of a Hans-Rudolph valve, through which each animal breathed during 30 min/d, 5 times/wk (loaded group, n = 10). These rats were compared with animals breathing through the same device without inspiratory resistance (control group, n = 10). During loading, animals generated mean inspiratory pressures of -3.2 +/- 1.7 cm H2O with a TI/Ttot of 0.69 +/- 0.06, resulting in a tension-time index of 0.050. At the end of training, the diaphragm mass increased in loaded animals (0.17 +/- 0.01% body mass) compared with control animals (0.15 +/- 0.01%, p < 0.01), while scalene and gastrocnemius mass remained unchanged. Diaphragmatic force as well as fatigue resistance were similar in both groups, whereas time to peak tension was significantly (p < 0.01) shorter in loaded rats (18.8 +/- 1.7 ms) compared with control rats (21.2 +/- 1.8 ms), half-relaxation time remaining unchanged. Finally, hypertrophy of diaphragmatic type IIa (+19%, p < 0.01) and IIx/b (+12%, p < 0.05) was present in the loaded group. Histochemistry of the scalenes remained unchanged, whereas type IIx/b hypertrophy (+12%, p < 0.001) was observed in the gastrocnemius internus. We speculate that the latter was due to multiple escape maneuvers. We conclude that intermittent inspiratory muscle training: (1) caused fast twitch fiber hypertrophy in the diaphragm; (2) did not produce any effect in the scalenes.

Reliability of a commercially available threshold loading device in healthy subjects and in patients with chronic obstructive pulmonary disease.

BACKGROUND: Threshold loading with the Nickerson and Keens' device is frequently applied in the training and assessment of inspiratory muscles. However, this equipment is not easily applied in clinical practice and training. A study was therefore designed to investigate the accuracy and reliability of the Threshold, a commercially available threshold loading device. METHODS: The resolution (accuracy) of the system was determined by measuring variation of pressure and flow during one minute in an experimental setup. The reproducibility and flow independence were then determined during threshold loading at six different inspiratory loads between 25% and 50% maximal inspiratory pressure (PImax) in 10 patients with chronic obstructive pulmonary disease (COPD) and eight healthy subjects. RESULTS: In the first experiment the mean variation of the sustained pressure for all loads was 1.7%. The mean coefficients of variation for pressure and flow measurements were 0.2% and 3%, respectively. In the second experiment the healthy subjects showed mean coefficients of variation for pressure and flow of 0.8% and 20.5%, respectively, and the patients showed mean coefficients of variation of 0.6% and 14.5%, respectively. CONCLUSIONS: During the in vitro experiment as well as during the experiments in patients with COPD and in healthy subjects only small variations in pressure were observed despite large variations in flow. The Threshold is a reliable and reproducible device for loading inspiratory muscles in patients with COPD as well as in healthy subjects.