Inspiratory muscle training in chronic airflow limitation: comparison of two different training loads with a threshold device

Inspiratory muscle training, with or without concomitant pulmonary rehabilitation, for chronic obstructive pulmonary disease (COPD)

BACKGROUND

Inspiratory muscle training (IMT) aims to improve respiratory muscle strength and endurance. Clinical trials used various training protocols, devices and respiratory measurements to check the effectiveness of this intervention. The current guidelines reported a possible advantage of IMT, particularly in people with respiratory muscle weakness. However, it remains unclear to what extent IMT is clinically beneficial, especially when associated with pulmonary rehabilitation (PR).   OBJECTIVES: To assess the effect of inspiratory muscle training (IMT) on chronic obstructive pulmonary disease (COPD), as a stand-alone intervention and when combined with pulmonary rehabilitation (PR).

SEARCH METHODS

We searched the Cochrane Airways trials register, CENTRAL, MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCO, Physiotherapy Evidence Database (PEDro) ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform on 20 October 2021. We also checked reference lists of all primary studies and review articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared IMT in combination with PR versus PR alone and IMT versus control/sham. We included different types of IMT irrespective of the mode of delivery. We excluded trials that used resistive devices without controlling the breathing pattern or a training load of less than 30% of maximal inspiratory pressure (PImax), or both.

DATA COLLECTION AND ANALYSIS

We used standard methods recommended by Cochrane including assessment of risk of bias with RoB 2. Our primary outcomes were dyspnea, functional exercise capacity and health-related quality of life.  MAIN RESULTS: We included 55 RCTs in this review. Both IMT and PR protocols varied significantly across the trials, especially in training duration, loads, devices, number/ frequency of sessions and the PR programs. Only eight trials were at low risk of bias. PR+IMT versus PR We included 22 trials (1446 participants) in this comparison. Based on a minimal clinically important difference (MCID) of -1 unit, we did not find an improvement in dyspnea assessed with the Borg scale at submaximal exercise capacity (mean difference (MD) 0.19, 95% confidence interval (CI) -0.42 to 0.79; 2 RCTs, 202 participants; moderate-certainty evidence).   We also found no improvement in dyspnea assessed with themodified Medical Research Council dyspnea scale (mMRC) according to an MCID between -0.5 and -1 unit (MD -0.12, 95% CI -0.39 to 0.14; 2 RCTs, 204 participants; very low-certainty evidence).  Pooling evidence for the 6-minute walk distance (6MWD) showed an increase of 5.95 meters (95% CI -5.73 to 17.63; 12 RCTs, 1199 participants; very low-certainty evidence) and failed to reach the MCID of 26 meters. In subgroup analysis, we divided the RCTs according to the training duration and mean baseline PImax. The test for subgroup differences was not significant. Trials at low risk of bias (n = 3) demonstrated a larger effect estimate than the overall. The summary effect of the St George's Respiratory Questionnaire (SGRQ) revealed an overall total score below the MCID of 4 units (MD 0.13, 95% CI -0.93 to 1.20; 7 RCTs, 908 participants; low-certainty evidence).  The summary effect of COPD Assessment Test (CAT) did not show an improvement in the HRQoL (MD 0.13, 95% CI -0.80 to 1.06; 2 RCTs, 657 participants; very low-certainty evidence), according to an MCID of -1.6 units.  Pooling the RCTs that reported PImax showed an increase of 11.46 cmH₂O (95% CI 7.42 to 15.50; 17 RCTs, 1329 participants; moderate-certainty evidence) but failed to reach the MCID of 17.2 cmH₂O.  In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.  One abstract reported some adverse effects that were considered "minor and self-limited". IMT versus control/sham Thirty-seven RCTs with 1021 participants contributed to our second comparison. There was a trend towards an improvement when Borg was calculated at submaximal exercise capacity (MD -0.94, 95% CI -1.36 to -0.51; 6 RCTs, 144 participants; very low-certainty evidence). Only one trial was at a low risk of bias. Eight studies (nine arms) used the Baseline Dyspnea Index - Transition Dyspnea Index (BDI-TDI). Based on an MCID of +1 unit, they showed an improvement only with the 'total score' of the TDI (MD 2.98, 95% CI 2.07 to 3.89; 8 RCTs, 238 participants; very low-certainty evidence). We did not find a difference between studies classified as with and without respiratory muscle weakness. Only one trial was at low risk of bias. Four studies reported the mMRC, revealing a possible improvement in dyspnea in the IMT group (MD -0.59, 95% CI -0.76 to -0.43; 4 RCTs, 150 participants; low-certainty evidence). Two trials were at low risk of bias. Compared to control/sham, the MD in the 6MWD following IMT was 35.71 (95% CI 25.68 to 45.74; 16 RCTs, 501 participants; moderate-certainty evidence). Two studies were at low risk of bias. In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.  Six studies reported theSGRQ total score, showing a larger effect in the IMT group (MD -3.85, 95% CI -8.18 to 0.48; 6 RCTs, 182 participants; very low-certainty evidence). The lower limit of the 95% CI exceeded the MCID of -4 units. Only one study was at low risk of bias. There was an improvement in life quality with CAT (MD -2.97, 95% CI -3.85 to -2.10; 2 RCTs, 86 participants; moderate-certainty evidence). One trial was at low risk of bias. Thirty-two RCTs reported PImax, showing an improvement without reaching the MCID (MD 14.57 cmH₂O, 95% CI 9.85 to 19.29; 32 RCTs, 916 participants; low-certainty evidence). In subgroup analysis, we did not find a difference between different training durations and between studies judged with and without respiratory muscle weakness.   None of the included RCTs reported adverse events.

AUTHORS' CONCLUSIONS

IMT may not improve dyspnea, functional exercise capacity and life quality when associated with PR. However, IMT is likely to improve these outcomes when provided alone. For both interventions, a larger effect in participants with respiratory muscle weakness and with longer training durations is still to be confirmed.

Ventilation asymmetry, diaphragmatic mobility and exercise capacity in men with traumatic brachial plexus injury

OBJECTIVE

To investigate the repercussions of traumatic brachial plexus injury (TBPI) on diaphragmatic mobility and exercise capacity, compartmental volume changes, as well as volume contribution of each hemithorax and ventilation asymmetry during different respiratory maneuvers, and compare with healthy individuals. The velocity of shortening of the diaphragm, inspiratory, and expiratory muscles were also assessed.

PARTICIPANTS

The cross-sectional study was conducted with 40 male individuals (20 with TBPI who have not undergone nerve transfer surgery [mean age 30.1 ± 5.3] and 20 healthy paired by age and body mass index). Only patients with C8-T1 root avulsion were studied.

MAIN OUTCOME

Compartmental and hemithoracic volumes, as well as asymmetry between the affected and unaffected sides were assessed using optoelectronic plethysmography. The 6 minute walking test was performed to evaluate exercise capacity, while diaphragm mobility was assessed during quiet breathing (QB) using an ultrasound device.

RESULTS

TBPI patients with mean lesion time of 174 ± 45.24 days showed a decreased pulmonary function, respiratory muscle strength, exercise capacity, and diaphragm mobility (all p < .001) compared with healthy. The pulmonary ribcage compartment of the affected side was the main contributor to the reduction in volume during inspiratory capacity, vital capacity, and inspiratory load imposition (all p < .05). This compartment also exhibited a higher ventilation asymmetry with reduced shortening velocity of the inspiratory ribcage muscles.

CONCLUSION

Compared with healthy, TBPI patients who have not undergone nerve transfer surgery present low exercise capacity and diaphragmatic mobility, as well as reduced volume of the upper ribcage compartment on the affected side that leads to reduced shortening velocity and ventilation asymmetry.

Time to Move Beyond a "One-Size Fits All" Approach to Inspiratory Muscle Training

Inspiratory muscle training (IMT) has been studied as a rehabilitation tool and ergogenic aid in clinical, athletic, and healthy populations. This technique aims to improve respiratory muscle strength and endurance, which has been seen to enhance respiratory pressure generation, respiratory muscle weakness, exercise capacity, and quality of life. However, the effects of IMT have been discrepant between populations, with some studies showing improvements with IMT and others not. This may be due to the use of standardized IMT protocols which are uniformly applied to all study participants without considering individual characteristics and training needs. As such, we suggest that research on IMT veer away from a standardized, one-size-fits-all intervention, and instead utilize specific IMT training protocols. In particular, a more personalized approach to an individual's training prescription based upon goals, needs, and desired outcomes of the patient or athlete. In order for the coach or practitioner to adjust and personalize a given IMT prescription for an individual, factors, such as frequency, duration, and modality will be influenced, thus inevitably affecting overall training load and adaptations for a projected outcome. Therefore, by integrating specific methods based on optimization, periodization, and personalization, further studies may overcome previous discrepancies within IMT research.

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.

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.

Respiratory Muscle Rehabilitation in Patients with Prolonged Mechanical Ventilation: A Targeted Approach

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

PHYSIOTHERAPEUTIC APPROACHES AND THE EFFECTS ON INSPIRATORY MUSCLE FORCE IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE IN THE PRE-OPERATIVE PREPARATION FOR ABDOMINAL SURGICAL PROCEDURES

Background:

Abdominal disorders can alter respiratory function and increase the morbidity and mortality of patients with chronic obstructive pulmonary disease.

Aim:

To improve the physiotherapeutic and muscular capacity in chronic obstructive pulmonary muscular inspiration in the preoperative preparation in abdominal surgeries.

Method:

Retrospective and documentary study using SINPE^© , clinical database software of patients with chronic obstructive pulmonary disease and candidates to abdominal operation. The sample consisted of 100 men aged 55-70 years, all with chronic obstructive pulmonary disease who underwent preoperative physiotherapeutic treatment. They were divided into two groups of 50 individuals (group A and group B). In group A the patients were treated with modern mobility techniques for bronchial clearance and the strengthening of the respiratory muscles was performed with IMT^® Threshold. In group B the treatment performed for bronchial obstruction was with classic maneuvers and for the strengthening of the respiratory muscles for flow incentive was used Respiron^® .

Results:

Both groups obtained improvement in the values ​​of the PiMáx after the different treatments. Group A obtained greater change in the intervals and a more significant increase of the values of the PiMax in relation to the average pre and post-treatment. However, when analyzing the variance and the standard deviation of the samples, group B presented the best results showing more homogeneity.

Conclusions:

The modern and traditional bronchial clearance techniques associated with inspiratory muscle training were equally effective in gaining inspiratory muscle strength with increased Pmax. In this way, the two can be used in the preoperative preparation of patients with chronic obstructive pulmonary disease and referred to abdominal operations.

Inspiratory muscle training reduces diaphragm activation and dyspnea during exercise in COPD

Among patients with chronic obstructive pulmonary disease (COPD), those with the lowest maximal inspiratory pressures experience greater breathing discomfort (dyspnea) during exercise. In such individuals, inspiratory muscle training (IMT) may be associated with improvement of dyspnea, but the mechanisms for this are poorly understood. Therefore, we aimed to identify physiological mechanisms of improvement in dyspnea and exercise endurance following inspiratory muscle training (IMT) in patients with COPD and low maximal inspiratory pressure (Pi_max). The effects of 8 wk of controlled IMT on respiratory muscle function, dyspnea, respiratory mechanics, and diaphragm electromyography (EMGdi) during constant work rate cycle exercise were evaluated in patients with activity-related dyspnea (baseline dyspnea index <9). Subjects were randomized to either IMT or a sham training control group ( n = 10 each). Twenty subjects (FEV₁ = 47 ± 19% predicted; Pi_max  = -59 ± 14 cmH₂O; cycle ergometer peak work rate = 47 ± 21% predicted) completed the study; groups had comparable baseline lung function, respiratory muscle strength, activity-related dyspnea, and exercise capacity. IMT, compared with control, was associated with greater increases in inspiratory muscle strength and endurance, with attendant improvements in exertional dyspnea and exercise endurance time (all P < 0.05). After IMT, EMGdi expressed relative to its maximum (EMGdi/EMGdi_max) decreased ( P < 0.05) with no significant change in ventilation, tidal inspiratory pressures, breathing pattern, or operating lung volumes during exercise. In conclusion, IMT improved inspiratory muscle strength and endurance in mechanically compromised patients with COPD and low Pi_max. The attendant reduction in EMGdi/EMGdi_max helped explain the decrease in perceived respiratory discomfort despite sustained high ventilation and intrinsic mechanical loading over a longer exercise duration. NEW & NOTEWORTHY In patients with COPD and low maximal inspiratory pressures, inspiratory muscle training (IMT) may be associated with improvement of dyspnea, but the mechanisms for this are poorly understood. This study showed that 8 wk of home-based, partially supervised IMT improved respiratory muscle strength and endurance, dyspnea, and exercise endurance. Dyspnea relief occurred in conjunction with a reduced activation of the diaphragm relative to maximum in the absence of significant changes in ventilation, breathing pattern, and operating lung volumes.

Breathing techniques in patients with chronic obstructive pulmonary disease (COPD)

Background:Breathing techniques are included in the rehabilitation program of patients with chronic obstructive pulmonary disease (COPD). The efficacy of breathing techniques aiming at improving symptoms of dyspnea and eliciting physiological effects is discussed in this paper. In patients with COPD, breathing techniques aim to relieve symptoms and ameliorate adverse physiological effects by: 1) increasing strength and endurance of the respiratory muscles; 2) optimizing the pattern of thoracoabdominal motion; and 3) reducing dynamic hyperinflation of the rib cage and improving gas exchange. Evidence exists to support the effectiveness of pursed lips breathing, forward leaning position, active expiration and inspiratory muscle training, but not for diaphragmatic breathing. Careful patient selection, proper and repeated instruction and control of the techniques, and assessment of the effects are necessary. Despite the evidence that breathing techniques are effective, several problems need to be resolved. The limited evidence for the transfer of the effects of breathing techniques during resting conditions to exercise conditions raises several questions. Do breathing techniques have to be practiced during activities of daily living?

Evaluation of the effectiveness of a home-based inspiratory muscle training programme in patients with chronic obstructive pulmonary disease using multiple inspiratory muscle tests

PURPOSE

To evaluate the effectiveness of a home-based inspiratory muscle training (IMT) programme using multiple inspiratory muscle tests.

METHOD

Sixty-eight patients (37 M) with moderate to severe chronic obstructive pulmonary disease (COPD) (Mean [SD], FEV1 36.1 [13.6]% pred.; FEV1/FVC 35.7 [11.2]%) were randomised into an experimental or control group and trained with a threshold loading device at intensity >30% maximum inspiratory pressure (PImax) or <15% PImax, respectively, for 7 weeks. Thirty-nine patients (23 M) completed the study. The following measures were assessed pre- and post-IMT: PImax, sniff inspiratory nasal pressure (SNIP), diaphragm contractility (Pdi,tw), incremental shuttle walk test (ISWT), respiratory muscle endurance (RME), chronic respiratory disease questionnaire (CRDQ), the hospital anxiety and depression scale (HADS) and the SF-36. Between-group changes were assessed using one-way analysis of variance (ANOVA).

RESULTS

PImax and perception of well-being improved significantly post-IMT [p = 0.04 and <0.05 in four domains, respectively]. This was not reflected in SNIP [p = 0.7], Pdi,tw [p = 0.8], RME [p = 0.9] or ISWT [p = 0.5].

CONCLUSIONS

A seven-week, community-based IMT programme, with realistic use of health-care resources, improves PImax and perception of well-being but a different design may be required for improvement in other measures. Multiple tests provide a more comprehensive evaluation of changes in muscle function post-IMT.

IMPLICATIONS FOR REHABILITATION

A seven-week, home-based inspiratory muscle training programme improves maximal inspiratory pressure and perception of well-being in patients with moderate to severe COPD but not sniff nasal inspiratory pressure or diaphragm contractility, respiratory muscle endurance and exercise capacity. Multiple tests are recommended for a more comprehensive assessment of changes in muscle function following inspiratory muscle training programmes. Therapists need to explore different community-based inspiratory muscle training regimes for COPD patients and identify the optimal exercise protocol that is likely to lead to improvements in diaphragm contractility and exercise capacity.

Effects of inspiratory and expiratory muscle training in normal subjects

The present study aimed to clarify the effects of inspiratory muscle training (IMT) and expiratory muscle training (EMT) on ventilatory muscle strength, pulmonary function and responses during exercise testing. Young healthy women were randomly assigned to 3 groups: IMT (n=16); EMT (n=16); or untrained normal controls (NC, n=8). Subjects in the IMT and EMT groups trained for 15 minutes twice daily over 2 weeks at loads of 30% maximal inspiratory and expiratory muscle strength, respectively. Ventilatory muscle strength (maximal inspiratory and expiratory muscle strength; PImax and PEmax, respectively), pulmonary function and progressive exercise testing was performed. Both PImax and PEmax increased in the IMT group, and PEmax increased in the EMT group. Neither trained group demonstrated any change in pulmonary function or peak values during exercise testing. In the IMT group, exercise-induced increases in heart rate, oxygen uptake (VO2/kg) and rating of perceived exertion (RPE) decreased with training, as did increases in VO2/kg and RPE in the EMT group. The increased ventilatory muscle strength in both IMT and EMT groups might improve ventilatory efficacy during exercise, and increased inspiratory muscle strength might facilitate oxygen delivery through improved circulatory responses.

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.

Protocol: inspiratory muscle training for promoting recovery and outcomes in ventilated patients (IMPROVe): a randomised controlled trial

INTRODUCTION

Inspiratory muscle weakness is a known consequence of mechanical ventilation and a potential contributor to difficulty in weaning from ventilatory support. Inspiratory muscle training (IMT) reduces the weaning period and increases the likelihood of successful weaning in some patients. However, it is not known how this training affects the residual inspiratory muscle fatigability following successful weaning nor patients' quality of life or functional outcomes.

METHODS AND ANALYSIS

This dual centre study includes two concurrent randomised controlled trials of IMT in adult patients who are either currently ventilator-dependent (>7 days) (n=70) or have been recently weaned from mechanical ventilation (>7 days) in the past week (n=70). Subjects will be stable, alert and able to actively participate and provide consent. There will be concealed allocation to either treatment (IMT) or usual physiotherapy (including deep breathing exercises without a resistance device). Primary outcomes are inspiratory muscle fatigue resistance and maximum inspiratory pressures. Secondary outcomes are quality of life (Short Form-36v2, EQ-5D), functional status (Acute Care Index of Function), rate of perceived exertion (Borg Scale), intensive care length of stay (days), post intensive care length of stay (days), rate of reintubation (%) and duration of ventilation (days).

ETHICS AND DISSEMINATION

Ethics approval has been obtained from relevant institutions, and results will be published with a view to influencing physiotherapy practice in the management of long-term ventilator-dependent patients to accelerate weaning and optimise rehabilitation outcomes.

TRIAL REGISTRATION NUMBER

ACTRN12610001089022.

Inspiratory muscle training in quadriplegic patients

OBJECTIVE

To determine whether inspiratory muscle training can increase strength and endurance of these muscles in quadriplegic patients.

METHODS

Eight quadriplegic patients (7 males and 1 female) with injury to the lower cervical spine (segments C4-C7) were submitted to inspiratory muscle training with a threshold inspiratory muscle trainer adjusted to 30% of MIP. The training sessions were carried out with the patients in a sitting position, 5 days a week for 8 weeks. Endurance time, MIP, MEP and FVC were determined at baseline, week 4 and week 8.

RESULTS

In comparison with the mean baseline value, there was an increase in MIP, measured in the sitting position, at weeks 4 and 8 (-83.0 +/- 18.9 cmH2O vs. -104.0 +/- 19.4 cmH2O and -111.3 +/- 22.7 cmH2O). There was an increase in MEP, also in the sitting position, at week 4 (from 36.8 +/- 8.1 to 42.6 +/- 8.8 cmH2O). There was an improvement in FVC at week 4 (from 2.1 +/- 0.8 to 2.5 +/- 0.6 L, representing an increase of 24 +/- 22%). Although there was an increase in endurance (sitting) at week 8, the difference was not significant in comparison with the baseline value (29.8 +/- 21.0 vs. 35.9 +/- 15.5 min, an increase of 173 +/- 233%).

CONCLUSIONS

Quadriplegic patients can benefit from training at low loads (30% of MIP), which can improve inspiratory muscle strength, FVC and expiratory muscle performance.

Ventilation and speech characteristics during submaximal aerobic exercise

PURPOSE

This study examined alterations in ventilation and speech characteristics as well as perceived dyspnea during submaximal aerobic exercise tasks.

METHOD

Twelve healthy participants completed aerobic exercise-only and simultaneous speaking and aerobic exercise tasks at 50% and 75% of their maximum oxygen consumption (VO(2) max). Measures of ventilation, oxygen consumption, heart rate, perceived dyspnea, syllables per phrase, articulation rate, and inappropriate linguistic pause placements were obtained at baseline and throughout the experimental tasks.

RESULTS

Ventilation was significantly lower during the speaking tasks compared with the nonspeaking tasks. Oxygen consumption, however, did not significantly differ between speaking and nonspeaking tasks. The perception of dyspnea was significantly higher during the speaking tasks compared with the nonspeaking tasks. All speech parameters were significantly altered over time at both task intensities.

CONCLUSIONS

It is speculated that decreased ventilation without a reduction in oxygen consumption implies that utilization of oxygen by the working muscles was increased during the speaking tasks to meet the metabolic needs. A greater ability to utilize oxygen from inspired air is found in individuals who are at higher fitness levels, and therefore these findings may have implications for individuals who must complete simultaneous speech and exercise for occupational purposes (e.g., fitness/military drill instructors, singers performing choreography).

Validity and Responsiveness of the Self-Administered Computerized Versions of the Baseline and Transition Dyspnea Indexes

BACKGROUND

Numerous instruments have been developed to examine the impact of activities on breathlessness. The primary purpose of this study was to examine the validity and responsiveness of the self-administered computerized (SAC) versions of the multidimensional baseline dyspnea index (BDI) and the transition dyspnea index (TDI).

METHODS

Sixty-five patients with COPD who complained of exertional breathlessness were evaluated at an initial visit and after receiving standard therapy at two academic medical centers. Dyspnea scores from the SAC versions were compared with those obtained with the Medical Research Council (MRC) scale and with the original interview versions of the BDI and TDI.

RESULTS

At the initial visit, all three dyspnea instruments showed similar correlations among themselves and with lung function. At the follow-up visit (mean [+/- SD] time after initial visit, 48 +/- 16 days), breathlessness scores were improved on all three instruments. Correlations were consistently higher for both versions of the TDI, and changes in lung function compared with corresponding values for DeltaMRC scale. Although 55% of patients reported no change in breathlessness on the MRC scale following treatment, the mean SAC and interview TDI scores were increased by 1.0 +/- 2.4 and 1.4 +/- 2.5, respectively, in these same patients.

CONCLUSIONS

Both versions of the BDI and the MRC scale showed concurrent validity at the initial visit. The SAC TDI demonstrated responsiveness to standard therapy that was comparable with the findings of the interview TDI, but was better than that recorded with the MRC scale. The advantages of the SAC TDI include a patient-reported score on a continuous scale using computer technology.

The MCID of the transition dyspnea index is a total score of one unit

The Baseline (BDI) and Transition (TDI) Dyspnea Indexes provide interview-based measurements of breathlessness related to activities of daily living. The BDI is a discriminative instrument that includes specific criteria for each of three components at a single point in time. The TDI is an evaluative instrument that includes specific criteria for each of three components to measure changes from a baseline state. Observational studies have shown that patients with COPD generally experience a gradual progression of breathing difficulty as measured by the TDI over time. Randomized controlled trials have demonstrated excellent measurement characteristics of the TDI; these include responsiveness (ability to detect change) and construct validity (a change in the TDI correlates with changes in other variables). Supporting evidence for one unit as the minimal clinically important difference (MCID) of the TDI is based on: expert preference; use of the physician's global evaluation score as an anchor; and distribution estimates (standard error of measurement and 0.5 of the standard deviation). As an alternative to the interview process, self-administered computerized (SAC) versions of the BDI/TDI have been developed to provide direct patient-reported ratings of dyspnea. To further establish the MCID of the interview-administered and/or the SAC TDI, we recommend that a patient's report of global ratings of change by used as an independent standard or anchor.

Respiratory muscles training in COPD patients

It is known that respiratory muscles undergo adaptation in response to overload stimuli during exercise training in stable COPD patients, thus resulting in significant increase of respiratory muscle function as well as the individual's improvements. The present article reviews the most updated evidence with regard to the use of respiratory muscle training (RMT) methods in COPD patients. Basically, three types of RMT (resistive training, pressure threshold loading, and normocapnic hyperpnea) have been reported. Frequency, duration, and intensity of exercise must be carefully considered for a training effect. In contrast with the plentitude of existing data inherent to inspiratory muscle training (IMT), literature is still lacking in showing clinical and physiological studies related to expiratory muscle training (EMT). In particular, while it seems that IMT is slightly superior to EMT in providing additional benefits other than respiratory muscle function such as a reduction in dyspnea, both the effects and the safety of EMT is still to be definitively elucidated in patients with COPD.

Development of self-administered versions of modified baseline and transition dyspnea indexes in COPD

In this study we developed self-administered versions of modified baseline and transition dyspnea indexes and compared the scores obtained by this method with the mean value obtained by two trained interviewers. Twenty-five patients (14 males/11 females) with chronic obstructive disease who had a chief complaint of "breathlessness" were tested. Age was 66+/-11 years; forced expiratory volume in one second was 48+/-23% predicted. The baseline total scores were 5.0+/-1.8 for the interviewers and 5.4+/-2.0 for the self-administered method. For the baseline dyspnea scores the correlations were 0.83 (p<0.0001) between self-administration and the mean value of two interviewers and 0.75 (p<0.0001) between the two interviewers. The transition total scores, obtained an average of 102 days (range, 7-377 days) later, were - 0.1+/-3.0 for the interviewers and - 0.4+/-3.0 for the self-administered method. For the transition dyspnea scores the correlations were 0.94 (p<0.0001) between self-administration and the mean value of two interviewers and 0.83 (p<0.0001) between the two interviewers. The self-administered dyspnea scores had similar correlations with measures of lung function as did the interview dyspnea scores. We conclude that self-administered versions of the modified baseline and transition dyspnea indexes provide comparable scores as those obtained by trained and experienced interviewers. The advantages of the self-administered versions include standardized methodology and computerized scoring.

Home respiratory muscle training in patients with chronic obstructive pulmonary disease

OBJECTIVE AND BACKGROUND

The benefits of inspiratory muscle strength training in decreasing symptoms, disability or handicap of patients affected by COPD are not well established. The objective of this study was to assess the efficacy of the constant use of a new flow-volumetric inspiratory exerciser, named Respivol, in improving respiratory functional parameters in COPD patients.

METHODS

Twenty consecutive ambulatory patients affected by COPD were enrolled. Each patient was assessed, before and after 3 and 6 months inspiratory exercise with Respivol, for the following clinical parameters: maximal inspiratory pressure, maximal expiratory pressure, dyspnoea grade, quality of life by a self-administered St George questionnaire and a 6-min walking test. After a brief progressive ambulatory training programme, inspiratory exercise with Respivol was performed at home for 6 months. All patients used Respivol together with medical treatment.

RESULTS

Maximal inspiratory pressure and maximal expiratory pressure values were significantly increased after 3 and 6 months of exercise. Dyspnoea grade was significantly reduced and the 6-min walking test showed an increase in effort tolerance, after 6 months of home training. Quality of life assessment showed an improvement, associated with a decrease of respiratory disease symptoms.

CONCLUSIONS

Inspiratory muscle strength training with Respivol seems to be efficient in reducing symptoms and improving quality of life in adults with COPD.

Exercise Performance Improves in Patients With COPD due to Respiratory Muscle Endurance Training

BACKGROUND

Impaired exercise tolerance is frequently observed in patients with COPD. Respiratory muscle endurance training (RMET) by means of normocapnic hyperpnea can be used to improve respiratory muscle function and probably exercise capacity. RMET is not applied on a large scale because complicated equipment is needed to maintain carbon dioxide homeostasis during hyperpnea, which can also be done by enlarging the dead space of the ventilatory system by breathing through a tube. Therefore, tube breathing might be a new, inexpensive method for home-based RMET. The aim of this study was to assess whether home-based RMET by means of tube breathing improves endurance exercise performance in patients with COPD.

METHODS

We randomized 36 patients with moderate-to-severe COPD to RMET by paced tube breathing (n = 18) or sham training (control, n = 18). Both groups trained twice daily for 15 min, 7 days per week, for 5 weeks.

RESULTS

Patients receiving RMET showed significant improvements in endurance exercise capacity (constant-load exercise on cycle ergometry; 18 min vs 28 min, p < 0.001), in perception of dyspnea (Borg score; 8.4 vs 5.4, p < 0.001), and respiratory muscle endurance capacity (sustainable inspiratory pressure; 25 cm H(2)O vs 31 cm H(2)O, p = 0.005). Quality of life (chronic respiratory disease questionnaire) also improved (78.7 to 86.6, p = 0.001). The control group showed no significant changes.

CONCLUSION

Home-based RMET by means of tube breathing leads to a significant improvement of endurance exercise capacity, a reduction in perception of dyspnea, and an improvement in quality of life in patients with moderate-to-severe COPD.

Reproducibility of measurements of inspiratory work capacity in cystic fibrosis patients

The evaluation of respiratory muscle endurance (RME) is regarded as being clinically relevant to the assessment of respiratory muscle function. The reproducibility of a non-invasive measure of assessing RME was determined by measuring inspiratory work capacity (IWC) (using a computerised system). Measurements were obtained on two occasions in 20 adult cystic fibrosis (CF) patients (22.7+/-3.4 years, mean+/-S.D.) and 20 age (23.4+/-4.4 years) and gender (10 male, 10 female in each group) matched healthy controls. The coefficients of reliability (CR), intra-class correlation coefficients (ICC) and limits of agreement (bias+/-2 S.D.) were determined. CR values for the CF patients and controls were above 90% and with ICC of 0.99 in both CF patients and controls. The differences in IWC between study days were within +/-2 S.D. of the mean difference in all but one CF and one control subject. These data suggest that measures of IWC may be considered reliable when used to assess RM function in both controls and in patients with CF.

Exercise training and inspiratory muscle training in patients with bronchiectasis

BACKGROUND

Bronchiectasis is a chronic suppurative lung disease often characterised by airflow obstruction and hyperinflation, and leading to decreased exercise tolerance and reduced health status. The role of pulmonary rehabilitation (PR) and inspiratory muscle training (IMT) has not been investigated in this group of patients.

METHODS

Thirty two patients with idiopathic bronchiectasis were randomly allocated to one of three groups: PR plus sham IMT (PR-SHAM), PR plus targeted IMT (PR-IMT), or control. All patients (except the control group) underwent an 8 week training programme of either PR or PR plus targeted IMT. Exercise training during PR was performed three times weekly at 80% of the peak heart rate. IMT was performed at home for 15 minutes twice daily over the 8 week period.

RESULTS

PR-SHAM and PR-IMT resulted in significant increases in the incremental shuttle walking test of 96.7 metres (95% confidence interval (CI) 59.6 to 133.7) and 124.5 metres (95% CI 63.2 to 185.9), respectively, and in endurance exercise capacity of 174.9% (95% CI 34.7 to 426.1) and 205.7% (95% CI 31.6 to 310.6). There were no statistically significant differences in the improvements in exercise between the two groups. Significant improvements in inspiratory muscle strength were also observed both in the PR-IMT group (21.4 cm H2O increase, 95% CI 9.3 to 33.4; p = 0.008) and the PR-SHAM group (12.0 cm H2O increase, 95% CI 1.1 to 22.9; p = 0.04), the magnitude of which were also similar (p = 0.220). Improvements in exercise capacity were maintained in the PR-IMT group 3 months after training, but not in the PR-SHAM group.

CONCLUSION

PR is effective in improving exercise tolerance in bronchiectasis but there is no additional advantage of simultaneous IMT. IMT may, however, be important in the longevity of the training effects.

Efficacy and safety of a monoclonal antibody recognizing interleukin-8 in COPD: a pilot study

STUDY OBJECTIVE

To investigate the efficacy and safety of a fully human monoclonal antibody recognizing the chemokine interleukin (IL)-8 in patients with COPD.

DESIGN

Randomized, double-blind, parallel-group, placebo-controlled trial.

SETTING

Eighteen clinics/hospitals in the United States.

PATIENTS

One hundred nine patients with stable COPD.

INTERVENTIONS

Three IV infusions of either monoclonal antibody recognizing IL-8 (800-mg loading dose; 400-mg subsequent doses) or active buffer solution administered monthly over a 3-month period.

MEASUREMENTS AND RESULTS

The differences in the transition dyspnea index (TDI) total score, the primary outcome measure, between fully human monoclonal IgG(2) antibody directed against IL-8 and placebo were 0.8, 1.0, 0.8, and 0.3 at week 2 (p = 0.046) and months 1 to 3, respectively. At all time points, the proportion of patients achieving >/= 1 point improvement in the TDI was greater for the monoclonal antibody group compared with the placebo group: 28% vs 11% at week 2 (p = 0.028). There were no significant differences observed for lung function, health status, 6-min walking distance, and adverse events between groups.

CONCLUSIONS

The results of this phase 2 study suggest that neutralization of IL-8 with monoclonal antibody therapy may improve dyspnea in patients with COPD. These results support the further investigation of monoclonal antibody therapy targeting IL-8 for the treatment of this disease.

Dyspnoea in health and obstructive pulmonary disease : the role of respiratory muscle function and training

A consistent finding of recent research on respiratory muscle training (RMT) in healthy humans has been an attenuation of respiratory discomfort (dyspnoea) during exercise. We argue that the neurophysiology of dyspnoea can be explained in terms of Cambell's paradigm of length-tension inappropriateness. In the context of this paradigm, changes in the contractile properties of the respiratory muscles modify the intensity of dyspnoea predominantly by changing the required level of motor outflow to these respiratory muscles. Thus, factors that impair the contractile properties of the respiratory muscles (e.g. the pattern of tension development, functional weakening and fatigue) have the potential to increase the intensity of dyspnoea, while factors that improve the contractile properties of these respiratory muscles (e.g. RMT) have the potential to reduce the intensity of dyspnoea. In patients with obstructive pulmonary disease, functional weakening of the inspiratory muscles in response to dynamic lung hyperinflation appears to be a central component of dyspnoea. A decrease in the intensity of respiratory effort sensation (during exercise and loaded breathing) has been observed in both healthy individuals and patients with obstructive pulmonary disease after RMT. We conclude that RMT has the potential to reduce the severity of dyspnoea in healthy individuals and in patients with obstructive pulmonary disease, and that this probably occurs via a reduction in the level of motor outflow. Further work is required to clarify the role of RMT in the management of other disease conditions in which the function of the respiratory muscles is impaired, or the loads that they must overcome are elevated (e.g. cardiorespiratory and neuromuscular disorders).

Efeitos de programa de exercícios físicos direcionado ao aumento da mobilidade torácica em pacientes portadores de doença pulmonar obstrutiva crônica

INTRODUÇÃO: A doença pulmonar obstrutiva crônica acarreta prejuízos na mecânica pulmonar e musculatura periférica. O treinamento físico dos pacientes com doença pulmonar obstrutiva crônica é geralmente voltado à melhora das condições aeróbias e são raros os programas que abordam especificamente as alterações da caixa e musculatura torácicas. OBJETIVO: Avaliar o efeito de um programa de exercícios físicos direcionados ao aumento da mobilidade da caixa torácica sobre a capacidade funcional e psicossocial de pacientes portadores de doença pulmonar obstrutiva crônica moderada e grave. MÉTODO: Foram estudados 30 pacientes portadores de doença pulmonar obstrutiva crônica moderada e grave, divididos aleatoriamente em dois grupos: controle (GC) e tratado (GT). O GC foi submetido a um programa de educação e o GT foi submetido ao mesmo programa educacional e a um programa de exercícios físicos objetivando o aumento da mobilidade torácica. Os efeitos dos programas foram avaliados pela espirometria, mobilidade torácica, qualidade de vida, níveis de ansiedade e depressão e teste da caminhada de seis minutos (TC6). RESULTADOS: Após dois meses de treinamento, somente o GT apresentou aumento na expansibilidade torácica (de 4,20 ± 0,58cm para 5,27 ± 0,58cm; p = 0,05) e no TC6 (de 469,73 ± 31,99m para 500,60 ± 27,38m; p = 0,01). Foi observado também que o GT apresentou melhora na qualidade de vida avaliada pelo St. George's Respiratory Questionnaire (SGRQ) e Chronic Respiratory Questionnaire (CRQ), bem como nos níveis de depressão após dois meses de tratamento. Não houve melhora da função pulmonar em nenhum dos dois grupos estudados. CONCLUSÃO: Exercícios direcionados ao aumento da mobilidade da caixa torácica melhoram a expansibilidade torácica, a qualidade de vida e a capacidade submáxima de exercício, bem como reduzem a dispnéia e os níveis de depressão nos pacientes portadores de doença pulmonar obstrutiva crônica.

Effect of inspiratory muscle training in patients with multiple sclerosis

OBJECTIVE

To evaluate whether inspiratory muscle training (IMT) improves inspiratory muscle strength, respiratory capacity, fatigue, and subjective perception of physical endurance in patients with advanced multiple sclerosis (MS).

DESIGN

Randomized controlled trial.

SETTING

Outpatient clinic in Sweden.

PARTICIPANTS

Fifteen severely disabled patients with MS, randomized to a training or control group.

INTERVENTION

Seven patients trained with a Threshold inspiratory muscle trainer, twice every other day, with 3 sets of 10 loaded inspirations (40%-60% of patients' maximal inspiratory pressure [Pimax]) over a 10-week period.

MAIN OUTCOME MEASURES

Spirometry, Pimax, maximal expiratory pressure (Pemax), clinical assessments, and questionnaires on the patients' fatigue severity and physical endurance were evaluated.

RESULTS

After training, the Pimax (P<.008) and Pemax (P<.02) increased in the training group. The improvement in Pimax after 10 weeks of training was higher than the improvement in the control group (P<.01) and was maintained 1 month after the training period ended. The training affected neither respiratory function nor the patients' symptoms.

CONCLUSIONS

IMT had a beneficial effect on inspiratory muscle strength in patients with MS and is recommended as a complement to ordinary physical training.

Breathing retraining and exercise conditioning in patients with chronic obstructive pulmonary disease (COPD): a physiological approach

In this review we shall consider the commonest techniques to reduce dyspnea that are being applied to patients with chronic obstructive pulmonary disease (COPD) subjected to a pulmonary rehabilitation program (PRP). Pursed lip breathing (PLB) and diaphragmatic breathing (DB) are breathing retraining strategies employed by COPD patients in order to relieve and control dyspnea. However, the effectiveness of PLB in reducing dyspnoea is controversial. Moreover, DB may be associated with asynchronous and paradoxical breathing movements, reflecting a decrease in the efficiency ofthe diaphragm. Exercise training (EXT) is a mandatory component of PRP.EXT has been shown to improve exercise performances and peripheral muscle strength. Recent studies have focused on the effect of EXT on breathlessness. However, concerns persist as to whether the decreased sensation of dyspnea for a given exercise stimulus is principally due to psychological benefits of rehabilitation or to improved physiological ability to perform exercise. The effect of EXT on breathlessness may be reinforced by inhaling oxygen. However, two studies have recently shown that breathing supplemental oxygen during training has either a marginal effect or no advantage over training. In a comprehensive PRP, strength training (ST) and arm endurance training (AET) could have a role in decreasing peripheral muscle weakness and metabolic and ventilatory requirements for AET. The role of unloading the respiratory muscles during EXT has to be

Evaluation of dyspnea in the elderly

The word "dyspnea" encompasses many different features. It can be considered to be a sensation, a symptom, or an illness. From a practical perspective many physicians and nurses use dyspnea to refer to difficult or labored breathing or an uncomfortable awareness of breathing. The American Thoracic Society recently defined dyspnea as a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity.

Effect of inspiratory muscle strength training on inspiratory motor drive and RREP early peak components

This study investigated the effect of inspiratory muscle strength training (IMST) on inspiratory motor drive [mouth occlusion pressure at 0.1 s (P(0.1))] and respiratory-related evoked potentials (RREP). It was hypothesized that, if IMST increased inspiratory muscle strength, inspiratory motor drive would decrease. If motor drive were related to the RREP, it was further hypothesized that an IMST-related decrease in drive would change RREP latency and/or amplitude. Twenty-three subjects received IMST at 75% of their maximal inspiratory pressure (Pi(max)) with the use of a pressure threshold valve. IMST consisted of four sets of six breaths daily for 4 wk. P(0.1) and the RREP were recorded before and after IMST. Posttraining, Pi(max) increased significantly by 36.0 +/- 2.7%. P(0.1) decreased significantly by 21.9 +/- 5.2%. The increase in Pi(max) was significantly correlated to the decrease in P(0.1). RREP peaks P(1a), N(f), P(1), and N(1) were identified pre- and post-IMST, and there was no difference in either amplitude or latency for those peaks. These results demonstrate that high-intensity IMST significantly increased Pi(max), decreased P(0.1), but did not change the RREP.

Inspiratory muscle training in patients with chronic obstructive pulmonary disease: structural adaptation and physiologic outcomes

The present study was aimed at evaluating the effects of a specific inspiratory muscle training protocol on the structure of inspiratory muscles in patients with chronic obstructive pulmonary disease. Fourteen patients (males, FEV1, 24 +/- 7% predicted) were randomized to either inspiratory muscle or sham training groups. Supervised breathing using a threshold inspiratory device was performed 30 minutes per day, five times a week, for 5 consecutive weeks. The inspiratory training group was subjected to inspiratory loading equivalent to 40 to 50% of their maximal inspiratory pressure. Biopsies from external intercostal muscles and vastus lateralis (control muscle) were taken before and after the training period. Muscle samples were processed for morphometric analyses using monoclonal antibodies against myosin heavy chain isoforms I and II. Increases in both the strength and endurance of the inspiratory muscles were observed in the inspiratory training group. This improvement was associated with increases in the proportion of type I fibers (by approximately 38%, p < 0.05) and in the size of type II fibers (by approximately 21%, p < 0.05) in the external intercostal muscles. No changes were observed in the control muscle. The study demonstrates that inspiratory training induces a specific functional improvement of the inspiratory muscles and adaptive changes in the structure of external intercostal muscles.

High-intensity inspiratory muscle training in patients with chronic obstructive pulmonary disease and severely reduced function

PURPOSE

This study examined the effects of inspiratory muscle training (IMT) with high-intensity inspiratory pressure loads on respiratory muscle performance and exertional dyspnea.

METHODS

This was a randomized single-blind clinical trial. Twenty-seven patients with chronic obstructive pulmonary disease (18 men, 9 women) with severe to very severe airflow obstruction and severely limited functional performance were assigned randomly to an IMT group (n = 12) or an educational control group (n = 15). The IMT group trained with a threshold loaded device for 30 minutes a day for 16 weeks using interval training techniques. Training was initiated with inspiratory pressure loads equal to 30% of maximal inspiratory pressure (Plmax) and increased as tolerated to 60% of Plmax. Dependent variables were measured before and after 4 months of IMT: inspiratory muscle strength (Plmax), respiratory muscle endurance (discontinuous incremental threshold loading test [DC-ITL]), dyspnea (Chronic Respiratory Disease Questionnaire [CRQ]), and the Borg Category-Ratio Scale ratings of perceived breathing difficulty (RPBD) at equal loads during the DC-ITL.

RESULTS

In the IMT group, Plmax increased from 64 +/- 15 to 75 +/- 17 cm H2O (P < .05), performance on the DC-ITL test increased from a maximal load of 37 +/- 12 to 53 +/- 13 cm H2O (P < .05), RPBD decreased from 5.5 +/- 2.5 to 3.8 +/- 2.6 for equal loads on the DC-ITL (P < .05) and the CRQ Dyspnea Scale improved from 18.1 +/- 5.1 to 22.4 +/- 5.2 (P < .05).

CONCLUSIONS

Inspiratory muscle training at high-intensity loads significantly improved inspiratory muscle strength, respiratory muscle endurance, and respiratory symptoms during daily activities and respiratory exertion.

Exercise training in chronic obstructive pulmonary disease

Exercise limitation is a common and disturbing manifestation of COPD. The exercise intolerance is often caused by multiple interrelated anatomic and physiologic disturbances. Importantly, exercise tolerance can be improved despite the presence of fixed structural abnormalities in the lung. Exercise training, undertaken alone or in the context of comprehensive PR, improves exercise endurance and, to a lesser degree, the maximal tolerated workload of patients with COPD. Pulmonary rehabilitation also improves dyspnea and QOL. Exercise training and PR should be considered for all patients lacking contraindications who experience exercise intolerance despite optimal medical therapy. Lower-extremity training should be included routinely in the exercise prescription. The choice of type and intensity of training should be based primarily on the patient's individual baseline functional status, symptoms, needs, and long-term goals. When tolerated, high-intensity (continuous or interval) training may lead to greater improvements in aerobic fitness than low-intensity training but is not absolutely necessary to achieve gains in exercise endurance. Upper-extremity training should be undertaken when possible. Ventilatory muscle training should be considered for patients who continue to experience exercise limitation and breathlessness despite medical therapy and general exercise reconditioning. Exercise tolerance may improve following exercise training because of gains in aerobic fitness or peripheral muscle strength; enhanced mechanical skill and efficiency of exercise; improvements in respiratory muscle function, breathing pattern, or lung hyperinflation; as well as reduction in anxiety, fear, and dyspnea associated with exercise. Gains made in exercise tolerance can last up to 2 years following a limited duration (6-12 week) rehabilitation program.

Respiratory muscle endurance training in chronic obstructive pulmonary disease: impact on exercise capacity, dyspnea, and quality of life

Inspiratory muscle training may have beneficial effects in certain patients with chronic obstructive pulmonary disease (COPD). Because of the lack of a home training device, normocapnic hyperpnea has rarely been used as a training mode for patients with COPD, and is generally considered unsuitable to large-scale application. To study the effects of hyperpnea training, we randomized 30 patients with COPD and ventilatory limitation to respiratory muscle training (RMT; n = 15) with a new portable device or to breathing exercises with an incentive spirometer (controls; n = 15). Both groups trained twice daily for 15 min for 5 d per week for 8 wk. Training-induced changes were significantly greater in the RMT than in the control group for the following variables: respiratory muscle endurance measured through sustained ventilation (+825 +/- 170 s [mean +/- SEM] versus -27 +/- 61 s, p < 0.001), inspiratory muscle endurance measured through incremental inspiratory threshold loading (+58 +/- 10 g versus +21.7 +/- 9.5 g, p = 0.016), maximal expiratory pressure (+20 +/- 7 cm H(2)O versus -6 +/- 6 cm H(2)O, p = 0.009), 6-min walking distance (+58 +/- 11 m versus +11 +/- 11 m, p = 0.002), V O(2peak) (+2.5 +/- 0.6 ml/kg/min versus -0.3 +/- 0.9 ml/kg/min, p = 0.015), and the SF-12 physical component score (+9.9 +/- 2.7 versus +1.8 +/- 2.4, p = 0.03). Changes in dyspnea, maximal inspiratory pressure, treadmill endurance, and the SF-12 mental component score did not differ significantly between the RMT and control groups. In conclusion, home-based respiratory muscle endurance training with the new device used in this study is feasible and has beneficial effects in subjects with COPD and ventilatory limitation.

Inspiratory muscle training in patients with prior polio who use part-time assisted ventilation

OBJECTIVE

To evaluate whether inspiratory muscle training in patients with prior poliomyelitis (and with symptoms and signs of hypoventilation) who use part-time assisted ventilation could improve symptoms and respiratory muscle function without adverse effects.

DESIGN

Intervention study with before-after trial.

SETTING

Training was performed in the patients' homes; assessments were performed at the hospital.

PATIENTS

Ten prior-polio patients were included. Three of them did not complete the trial, and their data were not included in results of training.

INTERVENTION

Ten weeks of daily inspiratory muscle training.

MAIN OUTCOME MEASURES

Spirometry, maximal inspiratory and expiratory pressures, inspiratory muscle endurance, and questions regarding activities of daily living were performed.

RESULTS

Inspiratory endurance capacity over 5 minutes improved from 10.7 to 16.7cm H2O (p < .05) assessed at 15 on the Borg scale, and most patients improved in activities of daily living. The whole-body endurance capacity remained stable over the studied period.

CONCLUSION

Inspiratory muscle training and close supervision can increase respiratory muscle endurance and improve well-being in patients with prior polio who use part-time assisted ventilation.

[Respiratory muscle force and resistance in patients with SAHS. The effect of using nighttime CPAP]

During nighttime episodes of obstructive apnea in patients with sleep apnea-hypopnea syndrome (SAHS), repeated and progressive inspiratory efforts are made. Such intense nighttime activity can have a deleterious effect on daytime function of respiratory muscles.

OBJECTIVE

The objective of this study was to evaluate daytime respiratory muscle function in a group of SAHS patients before and after two months of treatment with nighttime continuous positive airway pressure (CPAP).

METHODS

We enrolled 12 patients with SAHS and 10 normal subjects (control group). To evaluate respiratory muscle strength we measured maximum esophageal pressure (Pesmax), transdiaphragmatic pressure (Pdimax) and inspiratory pressure in the mouth (PM). Respiratory muscle resistance was assessed using peak pressure in the mouth (PMPeak), time of tolerance (Tlim) and maximum inspiratory pressure-time index (PTimax). We also analyzed the nighttime function of respiratory muscles during apneic episodes in 10 of the 12 SAHS patients. We propose and define an index of nighttime respiratory muscle activity (RMian) as the product of the tension-time index for the diaphragm observed at the end of nighttime apneic episodes (TTdiapnea) and the apnea-hypopnea index (AHI).

RESULTS

Respiratory muscle strength was similar in the two groups and no changes were observed in SAHS patients after treatment with nighttime CPAP. However, tolerance was lower in SAHS patients (PMpeak--30%, Tlim--31% and PTimax--49%). Two months of nighttime CPAP normalized all three variables in these patients. MRian was related to percent improvement in PMpeak after treatment with nighttime CPAP in SAHS patients (r = 0.66, p < 0.04).

CONCLUSION

SAHS has an adverse effect on the daytime endurance of respiratory muscles that is proportional to the increase of nighttime mechanical muscle activity. The application of nighttime CPAP is restorative, probably because it allows respiratory muscles to rest.

Cycle ergometer and inspiratory muscle training in chronic obstructive pulmonary disease

In patients with chronic obstructive pulmonary disease (COPD) the intensity of aerobic training is limited by dyspnea. Improving strength of the inspiratory muscles could enhance aerobic exercise training by reducing exercise-related dyspnea. We examined effects of home-based inspiratory muscle training (IMT) and cycle ergometry training (CET) in 53 patients with moderate to severe COPD (FEV(1)% pred, 50 +/- 17 [mean +/- SD]). Patients were randomly assigned to 4 mo of training in one of four groups: IMT, CET, CET + IMT, or health education (ED). Patients were encouraged to train to the limits of their dyspnea. Inspiratory muscle strength and endurance increased in IMT and CET + IMT groups compared with CET and ED groups (p < 0. 01). Peak oxygen uptake increased and heart rate, minute ventilation, dyspnea, and leg fatigue decreased at submaximal work rates in the CET and CET + IMT groups compared with the IMT and ED groups (p < 0. 01). There were no differences between the CET and CET + IMT groups. Home-based CET produced a physiological training effect and reduced exercise-related symptoms while IMT increased respiratory muscle strength and endurance. The combination of CET and IMT did not produce additional benefits in exercise performance and exercise-related symptoms. This is the first study to demonstrate a physiological training effect with home-based exercise training.

Inspiratory muscle training protocol using a pressure threshold device: effect on dyspnea in chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the ability of patients with chronic obstructive pulmonary disease (COPD) to accomplish 6 weeks of inspiratory muscle training (IMT) using a pressure threshold device, and to observe how the training affected inspiratory muscle strength and dyspnea.

DESIGN

Pilot study comparing baseline values with posttest values.

SUBJECTS

Four adults with severe COPD (the mean of the forced expiratory volume in 1 second [FEV1] was 28% of predicted value).

METHODS

Daily IMT sessions of 5 to 30 minutes' duration and weekly training load increments of -2 to -4cmH2O over a 6-week period with the training device at loads of >30% of baseline maximal inspiratory pressure (PImax).

OUTCOME MEASURES

Dyspnea measures were Mahler's Baseline and Transition Dyspnea Index and the Borg category-ratio scale administered during a submaximal exercise protocol.

RESULTS

All subjects tolerated the training load, improved their inspiratory muscle strength, and reported reduced dyspnea.

CONCLUSION

Using a constant-load pressure threshold device to attain loads of >30% of the patient's baseline PImax is a feasible way to accomplish inspiratory muscle training in adults with severe COPD.