Developing concepts in the pulmonary rehabilitation of COPD

Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews Issue 1, 2013 on Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease.Patients with advanced progressive disease often experience muscle weakness, which can impact adversely on their ability to be independent and their quality of life. In those patients who are unable or unwilling to undertake whole-body exercise, neuromuscular electrical stimulation (NMES) may be an alternative treatment to enhance lower limb muscle strength. Programmes of NMES appear to be acceptable to patients and have led to improvements in muscle function, exercise capacity, and quality of life. However, estimates regarding the effectiveness of NMES based on individual studies lack power and precision.

OBJECTIVES

Primary objective: to evaluate the effectiveness of NMES on quadriceps muscle strength in adults with advanced disease. Secondary objectives: to examine the safety and acceptability of NMES, and its effect on peripheral muscle function (strength or endurance), muscle mass, exercise capacity, breathlessness, and health-related quality of life.

SEARCH METHODS

We identified studies from searches of the Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews (CDSR), and Database of Abstracts of Reviews of Effects (DARE) (the Cochrane Library), MEDLINE (OVID), Embase (OVID), CINAHL (EBSCO), and PsycINFO (OVID) databases to January 2016; citation searches, conference proceedings, and previous systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials in adults with advanced chronic respiratory disease, chronic heart failure, cancer, or HIV/AIDS comparing a programme of NMES as a sole or adjunct intervention to no treatment, placebo NMES, or an active control. We imposed no language restriction.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on study design, participants, interventions, and outcomes. We assessed risk of bias using the Cochrane 'Risk of bias' tool. We calculated mean differences (MD) or standardised mean differences (SMD) between intervention and control groups for outcomes with sufficient data; for other outcomes we described findings from individual studies. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Eighteen studies (20 reports) involving a total of 933 participants with COPD, chronic respiratory disease, chronic heart failure, and/or thoracic cancer met the inclusion criteria for this update, an additional seven studies since the previous version of this review. All but one study that compared NMES to resistance training compared a programme of NMES to no treatment or placebo NMES. Most studies were conducted in a single centre and had a risk of bias arising from a lack of participant or assessor blinding and small study size. The quality of the evidence using GRADE comparing NMES to control was low for quadriceps muscle strength, moderate for occurrence of adverse events, and very low to low for all other secondary outcomes. We downgraded the quality of evidence ratings predominantly due to inconsistency among study findings and imprecision regarding estimates of effect. The included studies reported no serious adverse events and a low incidence of muscle soreness following NMES.NMES led to a statistically significant improvement in quadriceps muscle strength as compared to the control (12 studies; 781 participants; SMD 0.53, 95% confidence interval (CI) 0.19 to 0.87), equating to a difference of approximately 1.1 kg. An increase in muscle mass was also observed following NMES, though the observable effect appeared dependent on the assessment modality used (eight studies, 314 participants). Across tests of exercise performance, mean differences compared to control were statistically significant for the 6-minute walk test (seven studies; 317 participants; 35 m, 95% CI 14 to 56), but not for the incremental shuttle walk test (three studies; 434 participants; 9 m, 95% CI -35 to 52), endurance shuttle walk test (four studies; 452 participants; 64 m, 95% CI -18 to 146), or for cardiopulmonary exercise testing with cycle ergometry (six studies; 141 participants; 45 mL/minute, 95% CI -7 to 97). Limited data were available for other secondary outcomes, and we could not determine the most beneficial type of NMES programme.

AUTHORS' CONCLUSIONS

The overall conclusions have not changed from the last publication of this review, although we have included more data, new analyses, and an assessment of the quality of the evidence using the GRADE approach. NMES may be an effective treatment for muscle weakness in adults with advanced progressive disease, and could be considered as an exercise treatment for use within rehabilitation programmes. Further research is very likely to have an important impact on our confidence in the estimate of effect and may change the estimate. We recommend further research to understand the role of NMES as a component of, and in relation to, existing rehabilitation approaches. For example, studies may consider examining NMES as an adjuvant treatment to enhance the strengthening effect of programmes, or support patients with muscle weakness who have difficulty engaging with existing services.

Inspiratory high frequency airway oscillation attenuates resistive loaded dyspnea and modulates respiratory function in young healthy individuals

Direct chest-wall percussion can reduce breathlessness in Chronic Obstructive Pulmonary Disease and respiratory function may be improved, in health and disease, by respiratory muscle training (RMT). We tested whether high-frequency airway oscillation (HFAO), a novel form of airflow oscillation generation can modulate induced dyspnoea and respiratory strength and/or patterns following 5 weeks of HFAO training (n = 20) compared to a SHAM-RMT (conventional flow-resistive RMT) device (n = 15) in healthy volunteers (13 males; aged 20–36 yrs). HFAO causes oscillations with peak-to-peak amplitude of 1 cm H₂O, whereas the SHAM-RMT device was identical but created no pressure oscillation. Respiratory function, dyspnoea and ventilation during 3 minutes of spontaneous resting ventilation, 1 minute of maximal voluntary hyperventilation and 1 minute breathing against a moderate inspiratory resistance, were compared PRE and POST 5-weeks of training (2×30 breaths at 70% peak flow, 5 days a week). Training significantly reduced NRS dyspnoea scores during resistive loaded ventilation, both in the HFAO (p = 0.003) and SHAM-RMT (p = 0.005) groups. Maximum inspiratory static pressure (cm H₂O) was significantly increased by HFAO training (vs. PRE; p<0.001). Maximum inspiratory dynamic pressure was increased by training in both the HFAO (vs. PRE; p<0.001) and SHAM-RMT (vs. PRE; p = 0.021) groups. Peak inspiratory flow rate (L.s⁻¹) achieved during the maximum inspiratory dynamic pressure manoeuvre increased significantly POST (vs. PRE; p = 0.001) in the HFAO group only. HFAO reduced inspiratory resistive loading–induced dyspnoea and augments static and dynamic maximal respiratory manoeuvre performance in excess of flow-resistive IMT (SHAM-RMT) in healthy individuals without the respiratory discomfort associated with RMT.

Neuromuscular electrical stimulation for muscle weakness in adults with advanced disease

BACKGROUND

Patients with progressive diseases often experience muscle weakness, which impacts adversely on levels of independence and quality of life. In those who are unable or unwilling to undertake traditional forms of exercise, neuromuscular electrical stimulation (NMES) may provide an alternative method of enhancing leg muscle strength. Programmes appear to be well tolerated and have led to improvements in muscle function, exercise capacity and quality of life. However, estimates regarding the effectiveness of NMES from individual studies lack power and precision.

PRIMARY OBJECTIVE

to evaluate the effectiveness of NMES for improving muscle strength in adults with advanced disease.

SECONDARY OBJECTIVE

to examine the acceptability and safety of NMES, and changes in muscle function (strength or endurance), muscle mass, exercise capacity, breathlessness and health-related quality of life.

SEARCH METHODS

Studies were identified from searches of The Cochrane Library, MEDLINE, EMBASE, CINAHL and PsycINFO databases to July 2012, citation searches, conference proceedings and previous systematic reviews.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in adults with advanced chronic obstructive pulmonary disease (COPD), chronic heart failure, cancer or human immunodeficiency virus/acquired immunodeficency syndrome (HIV/AIDS) comparing a programme of NMES as a sole or adjunct intervention to no treatment, placebo NMES or an active control. We imposed no language restriction.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data on study design, participants, interventions and outcomes. We assessed risk of bias using the Cochrane Collaboration's tool. We calculated mean differences (MD) or standardised mean differences (SMD) between intervention and control groups for outcomes with sufficient data; for other outcomes we described findings from individual studies.

MAIN RESULTS

Eleven studies involving a total of 218 participants met the inclusion criteria across COPD, chronic heart failure and thoracic cancer. NMES significantly improved quadriceps strength by a SMD of 0.9 (95% confidence interval (CI) 0.33 to 1.46), equating to approximately 25 Newton metres (Nm) (95% CI 9 to 41). Mean differences across various walking tests, favouring NMES, were 40 m (95% CI -4 to 84) for the six-minute walk test, 69 m (95% CI 19 to 119) for the incremental shuttle walk test and 160 m (95% CI 34 to 287) for the endurance shuttle walk test. Limited evidence was available for the assessment of other secondary outcomes.

AUTHORS' CONCLUSIONS

NMES appears an effective means of improving muscle weakness in adults with progressive diseases such as COPD, chronic heart failure and cancer. Further research is required to clarify its place in clinical practice, by determining the optimal parameters for a NMES programme, the patients most likely to benefit, and its impact on morbidity and service use.

[Limitations of current treatment: unmet needs in the treatment of COPD]

In the last few years, considerable interest has been aroused in the treatment of chronic obstructive pulmonary disease (COPD) and the dearth of therapeutic options has been replaced by a far more proactive treatment approach, reflected in the development of the various guidelines and recommendations of the scientific societies. There are three main steps in the treatment of COPD: prevention of the disease, treatment of its symptoms, progression and complications, and recovery of physical function through respiratory rehabilitation. Considerable advances have been produced in these three dimensions, but limitations have been detected, indicating areas for improvement. The most effective means to prevent the disease is smoking cessation. While there are moderately effective drugs to help individuals quit, no drugs are available to prevent relapses. Moreover, due to health policies, most patients with COPD do not receive drug treatment for smoking. The treatment of COPD and its complications is based on the use of bronchodilators, which improve symptoms and quality of life and, to a greater or lesser extent, prevent exacerbations. However, treatment aimed at the underlying pathogenic causes of the disease, which should be antiinflammatory treatment, remains an unresolved issue due to the discouraging results obtained with inhaled corticosteroids, which should always be used in combination with a bronchodilator. The development of new antiinflammatory agents, such as roflumilast, could improve the management of patients with the most severe disease and repeated exacerbations. Lastly, although respiratory rehabilitation is highly effective in helping patients recover their ability to exercise, few patients have access to this option. As with the treatment of smoking, there is a need to implement respiratory rehabilitation through simple and effective programs and with the support of the health administration.

Self-efficacy as a predictor of improvement in health status and overall quality of life in pulmonary rehabilitation--an exploratory study

OBJECTIVE

To evaluate developments in health status (HS) and overall quality of life (QOL), and the impact of self-efficacy on HS and QOL in relation to COPD pulmonary rehabilitation (PR).

METHODS

A longitudinal study of 100 COPD patients before and up to 3 months after COPD PR. Self-efficacy was measured by the COPD self-efficacy scale, HS by the St. George Respiratory Questionnaire and QOL by the Quality of Life Scale. Mixed effect models were used.

RESULTS

Patients reported significantly reduced psychosocial impact of disease (estimate=-4.05, p=0.019) immediately after the PR programme. Higher levels of self-efficacy at baseline predicted significantly reduced psychosocial impact of disease and improved physical activity, total HS and QOL (p<0.05). Better exercise capacity at baseline predicted significantly reduced psychosocial impact of disease, improved physical activity and QOL (p<0.05). Older age at baseline predicted significantly fewer respiratory symptoms and improved total HS (p<0.05).

CONCLUSIONS

Patients reported significantly reduced psychosocial impact of disease immediately after a COPD PR, and better exercise capacity and higher self-efficacy at baseline predicted significantly improved HS and QOL.

PRACTICE IMPLICATIONS

Increasing self-efficacy is suggested to be an important aim in relation to COPD PR.

Does pulmonary rehabilitation work in clinical practice? A review on selection and dropout in randomized controlled trials on pulmonary rehabilitation

Aim:

To analyze randomized controlled trials (RCTs) on pulmonary rehabilitation (PR) to determine whether the patients who complete PR form a representative subset of the chronic obstructive pulmonary disease (COPD) target population and to discuss what impact this may have for the generalizability and implementation of PR in practice.

Material and methods:

A review of 26 RCTs included in a Cochrane Review 2007. We analyzed the selection at three different levels: 1) sampling; 2) inclusion and exclusion; 3) and dropout.

Results:

Of 26 studies only 3 (12%) described the sampling as the number of patients contacted. In these studies 28% completed PR. In all we found, that 75% of the patients suitable for PR programs were omitted due to sampling exclusion and dropout. Most of the study populations are not representative of the target population.

Conclusion:

The RCTs selected for the Cochrane review gave sparse information about the sampling procedure. The demand for high internal validity in studies on PR reduced their external validity. The patients completing PR programs in RCTs were not drawn from a representative subset of the target population. The ability to draw conclusions relevant to clinical practice from the results of the RCTs on PR is impaired.