Airway clearance by exercising in mild cystic fibrosis (ACE-CF): A feasibility study

Active cycle of breathing technique for cystic fibrosis

BACKGROUND

People with cystic fibrosis (CF) experience chronic airway infections as a result of mucus buildup within the lungs. Repeated infections often cause lung damage and disease. Airway clearance therapies aim to improve mucus clearance, increase sputum production, and improve airway function. The active cycle of breathing technique (ACBT) is an airway clearance method that uses a cycle of techniques to loosen airway secretions including breathing control, thoracic expansion exercises, and the forced expiration technique. This is an update of a previously published review.

OBJECTIVES

To compare the clinical effectiveness of ACBT with other airway clearance therapies in CF.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched clinical trials registries and the reference lists of relevant articles and reviews. Date of last search: 29 March 2021.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled clinical studies, including cross-over studies, comparing ACBT with other airway clearance therapies in CF.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened each article, abstracted data and assessed the risk of bias of each study. We used GRADE to assess our confidence in the evidence assessing quality of life, participant preference, adverse events, forced expiratory volume in one second (FEV1) % predicted, forced vital capacity (FVC) % predicted, sputum weight, and number of pulmonary exacerbations.

MAIN RESULTS

Our search identified 99 studies, of which 22 (559 participants) met the inclusion criteria. Eight randomised controlled studies (259 participants) were included in the analysis; five were of cross-over design. The 14 remaining studies were cross-over studies with inadequate reports for complete assessment. The study size ranged from seven to 65 participants. The age of the participants ranged from six to 63 years (mean age 18.7 years). In 13 studies follow up lasted a single day. However, there were two long-term randomised controlled studies with follow up of one to three years. Most of the studies did not report on key quality items, and therefore, have an unclear risk of bias in terms of random sequence generation, allocation concealment, and outcome assessor blinding. Due to the nature of the intervention, none of the studies blinded participants or the personnel applying the interventions. However, most of the studies reported on all planned outcomes, had adequate follow up, assessed compliance, and used an intention-to-treat analysis. Included studies compared ACBT with autogenic drainage, airway oscillating devices (AOD), high-frequency chest compression devices, conventional chest physiotherapy (CCPT), positive expiratory pressure (PEP), and exercise. We found no difference in quality of life between ACBT and PEP mask therapy, AOD, other breathing techniques, or exercise (very low-certainty evidence). There was no difference in individual preference between ACBT and other breathing techniques (very low-certainty evidence). One study comparing ACBT with ACBT plus postural exercise reported no deaths and no adverse events (very low-certainty evidence). We found no differences in lung function (forced expiratory volume in one second (FEV1) % predicted and forced vital capacity (FVC) % predicted), oxygen saturation or expectorated sputum between ACBT and any other technique (very low-certainty evidence). There were no differences in the number of pulmonary exacerbations between people using ACBT and people using CCPT (low-certainty evidence) or ACBT with exercise (very low-certainty evidence), the only comparisons to report this outcome.

AUTHORS' CONCLUSIONS

There is little evidence to support or reject the use of the ACBT over any other airway clearance therapy and ACBT is comparable with other therapies in outcomes such as participant preference, quality of life, exercise tolerance, lung function, sputum weight, oxygen saturation, and number of pulmonary exacerbations. Longer-term studies are needed to more adequately assess the effects of ACBT on outcomes important for people with cystic fibrosis such as quality of life and preference.

Active cycle of breathing technique versus oscillating PEP therapy versus walking with huffing during an acute exacerbation of bronchiectasis: a randomised, controlled trial protocol

BACKGROUND

Airway clearance techniques (ACTs) for individuals with bronchiectasis are routinely prescribed in clinical practice and recommended by international guidelines, especially during an acute exacerbation. However, there is limited evidence of the efficacy of these techniques during an exacerbation to improve sputum expectoration, health-related quality-of-life (HRQOL) or exercise tolerance. The primary aim of this study is to compare the effects of the active cycle of breathing technique (ACBT), oscillating positive expiratory pressure (O-PEP) therapy, and walking with huffing on sputum expectoration for adults hospitalised with an acute exacerbation of bronchiectasis. Secondary aims are to compare the effects of these interventions on HRQOL, health status, exacerbation rates and hospital admissions in a six-month period following hospital discharge.

METHODS

This multi-centre randomised controlled trial will recruit adults with an acute exacerbation of bronchiectasis requiring hospital admission. Participants will be randomised to receive one of three interventions: ACBT, O-PEP therapy, and walking with huffing. Outcome measures including sputum volume during and 1-h post ACT session, and 24-h sputum, as well as health status, HRQOL and exercise capacity will be completed during inpatient stay on day 2 and day 6 of admission, and within 24 h of hospital discharge. Time to first exacerbation, and time to first hospitalisation will be monitored via monthly phone calls for six months post hospital discharge. Health status and HRQOL will be assessed after discharge at two and six months, and exercise capacity will be assessed at six months post hospital discharge.

DISCUSSION

Despite recommendations regarding the importance of ACT for individuals with bronchiectasis during an acute exacerbation, there is a gap in the literature regarding effectiveness of ACT when undertaken by individuals in this clinical state. This study will add to the evidence base regarding the effectiveness of commonly implemented ACTs during a hospital admission with an exacerbation of bronchiectasis. Additionally, it will contribute to knowledge of the long term effects on important and patient-centred outcomes, including incidence of future exacerbations, and HRQOL, which has not been previously established. Trial registration Registered on the Australian and New Zealand Clinical Trials Registry (ACTRN12621000428864).

Exercise as an Airway Clearance Technique in people with Cystic Fibrosis (ExACT-CF): rationale and study protocol for a randomised pilot trial

Background

Chest physiotherapy is an established cornerstone of care for people with cystic fibrosis (pwCF), but is often burdensome. Guidelines recommend at least one chest physiotherapy session daily, using various airway clearance techniques (ACTs). Exercise (with huffs and coughs) may offer an alternative ACT, however the willingness of pwCF to be randomised into a trial needs testing. The 'ExACT-CF: Exercise as an Airway Clearance Technique in people with Cystic Fibrosis' trial will test the feasibility of recruiting pwCF to be randomised to continue usual care (chest physiotherapy) or replace it with exercise ACT (ExACT) for 28-days. Secondary aims include determining the short-term clinical impact (and safety) of stopping routine chest physiotherapy and replacing it with ExACT, and effects on physical activity, sleep, mood, quality of life and treatment burden, alongside preliminary health economic measures and acceptability.

Methods

Multi-centre, two-arm, randomised (1:1 allocation using minimisation), pilot trial at two sites. Fifty pwCF (≥10 years, FEV 1 >40% predicted, stable on Elexacaftor/Tezacaftor/Ivacaftor (ETI)) will be randomised to an individually-customised ExACT programme (≥once daily aerobic exercise of ≥20-minutes duration at an intensity that elicits deep breathing, with huffs and coughs), or usual care. After baseline assessments, secondary outcomes will be assessed after 28-days, with additional home lung function and exacerbation questionnaires at 7, 14 and 21-days, physical activity and sleep monitoring throughout, and embedded qualitative and health-economic components. Feasibility measures include recruitment, retention, measurement completion, adverse events, interviews exploring the acceptability of trial procedures, and a trial satisfaction questionnaire.

Discussion

Co-designed with the UK CF community, the ExACT-CF pilot trial is the first multi-centre RCT to test the feasibility of recruiting pwCF stable on ETI into a trial investigating ExACT. This pilot trial will inform the feasibility, design, management, likely external validity for progression to a main phase randomised controlled trial.

Registration

Clinicaltrials.gov ( NCT05482048).

Feasibility and acceptability of a physical activity behavioural modification tele-coaching intervention in lung transplant recipients

BACKGROUND

Despite improvements in pulmonary function following lung transplantation (LTx), physical activity levels remain significantly lower than the general population. To date, there is little research investigating interventions to improve daily physical activity in LTx recipients. This study assessed the feasibility and acceptability of a novel, 12-weeks physical activity tele-coaching (TC) intervention in LTx recipients.

METHODS

Lung transplant recipients within 2 months of hospital discharge were recruited and randomised (1:1) to TC or usual care (UC). TC consists of a pedometer and smartphone app, allowing transmission of activity data to a platform that provides feedback, activity goals, education, and contact with the researcher as required. Recruitment and retention, occurrence of adverse events, intervention acceptability and usage were used to assess feasibility.

RESULTS

Key criteria for progressing to a larger study were met. Of the 15 patients eligible, 14 were recruited and randomised to TC or UC and 12 completed (67% male; mean ± SD age; 58 ± 7 years; COPD n = 4, ILD n = 6, CF n = 1, PH n = 1): TC (n = 7) and UC (n = 5). TC was well accepted by patients, with 86% indicating that they enjoyed taking part. Usage of the pedometer was excellent, with all patients wearing it for over 90% of days and rating the pedometer and telephone contact as the most vital aspects. There were no adverse events related to the intervention. After 12 weeks, only TC displayed improvements in accelerometry steps/day (by 3475 ± 3422; p = .036) and movement intensity (by 153 ± 166 VMU; p = .019), whereas both TC and UC groups exhibited clinically important changes in physical SF-36 scores (by 11 ± 14 and 7 ± 9 points, respectively).

CONCLUSION

TC appears to be a feasible, safe, and well-accepted intervention in LTx.

Physical activity and exercise training in cystic fibrosis

BACKGROUND

Physical activity (including exercise) may form an important part of regular care for people with cystic fibrosis (CF). This is an update of a previously published review.

OBJECTIVES

To assess the effects of physical activity interventions on exercise capacity by peak oxygen uptake, lung function by forced expiratory volume in one second (FEV1), health-related quality of life (HRQoL) and further important patient-relevant outcomes in people with cystic fibrosis (CF).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. The most recent search was on 3 March 2022. We also searched two ongoing trials registers: clinicaltrials.gov, most recently on 4 March 2022; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP), most recently on 16 March 2022.  SELECTION CRITERIA: We included all randomised controlled trials (RCTs) and quasi-RCTs comparing physical activity interventions of any type and a minimum intervention duration of two weeks with conventional care (no physical activity intervention) in people with CF.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected RCTs for inclusion, assessed methodological quality and extracted data. We assessed the certainty of the evidence using GRADE.  MAIN RESULTS: We included 24 parallel RCTs (875 participants). The number of participants in the studies ranged from nine to 117, with a wide range of disease severity. The studies' age demographics varied: in two studies, all participants were adults; in 13 studies, participants were 18 years and younger; in one study, participants were 15 years and older; in one study, participants were 12 years and older; and seven studies included all age ranges. The active training programme lasted up to and including six months in 14 studies, and longer than six months in the remaining 10 studies. Of the 24 included studies, seven implemented a follow-up period (when supervision was withdrawn, but participants were still allowed to exercise) ranging from one to 12 months. Studies employed differing levels of supervision: in 12 studies, training was supervised; in 11 studies, it was partially supervised; and in one study, training was unsupervised. The quality of the included studies varied widely. This Cochrane Review shows that, in studies with an active training programme lasting over six months in people with CF, physical activity probably has a positive effect on exercise capacity when compared to no physical activity (usual care) (mean difference (MD) 1.60, 95% confidence interval (CI) 0.16 to 3.05; 6 RCTs, 348 participants; moderate-certainty evidence). The magnitude of improvement in exercise capacity is interpreted as small, although study results were heterogeneous. Physical activity interventions may have no effect on lung function (forced expiratory volume in one second (FEV1) % predicted) (MD 2.41, 95% CI ‒0.49 to 5.31; 6 RCTs, 367 participants), HRQoL physical functioning (MD 2.19, 95% CI ‒3.42 to 7.80; 4 RCTs, 247 participants) and HRQoL respiratory domain (MD ‒0.05, 95% CI ‒3.61 to 3.51; 4 RCTs, 251 participants) at six months and longer (low-certainty evidence). One study (117 participants) reported no differences between the physical activity and control groups in the number of participants experiencing a pulmonary exacerbation by six months (incidence rate ratio 1.28, 95% CI 0.85 to 1.94) or in the time to first exacerbation over 12 months (hazard ratio 1.34, 95% CI 0.65 to 2.80) (both high-certainty evidence); and no effects of physical activity on diabetic control (after 1 hour: MD ‒0.04 mmol/L, 95% CI ‒1.11 to 1.03; 67 participants; after 2 hours: MD ‒0.44 mmol/L, 95% CI ‒1.43 to 0.55; 81 participants; moderate-certainty evidence). We found no difference between groups in the number of adverse events over six months (odds ratio 6.22, 95% CI 0.72 to 53.40; 2 RCTs, 156 participants; low-certainty evidence). For other time points (up to and including six months and during a follow-up period with no active intervention), the effects of physical activity versus control were similar to those reported for the outcomes above. However, only three out of seven studies adding a follow-up period with no active intervention (ranging between one and 12 months) reported on the primary outcomes of changes in exercise capacity and lung function, and one on HRQoL. These data must be interpreted with caution. Altogether, given the heterogeneity of effects across studies, the wide variation in study quality and lack of information on clinically meaningful changes for several outcome measures, we consider the overall certainty of evidence on the effects of physical activity interventions on exercise capacity, lung function and HRQoL to be low to moderate.

AUTHORS' CONCLUSIONS

Physical activity interventions for six months and longer likely improve exercise capacity when compared to no training (moderate-certainty evidence). Current evidence shows little or no effect on lung function and HRQoL (low-certainty evidence). Over recent decades, physical activity has gained increasing interest and is already part of multidisciplinary care offered to most people with CF. Adverse effects of physical activity appear rare and there is no reason to actively discourage regular physical activity and exercise. The benefits of including physical activity in an individual's regular care may be influenced by the type and duration of the activity programme as well as individual preferences for and barriers to physical activity. Further high-quality and sufficiently-sized studies are needed to comprehensively assess the benefits of physical activity and exercise in people with CF, particularly in the new era of CF medicine.

Exercise versus airway clearance techniques for people with cystic fibrosis

BACKGROUND

There are many accepted airway clearance techniques (ACTs) for managing the respiratory health of people with cystic fibrosis (CF); none of which demonstrate superiority. Other Cochrane Reviews have reported short-term effects related to mucus transport, but no evidence supporting long-term benefits. Exercise is an alternative ACT thought to produce shearing forces within the lung parenchyma, which enhances mucociliary clearance and the removal of viscous secretions. Recent evidence suggests that some people with CF are using exercise as a substitute for traditional ACTs, yet there is no agreed recommendation for this. Additionally, one of the top 10 research questions identified by people with CF is whether exercise can replace other ACTs. Systematically reviewing the evidence for exercise as a safe and effective ACT will help people with CF decide whether to incorporate this strategy into their treatment plans and potentially reduce their treatment burden. The timing of this review is especially pertinent given the shifting landscape of CF management with the advent of highly-effective small molecule therapies, which are changing the way people with CF are cared for.

OBJECTIVES

To compare the effect of exercise to other ACTs for improving respiratory function and other clinical outcomes in people with CF and to assess the potential adverse effects associated with this ACT.

SEARCH METHODS

On 28 February 2022, we searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. We searched online clinical trial registries on 15 February 2022. We emailed authors of studies awaiting classification or potentially eligible abstracts for additional information on 1 February 2021.

SELECTION CRITERIA

We selected randomised controlled studies (RCTs) and quasi-RCTs comparing exercise to another ACT in people with CF for at least two treatment sessions.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed risk of bias for the included studies. They assessed the certainty of the evidence using GRADE. Review authors contacted investigators for further relevant information regarding their publications.

MAIN RESULTS

We included four RCTs. The 86 participants had a wide range of disease severity (forced expiratory volume in one second (FEV1) ranged from 54% to 95%) and were 7 to 41 years old. Two RCTs were cross-over and two were parallel in design. Participants in one RCT were hospitalised with an acute respiratory exacerbation, whilst the participants in three RCTs were clinically stable. All four RCTs compared exercise either alone or in combination with another ACT, but these were too diverse to allow us to combine results. The certainty of the evidence was very low; we downgraded it due to low participant numbers and high or unclear risks of bias across all domains. Exercise versus active cycle of breathing technique (ACBT) One cross-over trial (18 participants) compared exercise alone to ACBT. There was no change from baseline in our primary outcome FEV1, although it increased in the exercise group before returning to baseline after 30 minutes; we are unsure if exercise affected FEV1 as the evidence is very low-certainty. Similar results were seen for other measures of lung function. No adverse events occurred during the exercise sessions (very low-certainty evidence). We are unsure if ACBT was perceived to be more effective or was the preferred ACT (very low-certainty evidence). 24-hour sputum volume was less in the exercise group than with ACBT (secondary outcome). Exercise capacity, quality of life, adherence, hospitalisations and need for additional antibiotics were not reported. Exercise plus postural drainage and percussion (PD&P) versus PD&P only Two trials (55 participants) compared exercise and PD&P to PD&P alone. At two weeks, one trial narratively reported a greater increase in FEV1 % predicted with PD&P alone. At six months, the other trial reported a greater increase with exercise combined with PD&P, but did not provide data for the PD&P group. We are uncertain whether exercise with PD&P improves FEV1 as the certainty of evidence is very low. Other measures of lung function did not show clear evidence of effect. One trial reported no difference in exercise capacity (maximal work rate) after two weeks. No adverse events were reported (1 trial, 17 participants; very low-certainty evidence). Adherence was high, with all PD&P sessions and 96% of exercise sessions completed (1 trial, 17 participants; very low-certainty evidence). There was no difference between groups in 24-hour sputum volume or in the mean duration of hospitalisation, although the six-month trial reported fewer hospitalisations due to exacerbations in the exercise and PD&P group. Quality of life, ACT preference and need for antibiotics were not reported. Exercise versus underwater positive expiratory pressure (uPEP) One trial (13 participants) compared exercise to uPEP (also known as bubble PEP). No adverse events were recorded in either group (very low-certainty evidence). Trial investigators reported that participants perceived exercise as more fatiguing but also more enjoyable than bubble PEP (very low-certainty evidence). There were no differences found in the total weight of sputum collected during treatment sessions. The trial did not report the primary outcomes (FEV1, quality of life, exercise capacity) or the secondary outcomes (other measures of lung function, adherence, need for antibiotics or hospitalisations).

AUTHORS' CONCLUSIONS

As one of the top 10 research questions identified by clinicians and people with CF, it is important to systematically review the literature regarding whether or not exercise is an acceptable and effective ACT, and whether it can replace traditional methods. We identified an insufficient number of trials to conclude whether or not exercise is a suitable alternative ACT, and the diverse design of included trials did not allow for meta-analysis of results. The evidence is very low-certainty, so we are uncertain about the effectiveness of exercise as an ACT. Longer studies examining outcomes that are important to people with CF are required to answer this question.

Airway clearance and exercise for people with cystic fibrosis: Balancing longevity with life

Airway clearance has been an integral part of cystic fibrosis (CF) care for almost as long as CF has been identified as a condition. From diagnosis as a neonate through to end-of-life care, airway clearance is an everyday aspect of life, adding a considerable treatment burden to the lives of people with CF. There are many different techniques used for airway clearance which have evolved over time with an aim to improve effectiveness, support adherence and, more recently, to consider the impact of burden. A popular thought is whether airway clearance could be replaced by exercise. With new precision therapies in the form of CFTR modulators available, the CF landscape is rapidly changing, raising the question of whether certain treatments are needed at all. Depending on factors such as CFTR mutation, age, and pre-existing lung damage before starting a CFTR modulator, individuals with CF may need different levels of intensity and type of maintenance treatment. Precision medicine is likely to lead to the need for increased precision and individualized management around other maintenance therapies such as airway clearance.

Effectiveness of positive expiratory pressure on patients over 16 years of age with cystic fibrosis: systematic review and meta-analysis

Introduction:

Cystic fibrosis (CF) is an autosomal recessive disease that involves the cells that produce mucus and sweat, affecting many organs, especially the lungs. Positive expiratory pressure (PEP) devices generate a pressure opposite to that exerted by the airways during expiration, thus improving mucociliary clearance.

Objectives:

To evaluate the efficacy of PEP devices as a resource to facilitate the mucus removal and other outcomes in people with CF, as well as the possible adverse effects derived from their use.

Material and Method:

A systematic review and meta-analysis was conducted according to PRISMA standards. The descriptors were ‘cystic fibrosis’, ‘PEP’, and ‘physiotherapy and/or physical therapy’. The search was performed in four databases: PubMed, PEDro, and Web of Science and Scopus, in July 2021. The inclusion criteria were randomized controlled trials (RCTs) over the last 10 years. The methodological quality of the studies was analyzed and meta-analysis was performed with Review Manager software.

Results:

Ten RCTs met the objectives and criteria, with a total of 274 participants. The trials score a moderate methodological quality on the PEDro scale. No clear results were obtained on whether PEP provides better lung function than other breathing techniques (such as airway clearance); but it does achieve a higher rate of lung clearance than physical exercise.

Conclusions:

PEP is more effective than usual care or no intervention, although there is not enough evidence to confirm that PEP achieves improvements in forced expiratory volume in the first second (FEV₁) compared with other techniques. It is a safe technique, without adverse effects.

Exercise as a substitute for traditional airway clearance in cystic fibrosis: a systematic review

BACKGROUND

Exercise and traditional airway clearance techniques (ACTs) are both routinely recommended for people with cystic fibrosis (CF), with some people using exercise as a substitute for traditional ACTs. The effectiveness of this is unclear. We systematically reviewed the evidence for using exercise as a substitute for traditional ACTs in people with CF.

METHODS

A systematic database and literature search were undertaken of studies comparing exercise to rest or traditional ACTs. Primary outcomes were respiratory function, respiratory exacerbations and health-related quality of life. Secondary outcomes included mucociliary clearance (MCC), sputum weight and ease of expectoration. Data are mean difference (95% CI).

RESULTS

A total of 12 studies (15 reports) were included, all of short duration (single session to 2 weeks). In crossover trials, exercise did not improve forced expiratory volume in one second in comparison to rest, but peak expiratory flow was increased during treadmill exercise (mean difference (MD) range 1.00-1.16 L/s) and cycle ergometry (1.19 (0.96 to 1.42) L/s). Treadmill exercise improved MCC (2.6 (1.6 to 3.6)%) and ease of expectoration (MD range 1.3-1.8 cm) compared with rest. No consistent differences in respiratory function were evident when exercise was compared with traditional ACTs (four crossover studies). There was no significant difference in MCC or sputum weight in studies where forced expirations were included in the exercise intervention.

CONCLUSIONS

Exercise improves ease of expectoration and sputum clearance compared with rest. Exercise, incorporating forced expirations, may have similar effects to traditional ACTs over the short term. There are no data comparing exercise to traditional ACTs over the longer term.

PROSPERO REGISTRATION NUMBER

CRD42018102780.

Positive expiratory pressure physiotherapy for airway clearance in people with cystic fibrosis

BACKGROUND

Chest physiotherapy is widely prescribed to assist the clearance of airway secretions in people with cystic fibrosis (CF). Positive expiratory pressure (PEP) devices provide back pressure to the airways during expiration. This may improve clearance by building up gas behind mucus via collateral ventilation and by temporarily increasing functional residual capacity. The developers of the PEP technique recommend using PEP with a mask in order to avoid air leaks via the upper airways and mouth. In addition, increasing forced residual capacity (FRC) has not been demonstrated using mouthpiece PEP. Given the widespread use of PEP devices, there is a need to determine the evidence for their effect. This is an update of a previously published review.

OBJECTIVES

To determine the effectiveness and acceptability of PEP devices compared to other forms of physiotherapy as a means of improving mucus clearance and other outcomes in people with CF.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. The electronic database CINAHL was also searched from 1982 to 2017. Most recent search of the Group's CF Trials Register: 20 February 2019.

SELECTION CRITERIA

Randomised controlled studies in which PEP was compared with any other form of physiotherapy in people with CF. This included, postural drainage and percussion (PDPV), active cycle of breathing techniques (ACBT), oscillating PEP devices, thoracic oscillating devices, bilevel positive airway pressure (BiPaP) and exercise.

DATA COLLECTION AND ANALYSIS

Three authors independently applied the inclusion and exclusion criteria to publications, assessed the risk of bias of the included studies and assessed the quality of the evidence using the GRADE recommendations.

MAIN RESULTS

A total of 28 studies (involving 788 children and adults) were included in the review; 18 studies involving 296 participants were cross-over in design. Data were not published in sufficient detail in most of these studies to perform any meta-analysis. In 22 of the 28 studies the PEP technique was performed using a mask, in three of the studies a mouthpiece was used with nose clips and in three studies it was unclear whether a mask or mouthpiece was used. These studies compared PEP to ACBT, autogenic drainage (AD), oral oscillating PEP devices, high-frequency chest wall oscillation (HFCWO) and BiPaP and exercise. Forced expiratory volume in one second was the review's primary outcome and the most frequently reported outcome in the studies (24 studies, 716 participants). Single interventions or series of treatments that continued for up to three months demonstrated little or no difference in effect between PEP and other methods of airway clearance on this outcome (low- to moderate-quality evidence). However, long-term studies had equivocal or conflicting results regarding the effect on this outcome (low- to moderate-quality evidence). A second primary outcome was the number of respiratory exacerbations. There was a lower exacerbation rate in participants using PEP compared to other techniques when used with a mask for at least one year (five studies, 232 participants; moderate- to high-quality evidence). In one of the included studies which used PEP with a mouthpiece, it was reported (personal communication) that there was no difference in the number of respiratory exacerbations (66 participants, low-quality evidence). Participant preference was reported in 10 studies; and in all studies with an intervention period of at least one month, this was in favour of PEP. The results for the remaining outcome measures (including our third primary outcome of mucus clearance) were not examined or reported in sufficient detail to provide any high-quality evidence; only very low- to moderate-quality evidence was available for other outcomes. There was limited evidence reported on adverse events; these were measured in five studies, two of which found no events. In a study where infants performing either PEP or PDPV experienced some gastro-oesophageal reflux , this was more severe in the PDPV group (26 infants, low-quality evidence). In PEP versus oscillating PEP, adverse events were only reported in the flutter group (five participants complained of dizziness, which improved after further instructions on device use was provided) (22 participants, low-quality evidence). In PEP versus HFCWO, from one long-term high-quality study (107 participants) there was little or no difference in terms of number of adverse events; however, those in the PEP group had fewer adverse events related to the lower airways when compared to HFCWO (high-certainty evidence). Many studies had a risk of bias as they did not report how the randomisation sequence was either generated or concealed. Most studies reported the number of dropouts and also reported on all planned outcome measures.

AUTHORS' CONCLUSIONS

The evidence provided by this review is of variable quality, but suggests that all techniques and devices described may have a place in the clinical treatment of people with CF. Following meta-analyses of the effects of PEP versus other airway clearance techniques on lung function and patient preference, this Cochrane Review demonstrated that there was high-quality evidence that showed a significant reduction in pulmonary exacerbations when PEP using a mask was compared with HFCWO. It is important to note that airway clearance techniques should be individualised throughout life according to developmental stages, patient preferences, pulmonary symptoms and lung function. This also applies as conditions vary between baseline function and pulmonary exacerbations.

Exercise as a therapeutic intervention for people with cystic fibrosis

INTRODUCTION

The complex multisystem nature of cystic fibrosis (CF) commonly results in reduced exercise tolerance, which is independently associated with poor clinical outcomes. Exercise is routinely recommended as part of the therapeutic regimen in CF to improve both respiratory and non-respiratory impairments. Areas covered: This article summarises the most recent evidence regarding the use of exercise as a therapeutic intervention in CF and discusses some of the practical considerations for exercise prescription in this setting. Clinical trials in progress and future research priorities are outlined. Expert opinion: On the balance of available evidence, exercise is likely to assist in improving physical fitness and health-related quality of life (HRQOL) and may be associated with a slower rate of decline in respiratory function in CF. Limitations to current studies include small sample sizes, study durations insufficient to achieve a training effect and difficulty distinguishing the effects of exercise training from that of other interventions implemented as part of a package of care. Larger, multi-centred trials are required to clarify the role of exercise in CF in improving physical fitness, respiratory function, HRQOL, as a substitute for traditional airway clearance techniques and in the management of common CF-related comorbidities.