WS10.6 Canadian national airway clearance study: positive expiratory pressure mask versus high frequency chest wall oscillation

Airway clearance techniques compared to no airway clearance techniques for cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is an inherited progressive life-limiting disease characterised by the build-up of abnormally thick, sticky mucus affecting mostly the lungs, pancreas, and digestive system. Airway clearance techniques (ACTs), traditionally referred to as chest physiotherapy, are recommended as part of a complex treatment programme for people with CF. The aim of an ACTs is to enhance mucociliary clearance and remove viscous secretions from the airways within the lung to prevent distal airway obstruction. This reduces the infective burden and associated inflammatory effects on the airway epithelia.  There are a number of recognised ACTs, none of which have shown superiority in improving short-term outcomes related to mucus transport. This systematic review, which has been updated regularly since it was first published in 2000, considers the efficacy of ACTs compared to not performing any ACT in adults and children with CF. It is important to continue to review this evidence, particularly the long-term outcomes, given the recent introduction of highly effective modulator therapies and the improved health outcomes and potential changes to CF management associated with these drugs.

OBJECTIVES

To determine the effectiveness and acceptability of airway clearance techniques compared to no airway clearance techniques or cough alone in people with cystic fibrosis.

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, to 17 October 2022. We searched ongoing trials registers (Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform) to 7 November 2022.

SELECTION CRITERIA

We included randomised or quasi-randomised studies that compared airway clearance techniques (chest physiotherapy) with no airway clearance techniques or spontaneous cough alone in people with CF.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed study eligibility, extracted data, and assessed the risk of bias of the included studies. We used GRADE methodology to assess the certainty of the evidence.

MAIN RESULTS

We included 11 cross-over studies (153 participants) and one parallel study (41 participants). There were differences between studies in how the interventions were delivered, with several intervention groups combining more than one ACT. One study used autogenic drainage; five used conventional chest physiotherapy; nine used positive expiratory pressure (PEP), with one study varying the water pressure between arms; three studies used oscillating PEP; two used exercise; and two used high-frequency chest wall oscillation (HFCWO). Of the 12 included studies, 10 were single-treatment studies, and two delivered the intervention over two consecutive days (once daily in one study, twice daily in the second). This substantial heterogeneity in the treatment interventions precluded pooling of data for meta-analysis. Blinding of participants, caregivers, and clinicians is impossible in airway clearance studies; we therefore judged all studies at unclear risk of performance bias. Lack of information in eight studies made assessment of risk of bias unclear for most other domains.  We rated the certainty of evidence as low or very low due to the short-term cross-over trial design, small numbers of participants, and uncertain risk of bias across most or all domains. Six studies (84 participants) reported no effect on pulmonary function variables following intervention; but one study (14 participants) reported an improvement in pulmonary function following the intervention in some of the treatment groups. Two studies reported lung clearance index: one (41 participants) found a variable response to treatment with HFCWO, whilst another (15 participants) found no effect on lung clearance index with PEP therapy (low-certainty evidence). Five studies (55 participants) reported that ACTs, including coughing, increased radioactive tracer clearance compared to control, while a further study (eight participants) reported no improvement in radioactive tracer clearance when comparing PEP to control, although coughing was discouraged during the PEP intervention. We rated the certainty of evidence on the effect of ACTs on radioactive tracer clearance as very low. Four studies (46 participants) investigated the weight of mucus cleared from the lungs and reported greater secretions during chest physiotherapy compared to a control. One study (18 participants) reported no differences in sputum weight (very low-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence from this review shows that ACTs may have short-term effects on increasing mucus transport in people with CF. All included studies had short-term follow-up; consequently, we were unable to draw any conclusions on the long-term effects of ACTs compared to no ACTs in people with CF. The evidence in this review represents the use of airway clearance techniques in a CF population before widespread use of cystic fibrosis transmembrane conductance regulator (CFTR) modulators. Further research is needed to determine the effectiveness and acceptability of airway clearance in those treated with highly effective CFTR modulators.

Oscillating devices 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. Oscillating devices generate intra- or extra-thoracic oscillations orally or external to the chest wall. Internally they create variable resistances within the airways, generating controlled oscillating positive pressure which mobilises mucus. Extra-thoracic oscillations are generated by forces outside the respiratory system, e.g. high frequency chest wall oscillation. This is an update of a previously published review.

OBJECTIVES

To identify whether oscillatory devices, oral or chest wall, are effective for mucociliary clearance and whether they are equivalent or superior to other forms of airway clearance in the successful management of secretions in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. Latest search of the Cystic Fibrosis Trials Register: 29 July 2019. In addition we searched the trials databases ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. Latest search of trials databases: 15 August 2019.

SELECTION CRITERIA

Randomised controlled studies and controlled clinical studies of oscillating devices compared with any other form of physiotherapy in people with cystic fibrosis. Single-treatment interventions (therapy technique used only once in the comparison) were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria to publications, assessed the quality of the included studies and assessed the evidence using GRADE.

MAIN RESULTS

The searches identified 82 studies (330 references); 39 studies (total of 1114 participants) met the inclusion criteria. Studies varied in duration from up to one week to one year; 20 of the studies were cross-over in design. The studies also varied in type of intervention and the outcomes measured, data were not published in sufficient detail in most of these studies, so meta-analysis was limited. Few studies were considered to have a low risk of bias in any domain. It is not possible to blind participants and clinicians to physiotherapy interventions, but 13 studies did blind the outcome assessors. The quality of the evidence across all comparisons ranged from low to very low. Forced expiratory volume in one second was the most frequently measured outcome and while many of the studies reported an improvement in those people using a vibrating device compared to before the study, there were few differences when comparing the different devices to each other or to other airway clearance techniques. One study identified an increase in frequency of exacerbations requiring antibiotics whilst using high frequency chest wall oscillation when compared to positive expiratory pressure (low-quality evidence). There were some small but significant changes in secondary outcome variables such as sputum volume or weight, but not wholly in favour of oscillating devices and due to the low- or very low-quality evidence, it is not clear whether these were due to the particular intervention. Participant satisfaction was reported in 13 studies but again with low- or very low-quality evidence and not consistently in favour of an oscillating device, as some participants preferred breathing techniques or techniques used prior to the study interventions. The results for the remaining outcome measures were not examined or reported in sufficient detail to provide any high-level evidence.

AUTHORS' CONCLUSIONS

There was no clear evidence that oscillation was a more or less effective intervention overall than other forms of physiotherapy; furthermore there was no evidence that one device is superior to another. The findings from one study showing an increase in frequency of exacerbations requiring antibiotics whilst using an oscillating device compared to positive expiratory pressure may have significant resource implications. More adequately-powered long-term randomised controlled trials are necessary and outcomes measured should include frequency of exacerbations, individual preference, adherence to therapy and general satisfaction with treatment. Increased adherence to therapy may then lead to improvements in other parameters, such as exercise tolerance and respiratory function. Additional evidence is needed to evaluate whether oscillating devices combined with other forms of airway clearance is efficacious in people with cystic fibrosis.There may also be a requirement to consider the cost implication of devices over other forms of equally advantageous airway clearance techniques. Using the GRADE method to assess the quality of the evidence, we judged this to be low or very low quality, which suggests that further research is very likely to have an impact on confidence in any estimate of effect generated by future interventions.

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.

Oscillating devices 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. Oscillating devices generate intra- or extra-thoracic oscillations orally or external to the chest wall. Internally they create variable resistances within the airways, generating controlled oscillating positive pressure which mobilises mucus. Extra-thoracic oscillations are generated by forces outside the respiratory system, e.g. high frequency chest wall oscillation. This is an update of a previously published review.

OBJECTIVES

To identify whether oscillatory devices, oral or chest wall, are effective for mucociliary clearance and whether they are equivalent or superior to other forms of airway clearance in the successful management of secretions in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. Latest search of the Cystic Fibrosis Trials Register: 27 April 2017.In addition we searched the trials databases ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. Latest search of trials databases: 26 April 2017.

SELECTION CRITERIA

Randomised controlled studies and controlled clinical studies of oscillating devices compared with any other form of physiotherapy in people with cystic fibrosis. Single-treatment interventions (therapy technique used only once in the comparison) were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria to publications and assessed the quality of the included studies.

MAIN RESULTS

The searches identified 76 studies (302 references); 35 studies (total of 1138 participants) met the inclusion criteria. Studies varied in duration from up to one week to one year; 20 of the studies were cross-over in design. The studies also varied in type of intervention and the outcomes measured, data were not published in sufficient detail in most of these studies, so meta-analysis was limited. Few studies were considered to have a low risk of bias in any domain. It is not possible to blind participants and clinicians to physiotherapy interventions, but 11 studies did blind the outcome assessors.Forced expiratory volume in one second was the most frequently measured outcome. One long-term study (seven months) compared oscillatory devices with either conventional physiotherapy or breathing techniques and found statistically significant differences in some lung function parameters in favour of oscillating devices. One study identified an increase in frequency of exacerbations requiring antibiotics whilst using high frequency chest wall oscillation when compared to positive expiratory pressure. There were some small but significant changes in secondary outcome variables such as sputum volume or weight, but not wholly in favour of oscillating devices. Participant satisfaction was reported in 15 studies but this was not specifically in favour of an oscillating device, as some participants preferred breathing techniques or techniques used prior to the study interventions. The results for the remaining outcome measures were not examined or reported in sufficient detail to provide any high level evidence.

AUTHORS' CONCLUSIONS

There was no clear evidence that oscillation was a more or less effective intervention overall than other forms of physiotherapy; furthermore there was no evidence that one device is superior to another. The findings from one study showing an increase in frequency of exacerbations requiring antibiotics whilst using an oscillating device compared to positive expiratory pressure may have significant resource implications. More adequately-powered long-term randomised controlled trials are necessary and outcomes measured should include frequency of exacerbations, individual preference, adherence to therapy and general satisfaction with treatment. Increased adherence to therapy may then lead to improvements in other parameters, such as exercise tolerance and respiratory function. Additional evidence is needed to evaluate whether oscillating devices combined with other forms of airway clearance is efficacious in people with cystic fibrosis.There may also be a requirement to consider the cost implication of devices over other forms of equally advantageous airway clearance techniques. Using the GRADE method to assess the quality of the evidence, we judged this to be low or very low quality, which suggests that further research is very likely to have an impact on confidence in any estimate of effect generated by future interventions.

Chest physiotherapy compared to no chest physiotherapy for cystic fibrosis

BACKGROUND

Chest physiotherapy is widely used in people with cystic fibrosis in order to clear mucus from the airways. This is an updated version of previously published reviews.

OBJECTIVES

To determine the effectiveness and acceptability of chest physiotherapy compared to no treatment or spontaneous cough alone to improve mucus clearance in cystic fibrosis.

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.Date of the most recent search of the Group's Cystic Fibrosis Trials Register: 02 June 2015.

SELECTION CRITERIA

Randomised or quasi-randomised clinical studies in which a form of chest physiotherapy (airway clearance technique) were taken for consideration in people with cystic fibrosis compared with either no physiotherapy treatment or spontaneous cough alone.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed study eligibility, extracted data and assessed the risk of bias in the included studies. There was heterogeneity in the published outcomes, with variable reporting which meant pooling of the data for meta-analysis was not possible.

MAIN RESULTS

The searches identified 157 studies, of which eight cross-over studies (data from 96 participants) met the inclusion criteria. There were differences between studies in the way that interventions were delivered, with several of the intervention groups combining more than one treatment modality. One included study looked at autogenic drainage, six considered conventional chest physiotherapy, three considered oscillating positive expiratory pressure, seven considered positive expiratory pressure and one considered high pressure positive expiratory pressure. Of the eight studies, six were single-treatment studies and in two, the treatment intervention was performed over two consecutive days (once daily in one, twice daily in the other). This enormous heterogeneity in the treatment interventions prevented any meta-analyses from being performed. Blinding of participants, caregivers or clinicians in airway clearance studies is impossible; therefore this was not considered as a high risk of bias in the included studies. Lack of protocol data made assessment of risk of bias unclear for the majority of other criteria.Four studies, involving 28 participants, reported a higher amount of expectorated secretions during chest physiotherapy as compared to a control. One study, involving 18 participants, reported no significant differences in sputum weight. In five studies radioactive tracer clearance was used as an outcome variable. In three of these (28 participants) it was reported that chest physiotherapy, including coughing, increased radioactive tracer clearance as compared to the control period. One study (12 participants) reported increased radioactive tracer clearance associated with all interventions compared to control, although this was only reported to have reached significance for postural drainage with percussion and vibrations; and the remaining study (eight participants) reported no significant difference in radioactive tracer clearance between chest physiotherapy, without coughing, compared to the control period. Three studies, involving 42 participants reported no significant effect on pulmonary function variables following intervention; but one further study did report significant improvement in pulmonary function following the intervention in some of the treatment groups.

AUTHORS' CONCLUSIONS

The results of this review show that airway clearance techniques have short-term effects in the terms of increasing mucus transport. No evidence was found on which to draw conclusions concerning the long-term effects.

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. 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. 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 cystic fibrosis.

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 2013.Most recent search of the Group's Cystic Fibrosis Trial Register: 02 December 2014.

SELECTION CRITERIA

Randomised controlled studies in which PEP was compared with any other form of physiotherapy in people with cystic fibrosis. This included, postural drainage and percussion, active cycle of breathing techniques, oscillating PEP devices, thoracic oscillating devices, bilevel positive airway pressure (BiPaP) and exercise. Studies also had to include one or more of the following outcomes: change in forced expiratory volume in one second; number of respiratory exacerbations; a direct measure of mucus clearance; weight of expectorated secretions; other pulmonary function parameters; a measure of exercise tolerance; ventilation scans; cost of intervention; and adherence to treatment.

DATA COLLECTION AND ANALYSIS

Three authors independently applied the inclusion and exclusion criteria to publications and assessed the risk of bias of the included studies.

MAIN RESULTS

A total of 26 studies (involving 733 participants) were included in the review. Eighteen 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. These studies compared PEP to active cycle of breathing techniques (ACBT), autogenic drainage (AD), oral oscillating PEP devices, high frequency chest wall oscillation (HFCWO) and Bi level PEP devices (BiPaP) and exercise.Forced expiratory volume in one second was the review's primary outcome and the most frequently reported outcome in the studies. Single interventions or series of treatments that continued for up to three months demonstrated no significant difference in effect between PEP and other methods of airway clearance on this outcome. However, long-term studies had equivocal or conflicting results regarding the effect on this outcome. 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. 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 were not examined or reported in sufficient detail to provide any high-level evidence. The only reported adverse event was in a study where infants performing either PEP or postural drainage with percussion experienced some gastro-oesophageal reflux. This was more severe in the postural drainage with percussion group. 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

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 a significant reduction in pulmonary exacerbations in people using PEP compared to those using HFCWO in the study where exacerbation rate was a primary outcome measure. It is important to note, however, that there may be individual preferences with respect to airway clearance techniques and that each patient needs to be considered individually for the selection of their optimal treatment regimen in the short and long term, throughout life, as circumstances including developmental stages, pulmonary symptoms and lung function change over time. This also applies as conditions vary between baseline function and pulmonary exacerbations.However, meta-analysis in this Cochrane review has shown a significant reduction in pulmonary exacerbations in people using PEP in the few studies where exacerbation rate was a primary outcome measure.

Oscillating devices 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. Oscillating devices generate intra- or extra-thoracic oscillations orally or external to the chest wall. Internally they create variable resistances within the airways, generating controlled oscillating positive pressure which mobilises mucus. Extra-thoracic oscillations are generated by forces outside the respiratory system, e.g. high frequency chest wall oscillation.

OBJECTIVES

To identify whether oscillatory devices, oral or chest wall, are effective for mucociliary clearance and whether they are equivalent or superior to other forms of airway clearance in the successful management of secretions in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and hand searches of relevant journals and abstract books of conference proceedings. Latest search of the Cystic Fibrosis Trials Register: 13 January 2014.

SELECTION CRITERIA

Randomised controlled studies and controlled clinical studies of oscillating devices compared with any other form of physiotherapy in people with cystic fibrosis. Single-treatment interventions (therapy technique used only once in the comparison) were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the inclusion criteria to publications and assessed the quality of the included studies.

MAIN RESULTS

The searches identified 68 studies with a total of 288 references; 35 studies (total of 1050 participants) met the inclusion criteria. Studies varied in duration from up to one week to one year; 20 of the studies were cross-over in design. The studies also varied in type of intervention and the outcomes measured, furthermore data were not published in sufficient detail in most of these studies, so meta-analysis was limited. Few studies were considered to have a low risk of bias in any domain. It is not possible to blind participants and clinicians to physiotherapy interventions, but 10 studies did blind the outcome assessors.Forced expiratory volume in one second was the most frequently measured outcome. One long-term study (seven months) compared oscillatory devices with either conventional physiotherapy or breathing techniques and found statistically significant differences in some lung function parameters in favour of oscillating devices. One study identified an increase in frequency of exacerbations requiring antibiotics whilst using high frequency chest wall oscillation when compared to positive expiratory pressure. There were some small but significant changes in secondary outcome variables such as sputum volume or weight, but not wholly in favour of oscillating devices. Participant satisfaction was reported in 15 studies but this was not specifically in favour of an oscillating device, as some participants preferred breathing techniques or techniques used prior to the study interventions. The results for the remaining outcome measures were not examined or reported in sufficient detail to provide any high level evidence.

AUTHORS' CONCLUSIONS

There was no clear evidence that oscillation was a more or less effective intervention overall than other forms of physiotherapy; furthermore there was no evidence that one device is superior to another. The findings from one study showing an increase in frequency of exacerbations requiring antibiotics whilst using an oscillating device compared to positive expiratory pressure may have significant resource implications. More adequately-powered long-term randomised controlled trials are necessary and outcomes measured should include frequency of exacerbations, patient preference, adherence to therapy and general satisfaction with treatment. Increased adherence to therapy may then lead to improvements in other parameters, such as exercise tolerance and respiratory function. Additional evidence is needed to evaluate whether oscillating devices combined with other forms of airway clearance is efficacious in people with cystic fibrosis.

Chest physiotherapy compared to no chest physiotherapy for cystic fibrosis

BACKGROUND

Chest physiotherapy is widely used in people with cystic fibrosis in order to clear mucus from the airways.

OBJECTIVES

To determine the effectiveness and acceptability of chest physiotherapy compared to no treatment or spontaneous cough alone to improve mucus clearance in cystic fibrosis.

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.Date of the most recent search of the Group's Cystic Fibrosis Trials Register: 04 February 2013.

SELECTION CRITERIA

Randomised or quasi-randomised clinical studies in which a form of chest physiotherapy (airway clearance technique) were taken for consideration in people with cystic fibrosis compared with either no physiotherapy treatment or spontaneous cough alone.

DATA COLLECTION AND ANALYSIS

Both authors independently assessed study eligibility, extracted data and assessed study quality. There was heterogeneity in the published outcomes, with variable reporting which meant pooling of the data for meta-analysis was not possible.

MAIN RESULTS

The searches identified 144 studies, of which eight cross-over studies (data from 96 participants) met the inclusion criteria. There were differences between studies in the way that interventions were delivered, with several of the intervention groups combining more than one treatment modality. One included study looked at autogenic drainage, six considered conventional chest physiotherapy, three considered oscillating positive expiratory pressure, seven considered positive expiratory pressure and one considered high pressure positive expiratory pressure. Of the eight studies, six were single-treatment studies and in two, the treatment intervention was performed over two consecutive days (once daily in one, twice daily in the other). This enormous heterogeneity in the treatment interventions prevented any meta-analyses from being performed.Four studies, involving 28 participants, reported a higher amount of expectorated secretions during chest physiotherapy as compared to a control. One study, involving 18 participants, reported no significant differences in sputum weight. In five studies radioactive tracer clearance was used as an outcome variable. In three of these (28 participants) it was reported that chest physiotherapy, including coughing, increased radioactive tracer clearance as compared to the control period. One study (12 participants) reported increased radioactive tracer clearance associated with all interventions compared to control, although this was only reported to have reached significance for postural drainage with percussion and vibrations; and the remaining study (eight participants) reported no significant difference in radioactive tracer clearance between chest physiotherapy, without coughing, compared to the control period. Three studies, involving 42 participants reported no significant effect on pulmonary function variables following intervention; but one further study did report significant improvement in pulmonary function following the intervention in some of the treatment groups.

AUTHORS' CONCLUSIONS

The results of this review show that airway clearance techniques have short-term effects in the terms of increasing mucus transport. No evidence was found on which to draw conclusions concerning the long-term effects.

What is the best airway clearance technique in cystic fibrosis?

The global development of airway clearance techniques (ACTs) for cystic fibrosis (CF) and corresponding research spans over four decades. Five Cochrane reviews synthesising the evidence from a plethora of early short and medium term studies have not uncovered any superior method. Four recent long term RCT studies exposed fundamental shortcomings in the standard RCT trial design and the insensitivity of FEV1 in physiotherapy studies. Strong patient preference, lack of blinding and the requirement for effortful and demanding participation over long intervals will continue to derail efforts to find the best ACT for CF, unless they are addressed in future clinical trials.