Regional mucus transport following unproductive cough and forced expiration technique in patients with airways obstruction

The role of lung volume recruitment therapy in neuromuscular disease: a narrative review

Respiratory muscle weakness results in substantial discomfort, disability, and ultimately death in many neuromuscular diseases. Respiratory system impairment manifests as shallow breathing, poor cough and associated difficulty clearing mucus, respiratory tract infections, hypoventilation, sleep-disordered breathing, and chronic ventilatory failure. Ventilatory support (i.e., non-invasive ventilation) is an established and key treatment for the latter. As survival outcomes improve for people living with many neuromuscular diseases, there is a shift towards more proactive and preventative chronic disease multidisciplinary care models that aim to manage symptoms, improve morbidity, and reduce mortality. Clinical care guidelines typically recommend therapies to improve cough effectiveness and mobilise mucus, with the aim of averting acute respiratory compromise or respiratory tract infections. Moreover, preventing recurrent infective episodes may prevent secondary parenchymal pathology and further lung function decline. Regular use of techniques that augment lung volume has similarly been recommended (volume recruitment). It has been speculated that enhancing lung inflation in people with respiratory muscle weakness when well may improve respiratory system "flexibility", mitigate restrictive chest wall disease, and slow lung volume decline. Unfortunately, clinical care guidelines are based largely on clinical rationale and consensus opinion rather than level A evidence. This narrative review outlines the physiological changes that occur in people with neuromuscular disease and how these changes impact on breathing, cough, and respiratory tract infections. The biological rationale for lung volume recruitment is provided, and the clinical trials that examine the immediate, short-term, and longer-term outcomes of lung volume recruitment in paediatric and adult neuromuscular diseases are presented and the results synthesised.

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.

Comparison of physical properties of voluntary coughing, huffing and swallowing in healthy subjects

Coughing, huffing and swallowing protect the airway from aspiration. This study was conducted to compare the physical properties of voluntary coughing, huffing and swallowing in healthy subjects. Ten healthy men were asked to huff, cough and swallow repeatedly. Electromyograms (EMGs) were recorded from the left side of the external oblique (EO), sternocleidomastoid, suprahyoid (SH) and thyrohyoid muscles. Airflow was recorded using a face mask with two-way non-rebreathing valves. The expiratory velocity of huffing and coughing and the SH EMG of all actions presented high intraclass correlation coefficients (> 0.8). The inspiratory and expiratory velocities did not differ significantly between coughing and huffing. The expiratory acceleration of coughing was significantly higher than that of huffing, whereas the expiratory volume of coughing was significantly smaller than that of huffing. The EO EMG of coughing and huffing were significantly larger than that of swallowing. The EO EMG activity during the expiratory phase was significantly higher than that of the other phases of both coughing and huffing. The SH EMG of coughing and huffing were significantly smaller than that of swallowing. Correlation analysis revealed that the expiratory velocity of coughing was strongly positively correlated with that of huffing. The expiratory volume of huffing was significantly positively correlated with hand grip strength. These results suggest that EO and SH muscle activities during huffing or coughing differ those during swallowing, and huffing and coughing may work similarly in expiratory function.

The application of "upper-body yoga" in elderly patients with acute hip fracture: a prospective, randomized, and single-blind study

Purposes

Hip fracture leads to decreased activity and an increased risk of pulmonary complications. The main purpose of this study was to observe the lung capacity, cough capacity of the elderly patient with acute hip fracture, and assess the effects and the feasibility of using a special-designed “upper-body yoga” training to treat elderly patients with hip fracture.

Methods

This was a prospective, randomized, and single-blind study. Eighty-four subjects aged over 65 years were randomly divided into either a control group or a yoga group to undergo an abdominal breathing program or an “upper-body yoga” program until 4 weeks after surgery. The primary outcomes were forced vital capacity/predicted value (FVC%), peak cough flow (PCF), Barthel Index (BI), and the incidence of pneumonia. The secondary outcomes were the rates of right skills and inclination.

Results

Thirty-nine subjects in the yoga group and 40 subjects in the control group completed this study. At the end of the first training week, FVC% (74.14% ± 13.11% vs. 70.87% ± 10.46%, P = 0.231) showed no significant difference between the two groups, while the value of PCF (204.80 ± 33.45 L/min vs. 189.06 ± 34.80 L/min, P = 0.048) and BI (38.59 ± 8.66 vs. 33.00 ± 9.32, P = 0.009) in the yoga group was higher. After 4 weeks of treatment, FVC%, PCF, and BI were higher in the yoga group (78.83% ± 13.31 % vs. 72.20% ± 10.53%, P = 0.016; 216.16 ± 39.29 L/min vs. 194.95 ± 31.14 L/min, P = 0.008; 70.77 ± 10.23 vs. 65.75 ± 11.30, P = 0.019). One in the control group and nobody in the yoga group was diagnosed with pneumonia. There was no significant difference between the two groups in terms of the rates of right skills, whereas more elderly people preferred the training program of the “upper-body yoga.”

Conclusion

Elderly patients with acute hip fractures are at risk of impaired lung capacity and inadequate cough. “Upper-body yoga” training may improve the quality of daily life, vital capacity, and cough flow in elderly patients, making it a better choice for bedridden patients with hip fracture.

Seven-day intensive preoperative rehabilitation for elderly patients with lung cancer: a randomized controlled trial

BACKGROUND

As a newly developed treatment, preoperative pulmonary rehabilitation (PR) has been studied in depth. However, few studies have assessed the relationship between advanced age and a shorter term intensive pattern of preoperative PR in patients with lung cancer (LC) and especially those patients waiting for therapeutic LC surgeries. This study investigated short-term preoperative PR combined with inspiratory muscle training (IMT) and aerobic endurance training in elderly patients scheduled to undergo LC lobectomy.

METHODS

A prospective randomized controlled trial with a total of 60 subjects aged ≥70 y was conducted. The intervention group (PR group) was treated for 1 wk with systematic and highly intensive preoperative PR training before lobectomy, and the control group (NPR group) was treated with conventional preoperative respiratory management. We analyzed the 6-min walking distance (6-MWD), the peak expiratory flow (PEF), and quality-of-life scores before and after the rehabilitation regimen as well as the incidence of postoperative pulmonary complications (PPCs).

RESULTS

In total, 30 patients (PR group) completely executed the 7-d intensive preoperative PR, and 30 patients (NPR group) served as the control group. The two groups were comparable at baseline. During the preoperative PR, a significantly longer 6-MWD (increase: 28.6 ± 18.2 versus 9.4 ± 27.0 m; between-groups difference: 19.2 m, P = 0.029) and an increased PEF (increase: 26.2 ± 22.5 versus 8.2 ± 10.3 L/min; between-groups difference: 18.0 L/min, P < 0.001) were noted in the PR group compared with the NPR group. After LC surgery, the mean postoperative length of stay (6.9 ± 4.4 versus 10.7 ± 6.4 d, P = 0.010) and total hospital stay (16.0 ± 4.5 versus 19.7 ± 6.5 d, P = 0.012) were significantly reduced in the PR group. Thirty-day PPCs were noted in four (13.3%) patients in the PR group and 11 (36.7%) patients in the NPR group, with a significant difference between the two groups (P = 0.037).

CONCLUSIONS

For elderly LC patients scheduled to undergo surgery in China, a 7-d intensive pattern of preoperative PR combined with IMT and aerobic endurance training may be a feasible rehabilitation strategy with positive physical and psychological effects.

Is there a role for airway clearance techniques in chronic obstructive pulmonary disease?

Chronic cough and sputum production are common featuresof chronic obstructive pulmonary disease (COPD) and havea significant impact on exacerbation frequency and qualityof life. Despite this, techniques to assist with removal of sputum from the airway do not have a well-defined role in COPD management. Clinical trials of airway clearance techniques (ACTs) in COPD have shown mixed results with little evidence of long-term benefit. However many studies havefailed to account for the heterogeneity of COPD lung disease, particularly with regard to the presence of bronchiectasis. Analysis of short-term studies suggests that there may be a cohort of patients who will benefit from prescription of a sputum clearance regimen. This review proposes a physiological rationale for the use of ACTs in COPD, taking into consideration the presence of bronchiectasis, the amount of sputum produced, the degree of airflow obstruction and the presence of decreased lung elastic recoil. The selection of an optimal ACT for individuals with COPD should take into account its effects on lung vloumes, expiratory flow and dynamic airway compression. Care should be taken to avoid airway collapse during forced expirations in patients with reduced lung recoil pressure; positive expiratory pressure therapy or autogenic drainage may prove effective in this patient group. The acceptability of ACTs to patients should also be considered, especially where long-term adherence is required. Future research should focus on more appropriate matching of the physiological effects of individual ACTs to the pathophysiology of lung disease in COPD.

Active cycle of breathing technique for cystic fibrosis

BACKGROUND

People with cystic fibrosis experience chronic airway infections as a result of mucus build up 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 (also known as 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 the active cycle of breathing technique with other airway clearance therapies in cystic fibrosis.

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 the reference lists of relevant articles and reviews.Date of last search: 25 April 2016.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical studies, including cross-over studies, comparing the active cycle of breathing technique with other airway clearance therapies in cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened each article, abstracted data and assessed the risk of bias of each study.

MAIN RESULTS

Our search identified 62 studies, of which 19 (440 participants) met the inclusion criteria. Five randomised controlled studies (192 participants) were included in the meta-analysis; three 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 22.33 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 the active cycle of breathing technique with autogenic drainage, airway oscillating devices, high frequency chest compression devices, conventional chest physiotherapy, and positive expiratory pressure. Preference of technique varied: more participants preferred autogenic drainage over the active cycle of breathing technique; more preferred the active cycle of breathing technique over airway oscillating devices; and more were comfortable with the active cycle of breathing technique versus high frequency chest compression. No significant difference was seen in quality of life, sputum weight, exercise tolerance, lung function, or oxygen saturation between the active cycle of breathing technique and autogenic drainage or between the active cycle of breathing technique and airway oscillating devices. There was no significant difference in lung function and the number of pulmonary exacerbations between the active cycle of breathing technique alone or in conjunction with conventional chest physiotherapy. All other outcomes were either not measured or had insufficient data for analysis.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or reject the use of the active cycle of breathing technique over any other airway clearance therapy. Five studies, with data from eight different comparators, found that the active cycle of breathing technique was 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 the active cycle of breathing technique on outcomes important for people with cystic fibrosis such as quality of life and preference.

Oscillatory Positive Expiratory Pressure in Chronic Obstructive Pulmonary Disease

Evidence-based guidance for the use of airway clearance techniques (ACT) in chronic obstructive pulmonary disease (COPD) is lacking in-part because well-established measurements of pulmonary function such as the forced expiratory volume in 1s (FEV1) are relatively insensitive to ACT. The objective of this crossover study was to evaluate daily use of an oscillatory positive expiratory pressure (oPEP) device for 21-28 days in COPD patients who were self-identified as sputum-producers or non-sputum-producers. COPD volunteers provided written informed consent to daily oPEP use in a randomized crossover fashion. Participants completed baseline, crossover and study-end pulmonary function tests, St. George's Respiratory Questionnaire (SGRQ), Patient Evaluation Questionnaire (PEQ), Six-Minute Walk Test and (3)He magnetic resonance imaging (MRI) for the measurement of ventilation abnormalities using the ventilation defect percent (VDP). Fourteen COPD patients, self-identified as sputum-producers and 13 COPD-non-sputum-producers completed the study. Post-oPEP, the PEQ-ease-bringing-up-sputum was improved for sputum-producers (p = 0.005) and non-sputum-producers (p = 0.04), the magnitude of which was greater for sputum-producers (p = 0.03). There were significant post-oPEP improvements for sputum-producers only for FVC (p = 0.01), 6MWD (p = 0.04), SGRQ total score (p = 0.01) as well as PEQ-patient-global-assessment (p = 0.02). Clinically relevant post-oPEP improvements for PEQ-ease-bringing-up-sputum/PEQ-patient-global-assessment/SGRQ/VDP were observed in 8/7/9/6 of 14 sputum-producers and 2/0/3/3 of 13 non-sputum-producers. The post-oPEP change in (3)He MRI VDP was related to the change in PEQ-ease-bringing-up-sputum (r = 0.65, p = 0.0004) and FEV1 (r = -0.50, p = 0.009). In COPD patients with chronic sputum production, PEQ and SGRQ scores, FVC and 6MWD improved post-oPEP. FEV1 and PEQ-ease-bringing-up-sputum improvements were related to improved ventilation providing mechanistic evidence to support oPEP use in COPD. Clinical Trials # NCT02282189 and NCT02282202.

Correlation between Peak Expiratory Flow and Abdominal Muscle Thickness

[Purpose] The purpose of this study was to determine whether forced expiration is correlated with abdominal muscle thickness. [Subjects] Twenty-three healthy male volunteers participated in this study. [Methods] The peak expiratory flow (PEF) was obtained using a peak flow meter with subjects in the sitting position. The thicknesses of the right rectus abdominis, external oblique, internal oblique, and transverse abdominis muscles were measured using B-mode ultrasonography at the end of a relaxed expiration in the supine position. [Results] Among the abdominal muscles, only the thickness of the external oblique muscle displayed a significant correlation with PEF. [Conclusion] It appears that the thickness of the external oblique muscle might be associated with PEF during forced expiration.

Mucolytics for bronchiectasis

BACKGROUND

Bronchiectasis is predominantly an acquired disease process that represents the end stage of a variety of unrelated pulmonary insults. It is defined as persistent irreversible dilatation and distortion of medium-sized bronchi. It has been suggested that with widespread use of high-resolution computed tomography, more bronchiectasis diagnoses are being made. Patients diagnosed with bronchiectasis frequently have difficulty expectorating sputum. Sputum therefore is retained in the lungs and may become infected, leading to further lung damage. Mucolytic agents target hypersecretion or changed physiochemical properties of sputum to make it easier to clear. One drug, recombinant human DNase, breaks down the DNA that is released at the site of infection by neutrophils.Mucus clearance along with antimicrobial therapy remains an integral part of bronchiectasis management. Chest physiotherapy along with mucolytic agents is commonly used in practice without clear supportive evidence.

OBJECTIVES

To determine whether ingested or inhaled mucolytics are effective in the treatment of patients with bronchiectasis.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register and reference lists of relevant articles. We contacted experts in the field and drug companies. Searches were current as of June 2013.

SELECTION CRITERIA

Randomised trials of mucolytic treatment in people with bronchiectasis but not cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Data extraction was performed independently by two review authors. Study authors were contacted for confirmation.

MAIN RESULTS

Four trials (with a combined total of 528 adult participants) were included, but almost none of the data from these studies could be aggregated in a meta-analysis.One trial (with 88 participants) compared bromhexine versus placebo. Compared with placebo, high doses of bromhexine with antibiotics eased difficulty in expectoration (mean difference (MD) -0.53, 95% confidence interval (CI) -0.81 to -0.25 at 16 days); the quality of the evidence was rated as low. A reduction in sputum production was noted with bromhexine (MD -21.5%, 95% CI -38.9 to -4.1 at day 16); again the quality of the evidence was rated as low. No significant differences between bromhexine and placebo were observed with respect to reported adverse events (odds ratio (OR) 2.93; 95% CI 0.12 to 73.97), and again the quality of the evidence was rated as low.In a single small, blinded but not placebo-controlled trial of older (> 55 years) participants with stable bronchiectasis and mucus hypersecretion, erdosteine combined with physiotherapy over a 15-day period improved spirometry and sputum purulence more effectively compared with physiotherapy alone. The spirometric improvement was small (MD 200 mL in forced expiratory volume in one second (FEV1) and 300 mL in forced vital capacity (FVC)) and was apparent only at day 15, not at earlier time points.The remaining two studies (with a combined total of 410 participants) compared recombinant human DNase (RhDNase) versus placebo. These two studies were very different (one was a two-week study of 61 participants, and the other ran for 24 weeks and included 349 participants), and the opportunity for combining data from the two studies was very limited. Compared with placebo, recombinant human DNase showed no difference in FEV1 or FVC in the smaller study but showed a significant negative effect on FEV1 in the larger and longer study. For reported adverse events, no significant differences between recombinant human DNase and placebo were noted. In all of the above comparisons of recombinant human DNase versus placebo, the quality of the evidence was judged to be low.

AUTHORS' CONCLUSIONS

Given the harmful effects of recombinant human DNase in one trial and no evidence of benefit, this drug should be avoided in non-cystic fibrosis bronchiectasis, except in the context of clinical trials. Evidence is insufficient to permit evaluation of the routine use of other mucolytics for bronchiectasis. High doses of bromhexine coupled with antibiotics may help with sputum production and clearance, but long-term data and robust clinical outcomes are lacking. Similarly, erdosteine may be a useful adjunct to physiotherapy in stable patients with mucus hypersecretion, but robust longer-term trials are required.Generally, clinical trials in children on the use of various mucolytic agents are lacking. As the number of agents available on the market, such as RhDNase, acetylcysteine and bromhexine, is increasing, improvement of the evidence base is needed.

Positive expiratory pressure via mask does not improve ventilation inhomogeneity more than huffing and coughing in individuals with stable chronic obstructive pulmonary disease and chronic sputum expectoration

BACKGROUND

Positive expiratory pressure (PEP) has been used to promote airway clearance in individuals with chronic obstructive pulmonary disease (COPD) for many years; however, its mechanism of action and benefits are unclear. Previous authors have suggested that PEP improves collateral ventilation via changes in lung volumes.

OBJECTIVES

It was the aim of this study to determine whether PEP improves ventilation inhomogeneity more than controlled huffing and coughing in individuals with stable COPD.

METHODS

Twelve participants with COPD (mean forced expiratory volume in 1 s 45% predicted) and chronic sputum expectoration performed PEP therapy (10-20 cm H2O) or controlled huffing and coughing in random order on alternate study days with a 48-hour washout. Measures of acinar and conductive airway ventilation (S(acin), S(cond)), lung volumes, spirometry and sputum wet weight were recorded before, immediately after and 90 min following treatment. Ease of expectoration [visual analogue scale (VAS)] and oxyhaemoglobin saturation were assessed immediately following treatment.

RESULTS

There were no significant differences between the effect of either test condition at any time point for any test parameter. Mean Sacin immediately following PEP and control conditions was 0.465 and 0.438 litre(-1), respectively (p = 0.45 for comparison between conditions) and mean S(cond) was 0.042 and 0.039 litre(-1) (p = 0.55). PEP therapy did not significantly enhance total mean sputum expectoration compared to controlled huffing and coughing (7.06 vs. 6.15 g; p = 0.51) and did not improve ease of expectoration (VAS PEP 4.8 cm vs. control 4.1 cm; p = 0.53).

CONCLUSION

Any therapeutic benefits of PEP in individuals with COPD and chronic sputum expectoration are unlikely to be mediated by improvements in ventilation or lung volumes.

Effects of manual rib cage compressions on expiratory flow and mucus clearance during mechanical ventilation

OBJECTIVES

We investigated the effects of two different types of manual rib cage compression on expiratory flow and mucus clearance during prolonged mechanical ventilation in pigs.

DESIGN

Prospective randomized animal study.

SETTING

Animal research facility, University of Barcelona, Spain.

SUBJECTS

Nine healthy pigs.

MEASUREMENT AND MAIN RESULTS

Pigs were tracheally intubated, sedated, paralyzed, and mechanically ventilated. The animals were prone on a surgical bed in the anti-Trendelenburg position. The experiments were carried out at approximately 60 and 80 hrs from the beginning of mechanical ventilation. Two types of manual rib cage compressions were tested: Hard and brief rib cage compressions synchronized with early expiratory phase (hard manual rib cage compression) and soft and gradual rib cage compressions applied during the late expiratory phase (soft manual rib cage compression). The interventions were randomly applied for 15min with a 15-min interval between treatments. Respiratory flow and mucus movement were assessed during the interventions. Respiratory mechanics and hemodynamics were assessed prior to and after the interventions. Peak expiratory flow increased to 60.1±7.1L/min in comparison to 51.2±4.6L/min without treatment (p < 0.0015) and 48.7±4.3L/min with soft manual rib cage compression (p = 0.0002). Similarly, mean expiratory flow increased to 28.4±5.2L/min during hard manual rib cage compression vs. 15.9±2.2 and 16.6±2.8L/min without treatment and soft manual rib cage compression, respectively (p = 0.0006). During hard manual rib cage compression, mucus moved toward the glottis (1.01 ± 2.37mm/min); conversely, mucus moved toward the lungs during no treatment and soft manual rib cage compression, -0.28 ± 0.61 and -0.15±0.95mm/min, respectively (p = 0.0283). Soft manual rib cage compression slightly worsened static lung elastance and cardiac output (p = 0.0391).

CONCLUSIONS

Hard manual rib cage compression improved mucus clearance in animals positioned in the anti-Trendelenburg position. The technique appeared to be safe. Conversely, soft manual rib cage compression was not effective and potentially unsafe. These findings corroborate the predominant role of peak expiratory flow on mucus clearance.

Active cycle of breathing technique for cystic fibrosis

BACKGROUND

People with cystic fibrosis experience chronic airway infections as a result of mucus build up 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.

OBJECTIVES

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

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 the reference lists of relevant articles and reviews.Date of last search: 02 August 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical studies, including cross-over studies, comparing ACBT with other airway clearance therapies in cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened each article, abstracted data and assessed the risk of bias of each study.

MAIN RESULTS

Sixty studies were identified of which 18 (375 participants) met the inclusion criteria. Five randomised controlled studies (127 participants) were included in the meta-analysis; four were of cross-over design. The 13 remaining studies were cross-over studies with inadequate reports for complete assessment.Included studies compared ACBT to autogenic drainage, airway oscillating devices, high frequency chest compression devices, conventional chest physiotherapy, and positive expiratory pressure. Patient preference varied: more patients preferred autogenic drainage over ACBT; more preferred ACBT over airway oscillating devices; and more were comfortable with ACBT versus high frequency chest compression. No significant difference was seen in sputum weight, lung function, or oxygen saturation between ACBT and autogenic drainage or between ACBT and airway oscillating devices. There was no significant difference in lung function and the number of pulmonary exacerbations between ACBT and ACBT plus conventional chest physiotherapy. All other outcomes were either not measured or had insufficient data for analysis.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or reject the use of ACBT over any other airway clearance therapy. Five studies, with five different comparators, found that ACBT was comparable to other therapies in outcomes such as patient preference, 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 patients such as quality of life and patient preference.

Active cycle of breathing technique for cystic fibrosis

BACKGROUND

People with cystic fibrosis (CF) experience chronic airway infections as a result of mucus build up 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.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane CF 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.Last search: 05 August 2010.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical studies, including crossover 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.

MAIN RESULTS

Fifty-eight studies were identified of which 17 (346 participants) met the inclusion criteria. Four randomised controlled studies (98 participants) were included in the meta-analysis; three were of crossover design. The 13 remaining studies were crossover studies with inadequate reports for complete assessment.Included studies compared ACBT to autogenic drainage, airway oscillating devices, high frequency chest compression devices, and conventional chest physiotherapy. Patient preference varied: more patients preferred autogenic drainage over ACBT, more preferred ACBT over airway oscillating devices, and more were comfortable with ACBT versus high frequency chest compression. No significant difference was seen in sputum weight between ACBT and autogenic drainage or between ACBT and airway oscillating devices. There was no significant difference in lung function and the number of pulmonary exacerbations between ACBT and ACBT plus conventional chest physiotherapy. All other outcomes were either not measured or had insufficient data for analysis.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or reject the use of ACBT over any other airway clearance therapy. Four studies, with four different comparators, found that ACBT was comparable to other therapies in outcomes such as patient preference, 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 patients such as quality of life and patient preference.

Should lung transplant recipients routinely perform airway clearance techniques? A randomized trial

BACKGROUND AND OBJECTIVE

Despite the widespread use of airway clearance (AC) techniques to clear excessive secretions and improve lung function, little is known about their efficacy following lung transplantation (LTx). This study compared the effects of two AC strategies (proactive vs reactive) on a range of clinical outcomes following LTx.

METHODS

A prospective randomized trial was conducted. Uncomplicated patients were recruited 1 month postoperatively. Patients performed AC using positive expiratory pressure either twice daily (proactive strategy) or only in the presence chest infection (reactive strategy). Lung function (FEV(1) and FVC), CXR (Brasfield score) and bronchoscopic airway characteristics (anastomotic healing, patency and secretions) were assessed at 1, 2 and 3 months postoperatively. Adherence was measured.

RESULTS

Of 60 consecutive patients, 36 (18 proactive, 18 reactive) were recruited and completed the study. Both groups improved lung function (FEV(1) 72 +/- 4% to 81 +/- 4%, P < 0.0001; FVC 69 +/- 3% to 81 +/- 3%, P < 0.0001) and Brasfield scores (17.8 +/- 0.5 to 19.8 +/- 0.5, P < 0.002) over the study period. No significant differences for any outcome were found between the two groups. The vast majority of patients had fully healed, 100% patent anastomoses without secretions at 3 months. There were no significant differences between the two groups in airway characteristics and the incidence of chest infection. Adherence to both strategies was high (84% proactive, 100% reactive).

CONCLUSIONS

Proactive AC following lung transplantation was not associated with a reduced incidence of respiratory infection, alteration of CXR findings or improvement in airway characteristics.

Mucociliary clearance in COPD can be increased by both a D2/β2 and a standard β2 agonists

In addition to breathlessness and cough, excessive mucus production is one of the main symptoms of chronic obstructive pulmonary disease (COPD). Excess mucus coupled with deteriorating mucociliary clearance is associated with a decline in lung function and an increased risk of death from pulmonary infection. The effect of Viozan (Sibenadet HCl, AR-C68397AA), a novel dual D2 dopamine receptor, beta2-adrenoceptor agonist, on mucociliary clearance was investigated together with that of a beta2-adrenoceptor agonist, salbutamol. Using a double blind, parallel group study design, 15 patients with COPD, all habitual smokers, were randomised to receive nebulised sidenadet (3mg tid; n = 7) or salbutamol (5mg tid; n = 8) for 10 days. Lung mucociliary clearance rates were measured, by a standard radioaerosol technique, before and after the treatment period, as were 24-h sputum volumes. Both sibenadet and salbutamol therapies resulted in significant (P<0.02) enhancement of lung mucociliary clearance. The 24-h sputum volume was significantly reduced following sibenadet therapy (P<0.03) whereas salbutamol therapy had no effect. Our results, in addition to illustrating the effects of a standard beta2 agonist on mucociliary clearance, strongly suggest the potential dual benefit of dual-agonist compounds in lessening sputum production whilst simultaneously enhancing mucociliary clearance. For reasons unconnected with the present study, development work on this specific formulation is no Longer proceeding.

Active cycle of breathing techniques in non-invasive ventilation for acute hypercapnic respiratory failure

We hypothesised that applying the active cycle of breathing techniques (ACBT) in patients with acute hypercapnic respiratory failure undergoing non-invasive ventilation would improve patient outcome. Thirty-four patients were randomised so that 17 patients with acute hypercapnic respiratory failure received the ACBT and non-invasive ventilation (ACBT group), and 17 patients received non-invasive ventilation alone (control group). The primary outcome measure was length of time requiring non-invasive ventilation, and secondary outcome measures were change in acute physiology score, change in arterial blood gas values, total duration of non-invasive ventilation, and length of stay in the intensive care unit. Although not significant, there was a greater decrease in arterial carbon dioxide pressure in the ACBT group compared to the control group (-21.41 mmHg vs -17.45 mmHg, p = 0.27). Total duration of ventilation tended to be shorter in the ACBT group than in the control group (64.9 hours vs 84.1 hours, p = 0.15). Length of time in need of non-invasive ventilation was significantly lower in the ACBT group than in the control group (5.0 days vs 6.7 days, p = 0.03). There was no significant difference in length of stay in the intensive care unit between the two groups (8.0 vs 9.4 days, p = 0.31). The use of ACBT may have positive effects in the treatment of patients with acute hypercapnic respiratory failure, resulting in a shorter length of time requiring non-invasive ventilation.

The effect of huffing and directed coughing on energy expenditure in young asymptomatic subjects

Coughing and huffing have been shown to be effective airway clearance techniques and some authors have anecdotally reported that a huff requires less energy than a series of coughs commencing and finishing at the same lung volume. The aim of this study was to determine whether there is a difference in the energy expenditure between periods of huffing and directed voluntary coughing commencing from the same initial lung volume in young asymptomatic subjects. Energy expenditure was measured using open-circuit indirect calorimetry equipment. Twenty-four non-smoking asymptomatic subjects (12 male, 12 female, aged 18-24 years), without any form of disease and within 10% of their predicted pulmonary function, completed the study. Energy expenditure was measured over three 10min, randomly ordered sessions of huffing, directed coughing and rest. The forced expiratory sessions comprised a single huff or double-barrel cough (both starting at total lung capacity) at the end of every two minutes. Each session was separated by a 5min washout period. No significant difference in energy expenditure was found between the huffing and directed coughing periods (mean difference 0.003 mL/kg/min (95% CI -0.160 to 0.114) and both produced significantly greater energy expenditure than rest (rest and huff mean difference 0.309 mL/kg/min (95% CI 0.080 to 0.549) and rest and cough mean difference 0.306 mL/kg/min (95% CI 0.074 to 0.508)). The suggested benefits of huffing versus coughing in terms of energy conservation are yet to be shown.

Acute respiratory infection in patients with cystic fibrosis with mild pulmonary impairment: comparison of two physiotherapy regimens

Chest physiotherapy is an essential part of the management of cystic fibrosis, yet comparatively few studies have investigated the commonly used forms of chest physiotherapy during acute respiratory exacerbations. Fifteen subjects with cystic fibrosis and predominantly mild pulmonary impairment completed a randomised cross-over trial with 24 hours between treatments. The active cycle of breathing techniques (ACBT) assisted by a physiotherapist was compared with the ACBT performed independently by the patient. Measurement outcomes included pulmonary function tests, indirect calorimetry and oximetry parameters. Energy expenditure was not significantly different between the two treatment regimens, though significant improvements in pulmonary function were apparent 24 hours following the therapist-assisted ACBT. In this group of subjects, neither form of treatment proved superior in terms of energy consumption, but a reduction in airways obstruction was observed as a carry-over effect following the therapist-assisted ACBT.

The active cycle of breathing techniques--to tip or not to tip?

The active cycle of breathing techniques (ACBT) in gravity-assisted drainage positions is an effective airway clearance regimen for individuals who produce excess bronchial secretions. This study compared the ACBT in positions with and without a head-down tilt. Nineteen subjects (11 men), mean age 37.1 years (range 18-76 years), with bronchiectasis who produced more than 20 g of sputum per day and had a mean forced expiratory volume in 1 s (FEV1) of 56.9% predicted (range 23-90% pred.) were studied. There was no significant difference in the wet weight of sputum expectorated when using the ACBT in gravity-assisted drainage positions with or without a head-down tilt. Mean (SD) score for perception of breathlessness, measured on a visual analogue scale, increased significantly following treatment with a head-down tilt [2.3 (1.6) to 3.3 (2.0) cm, P = 0.02]. There was no significant difference in oxygenation or lung function (FEV1). Eighteen subjects preferred the ACBT without a head-down tilt. The ACBT in the horizontal position is a simple airway clearance regimen suitable for individuals who produce greater than 20 g of sputum per day. Subjects were less breathless and preferred the ACBT in the horizontal position, thus providing a treatment alternative that may improve adherence in individuals who are required to carry out daily airway clearance treatments.

Effect of oral antibiotics on lung mucociliary clearance during exacerbation of chronic obstructive pulmonary disease

It has been well established that lung mucociliary clearance is depressed in patients with chronic obstructive pulmonary disease. This study examines whether oral antibiotics have a detectable effect on this clearance mechanism during exacerbation in patients with such disease. Twelve patients with a mean +/- SE age of 63 +/- 2 years participated in a randomized, double-blind, parallel group study to assess the effect of 1 week of treatment with amoxycillin (500 mg t.d.s.) or ciprofloxacin (500 mg b.d.) on lung mucociliary clearance during exacerbation. Lung mucociliary clearance rates were measured by a non-invasive radioaerosol technique. Both drugs on average resulted in small, non-significant, enhancement of mucociliary clearance. Following treatment, the numbers of coughs were reduced in both groups and significantly (P < 0.05) after treatment with ciprofloxacin. Sputum production was also significantly reduced (P < 0.01) in both groups. The magnitude of improvement in lung mucociliary clearance was relatively modest following 1 week of treatment with either antibiotic. Since the number of coughs was significantly less after ciprofloxacin treatment the measured enhancement of lung mucociliary transport is probably, however, an underestimate.