Modeling the effects of external oscillations on mucus clearance in obstructed airways.

Various therapeutic methods are employed to facilitate the clearance of secretions accumulated in the respiratory tracts of individuals with lower respiratory tract disorders. High-frequency chest wall oscillation (HFCWO) device, designed to apply variable amplitude and frequency vibrations to the individuals' chests, stands out among these therapies. In this study, the effectiveness of this treatment method was investigated numerically using computational fluid dynamics (CFD) on the generated mucus-obstructed bronchial geometry. The conducted analyses compared the effects of vibrations acting in the axial, radial, and tangential directions on the clearance of mucus, which exhibits non-Newtonian flow behavior with shear-thinning properties. Simultaneously, the effects of changes in vibration amplitude and frequency, pressure differentials, fluid properties, and ciliary movements on the flow were separately examined and interpreted. The findings demonstrate that ciliary movements are insufficient in mucus-accumulated airways, applied vibrations enhance mucus clearance, and potential improvements in flow are quite sensitive to boundary conditions.

[Pneumatic instrumental airway clearance techniques: Description, settings and indications]. / Aides instrumentales mécaniques au désencombrement : définition, aide aux réglages et indications.

Airway clearance techniques aim to eliminate excess of bronchopulmonary secretions. Common airway clearance methods involve manual techniques or the use of (oscillatory) positive expiratory pressure systems. In some clinical situations, these techniques may be ineffective, and the physiotherapist will require pneumatic instrumental support. Unfortunately, these devices are expensive and burdensome. Moreover, as their utilization requires specialized expertise, they are seldom used by practitioners. This article describes the pneumatic instrumental supports mainly used in France for airway clearance techniques currently available. We explain their key characteristics, how they function, and their basic settings according to different indications.

Effectiveness of two high-frequency chest wall oscillation techniques in patients with bronchiectasis: a randomized controlled preliminary study.

BACKGROUND: Chest physiotherapy is an important tool in the treatment of bronchiectasis. High-frequency chest wall oscillation (HFCWO) is a technique designed to create a global percussion of the lung which moves secretions and probably clears the peripheral bronchial tree. We propose the comparison between an existing device (SmartVest) and a new device (RespIn 11). METHODS: Sixty patients were randomized into three groups: a group was treated with SmartVest, a group with RespIn 11, and a group with pharmacological therapy alone. Primary outcome measures included exacerbations at 3, 6 and 12 months after the end of treatment. Secondary outcome measures were pulmonary function testing, arterial blood gas analysis (ABG), and hematological examinations, cough, dyspnea, health and quality of life scores (Bronchiectasis Health Questionnaire [BHQ], Breathlessness, Cough, and Sputum Scale [BCSS], COPD Assessment Test [CAT], Leicester Cough Questionnaire [LCT]). A five-point Likert Scale was used to evaluate patient's preference. RESULTS: Both patients in the HFCWO groups showed a significant improvement in the tests of dyspnea, cough and health and quality of life score evaluations (BHQ, BCSS, CAT, LCT) compared to the control group, but not in pulmonary function tests and ABG. Only RespIn 11 significantly reduced exacerbations in comparison with the control group. RespIn 11 also had a higher score regarding patients' preference. CONCLUSIONS: The two machines have improved health and quality of life scores in patients with bronchiectasis. RespIn 11 also demonstrated a significant lowering of exacerbations and a better patient acceptance.

Development of a device to measure adherence and pressure characteristics of positive expiratory pressure therapies used by adults with cystic fibrosis.

INTRODUCTION: Positive expiratory pressure (PEP) and oscillating positive expiratory pressure (OscPEP) therapies are often used by people with cystic fibrosis (CF) to facilitate airway clearance. However, suboptimal adherence and poor technique may reduce their effectiveness. OBJECTIVE: To develop a device (PEPtrac) to accurately measure and provide preliminary clinical data of adherence and technique characteristics when airway clearance is performed using PEP/OscPEP devices. METHODS: This study comprised two distinct phases: 1) a benchtop validation study; and 2) clinical study. Benchtop study: Accuracy of PEPtrac was measured by comparing it to video analysis for five different PEP/OscPEP devices. Clinical study: Clinical data were then collected for 18 adults with CF using one of three PEP/OscPEP devices (PariPEP S®, Acapella DH® or Aerobika®) unsupervised. RESULTS: There was 100% agreement between PEPtrac and video analysis data. Clinical data revealed significant variability in expiratory duration and pressure properties between the three PEP/OscPEP devices and between participants. For example, expiratory duration with PariPEP S® (mean [SD] = 4.8 [1.2] sec) was longer (p < .001) than Acapella DH® (3.7 [0.8] sec) and Aerobika® (2.9 [1.1] sec) and Aerobika® had a higher oscillation amplitude than Acapella DH® (6.4 [1.7] vs 5.3 [1.5] cmH2O, p < .001). DISCUSSION: Accurate measurement of PEP/OscPEP adherence and technique using a device such as PEPtrac was possible. Further research is required to investigate the clinical importance of the variability in technique seen in our clinical data.

An initial evaluation of the safety of a disposable oscillating positive expiratory pressure device in patients with chronic obstructive pulmonary disease: a sort-term pilot study.

BACKGROUND: Handheld oscillating positive expiratory pressure (OPEP) devices have been a mainstay of treatment for patients with hypersecretory conditions such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) since the 1970s. Current devices are reusable and require regular cleaning and disinfection to prevent harbouring potentially pathogenic organisms. Adherence to cleaning regimens for respiratory devices is often poor and in response to this, a prototype disposable OPEP device-the 'UL-OPEP' (University of Limerick-Oscillating Positive Expiratory Pressure device)-was developed to mitigate the risk of contamination by pathogens. The device was previously evaluated successfully in a group of paediatric CF patients. The aim of the current study was to initially evaluate the safety of the prototype in patients with COPD over a period of 1 month to ensure no adverse events, negative impacts on lung function, exercise tolerance, or quality of life. Data on user experience of the device were also collected during post-study follow-up. METHODS: A sample of 50 volunteer participants were recruited from pulmonary rehabilitation clinics within the local hospital network. The patients were clinically stable, productive, and not current or previous users of OPEP devices. Participants were invited to use a prototype disposable OPEP device daily for a period of 1 month. Pre- and post-study lung function was assessed with standard spirometry, and exercise tolerance with the 6-min-walk-test (6MWT). Quality of life was assessed using the St. George's Respiratory Questionnaire (SGRQ), and user experience of the prototype device evaluated using a post-study questionnaire. RESULTS: 24 Participants completed the study: 9 were female. Overall median age was 67.5 years, range 53-85 years. Lung function, 6-min walk test, and SGRQ scores showed no significant change post-study. User feedback was positive overall. CONCLUSIONS: The results indicate that the UL-OPEP is safe to use in patients with COPD. No adverse events were recorded during the study or in the follow-up period of 2 weeks. The device did not negatively impact patients' lung function, exercise tolerance, or quality of life during short term use (1 month), and usability feedback received was generally positive. Larger, longer duration studies will be required to evaluate efficacy. Registration The study was approved as a Clinical Investigation by the Irish Health Products Regulatory Authority (CRN-2209025-CI0085).

A short-term evaluation of a prototype disposable Oscillating Positive Expiratory Pressure (OPEP) device in a cohort of children with cystic fibrosis.

BACKGROUND: Oscillating Positive Expiratory Pressure (OPEP) devices are important adjuncts to airway clearance therapy in patients with cystic fibrosis (CF). Current devices are typically reusable and require daily, or often more frequent, cleaning to prevent risk of infection by acting as reservoirs of potentially pathogenic organisms. In response, a daily disposable OPEP device, the UL-OPEP, was developed to mitigate the risk of contamination and eliminate the burdensome need for cleaning devices. METHODS: A convenience sample of 36 participants, all current OPEP device users, was recruited from a paediatric CF service. For one month, participants replaced their current OPEP device with a novel daily disposable device. Assessment included pre- and post-intervention lung function by spirometry, as well as Lung Clearance Index. Quality of life was assessed using the Cystic Fibrosis Questionnaire - Revised, while user experience was evaluated with a post-study survey. RESULTS: 31 participants completed the study: 18 males; median age 10 years, range 4-16 years. Lung function (mean difference ± SD, %FEV1 = 1.69 ± 11.93; %FVC = 0.58 ± 10.04; FEV1: FVC = 0.01 ± 0.09), LCI (mean difference ± SD, 0.08 ± 1.13), six-minute walk test, and CFQ-R were unchanged post-intervention. Participant-reported experiences of the device were predominantly positive. CONCLUSIONS: The disposable OPEP device maintained patients' lung function during short term use (≤ 1 month), and was the subject of positive feedback regarding functionality while reducing the risk of airway contamination associated with ineffective cleaning. REGISTRATION: The study was approved as a Clinical Investigation by the Irish Health Products Regulatory Authority (CRN-2209025-CI0085).

The effectiveness of a mobile high-frequency chest wall oscillation (HFCWO) device for airway clearance.

INTRODUCTION: High-frequency chest wall oscillation (HFCWO) is a commonly prescribed airway clearance technique (ACT) for patients whose ability to expectorate sputum is compromised. This study aimed to assess the effectiveness of a newly developed mobile ACT device (mHFCWO-The Monarch Airway Clearance System) in patients with cystic fibrosis (CF). A standard nonmobile HFCWO device (sHFCWO) was used as a comparator. METHODOLOGY: This was a randomized, open-label, crossover pilot study. CF patients were treated with each device. Sputum was collected during and after each therapy session, while spirometry tests, Brody score assessment and functional respiratory imaging were performed before and after treatments. RESULTS: Wet weight of sputum collected during and after treatment was similar for mHFCWO and sHFCWO (6.53 ± 8.55 vs 5.80 ± 5.82; P = .777). Interestingly, the mHFCWO treatment led to a significant decrease in specific airway volume (9.55 ± 9.96 vs 8.74 ± 9.70 mL/L; P < .001), while increasing specific airway resistance (0.10 ± 0.16 vs 0.16 ± 0.23 KPA*S; P < .001). These changes were heterogeneously-distributed throughout the lung tissue and were greater in the distal areas, suggesting a shift of mucus. Changes were accompanied by an overall improvement in the Brody index (57.71 ± 16.55 vs 55.20 ± 16.98; P = .001). CONCLUSION: The newly developed mobile device provides airway clearance for CF patients comparable to a nonmobile sHFCWO device, yielding a change in airway geometry and patency by the shift of mucus from the more peripheral regions to the central airways.

Acute Effects of Oscillatory PEP and Thoracic Compression on Secretion Removal and Impedance of the Respiratory System in Non-Cystic Fibrosis Bronchiectasis.

BACKGROUND: Bronchiectasis is characterized by abnormal and permanent dilatation of the bronchi, caused mainly by the progression of inflammatory processes and loss of the ability to remove mucus. Techniques to clear the airways are essential for the treatment of these patients. In this study, we aimed to evaluate the acute effects of oscillatory PEP and thoracic compression on both the clearance of secretions and impedance of airways in subjects with bronchiectasis. METHODS: This was a randomized crossover single-blinded study that involved both subjects with bronchiectasis and healthy subjects evaluated by using an impulse oscillometry system, which assessed resistance at 5 Hz and resistance 20 Hz, reactance at 5 Hz, reactance area, and resonant frequency, before, after, and 30 min after oscillatory PEP, chest compression, or control sessions. Dry and total weights, adhesiveness, purulence of the expectorated secretions, the dyspnea scale score, the acceptability and tolerance scale score, pulse oximetry, and difficulty in expectoration were also assessed. RESULTS: The dry and total weights of secretions were higher after the use of the oscillatory PEP technique than those in a control session (P = .005 and P = .039, respectively). In the bronchiectasis group, there was a decrease after oscillatory PEP in total airway resistance (P = .04), peripheral resistance (P = .005), and reactance area (P = .001). After compression, there was a decrease in peripheral resistance Hz (P = .001) and reactance area (P = .001). In the healthy group, there was an increase in resistance at 5 Hz (P = .02) after oscillatory PEP. There were no differences in acceptability and tolerance, dyspnea, and oxygen saturation. CONCLUSIONS: The oscillatory PEP technique was effective for the removal of secretions and in decreasing total and peripheral respiratory system resistance; thoracic compression had comparable positive effects on the peripheral resistance. Both techniques were safe and well tolerated by the subjects with bronchiectasis. ClinicalTrials.gov registration NCT02509637.).

Oscillating Positive Expiratory Pressure Therapy May Be Performed Poorly by Children With Cystic Fibrosis.

BACKGROUND: Oscillating positive expiratory pressure devices aid removal of excess secretions and reduce gas trapping in patients with hypersecretory pulmonary diseases, for example, cystic fibrosis. Oscillating positive expiratory pressure works when the patient exhales actively against a fixed resistor, which generates mean intrapulmonary pressures of 10-20 cm H2O with rapid fluctuations of at least 1 cm H2O from the mean. In this study, we evaluated the performance of oscillating positive expiratory pressure therapy by pediatric subjects with cystic fibrosis to determine adherence to target therapeutic pressures. METHODS: Twenty-one pediatric subjects were recruited. Each had a history of using an oscillating positive expiratory pressure device twice daily and had received standardized training and instructions from the same specialist physiotherapist. Performance was evaluated by using a flow and pressure sensor placed in-line between the participant's mouth and the device. The participants performed expirations as per their normal routine. RESULTS: None of the participants achieved target therapeutic pressure ranges during expiration. The mean ± SD pressure generated was 16.2 ± 6.8 cm H2O, whereas mean ± SD flow was 31.3 ± 8.9 L/min. The mean ± SD expiration length was 2.5 ± 1.4 s. CONCLUSIONS: Despite standardized instruction, the results demonstrated considerable variation among the participants and overall poor technique during use. Outcomes of this study indicated that airway clearance effects of oscillating positive expiratory pressure were compromised due to poor technique.

Airway clearance techniques for cystic fibrosis: an overview of Cochrane systematic reviews.

BACKGROUND: Cystic fibrosis is a life-limiting genetic condition in which thick mucus builds up in the lungs, leading to infections, inflammation, and eventually, deterioration in lung function. To clear their lungs of mucus, people with cystic fibrosis perform airway clearance techniques daily. There are various airway clearance techniques, which differ in terms of the need for assistance or equipment, and cost. OBJECTIVES: To summarise the evidence from Cochrane Reviews on the effectiveness and safety of various airway clearance techniques in people with cystic fibrosis. METHODS: For this overview, we included Cochrane Reviews of randomised or quasi-randomised controlled trials (including cross-over trials) that evaluated an airway clearance technique (conventional chest physiotherapy, positive expiratory pressure (PEP) therapy, high-pressure PEP therapy, active cycle of breathing techniques, autogenic drainage, airway oscillating devices, external high frequency chest compression devices and exercise) in people with cystic fibrosis.We searched the Cochrane Database of Systematic Reviews on 29 November 2018.Two review authors independently evaluated reviews for eligibility. One review author extracted data from included reviews and a second author checked the data for accuracy. Two review authors independently graded the quality of reviews using the ROBIS tool. We used the GRADE approach for assessing the overall strength of the evidence for each primary outcome (forced expiratory volume in one second (FEV1), individual preference and quality of life). MAIN RESULTS: We included six Cochrane Reviews, one of which compared any type of chest physiotherapy with no chest physiotherapy or coughing alone and the remaining five reviews included head-to-head comparisons of different airway clearance techniques. All the reviews were considered to have a low risk of bias. However, the individual trials included in the reviews often did not report sufficient information to adequately assess risk of bias. Many trials did not sufficiently report on outcome measures and had a high risk of reporting bias.We are unable to draw definitive conclusions for comparisons of airway clearance techniques in terms of FEV1, except for reporting no difference between PEP therapy and oscillating devices after six months of treatment, mean difference -1.43% predicted (95% confidence interval -5.72 to 2.87); the quality of the body of evidence was graded as moderate. The quality of the body of evidence comparing different airway clearance techniques for other outcomes was either low or very low. AUTHORS' CONCLUSIONS: There is little evidence to support the use of one airway clearance technique over another. People with cystic fibrosis should choose the airway clearance technique that best meets their needs, after considering comfort, convenience, flexibility, practicality, cost, or some other factor. More long-term, high-quality randomised controlled trials comparing airway clearance techniques among people with cystic fibrosis are needed.

Acute effects of combined exercise and oscillatory positive expiratory pressure therapy on sputum properties and lung diffusing capacity in cystic fibrosis: a randomized, controlled, crossover trial.

BACKGROUND: Regular airway clearance by chest physiotherapy and/or exercise is critical to lung health in cystic fibrosis (CF). Combination of cycling exercise and chest physiotherapy using the Flutter® device on sputum properties has not yet been investigated. METHODS: This prospective, randomized crossover study compared a single bout of continuous cycling exercise at moderate intensity (experiment A, control condition) vs a combination of interval cycling exercise plus Flutter® (experiment B). Sputum properties (viscoelasticity, yield stress, solids content, spinnability, and ease of sputum expectoration), pulmonary diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO) were assessed at rest, directly and 45 min post-exercise (recovery) at 2 consecutive visits. Primary outcome was change in sputum viscoelasticity (G', storage modulus; G", loss modulus) over a broad frequency range (0.1-100 rad.s- 1). RESULTS: 15 adults with CF (FEV1range 24-94% predicted) completed all experiments. No consistent differences between experiments were observed for G' and G" and other sputum properties, except for ease of sputum expectoration during recovery favoring experiment A. DLNO, DLCO, alveolar volume (VA) and pulmonary capillary blood volume (Vcap) increased during experiment A, while DLCO and Vcap increased during experiment B (all P < 0.05). We found no differences in absolute changes in pulmonary diffusing capacity and its components between experiments, except a higher VA immediately post-exercise favoring experiment A (P = 0.032). CONCLUSIONS: The additional use of the Flutter® to moderate intensity interval cycling exercise has no measurable effect on the viscoelastic properties of sputum compared to moderate intensity continuous cycling alone. Elevations in diffusing capacity represent an acute exercise-induced effect not sustained post-exercise. TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT02750722 ; URL: clinical.trials.gov; Registration date: April 25th, 2016.

High-Frequency Oscillatory Ventilation Use and Severe Pediatric ARDS in the Pediatric Hematopoietic Cell Transplant Recipient.

INTRODUCTION: The effectiveness of high-frequency oscillatory ventilation (HFOV) in the pediatric hematopoietic cell transplant patient has not been established. We sought to identify current practice patterns of HFOV, investigate parameters during HFOV and their association with mortality, and compare the use of HFOV to conventional mechanical ventilation in severe pediatric ARDS. METHODS: This is a retrospective analysis of a multi-center database of pediatric and young adult allogeneic hematopoietic cell transplant subjects requiring invasive mechanical ventilation for critical illness from 2009 through 2014. Twelve United States pediatric centers contributed data. Continuous variables were compared using a Wilcoxon rank-sum test or a Kruskal-Wallis analysis. For categorical variables, univariate analysis with logistic regression was performed. RESULTS: The database contains 222 patients, of which 85 subjects were managed with HFOV. Of this HFOV cohort, the overall pediatric ICU survival was 23.5% (n = 20). HFOV survivors were transitioned to HFOV at a lower oxygenation index than nonsurvivors (25.6, interquartile range 21.1-36.8, vs 37.2, interquartile range 26.5-52.2, P = .046). Survivors were transitioned to HFOV earlier in the course of mechanical ventilation, (day 0 vs day 2, P = .002). No subject survived who was transitioned to HFOV after 1 week of invasive mechanical ventilation. We compared subjects with severe pediatric ARDS treated only with conventional mechanical ventilation versus early HFOV (within 2 d of invasive mechanical ventilation) versus late HFOV. There was a trend toward difference in survival (conventional mechanical ventilation 24%, early HFOV 30%, and late HFOV 9%, P = .08). CONCLUSIONS: In this large database of pediatric allogeneic hematopoietic cell transplant subjects who had acute respiratory failure requiring invasive mechanical ventilation for critical illness with severe pediatric ARDS, early use of HFOV was associated with improved survival compared to late implementation of HFOV, and the subjects had outcomes similar to those treated only with conventional mechanical ventilation.

The Role of Multidetector Computed Tomography and the Forced Oscillation Technique in Assessing Lung Damage in Adults With Cystic Fibrosis.

BACKGROUND: With increased survival rates and the consequent emergence of an adult population with cystic fibrosis (CF), developing novel tools for periodic evaluations of these patients has become a new challenge. Thus, we sought to determine the contribution of lung-volume quantification using multidetector computed tomography (CT) in adults with CF and to investigate the association between structural changes and functional abnormalities. METHODS: This was a cross-sectional study in which 21 adults with CF and 22 control subjects underwent lung-volume quantification using multidetector CT. Voxel densities were divided into 4 bands: -1,000 to -900 Hounsfield units (HU) (hyperaerated region), -900 to -500 HU (normally aerated region), -500 to -100 HU (poorly aerated region), and -100 to 100 HU (non-aerated region). In addition, all participants performed pulmonary function tests including spirometry, body plethysmography, diffusion capacity for carbon monoxide, and the forced oscillation technique. RESULTS: Adults with CF had more non-aerated regions and poorly aerated regions with lung-volume quantification using multidetector CT than controls. Despite these abnormalities, total lung volume measured by lung-volume quantification using multidetector CT did not differ between subjects and controls. Total lung capacity (TLC) measured by body plethysmography correlated with both total lung volume (rs = 0.71, P < .001) and total air volume (rs = 0.71, P < .001) as measured with lung-volume quantification using multidetector CT. While the hyperaerated regions correlated with the functional markers of gas retention in the lungs (increased residual volume (RV) and RV/TLC ratio), the poorly aerated regions correlated with the resistive parameters measured by the forced oscillation technique (increased intercept resistance and mean resistance). We also observed a correlation between normally aerated regions and highest pulmonary diffusion values (rs = 0.68, P < .001). CONCLUSIONS: In adults with CF, lung-volume quantification using multidetector CT can destimate the lung volumes of compartments with different densities and determine the aerated and non-aerated contents of the lungs; furthermore, lung-volume quantification using multidetector CT is clearly related to pulmonary function parameters.

Cardiopulmonary exercise testing and second-line pulmonary function tests to detect obstructive pattern in symptomatic smokers with borderline spirometry.

BACKGROUND: The need for additional research on symptomatic smokers with normal spirometry has been recently emphasized. Albeit not meeting criteria for Chronic obstructive pulmonary disease (COPD) diagnosis, symptomatic smokers may experience activity limitation, evidence of airway disease, and exacerbations. We, therefore, evaluated whether symptomatic smokers with borderline spirometry (post-bronchodilator FEV1/FVC ratio between 5th to 20th percentile of predicted values) have pulmonary function abnormalities at rest and ventilatory constraints during exercise. METHODS: 48 subjects (aged 60 ± 8 years, mean ± SD, 73% males, 16 healthy, and 17 symptomatic smokers) underwent cardiopulmonary exercise testing (CPET), body plethysmography, nitrogen single-breath washout test (N2SBW), lung diffusion for carbon monoxide (DLCO), and forced oscillation technique (FOT). RESULTS: Compared to healthy subjects, symptomatic smokers showed: 1) reduced breathing reserve (36 ± 17 vs. 49 ± 12%, P = 0.050); 2) exercise induced dynamic hyperinflation (-0.20 ± 0.17 vs. -0.03 ± 0.21 L, P = 0.043); 3) higher residual volume (158 ± 22 vs. 112 ± 22%, P < 0.001); 4) phase 3 slope at N2SBW (4.7 ± 2.1 vs. 1.4 ± 0.6%, P < 0.001); 5) no significant differences in DLCO and FOT results. CONCLUSIONS: In smokers with borderline spirometry, CPET and second-line pulmonary function tests may detect obstructive pattern. These subjects should be referred for second line testing, to obtain a diagnosis, or at least to clarify the mechanisms underlying symptoms. Whether the natural history of these patients is similar to COPD, and they deserve a similar therapeutic approach is worth investigating.

Objective Measurement of Adherence to Out-Patient Airway Clearance Therapy by High-Frequency Chest Wall Compression in Cystic Fibrosis.

BACKGROUND: Objective measures of adherence to high-frequency chest wall compression (HFCWC), a form of airway clearance therapy for patients with cystic fibrosis, are lacking. We used a novel electronic monitoring device integrated into an HFCWC vest to measure adherence compared with self-reported adherence. We determined factors that influenced adherence and how adherence correlated with baseline pulmonary function and pulmonary exacerbations. METHODS: Data were collected by direct measurement of date, time of day, and duration of HFCWC use to determine the number of daily treatments and daily duration of treatments. Chart review provided prescribed airway clearance therapy treatment and demographic and clinical information. Subject and caregiver report of the daily number of airway clearance therapy treatments was obtained by telephone interviews. Analysis used 2-sample and paired t test, analysis of variance, and linear regression. RESULTS: Average adherence was 69%. Adherence was highest in children (82%, P = .02) and those receiving assistance with treatment (82%, P < .001). Subjects overestimated therapy duration from a mean ± SD of 127 ± 169% by adults to 19.2 ± 26.3% by parents or guardians of children. Average adherence decreased with increasing prescribed therapy time (P = .02). Average daily therapy time and adherence had significant positive associations with baseline FEV1 percent of predicted (P = .02 and P = .02, respectively) and negative associations with pulmonary exacerbations during the pre-study period and at baseline (P = .044 and P = .02, respectively). CONCLUSIONS: Greater adherence to HFCWC measured directly by a novel recorder was associated with better baseline pulmonary function and fewer exacerbations in the pre-study and baseline period. Adherence decreased with age and prescribed therapy time and increased with therapy assistance. Self-report overestimation is large and thus not an accurate measure of adherence.

Effects of treadmill exercise versus Flutter® on respiratory flow and sputum properties in adults with cystic fibrosis: a randomised, controlled, cross-over trial.

BACKGROUND: Treadmill exercise and airway clearance with the Flutter® device have previously been shown to improve mucus clearance mechanisms in people with cystic fibrosis (CF) but have not been compared. It is therefore not known if treadmill exercise is an adequate form of airway clearance that could replace established airway clearance techniques, such as the Flutter®. The aim of this study was to evaluate respiratory flow, sputum properties and subjective responses of treadmill exercise and Flutter® therapy, compared to resting breathing (control). METHODS: Twenty-four adults with mild to severe CF lung disease (FEV1 28-86% predicted) completed a three-day randomised, controlled, cross-over study. Interventions consisted of 20 min of resting breathing (control), treadmill exercise at 60% of the participant's peak oxygen consumption and Flutter® therapy. Respiratory flow was measured during the interventions. Sputum properties (solids content and mechanical impedance) and subjective responses (ease of expectoration and sense of chest congestion) were measured before, immediately after the interventions and after 20 min of recovery. RESULTS: Treadmill exercise and Flutter® resulted in similar significant increases in peak expiratory flow, but only Flutter® created an expiratory airflow bias (i.e. peak expiratory flow was at least 10% higher than peak inspiratory flow). Treadmill exercise and Flutter® therapy resulted in similar significant reductions in sputum mechanical impedance, but only treadmill exercise caused a transient increase in sputum hydration. Treadmill exercise improved ease of expectoration and Flutter® therapy improved subjective sense of chest congestion. CONCLUSIONS: A single bout of treadmill exercise and Flutter® therapy were equally effective in augmenting mucus clearance mechanisms in adults with CF. Only longer term studies, however, will determine if exercise alone is an adequate form of airway clearance therapy that could replace other airway clearance techniques. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, Registration number # ACTRN12609000168257 , Retrospectively registered (Date submitted to registry 26/2/2009, First participant enrolled 27/2/2009, Date registered 6/4/2009).

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.

Airway clearance techniques used by people with cystic fibrosis in the UK.

OBJECTIVES: To describe the current use of airway clearance techniques among people with cystic fibrosis (CF) in the UK, and the baseline characteristics for users of different airway clearance techniques. DESIGN: Analysis of the UK CF Registry 2011 data. SETTING AND PARTICIPANTS: All people with CF in the UK aged ≥11 years (n=6372). RESULTS: Of the 6372 people on the UK CF registry in 2011, 89% used airway clearance techniques. The most commonly used primary techniques were forced expiratory techniques (28%) and oscillating positive expiratory pressure (PEP) (23%). Postural drainage and high-frequency chest wall oscillation were used by 4% and 1% of people with CF, respectively. The male:female ratio of individuals who used exercise as their primary airway clearance technique was 2:1, compared with 1:1 for other techniques. Individuals with more severe lung disease tended to use devices such as non-invasive ventilation or high-frequency chest wall oscillation. CONCLUSIONS: Forced expiratory techniques and oscillating PEP are the most common airway clearance techniques used by people with CF in the UK, and postural drainage and high-frequency chest wall oscillation are the least common techniques. This is significant in terms of planning airway clearance technique trials, where postural drainage has been used traditionally as the comparator. The use of airway clearance techniques varies between countries, but the reasons for these differences are unknown.