Severity of bronchiectasis predicts use of and adherence to high frequency chest wall oscillation therapy - Analysis from the United States Bronchiectasis and NTM research registry.

BACKGROUND: High frequency chest wall oscillation (HFCWO) is a form of airway clearance therapy that has been available since the mid-1990s and is routinely used by patients suffering from retained pulmonary secretions. Patients with cystic fibrosis (CF), neuromuscular disease (NMD), and other disorders, including bronchiectasis (BE) and COPD (without BE), are commonly prescribed this therapy. Limited evidence exists describing HFCWO use in the BE population, its impact on long-term management of disease, and the specific patient populations most likely to benefit from this therapy. This study sought to characterize the clinical characteristics of patients with BE who have documented use of HFCWO at baseline and 1-year follow-up. METHODS: An analysis from a large national database registry of patients with BE was performed. Demographic and clinical characteristics of all patients receiving HFCWO therapy at baseline are reported. Patients were stratified into two groups based on continued or discontinued use of HFCWO therapy at 1-year follow-up. RESULTS: Over half (54.8 %) of patients who reported using HFCWO therapy had a Modified Bronchiectasis Severity Index (m-BSI) classified as severe, and the majority (81.4 %) experienced an exacerbation in the prior two years. Of patients with 1-year follow-up data, 73 % reported continued use of HFCWO. Compared to patients who discontinued therapy, these patients were more severe at baseline and at follow-up suggesting that patients with more severe disease are more likely to continue HFCWO therapy. CONCLUSIONS: Patients who have more severe disease and continue to experience exacerbations and hospitalizations are more likely to continue HFCWO therapy. CLINICAL TRIAL REGISTRATION: NA.

Airway Clearance Strategies and Secretion Management in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rare, neurodegenerative motor neuron disease that affects voluntary muscle movement. Often, difficulty in coughing, breathing, and swallowing are sequela associated with the condition, and the presence of bulbar muscle predominant weakness results in deleterious effects on airway clearance and secretion management. This narrative review will provide practical guidance for clinicians treating this population. Cough insufficiency in this population typically manifests as a prolonged, slow, weak cough effort that impedes the clearability of secretions and airway protection. Dystussia and dysphagia frequently occur simultaneously in bulbar dysfunction, subsequently impacting respiratory health. Measures of respiratory strength should be obtained and monitored every 3-6 months, preferably in a multidisciplinary clinic setting. Cough augmentation, whether manual or mechanical techniques, should be sought as early in the disease progression as possible to adequately control secretions in the proximal airways. This airway clearance strategy can aid in the prevention and treatment of respiratory tract infections (RTIs), which can pose a significant clinical hurdle to those with ALS. The use of mechanical insufflation-exsufflation may be complicated by severe bulbar dysfunction rendering this technique ineffective. Though peripheral airway clearance strategies, such as high-frequency chest-wall compression, have the advantage of being less impacted by bulbar dysfunction, it is only recommended this modality be used in conjunction with, versus in lieu of, proximal strategies. Salivary secretion management includes the use of anticholinergics, botulinum toxin, and radiation therapy depending on severity and desire for relief.

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.

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.

Design and initial testing of a novel disposable oscillating positive expiratory pressure device.

BACKGROUND: Oscillating positive expiratory pressure (OPEP) devices play a key role in airway clearance, particularly in patients with cystic fibrosis. These devices, however, have the potential to become reservoirs for pathogenic organisms and require daily, or even more frequent, cleaning. This places a large burden on patients and their carers. AIMS: The objective of this work was to develop a disposable OPEP device, with comparable mechanical performance to commercial devices, that negates the need for cleaning after use thus reducing microbiological risks. METHODS: 3D printing was used to iterate and develop a prototype disposable device (The University of Limerick OPEP, abbreviated to the UL-OPEP) that was compared with a selection of commercially available devices for mean pressure and oscillation amplitude (cmH2O), as well as oscillation frequency (Hz). All devices were tested using a healthy volunteer at a target expiratory flow of ~ 20 L/min. The target therapeutic range was 10-20 cmH2O at a flow rate of 10-20 L/min as is reported widely in the literature. RESULTS: The prototype disposable device achieved a mean pressure of 14.82 cmH2O at a mean flow rate of 18.82 L/min, and generated an oscillation frequency of 26 Hz with an amplitude of 1.28 cmH2O. These characteristics compare favourably with existing, more complex, reusable OPEP devices. CONCLUSIONS: The UL-OPEP device is a small, disposable OPEP device, that generates pressure and oscillation amplitudes for clinically effective airway clearance. The device negates the need for cleaning and disinfecting, removing the risk of devices acting as a potential reservoir for pathogenic organisms while maintaining mucus-clearing benefits.

[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).

[Effects of high frequency chest wall oscillatory (HFCWO) therapy on gas exchange and ventilation in healthy participants]. / Efectos en población sana de la terapia con oscilación de alta frecuencia sobre la pared torácica (HFCWO) a nivel de la dinámica de gases pulmonares y de la mecánica respiratoria.

INTRODUCTION: Chest physiotherapy is an essential part of the treatment of respiratory diseases with increased respiratory secretion and ineffective cough. To date, there have been no studies on the effect of high frequency chest wall oscillatory (HFCWO) therapy on respiratory muscle strength, ventilation and gas exchange. The aim of this study was therefore to assess these three factors in healthy participants. METHODS: Respiratory muscle strength was measured before and immediately after HFCWO therapy in 25 healthy participants. During the treatment, we continuously measured ventilation parameters, gas exchange, oxygen saturation and heart rate. All participants underwent HFCWO sessions twice (with 24hours difference) with the same procedure. Symptoms during the session and discomfort were measured with the visual analog scale (VAS). RESULTS: HFCWO therapy produced a change in breathing pattern with increased ventilation associated with altered gas exchange. Heart rate also increased, with no changes in oxygenation. There was no effect, either beneficial or deleterious, on the strength of respiratory muscles. Up to 20% of participants reported substantial discomfort (VAS≥5/10) during the session. CONCLUSIONS: This study shows that, during the application of HFCWO therapy in healthy participants, ventilation and heart rate increased. However, there were undesirable effects on gas exchange with a high degree of intolerance among volunteers, with no effects on respiratory muscle strength.

Objective Measures of Vest Therapy Adherence Among Pediatric Subjects With Cystic Fibrosis.

BACKGROUND: Airway clearance techniques (ACTs), including high-frequency chest wall oscillation (vest therapy), are important for maintaining lung function for patients with cystic fibrosis, but daily completion of ACTs is time-consuming and cumbersome. Patient adherence is a persistent challenge, and adherence data are largely patient reported, which may reduce accuracy. To provide definitive adherence data, this study utilized a Bluetooth-enabled vest therapy system to remotely collect objective adherence data from a cohort of pediatric subjects. METHODS: Vest usage data were collected over a 12-month period and compared to each subject vest prescription. Because vest prescriptions are multifaceted, we developed metrics to examine adherence to the various facets (eg, daily treatment, treatments per day, treatment duration, frequency settings, and frequency and pressure settings combined) as well as an overall adherence metric. RESULTS: Among the 73 enrolled subjects, 62 (50% male, age range 2-19 y) completed the study. Among adolescent subjects age 13-19 y, average adherence to daily vest therapy (44.0%) was significantly lower than that among subjects 0-6 y old (77.8%) and subjects 7-12 y old (89.5%). As more prescribed therapy components were combined into a single adherence metric, all age groups declined in mean adherence rates, with overall adherence a decreasing function of age. CONCLUSIONS: Employing new technology to remotely collect vest usage data allows for a granular examination of vest therapy adherence. While maintaining high levels of treatment adherence becomes increasingly difficult as children age, we also found substantial reductions in adherence rates among all age groups when more complex aspects of therapy prescriptions, such as frequency and pressure settings, were examined. These data illustrate areas providers and care teams can focus on to improve patient adherence to vest prescriptions.

Real-life experience with high-frequency chest wall oscillation vest therapy in adults with non-cystic fibrosis bronchiectasis.

BACKGROUND: High frequency chest wall oscillation (HFCWO) has long been used for airway clearance for patients with cystic fibrosis. Only limited research has evaluated this therapy in adult patients with non-cystic fibrosis bronchiectasis (NCFB). METHODS: Data from 2596 patients from a registry of adult bronchiectasis patients using HFCWO therapy was used to evaluate hospitalization patterns before and after initiation of HFCWO therapy, as well as antibiotic use and self-reported metrics of quality of life. Self-reported outcomes were also reviewed by cross-checking with sampled patient charts and found to be consistent. RESULTS: The number of patients who had at least one respiratory-related hospitalization decreased from 49.1% (192/391) in the year before to 24.0% (94/391) in the year after starting HFCWO therapy (p-value < 0.001). At the same time, the number of patients who required three or more hospitalizations dropped from 14.3% (56/391) to 5.6% (22/391). Patients currently taking oral antibiotics for respiratory conditions decreased from 57.7% upon initiation of therapy to 29.9% within 1 year (p < 0.001). Patients who subjectively rated their "overall respiratory health" as good to excellent increased from 13.6% upon initiation of therapy to 60.5% in 1 year (p < 0.001) and those who rated their "ability to clear your lungs" as good to excellent increased from 13.9% to 76.6% (p < 0.001). CONCLUSION: NCFB patients showed improved self-reported outcomes associated with the initiation of HFCWO therapy as measured by number of hospitalizations, antibiotic use, and the subjective experience of airway clearance. The improvement was observed early on after initiation of therapy and sustained for at least 1 year. The reviews of this paper are available via the supplemental material section.

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.

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.

Mechanical Ventilation Guided by Uncalibrated Esophageal Pressure May Be Potentially Harmful.

BACKGROUND: Esophageal balloon calibration was proposed in acute respiratory failure patients to improve esophageal pressure assessment. In a clinical setting characterized by a high variability of abdominal load and intrathoracic pressure (i.e., pelvic robotic surgery), the authors hypothesized that esophageal balloon calibration could improve esophageal pressure measurements. Accordingly, the authors assessed the impact of esophageal balloon calibration compared to conventional uncalibrated approach during pelvic robotic surgery. METHODS: In 30 adult patients, scheduled for elective pelvic robotic surgery, calibrated end-expiratory and end-inspiratory esophageal pressure, and the associated respiratory variations were obtained at baseline, after pneumoperitoneum-Trendelenburg application, and with positive end-expiratory pressure (PEEP) administration and compared to uncalibrated values measured at 4-ml filling volume, as per manufacturer recommendation. Data are expressed as median and [25th, 75th percentile]. RESULTS: Ninety calibrations were successfully performed. Chest wall elastance worsened with pneumoperitoneum-Trendelenburg and PEEP (19.0 [15.5, 24.6] and 16.7 [11.4, 21.7] cm H2O/l) compared to baseline (8.8 [6.3, 9.8] cm H2O/l; P < 0.0001 for both comparisons). End-expiratory and end-inspiratory calibrated esophageal pressure progressively increased from baseline (3.7 [2.2, 6.0] and 7.7 [5.9, 10.2] cm H2O) to pneumoperitoneum-Trendelenburg (6.2 [3.8, 10.2] and 16.1 [13.1, 20.6] cm H2O; P = 0.014 and P < 0.001) and PEEP (8.8 [7.7, 15.6] and 18.9 [16.3, 22.0] cm H2O; P < 0.0001 vs. baseline for both comparison; P < 0.001 and P = 0.002 vs. pneumoperitoneum-Trendelenburg) and, at each study step, they were persistently lower than uncalibrated esophageal pressure (P < 0.0001 for all comparisons). Overall, difference among uncalibrated and calibrated esophageal pressure was 5.1 [3.8, 8.4] cm H2O at end-expiration and 3.8 [3.0, 6.3] cm H2O at end-inspiration. Uncalibrated esophageal pressure swing was always lower than calibrated one (P < 0.0001 for all comparisons) with a difference of -1.0 [-1.8, -0.4] cm H2O. CONCLUSIONS: In a clinical setting with variable chest wall mechanics, uncalibrated measurements substantially overestimated absolute values and underestimated respiratory variations of esophageal pressure. Calibration could substantially improve mechanical ventilation guided by esophageal pressure.

The effects of high-frequency chest compression on end-tidal CO2.

INTRODUCTION: High-frequency chest compression (HFCC) is used for airway clearance, but may have other effects. We sought to determine if HFCC provides augmented ventilation. METHODS: During treatment, capnometry was measured with the HFCC vest set to 6-20 Hz. End-tidal CO2 (etCO2 ) was compared using generalized estimating equations. RESULTS: Twenty-four measurements were obtained from 15 subjects with mean age 15.2 ± 2.5 years and forced expiratory volume in one second (FEV1 ) % predicted 70 ± 23. EtCO2 decreased with HFCC at 6 Hz when compared with baseline (P < .001), with small changes with increasing oscillation frequency. Change in etCO2 was not predicted by FEV1 , body mass index, age, or sex. CONCLUSIONS: While HFCC has been shown to be a suitable method of airway clearance, investigators have failed to demonstrate differences between techniques. Assessment of these methodologies will become important as new airway clearance devices are proposed. Other outcome measures (besides FEV1 ) may be needed to assess effects of airway clearance, and we propose that physiologic measures might be one such measure which deserves further exploration.

Analysis of longitudinal adherence data: Hitting the target with consistency.

Typical descriptions of partial adherence summarize to what extent a patient follows a prescribed treatment plan. Another aspect of adherence relates to how consistently a patient behaves. We distinguish these two notions as "adherence target" and "adherence consistency." Most research on adherence focuses on the former concept, but the latter can be a useful idea in assessing patients' compliance. Quantifying these two notions goes beyond typical summaries of center and spread, because they may be related to each other. That is, the mean is often related to the standard deviation via the variance function. Our approach defines a parameter that measures consistency separate from the adherence target. For exponential dispersion or quasi-likelihood families, the parameter corresponds to the dispersion parameter. Assessing adherence consistency to medical treatment requires longitudinal data, which can be collected with new technology. Two examples from pediatric medicine demonstrate that detangling the notion of consistency from the adherence target is useful.