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Airway resistance measurements using oscillometry provide a potential alternative to spirometry in assessing airway obstruction and dynamics due to measurements taken during tidal breathing. Oscillometry typically requires participants to form a tight seal around a mouthpiece that can prove challenging for some people. To address this challenge, we conducted a prospective study to evaluate the effect of different interfaces like mouthpiece, mouth mask, and nasal mask on respiratory impedance results from oscillometry in a cohort of healthy adults. Ten healthy adults [7 females; mean age: 38.9 yr (SD ±15.5)] underwent oscillometry using each of the three interfaces. We measured resistance at 5 Hz (Rrs

BackgroundEffectiveness studies with biological therapies for asthma lack standardised outcome measures. The COMSA (Core Outcome Measures sets for paediatric and adult Severe Asthma) Working Group sought to develop Core Outcome Measures (COM) sets to facilitate better synthesis of data and appraisal of biologics in paediatric and adult asthma clinical studies.MethodsCOMSA utilised a multi-stakeholder consensus process among patients with severe asthma, adult and paediatric clinicians, pharmaceutical representatives, and health regulators from across Europe. Evidence included a systematic review of development, validity and reliability of selected outcome measures plus a narrative review and a pan-European survey to better understand patients’ and carers’ views about outcome measures. It was discussed using a modified GRADE (Grading of Recommendations Assessment, Development and Evaluation) Evidence to Decision framework. Anonymous voting was conducted using predefined consensus criteria.ResultsBoth adult and paediatric COM sets include forced expiratory volume in 1 s (FEV1) as z-scores, annual frequency of severe exacerbations and maintenance oral corticosteroid use. Additionally, the paediatric COM set includes the Paediatric Asthma Quality of Life Questionnaire and Asthma Control Test or Childhood Asthma Control Test, while the adult COM set includes the Severe Asthma Questionnaire and Asthma Control Questionnaire-6 (symptoms and rescue medication use reported separately).ConclusionsThis patient-centred collaboration has produced two COM sets for paediatric and adult severe asthma. It is expected that they will inform the methodology of future clinical trials, enhance comparability of efficacy and effectiveness of biological therapies, and help assess their socioeconomic value. COMSA will inform definitions of non-response and response to biological therapy for severe asthma.

Poor adherence to asthma preventer medication is associated with life-threatening asthma attacks. The quality and outcomes framework mandated primary care annual asthma review does not include adherence monitoring and the effect of poor adherence on lung function in paediatric primary care patients is unknown. The aim was to investigate the link between inhaled corticosteroid (ICS) adherence and spirometry, fraction of exhaled nitric oxide (FeNO) and asthma control in asthmatic school-age children in this cross-sectional observational study involving three Leicestershire general practices. Children 5–16 years on the practice’s asthma registers, were invited for a routine annual asthma review between August 2018 and August 2019. Prescription and clinical data were extracted from practice databases. Spirometry, bronchodilator reversibility (BDR) and FeNO testing were performed as part of the review. 130 of 205 eligible children (63.4%) attended their review. Mean adherence to ICS was 36.2% (SEM 2.1%) and only 14.6% of children had good adherence (≥75% prescriptions issued). We found no differences in asthma exacerbations in the preceding 12 months between the adherence quartiles. 28.6% of children in the lowest and 5.6% in the highest adherence quartile had BDR ≥ 12% but this was not statistically significant (p = 0.55). A single high FeNO value did not predict adherence to ICS. Adherence to ICS in children with asthma in primary care is poor. The link between adherence to ICS and asthma exacerbations, spirometry and FeNO is complex but knowledge of adherence to ICS is critical in the management of children with asthma.

BACKGROUND: Epidemiological studies use different questions to assess recurrent cough in children. In two independent population-based studies, we assessed how prevalence estimates of cough vary depending on the questions parents are asked about their child’s cough and how answers to the different questions overlap. METHODS: We analysed cross-sectional data from two population-based studies on respiratory health: LuftiBus in the School (LUIS), conducted in 2013-2016 among 6- to 17-year-school children in the Canton of Zurich, Switzerland, and the 1998 Leicester Respiratory Cohort (LRC) study, UK where we used data from 6- to 8-year-old children from the 2003 follow-up survey. Both studies used parental questionnaires that included the same three questions on the child’s cough, namely cough without a cold, dry cough at night and coughing more than others. We assessed how the prevalence of cough varied depending on the question and how answers to the different questions on cough overlapped. We also assessed how results were influenced by age, sex, presence of wheeze and parental education. RESULTS: We included 3457 children aged 6–17 years from LUIS and 2100 children aged 6–8 years from LRC. All respiratory outcomes – cough, wheeze and physician-diagnosed asthma – were reported twice as often in the LRC as in LUIS. We found large differences in the prevalence of parent-reported cough between the three cough questions. In LUIS, 880 (25%) parents reported cough without a cold, 394 (11%) dry night cough, and 159 (5%) reported that their child coughed more than other children. In the LRC, these numbers were 1003 (48%), 527 (25%) and 227 (11%). There was only partial overlap of answers, with 89 (3%) answering yes to all questions in LUIS and 168 (8%) in LRC. Prevalence of all types of cough and overlap between the cough questions was higher in children with current wheeze. CONCLUSION: In both population-based studies prevalence estimates of cough depended strongly on the question used to assess cough with only partial overlap of responses to different questions. Epidemiological studies on cough can only be compared if they used exactly the same questions for cough.

Acute cardiorespiratory breathlessness accounts for one in eight of all emergency hospitalizations. Early, noninvasive diagnostic testing is a clinical priority that allows rapid triage and treatment. Here, we sought to find and replicate diagnostic breath volatile organic compound (VOC) biomarkers of acute cardiorespiratory disease and understand breath metabolite network enrichment in acute disease, with a view to gaining mechanistic insight of breath biochemical derangements. We collected and analyzed exhaled breath samples from 277 participants presenting acute cardiorespiratory exacerbations and aged-matched healthy volunteers. Topological data analysis phenotypes differentiated acute disease from health and acute cardiorespiratory exacerbation subtypes (acute heart failure, acute asthma, acute chronic obstructive pulmonary disease, and community-acquired pneumonia). A multibiomarker score (101 breath biomarkers) demonstrated good diagnostic sensitivity and specificity (≥80%) in both discovery and replication sets and was associated with all-cause mortality at 2 years. In addition, VOC biomarker scores differentiated metabolic subgroups of cardiorespiratory exacerbation. Louvain clustering of VOCs coupled with metabolite enrichment and similarity assessment revealed highly specific enrichment patterns in all acute disease subgroups, for example, selective enrichment of correlated C5-7 hydrocarbons and C3-5 carbonyls in heart failure and selective depletion of correlated aldehydes in acute asthma. This study identified breath VOCs that differentiate acute cardiorespiratory exacerbations and associated subtypes and metabolic clusters of disease-associated VOCs.

Asthma is a chronic airways disease characterized by episodes of wheeze, chest tightness, and evidence of reversible airflow obstruction. Symptoms are frequently triggered by exercise, exposure to aeroallergens, and respiratory viruses. It is the commonest non-communicable respiratory condition in children, affecting over 5.5 million children in the European Union alone. Both over- and under- diagnosis of asthma are common for several reasons.The diagnosis is frequently based on parental or patient reported non-specific symptoms alone. All major asthma guidelines now recommend the use of objective tests, including spirometry, bronchodilator reversibility testing, fraction of exhaled nitric oxide measurements and challenge testing to confirm the diagnosis. Recently, the European Respiratory Society published the first evidence-based international guidelines for diagnosing asthma in school-age children using objective measures. Major barriers to implementation in primary care and less well-resourced healthcare settings are access to relevant objective tests for children and quality assurance to obtain reliable results.We highlight the importance of diagnosing asthma in school-age children using objective tests and outline a practical approach for the use of widely available tests. We also review challenges and barriers to implementation of objective testing in children managed outside specialist settings.

Objectives Implementation of guidelines into clinical practice is challenging and complex. This study aims to (1) identify the training needs and capacity requirements, and (2) explore the impact on healthcare utilisation and asthma-related quality of life of implementing both spirometry and fraction of exhaled nitric oxide in diagnosis of asthma among children in the UK primary care. Methods Ten UK general practitioner practices and a total of 612 children (5–16 years) with diagnosed or suspected asthma were invited to participate in this prospective observational study. The total times that the trainer and trainee clinical staff spent on developing the training package, providing and receiving, and performing and interpreting the two tests as part of routine child asthma review were collected, and costs were calculated. We compared healthcare utilisation and asthma-related and general health-related quality of life data between the 6 months before and after the asthma review guided by objective tests. Results The average training cost for the 27 primary care clinical members was £1395. The average cost to implement and deliver the test-guided asthma review among the 612 included children was £22. In the 6 months following the tests-guided asthma review, both unplanned primary care attendance, and hospital admissions were reduced, and the asthma-related health status increased significantly. Conclusion This study provides robust cost estimates of the resources needed to implement the National Institute for Health and Care Excellence asthma guideline. It also demonstrates the potential to save healthcare costs and improve health status among asthmatic children by implementing this guideline., Is FeNO testing in primary care cost effective? Yesℏ The average training cost for the 27 primary care clinical members was £1,395. The average cost to implement and deliver the tests-guided asthma review among the 612 included children was £22.

ObjectiveTo identify risk factors for asthma attacks and poor asthma control in children aged 5–16 years.MethodsProspective observational cohort study of 460 children with asthma or suspected asthma from 10 UK general practices.Gender, age, ethnicity, body mass index, practice deprivation decile, spirometry and fraction of exhaled nitric oxide (FeNO) were recorded at baseline. Asthma control scores, asthma medication ratio (AMR) and the number of asthma attacks were recorded at baseline and at 6 months.The above independent variables were included in binary multiple logistic regression analyses for the dependent variables of: (1) poor symptom control and (2) asthma attacks during follow-up.ResultsPoor symptom control at baseline predicted poor symptom control at 6 months (OR 4.4, p=0.001), while an increase in deprivation decile (less deprived) was negatively associated with poor symptom control at 6 months (OR 0.79, p=0.003). Higher FeNO levels (OR 1.02, pA decrease in AMR was also associated with an increased OR for future asthma attacks (OR 2.99, p=0.003) when included as an independent variable.ConclusionsWe identified risk factors for poor symptom control and asthma attacks in children. Routine assessment of these factors should form part of the asthma review to identify children at an increased risk of adverse asthma-related events.

Asthma is a heterogeneous disease, characterised by different phenotypes and endotypes. Precision medicine in asthma refers to the implementation of a targeted therapy for each individual child, based on the identification of treatable traits, including environmental, immunological and genetic factors. Severe asthma in children is associated with increased hospitalisation rates, a lower quality of life, increased healthcare costs and an increased mortality. In the era of new molecular biologics treatments, it is essential to improve deep phenotyping of children with severe asthma in order to deliver the most effective treatment to each individual child. In this review, we discuss the personalised approach to the assessment and management of severe asthma. We explore the indications and use of the currently licensed biologics, as well as the potential of other emerging treatments.

BACKGROUND Sensitization to thermotolerant fungi, including filamentous fungi and Candida albicans, is associated with poor lung function in adults with severe asthma. Data in children are lacking. Environmental exposure to fungi is linked with acute severe asthma attacks, but there are few studies reporting the presence of fungi in the airways during asthma attacks. METHODS We investigated the association between fungal sensitization and/or positive fungal sputum culture and markers of asthma severity in children with chronic and acute asthma. Sensitization was determined using serum-specific IgE and skin prick testing against a panel of five fungi. Fungal culture was focused towards detection of filamentous fungi from sputum samples. RESULTS We obtained sensitization data and/or sputum from 175 children: 99 with chronic asthma, 39 with acute asthma and 37 controls. 34.1% of children with chronic asthma were sensitized to thermotolerant fungi compared with no children without asthma (p =

BackgroundInvestigating airway inflammation and pathology in wheezy preschool children is both technically and ethically challenging. Identifying and validating non-invasive tests would be a huge clinical advance. Real-time analysis of exhaled volatile organic compounds (VOCs) in adults is established, however, the feasibility of this non-invasive method in young children remains undetermined.AimTo determine the feasibility and acceptability of obtaining breath samples from preschool children by means of real-time mass spectrometry analysis of exhaled VOCs.MethodsBreath samples from preschool children were collected and analysed in real time by proton transfer reaction–time of flight–mass spectrometry (PTR–TOF–MS) capturing unique breath profiles. Acetone (mass channel m/z 59) was used as a reference profile to investigate the breath cycle in more detail. Dynamic time warping (DTW) was used to compare VOC profiles from adult breath to those we obtained in preschool children.Results16 children were recruited in the study, of which eight had acute doctor-diagnosed wheeze (mean (range) age 3.2 (1.9–4.5) years) and eight had no history of wheezing (age 3.3 (2.2–4.1) years). Fully analysable samples were obtained in 11 (68%). DTW was used to ascertain the distance between the time series of mass channel m/z 59 (acetone) and the other 193 channels. Commonality of 12 channels (15, 31, 33, 41, 43, 51, 53, 55, 57, 60, 63 and 77) was established between adult and preschool child samples despite differences in the breathing patterns.ConclusionReal-time measurement of exhaled VOCs by means of PTR–MS is feasible and acceptable in preschool children. Commonality in VOC profiles was found between adult and preschool children.

AIM To study sputum mediator profiles pattern in children with acute severe asthma, compared with stable asthma and healthy controls. The mechanisms of acute severe asthma attacks, such as biomarkers cascades and immunological responses, are poorly understood. METHODS We conducted a prospective observational case-control study of children aged 5 to 17 years, who presented to hospital with an asthma attack. Children with stable asthma were recruited during outpatient asthma clinic visits. Control children without an asthma diagnosis were recruited from surgical wards. Sputum mediator profiles were measured, and sputum leukocyte differential cell counts were generated. RESULTS Sputum data were available in 48 children (acute asthma; n = 18, stable asthma; n = 17, healthy controls; n = 13). Acute-phase biomarkers and neutrophil attractants such as IL-6 and its receptor, IL-8 and cytokines linked with bacterial signals, including TNF-R1 and TNF-R2, were elevated in asthma attacks versus stable asthma and healthy controls. T-cell attractant cytokines, associated with viral infections, such as CCL-5, CXCL-10 and CXCL-11, and CXCL-9 (secreted from eosinophils after a viral trigger) were also raised. CONCLUSION Mediator profiles consistent with bacterial and viral respiratory infections, and T2 inflammation markers co-exist in the sputum of children with acute severe asthma attacks.

Introduction: The role of FeNO in guiding asthma treatment is uncertain. We tested the hypothesis that FeNO guided care reduces exacerbations in children with asthma. Methods: A multicentre RCT recruited children (6-16 years) with asthma on regular inhaled corticosteroids (ICS) with an exacerbation in the previous year. They were randomised to asthma treatment guided by FeNO plus symptoms (FeNO group) or by symptoms only (standard care). A web-based algorithm using symptom control, ICS adherence, current treatment and (within the FeNO group) changes in FeNO gave treatment recommendations. Participants attended 3, 6, 9 and 12 month follow-up. The primary outcome was exacerbation requiring oral steroid. Secondary outcomes included time to first exacerbation, asthma control and quality of life. Results: 509 children were recruited. The mean (SD) age was 10.1 (2.6) years (61% male), median (IQR) FeNO 21 ppb (10, 48), mean (SD) %FEV1 90% (18), 56% were treated with ≤400 microg budesonide equivalent and 33% >800 microg. The primary outcome occurred in 123/255 (48%) in the FeNO group and 129/251 (51%) in the standard care group. In adjusted intention to treat analysis the odds ratio (OR) for primary outcome was 0.88 [95%CI 0.61, 1.27]. This OR was consistent across pre-defined subgroups. On 377 of 1771 assessments, the algorithm’s recommendation was not followed. In complier average causal effect analysis, adjusting for algorithm adherence, the OR for primary outcome was 0.82 [95%CI 0.48, 1.41].There were no differences in secondary outcomes between groups. Conclusion: In this population, adding FeNO to standard care did not reduced exacerbations.

BackgroundSpirometry and fraction of exhaled nitric oxide (FeNO) are commonly used in specialist centres to monitor children with asthma. The National Institute for Health and Care Excellence recommends spirometry for asthma monitoring from 5 years in all healthcare settings. There is little spirometry and FeNO data in children managed for asthma in UK primary care to support their use.ObjectivesTo study the prevalence of abnormal spirometry and FeNO in children with asthma managed in primary care and to explore their relationship with asthma control and unplanned healthcare attendances (UHA).MethodsProspective observational cohort study in children aged 5–16 years with suspected or doctor-diagnosed asthma attending an asthma review in UK general practice. Spirometry, FeNO, asthma control test (ACT) scores and number of UHAs were studied.ResultsOf 612 children from 10 general practices, 23.5% had abnormal spirometry, 36.0% had raised FeNO ≥35 parts per billion and 41.8% reported poor control. Fifty-four per cent of children reporting good asthma control had abnormal spirometry and/or raised FeNO. At follow-up, the mean number of UHAs fell from 0.31/child in the 6 months preceding review to 0.20/child over the 6 months following review (p=0.0004). Median ACT scores improved from 20 to 22 (p=0.032), and children’s ACT from 21 to 23 (pConclusionsAbnormal lung function and FeNO are common in children attending for asthma review in primary care and relate poorly to symptom scores. A symptoms-based approach to asthma monitoring without objective testing is likely to miss children at high risk of future severe asthma attacks.

Background Chest computed tomography (CT) scans have a recognised role in investigating adults with severe asthma to exclude alternative diagnoses, but its role in children is less clear. The objective of this study was to review the CT findings of our local cohort of children with severe asthma and to explore whether clinical or pathobiological parameters predicted CT changes. Methods Retrospective observational single centre study including all children attending the Leicester difficult asthma clinic (DAC) who underwent a chest CT from 2006 to 2011. Additionally, we recruited eight age-matched, non-asthmatic controls to compare differences in CT findings between asthmatic and non-asthmatic children. All CT images were independently scored by two radiologists. The DAC patients were sub-divided into binary groups for each abnormality identified so that comparisons could be made against recorded clinical variables including age, lung function, serum total IgE levels, and sputum leukocyte differential cell counts. Results Thirty DAC patients (median 12 yrs., range 5–16) were included. The most common abnormalities were bronchial wall thickening (BWT) and air trapping (AT), observed in 80 and 60% of DAC patients. Bronchiectasis (BE) was identified in 27% of DAC patients. DAC patients with evidence of BE on CT images were older than those without BE (13.9 ± 0.67 vs 11.5 ± 0.61, p = 0.038). We also identified a positive correlation between increasing BE severity and extent with age (r = 0.400, p = 0.028). Conclusion Abnormal CT findings were highly prevalent in our cohort of children with severe asthma, with bronchiectasis identified in approximately one third of children. We found no alternative diagnoses that resulted in a change in clinical management.

Background: Eosinophilia is frequently a feature of asthma. Sputum analysis can help with the diagnosis and phenotyping of asthma. The current gold standard method is unsuitable for samples...

There is emerging evidence for the role of posaconazole in the management of Aspergillus-related cystic fibrosis (CF) lung disease. The tolerability and efficacy of posaconazole in paediatric CF is not well established. We report a prospective study over a fifty-three month period evaluating the safety, tolerability, and efficacy of posaconazole in pediatric CF. Fourteen children (seven males, median age 13 years, range 3–17 years) received a total of twenty-three courses of posaconazole (13 oral suspension and 10 tablet formulation). Of these patient episodes, nine received posaconazole for emerging or active allergic bronchopulmonary aspergillosis (ABPA) and two required a combination of posaconazole and systemic corticosteroids for difficult-to-treat ABPA. A subgroup of patients (n = 12) with persistent isolates of Aspergillus fumigatus, in the absence of serological markers of ABPA, received posaconazole monotherapy for pulmonary exacerbations not responding to conventional broad-spectrum antibiotic treatment. Posaconazole levels, full blood count, electrolytes, and liver function were monitored on day 7 of treatment and then monthly. Posaconazole was well tolerated in all but three patients. Therapeutic plasma levels >1 mg/l were achieved in all receiving the tablet formulation in comparison to 60% on the liquid preparation. There was a modest but significant improvement in FEV1 (% predicted) demonstrated for the cohort as a whole (p = 0.015) following posaconazole therapy. Posaconazole is well tolerated in children as young as six years old, improvements in lung function are observed, and therapeutic plasma levels are readily achieved in patients taking the tablet formulation and in adherent patients taking the liquid formulation.

Background: The benefit of fractional exhaled nitric oxide (FeNO) in guiding asthma treatment is uncertain. We evaluated the efficacy of adding FeNO to symptom-guided treatment in children with asthma versus only symptom-guided treatment. Methods: RAACENO was a multicentre, parallel, randomised, controlled, phase 3 trial done in 35 secondary care centres and 17 primary care recruitment sites (only seven primary care sites managed to recruit patients) in the UK. Patients with a confirmed asthma diagnosis, aged 6–15 years, prescribed inhaled corticosteroids, and who received a course of oral corticosteroids for at least one asthma exacerbation during the 12 months before recruitment were included. Participants were randomly assigned to either FeNO plus symptom-guided treatment (intervention) or symptom-guided treatment alone (standard care) using a 24 h in-house, web-based randomisation system. Participants and the clinical and research teams were not masked to the group allocation. A web-based algorithm gave treatment recommendations based on the Asthma Control Test (ACT) or Childhood ACT (CACT) score; current asthma treatment; adherence to study treatment in the past 3 months; and use of FeNO (in the intervention group). Follow-up occurred at 3-month intervals for 12 months. The primary outcome was any asthma exacerbation treated with oral corticosteroids in the 12 months after randomisation, assessed in the intention-to-treat population. This study is registered with the International Standard Randomised Controlled Trial Registry, ISRCTN67875351. Findings: Between June 22, 2017, and Aug 8, 2019, 535 children were assessed for eligibility, 20 were ineligible and six were excluded post-randomisation. 509 children were recruited and at baseline, the mean age of participants was 10·1 years (SD 2·6), and 308 (60·5%) were male. The median FeNO was 21 ppb (IQR 10–48), mean predicted FEV1 was 89·6% (SD 18·0), and median daily dose of inhaled corticosteroids was 400 μg budesonide equivalent (IQR 400–1000). Asthma was partly or fully controlled in 256 (50·3%) of 509 participants. The primary outcome, which was available for 506 (99%) of 509 participants, occurred in 123 (48·2%) of 255 participants in the intervention group and 129 (51·4%) of 251 in the standard care group, the intention-to-treat adjusted odds ratio (OR) was 0·88 (95% CI 0·61 to 1·27; p=0·49). The adjusted difference in the percentage of participants who received the intervention in whom the primary outcome occurred compared with those who received standard care was −3·1% (−11·9% to 5·6%). In 377 (21·3%) of 1771 assessments, the algorithm recommendation was not followed. Adverse events were reported by 27 (5·3%) of 509 participants (15 in the standard care group and 12 in the intervention group). The most common adverse event was itch after skin prick testing (reported by eight participants in each group). Interpretation: We found that the addition of FeNO to symptom-guided asthma treatment did not lead to reduced exacerbations among children prone to asthma exacerbation. Asthma symptoms remain the only tool for guiding treatment decisions. Funding: National Institute for Health Research.

The development of clinical breath-analysis is confounded by the variability of background volatile organic compounds (VOC). Interpretation of clinical breath-data at individual, and cohort levels requires characterisation of clinical-VOC levels and exposures. Active-sampling with thermal-desorption/gas chromatography-mass spectrometry recorded and evaluated VOC concentrations in 245 samples of indoor air from three sites in a large NHS provider trust in the UK over 27 months. 7344 clinical VOC were isolated and 328 VOC and 68 were observed in more than 5% and 30% of samples respectively; associated with exogenous and endogenous sources. 17 VOC were seasonal differentiators. Metabolites from the anaesthetic sevoflurane, and putative-disease biomarkers in room air indicated that exhaled VOC were a source of background-pollution in clinical breath-tests. Apart from solvents, and PPE-waxes, exhaled VOC concentrations above 3 µgm-3 are unlikely to arise from room air contamination. This level could be applied as a threshold for inclusion in studies.

The development of clinical breath-analysis is confounded by the variability of background volatile organic compounds (VOCs). Reliable interpretation of clinical breath-analysis at individual, and cohort levels requires characterisation of clinical-VOC levels and exposures. Active-sampling with thermal-desorption/gas chromatography-mass spectrometry recorded and evaluated VOC concentrations in 245 samples of indoor air from three sites in a large National Health Service (NHS) provider trust in the UK over 27 months. Data deconvolution, alignment and clustering isolated 7344 features attributable to VOC and described the variability (composition and concentration) of respirable clinical VOC. 328 VOC were observed in more than 5% of the samples and 68 VOC appeared in more than 30% of samples. Common VOC were associated with exogenous and endogenous sources and 17 VOC were identified as seasonal differentiators. The presence of metabolites from the anaesthetic sevoflurane, and putative-disease biomarkers in room air, indicated that exhaled VOC were a source of background-pollution in clinical breath-testing activity. With the exception of solvents, and waxes associated with personal protective equipment (PPE), exhaled VOC concentrations above 3 µg m−3 are unlikely to arise from room air contamination, and in the absence of extensive survey-data, this level could be applied as a threshold for inclusion in studies, removing a potential environmental confounding-factor in developing breath-based diagnostics.

Background Measures to address coronavirus (COVID-19) pandemic have included worldwide strict containment measures, informally known as ‘lockdown’. Acute severe episodes of wheezing are one of the commonest presentations to paediatric emergency departments (PED). The 2020 coronavirus pandemic has dramatically changed the pattern of PED attendances. Objectives To assess the impact of COVID-19 lockdown on the number of children presenting to PED with acute wheezing. Methods A single-centre prospective observational cohort study, comparing the total number of children aged 0 – 18 years presenting to PED of University Hospitals of Leicester between January 2018 to June 2020. Demographic data including age at presentation and gender were extracted. The patient group were further divided to under 5 years (aged 1 month to 5 years) and above 5 years (aged 5 year 1 month to 18 years). Results An average of 2892 children presented to PED per year with acute wheeze between 2018 and 2019 (62% male), of which 73% (n = 2112) were aged Conclusions Strict containment measures secondary to COVID-19 lockdown has had a positive impact in children with respiratory conditions. Whilst the current restrictions are not indefinitely sustainable, they demonstrate the potential health benefits of improved adherence to hand hygiene, pharmaceutical therapy, and sensible social distancing.

Allergy to airway-colonising, thermotolerant, filamentous fungi represents a distinct eosinophilic endotype of often severe lung disease. This endotype, which particularly affects adult asthma, but also complicates other airway diseases and sometimes occurs de novo, has a heterogeneous presentation ranging from severe eosinophilic asthma to lobar collapse. Its hallmark is lung damage, characterised by fixed airflow obstruction (FAO), bronchiectasis and lung fibrosis. It has a number of monikers including severe asthma with fungal sensitisation (SAFS) and allergic bronchopulmonary aspergillosis/mycosis (ABPA/M), but these exclusive terms constitute only sub-sets of the condition. In order to capture the full extent of the syndrome we prefer the inclusive term allergic fungal airway disease (AFAD), the criteria for which are IgE sensitisation to relevant fungi in association with airway disease. The primary fungus involved is Aspergillus fumigatus, but a number of other thermotolerant species from several genera have been implicated. The unifying mechanism involves germination of inhaled fungal spores in the lung in the context of IgE sensitisation, leading to a persistent and vigorous eosinophilic inflammatory response in association with release of fungal proteases. Most allergenic fungi, including Alternaria and Cladosporium species, are not thermotolerant and cannot germinate in the airways so only act as aeroallergens and do not cause AFAD. Studies of the airway mycobiome have shown that A. fumigatus colonises the normal as much as the asthmatic airway, suggesting it is the tendency to become IgE-sensitised that is the critical triggering factor for AFAD rather than colonisation per se. Treatment is aimed at preventing exacerbations with glucocorticoids and increasingly by the use of anti-T2 biological therapies. Anti-fungal therapy has a limited place in management, but is an effective treatment for fungal bronchitis which complicates AFAD in about 10% of cases., Video abstract Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/p7u_5UVQHb8

Small airway disease, characterised by ventilation heterogeneity (VH), is present in a subgroup of patients with asthma. Ventilation heterogeneity can be measured using multiple breath washout testing. Few studies have been reported in children. We studied the relationship between VH, asthma severity, and spirometry in a cross-sectional observational cohort study involving children with stable mild-moderate and severe asthma by GINA classification and a group of healthy controls. Thirty-seven participants aged 5–16 years completed multiple breath nitrogen washout (MBNW) testing (seven controls, seven mild-moderate asthma, 23 severe asthma). The lung clearance index (LCI) was normal in control and mild-moderate asthmatics. LCI was abnormal in 5/23 (21%) of severe asthmatics. The LCI negatively correlated with FEV1z-score.Conclusion: VH is present in asthmatic children and appears to be more common in severe asthma. The LCI was significantly higher in the cohort of children with severe asthma, despite no difference in FEV1 between the groups. This supports previous evidence that LCI is a more sensitive marker of airway disease than FEV1. MBNW shows potential as a useful tool to assess children with severe asthma and may help inform clinical decisions. What is Known:• Increased ventilation heterogeneity is present in some children with asthma• Spirometry is not sensitive enough to detect small airway involvement in asthma What is New• Lung clearance index is abnormal in a significant subgroup of children with severe asthma but rarely in children with mild-moderate asthma• Our data suggests that LCI monitoring should be considered in children with severe asthma

Introduction There is no ideal way to diagnose and monitor asthma in children and there is an urgent need for non-invasive biomarkers.1 A growing body of research suggests that volatile organic compounds (VOCs) in breath may have a role in diagnosing and monitoring asthma. The ReCIVA (Owlstone Medical Limited) is a breath sampler designed to standardise the collection of breath samples for the offline analysis of VOCs. However, it’s utility for paediatric sampling has not yet been fully established. Objective To discover whether the ReCIVA is effective at collecting breath samples from paediatric asthma patients. Methods We collected ReCIVA samples from 64 children (aged 5–15 years) with acute and stable asthma and healthy controls. The ReCIVA is a hand-held device consisting of a face mask, pressure and CO2 sensors, and sorbent tubes which sit above two pumps. As mask pressure changes with the breath cycle the pumps are activated, with the aim of collecting the end-tidal breath portion onto sorbent tubes. We evaluated the metadata to assess the validity and effectiveness of paediatric sampling using the ReCIVA. This included exploring pump activation alignment with the phase of breath, exhaled breath volume sampled, sample collection time and recorded errors in relation to two ReCIVA serial numbers, 42 and 53. Results Of 90 samples, 70 (77.8%) reached the 1L target breath volume collection. Similar sample characteristics were found between asthmatics and controls (table). 21 (23.3%) samples had recorded errors, the most common being a ‘leak detected’ error. Discrepancies were found in the timing of pump activation which appeared to be random. Differences occurred between the two ReCIVA serial number sample characteristics. Two samples were aborted, and one sample had almost no breath sampled despite a full collection time. Conclusions Overall, the results indicate that the ReCIVA is a viable option for standardised breath sampling in the paediatric population. Exploration of pump activation misalignments with the phase of breath is required to determine the reasons behind this. Further work is also needed to investigate whether a wider range of mask sizes improves the ‘leak detected’ error rate. Reference Breathe 2019;15(1):e20–7

Background Aerobic exercise capacity, as assessed by Cardiopulmonary exercise testing (CPET) is an independent predictor of mortality and morbidity in cystic fibrosis (CF). There is limited evidence on the change in exercise tolerance for patients treated with CFTR modulators. The aim of our study was to review the impact of Tezacaftor/Ivacaftor (Tez/Iva) on exercise capacity in our cohort of CF adolescents. Method Eligible CF adolescents performed CPET testing immediately before initiating Tez/Iva combination therapy with repeat testing at 7 to 8 months after commencing treatment. Results Four adolescents (Three males, mean age 16.3 years) participated in this study to date. All of them performed technically acceptable CPET, the results are shown in table 1. Peak VO2 decreased slightly in 3 of our 4 patients. In these 3 patients, the mean peak VO2% predicted reduced by 15%, 4% and 4% respectively; it improved by 22% predicted in the fourth patient. A low mean anaerobic threshold at the beginning of the study suggested some element of deconditioning. The VO2 values at anaerobic thresholds improved in all four patients by 4%, 14%, 19% and 79% respectively. The mean anaerobic threshold (calculated as VO2 AT/VO2max predicted), improved by 3%, 7% and 23% in three of our patients, there was no change noted in the fourth patient. Three children had an increase in their BMI. Conclusion Tez/Iva treatment improved the anaerobic threshold in our patients. Larger and longitudinal studies are required to ascertain the impact of these treatments on cardiopulmonary fitness in CF patients. Reference Hulzebos EH, Bomhof-Roordink H, van de Weert-van Leeuwen PB, et al. Prediction of mortality in adolescents with cystic fibrosis. Med Sci Sports Exerc 2014;46(11):2047–2052.

In this review, the Paediatric Assembly of the European Respiratory Society (ERS) presents a summary of the highlights and most relevant findings in the field of paediatric respiratory medicine presented at the virtual ERS International Congress 2020. Early Career Members of the ERS and Chairs of the different Groups comprising the Paediatric Assembly discuss a selection of the presented research. These cover a wide range of research areas, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis, respiratory infection and immunology, neonatology and intensive care, epidemiology, bronchology and lung and airway development. Specifically, we describe the long-term effect in lung function of premature birth, mode of delivery and chronic respiratory conditions such as cystic fibrosis. In paediatric asthma, we present risk factors, phenotypes and their progression with age, and the challenges in diagnosis. We confirm the value of the lung clearance index to detect early lung changes in cystic fibrosis. For bronchiectasis treatment, we highlight the importance of identifying treatable traits. The use of biomarkers and genotypes to identify infants at risk of long-term respiratory morbidity is also discussed. We present the long-term impact on respiratory health of early life and fetal exposures to maternal obesity and intrauterine hypoxia, mechanical ventilation hyperoxia, aeroallergens, air pollution, vitamin A deficient intake and bronchitis. Moreover, we report on the use of metabolomics and genetic analysis to understand the effect of these exposures on lung growth and alveolar development. Finally, we stress the need to establish multidisciplinary teams to treat complex airway pathologies., Highlights from the Paediatrics Assembly at the #ERSCongress 2020 https://bit.ly/3ptcnFr

Background: The benefit of Fractional Exhaled Nitric Oxide (FeNO) in guiding asthma treatment is uncertain. Our hypothesis was that FeNO plus symptom-guided treatment reduces exacerbations in children with asthma compared to symptom-guided treatment alone. Methods: A multicentre randomised controlled trial recruited 6-15 year olds with asthma treated with inhaled corticosteroids (ICS) with an exacerbation in the previous year. Randomisation was to asthma treatment guided by FeNO plus symptoms (intervention) or by symptoms only (standard care). A web-based algorithm using symptom control, ICS adherence, current treatment and (within the intervention group) FeNO gave treatment recommendations. Participants attended assessments 3, 6, 9 and 12-months post-randomisation. The primary outcome was exacerbation requiring oral corticosteroid over the 12 months post-randomisation. Findings: There were 509 children recruited. At randomisation, the mean (SD) age was 10∙1y (2.6), median (IQR) FeNO 21 ppb (10, 48), mean (SD) %FEV 1 90% (18), 56% received ≤400 microg budesonide equivalent ICS and 50% had controlled symptoms. The primary outcome occurred in 123/255 (48%) of the intervention group and 129/251 (51%) of the standard care group. The adjusted difference in percentage of participants who received the intervention where the primary outcome occurred exacerbation compared to those receiving standard care was -3∙13% (95% CI: -11∙9% to 5∙6%). In adjusted intention-to-treat analysis, the odds ratio (OR) for primary outcome was 0 ∙88 [95%CI 0∙61 to 1∙27]. In 377 of 1771 assessments, the algorithm recommendation was not followed. In complier average causal effect analysis, adjusting for algorithm adherence, the OR for those fully adherent was 0∙82 [95% CI 0∙48 to 1∙41]. There were no differences in secondary outcomes between groups. Interpretation: In this exacerbation-prone population, adding FeNO to symptom-guided treatment did not reduce exacerbations. Trial Registration: ISRCTN number #67875351. Funding: This study was funded by the Efficacy and Mechanisms Evaluation programme of the National Institute for Health Research (reference 15-18-14). Declaration of Interest: David Price has board membership with AstraZeneca, Boehringer Ingelheim, Chiesi, Mylan, Novartis, Regeneron Pharmaceuticals, Sanofi Genzyme, Thermofisher; consultancy agreements with Airway Vista Secretariat, AstraZeneca, Boehringer Ingelheim, Chiesi, EPG Communication Holdings Ltd, FIECON Ltd, Fieldwork International, GlaxoSmithKline, Mylan, Mundipharma, Novartis, OM Pharma SA, PeerVoice, Phadia AB, Spirosure Inc, Strategic North Limited, Synapse Research Management Partners S.L., Talos Health Solutions, Theravance and WebMD Global LLC; grants and unrestricted funding for investigator-initiated studies (conducted through Observational and Pragmatic Research Institute Pte Ltd) from AstraZeneca, Boehringer Ingelheim, Chiesi, Mylan, Novartis, Regeneron Pharmaceuticals, Respiratory Effectiveness Group, Sanofi Genzyme, Theravance and UK National Health Service; payment for lectures/speaking engagements from AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, GlaxoSmithKline, Kyorin, Mylan, Mundipharma, Novartis, Regeneron Pharmaceuticals and Sanofi Genzyme; payment for travel/accommodation/meeting expenses from AstraZeneca, Boehringer Ingelheim, Mundipharma, Mylan, Novartis, Thermofisher; stock/stock options from AKL Research and Development Ltd which produces phytopharmaceuticals; owns 74% of the social enterprise Optimum Patient Care Ltd (Australia and UK) and 92.61% of Observational and Pragmatic Research Institute Pte Ltd (Singapore); 5% shareholding in Timestamp which develops adherence monitoring technology; is peer reviewer for grant committees of the UK Efficacy and Mechanism Evaluation programme, and Health Technology Assessment; and was an expert witness for GlaxoSmithKline. Ethical Approval: The study was approved by the North of Scotland Research Ethics Committee (16/NS/0106).

Background Data handling in clinical bioinformatics is often inadequate. No freely available tools provide straightforward approaches for consistent, flexible metadata collection and linkage of related experimental data generated locally by vendor software. Results To address this problem, we created LabPipe, a flexible toolkit which is driven through a local client that runs alongside vendor software and connects to a light-weight server. The toolkit allows re-usable configurations to be defined for experiment metadata and local data collection, and handles metadata entry and linkage of data. LabPipe was piloted in a multi-site clinical breathomics study. Conclusions LabPipe provided a consistent, controlled approach for handling metadata and experimental data collection, collation and linkage in the exemplar study and was flexible enough to deal effectively with different data handling challenges.

Introduction Investigating acute multifactorial undifferentiated breathlessness and understanding the driving inflammatory processes can be technically challenging in both adults and children. Being able to validate noninvasive methods such as breath analysis would be a huge clinical advance. The ReCIVA® device allows breath samples to be collected directly onto sorbent tubes at the bedside for analysis of exhaled volatile organic compounds (eVOCs). We aimed to assess the feasibility of using this device in acutely breathless patients. Methods Adults hospitalised with acute breathlessness and children aged 5–16 years with acute asthma or chronic stable asthma, as well as healthy adult and child volunteers, were recruited. Breath samples were collected onto sorbent tubes using the ReCIVA® device and sent for analysis by means of two-dimensional gas chromatography-mass spectrometry (GCxGC-MS). The NASA Task Load Index (NASA-TLX) was used to assess the perceived task workload of undertaking sampling from the patient's perspective. Results Data were available for 65 adults and 61 children recruited. In total, 98.4% of adults and 75.4% of children were able to provide the full target breath sample using the ReCIVA® device. NASA-TLX measurements were available in the adult population with mean values of 3.37 for effort, 2.34 for frustration, 3.8 for mental demand, 2.8 for performance, 3.9 for physical demand and 2.8 for temporal demand. Discussion This feasibility study demonstrates it is possible and acceptable to collect breath samples from both adults and children at the bedside for breathomics analysis using the ReCIVA® device., It is feasible to collect breath samples for breath analysis at the bedside using the ReCIVA device in acutely breathless adults and children https://bit.ly/2ZTonWo

At the start of the school year, there is an influx of children with attacks of viral wheeze and asthma who present to children’s emergency departments. In the UK, the COVID-19 pandemic has resulted in extensive school lockdowns and the implementation of social distancing measures within schools. We aimed to determine the extent that SARS-CoV-2 has been identified in children admitted to hospital with viral wheeze and/or asthma at the start of the 2020 school year and compare presentation trends to previous years. Leicester was the first city in the UK to …

Background Early reports suggest that most children infected with severe acute respiratory syndrome coronavirus 2 (“SARS-CoV-2”) have mild symptoms. What is not known is whether children with chronic respiratory illnesses have exacerbations associated with SARS-CoV-2 virus. Methods An expert panel created a survey, which was circulated twice (in April and May 2020) to members of the Paediatric Assembly of the European Respiratory Society (ERS) and via the social media of the ERS. The survey stratified patients by the following conditions: asthma, cystic fibrosis (CF), bronchopulmonary dysplasia (BPD) and other respiratory conditions. Results In total 174 centres responded to at least one survey. 80 centres reported no cases, whereas 94 entered data from 945 children with coronavirus disease 2019 (COVID-19). SARS-CoV-2 was isolated from 49 children with asthma of whom 29 required no treatment, 19 needed supplemental oxygen and four children required mechanical ventilation. Of the 14 children with CF and COVID-19, 10 required no treatment and four had only minor symptoms. Among the nine children with BPD and COVID-19, two required no treatment, five required inpatient care and oxygen and two were admitted to a paediatric intensive care unit (PICU) requiring invasive ventilation. Data were available from 33 children with other conditions and SARS-CoV-2 of whom 20 required supplemental oxygen and 11 needed noninvasive or invasive ventilation. Conclusions Within the participating centres, in children with asthma and CF, infection with SARS-CoV-2 was well tolerated, but a substantial minority of children with BPD and other conditions required ventilatory support indicating that these latter groups are at risk from SARS-CoV-2 infection., Whereas children with asthma and CF seem not to be at increased risk of severe #COVID19, a minority of children with other respiratory diseases might be at increased risk and may benefit from being shielded https://bit.ly/3fiwUXp

It has been postulated that some children with recurrent cough but no wheeze have a mild form of asthma (cough variant asthma), with similar risk factors and an increased risk of future wheeze. This longitudinal study compared risk factors for isolated night cough and for wheeze in the Leicester Respiratory Cohort in children aged 1, 4, 6 and 9 years and compared prognosis of children with isolated night cough, children with wheeze and asymptomatic children. We included 4101 children aged 1 year, 2854 aged 4 years, 2369 aged 6 years and 1688 aged 9 years. The prevalence of isolated night cough was 10% at age 1 year and 18% in older children. Prevalence of wheeze decreased from 35% at 1 year to 13% at 9 years. Although several risk factors were similar for cough and wheeze, day care, reflux and family history of bronchitis were more strongly associated with cough, and male sex and family history of asthma with wheeze. Over one-third of preschool children with cough continued to cough at school age, but their risk of developing wheeze was similar to that of children who were asymptomatic at earlier surveys. Wheeze tracked more strongly throughout childhood than cough. In conclusion, our study showed that only some risk factors for cough and wheeze were shared but many were not, and there was little evidence for an increased risk of future wheeze in children with isolated night cough. This provides little support for the hypothesis that recurrent cough without wheeze may indicate a variant form of asthma., Children with isolated night cough do not have an increased risk of future wheeze, and risk factors for cough and wheeze only partially overlap. https://bit.ly/31IbXSC

BackgroundThe National Institute for Health and Care Excellence recommends the use of spirometry and measuring the fraction of exhaled nitric oxide (FeNO) as part of the diagnostic work-up for children with suspected asthma, and spirometry for asthma monitoring, across all care settings. However, the feasibility and acceptability of these tests within primary care are not known.AimTo investigate the feasibility, acceptability, training, and capacity requirements of performing spirometry and FeNO testing in children managed for asthma in UK primary care.Design and settingProspective observational study involving 10 general practices in the East Midlands, UK, and 612 children between 2016 and 2017.MethodTraining and support to perform spirometry and FeNO in children aged 5 to 16 years were provided to participating practices. Children on the practice’s asthma registers, and those with suspected asthma, were invited for a routine asthma review. Time for general practice staff to achieve competencies in performing and/or interpreting both tests, time to perform the tests, number of children able to perform the tests, and feedback on acceptability were recorded.ResultsA total of 27 general practice staff were trained in a mean time of 10.3 (standard deviation 2.7) hours. Usable spirometry and FeNO results were obtained in 575 (94%) and 472 (77%) children respectively. Spirometry is achievable in the majority of children aged ≥5 years, and FeNO in children aged ≥7 years. All of the staff and 97% of families surveyed provided positive feedback for the tests.ConclusionAfter training, general practice staff obtained quality spirometry and FeNO data from most children tested. Testing was acceptable to staff and families. The majority of general practice staff reported that spirometry helped them to manage children’s asthma better.

Introduction: Asthma is commonly monitored in primary care by assessing symptom control alone, but recent UK guidelines recommend the use of spirometry in adults and children from five years. The role of fraction of exhaled nitric oxide (FeNO) is unclear Objective: To assess how patient reported symptoms relate to spirometry and FeNO Methods: Ten general practices in the Midlands, UK were trained to perform spirometry and FeNO. Children (5-16yr) with GP diagnosed or suspected asthma were invited for review where spirometry and FeNO were attempted. Asthma control tests (ACT) for children aged 12-16 yrs, and children’s asthma control tests (CACT) for those aged 5-11 yrs were completed in all children. Results: We recruited 612 children. Usable spirometry was achieved in 575 (94%), and FeNO in 472 (77%) children. In children where both spirometry and FeNO data were available, 46% of children reporting good control (ACT/CACT score >19) had at least one objective test abnormality (table 1). By contrast, in those reporting poor control, 93 out of 191 (49%) children had normal spirometry and FeNO. Both FEV1 (p=0.013) and FEV1/FVC (p=0.0006) correlated with ACT but not CACT. There was an inverse trend between FeNO and ACT/CACT. Conclusion: Asthma assessments based on either symptoms or objective tests in isolation do not provide a full picture of the child with asthma.

Introduction: The relationship between airway inflammation and decline in lung function is not well understood. Previous studies have not consistently demonstrated correlation between FeNO and a commonly used spirometric parameter - FEV1 % predicted (Spergel et al. J Asthma 2005;42:879-883; Stanciulescu et al. Pneumologia 2015;64:40-44). Objective: To describe the relationship between FeNO and spirometry in children managed for asthma, using gold standard GLI reference equations and z-scores for FEV1 and FEV1/FVC. Methods: Cross-sectional observational study conducted in UK primary care. Children (5-16yr) with asthma or on asthma medication were invited for a spirometry and FeNO test. Absolute values for FEV1 and FEV1/FVC were converted into Z-scores using the GLI-2012 calculator. Results: Spirometry and FeNO were obtained in 465 children. Of these, 232 (50%) had at least one abnormal test result. Fifty-two (11%) children had obstructed spirometry but normal FeNO, 111 (24%) had raised FeNO ≥ 35ppb only, and 58 (12%) had both obstructed spirometry and raised FeNO. We found a significant but weak negative correlation between both FEV1 and FEV1/FVC with FeNO (Fig 1). Conclusion: Raised FeNO was associated with lower FEV1 and FEV1/FVC. Causality cannot be concluded from this observational study. Longitudinal studies are required to investigate whether a link exists between airway inflammation and more rapidly declining lung function.

Background Asthma is a heterogeneous disease and understanding this heterogeneity will enable the realisation of precision medicine. We sought to compare the sputum and serum inflammatory profiles in moderate-to-severe asthma during stable disease and exacerbation events. Methods We recruited 102 adults and 34 children with asthma. The adults were assessed at baseline, 3, 6, and 12-month follow-up visits. Thirty-seven subjects were assessed at onset of severe exacerbation. Forty sputum mediators and 43 serum mediators were measured. Receiver-operator characteristic (ROC) curves were constructed to identify mediators that distinguish between stable disease and exacerbation events. The strongest discriminating sputum mediators in the adults were validated in the children. Results The mediators that were significantly increased at exacerbations versus stable disease and by ≥1.5-fold were sputum IL-1β, IL-6, IL-6R, IL-18, CXCL9, CXCL10, CCL5, TNFα, TNF-R1, TNF-R2, and CHTR and serum CXCL11. No mediators decreased ≥1.5-fold at exacerbation. The strongest discriminators of an exacerbation in adults (ROC area under the curve [AUC]) were sputum TNF-R2 0.69 (95% CI: 0.60 to 0.78) and IL-6R 0.68 (95% CI: 0.58 to 0.78). Sputum TNF-R2 and IL-6R were also discriminatory in children (ROC AUC 0.85 [95% CI: 0.71 to 0.99] and 0.80 [0.64 to 0.96] respectively). Conclusions Severe asthma exacerbations are associated with increased pro-inflammatory and Type 1 (T1) immune mediators. In adults, sputum TNF-R2 and IL-6R were the strongest discriminators of an exacerbation, which were verified in children. Electronic supplementary material The online version of this article (10.1186/s12890-019-0906-7) contains supplementary material, which is available to authorized users.

Precision medicine has spurred new innovations in molecular pathology leading to recent advances in the analysis of exhaled breath as a non-invasive diagnostic tool. Volatile organic compounds (VOCs) detected in exhaled breath have the potential to reveal a wealth of chemical and metabolomic information. This study describes the development of a method for the analysis of breath, based on automated thermal desorption (TD) combined with flow modulated comprehensive two-dimensional gas chromatography (GC×GC) with dual flame ionisation and quadrupole mass spectrometric detection (FID and qMS). The constrained optimisation and analytical protocol was designed to meet the practical demands of a large-scale multi-site clinical study, while maintaining analytical rigour to produce high fidelity data. The results demonstrate a comprehensive method optimisation for the collection and analysis of breath VOCs by GC×GC, integral to the standardisation and integration of breath analysis within large clinical studies.

There is increasing evidence that ventilation heterogeneity and small airway disease are significant factors in asthma, with evidence suggesting that the small airways are involved from an early stage in childhood asthma. Spirometry is commonly used to monitor lung function in asthmatics; however, it is not sensitive to small airway disease. There has been renewed interest in multibreath washout (MBW) tests, with recognition of the lung clearance index (LCI) as a global index of abnormality in gas mixing of the lungs that therefore also reflects small airway disease. This review summarises the technical and practical aspects of the MBW/LCI in children, and the differences between commercially available equipment. Children with severe asthma are more likely to have an abnormal LCI, whereas most children with mild-to-moderate asthma have an LCI within the normal range, but slightly higher than age-matched healthy controls. Monitoring children with asthma with MBW alongside standard spirometry may provide useful additional information.