Bronchodilator Reversibility Testing Research Articles

A Review of the Latest Guidelines for Diagnosing and Managing Asthma in Children in the United States and Canada.

Globally, asthma remains the most widespread chronic respiratory condition in children, with a larger proportion of children being affected by the condition. Regardless of the higher prevalence rates, the outcomes of pediatric asthma have remained inadequate, even as there are numerous preventable deaths (approximately 300 children in the United States and 250 children in Canada, annually). The characteristic symptoms of pediatric asthma include wheezing, cough, and shortness of breath that are characteristically triggered by several potential stimuli. However, several diagnostic challenges exist and have resulted in either overdiagnosis or underdiagnosis, making pediatric asthma diagnosis and management problematic. Effective management of asthma in children entails a holistic approach that encompasses non-pharmacological and pharmacological management, alongside self-management and educational aspects. Working with pediatric asthma patients and their families/caregivers is vital to promoting and realizing better asthma diagnosis and management outcomes. Educational guidelines regarding the best ways for effective treatment, avoidance of triggers, modifiable risk factors, and the actions that should be taken during chronic asthma attacks through individualized action plans are vital. Thus, the objective of this systematic review is to provide an overview of the latest guidelines on pediatric asthma diagnosis and management. In this regard, this review presents several similarities in existing pediatric asthma diagnosis and management guidelines in the United States and Canada. For instance, most guidelines and studies reviewed have proposed the use of objective tests for confirmation of asthma diagnosis, particularly in symptomatic individuals. The peak flow variability measurement, bronchodilator reversibility testing, and spirometry have also been proposed by the guidelines and studies, even as the recommendations regarding the timing and hierarchy of the objective test substantially vary between the guidelines and studies. We hope that the present review will be helpful to physicians and healthcare service providers working within pediatric health contexts.

Characteristics of Adults With Severe Asthma in Childhood: A 60-Year Follow-Up Study

BackgroundChildhood asthma is a prevalent condition with potential impact on adult life. Research QuestionIn a 60-year follow-up study of adults with a history of severe childhood asthma, what are the potential differences in characteristics between individuals with persistent asthma and asthma remission in adulthood? Study Design and MethodsDanish adults with a history of childhood asthma and a 4-month stay in at an asthma care facility in Kongsberg, Norway (1950-1979) in childhood were included. Recruitment was done through social media and personal invitation letters. Participants completed questionnaires and underwent spirometry, bronchial provocation, and bronchodilator reversibility and blood tests. Asthma remission was defined as no use of asthma medication and no asthma symptoms within the past 12 months with the remaining participants being classified as having current asthma. ResultsAmong 1394 eligible participants, 232 completed the follow-up. Ninety percent had current asthma, of whom 26% reported exacerbations in the past year. Only 16% of all the participants were managed in secondary care. Common comorbidities were allergic rhinitis (60%), hypertension (21%), eczema (16%), and cataract (8%). Compared to participants in remission, participants with persistent asthma had higher total immunoglobulin E (p=0.03), and both lower FEV1%pred (p=0.03), and FEV1/FVC ratio (p<0.001), as well as numerically higher fractional exhaled nitric oxide and blood eosinophil count. InterpretationOur 60-year follow-up study of adults with a history of severe childhood asthma revealed that nine out of ten still had current asthma. Persistent asthma was associated with lower lung function and higher levels of type 2 inflammatory biomarkers compared to those with asthma remission.

The unusual connection between Right-Sided Aortic Arch and bronchial asthma

This work describes a rare clinical case of anomalous positioning of the aortic arch in a female patient with asthma. It highlights literature suggesting that this anomaly may sometimes mimic bronchial asthma, underscoring the importance of conducting bronchodilator reversibility tests more frequently to identify underlying asthma. The patient, a woman presenting with asthma symptoms, was found to have a Right-Sided Aortic Arch (RSAA), which is an unusual finding in the absence of congenital heart disease. Given the rarity of this presentation, it underscores the need for thorough evaluation and consideration of alternative diagnoses in patients with atypical asthma symptoms. This case emphasizes the importance of comprehensive diagnostic approaches, including spirometry and bronchodilator testing, to accurately diagnose and manage patients with asthma-like symptoms associated with rare anatomical variations such as RSAA.

The impact of time of day on the diagnostic performance of tests for asthma.

Performing fractional exhaled nitric oxide and bronchodilator reversibility tests in the morning is more likely to lead to a positive test result than when performed in the afternoon. Therefore, time of day should be considered during test interpretation. https://bit.ly/4b79e5J.

An unusual case of upper airways obstruction

Tracheal stenosis poses a diagnostic challenge that can mimic other respiratory pathologies, particularly bronchial asthma. It is characterized by a narrowing of the tracheal caliber, leading to respiratory symptoms such as dyspnea, cough, and wheezing. However, these manifestations can overlap with those of bronchial asthma, making the differential diagnosis a challenging yet crucial task for an appropriate therapeutic approach. This study aims to underscore the importance of a comprehensive clinical approach, utilizing bronchoscopy and global spirometry with bronchodilator reversibility testing, to differentiate tracheal stenosis from bronchial asthma, thereby contributing to accurate and timely surgical treatment. Bronchoscopy stands as a cornerstone in investigating tracheal stenosis, allowing for a direct assessment of the site, extent, and nature of the stenosis. Endoscopic observation of the morphological characteristics of the stenosis, such as concentric narrowing or mucosal irregularities, can guide towards a more precise diagnosis. Asthma, characterized by a reversible bronchial obstruction, responds positively to bronchodilators, whereas tracheal stenosis shows a limited or absent response.

What is the Best Way to Diagnose Possible Asthma Patients with Negative Bronchodilator Reversibility Tests?

The best method and strategy for the diagnosis of asthma remains unclear, especially in patients with negative bronchodilator reversibility test (BDRT). In our study, we aimed to investigate the diagnostic yield of peak expiratory flow (PEF) variability for this patient group. A total of 50 patients with suspected asthma, all with negative BDR test, were included in the study. Demographic information and symptoms were recorded and PEF variability was monitored for 2 weeks. Metacolinbronchial provocation test (mBPT) was performed. Asthma was diagnosed when PEF variability ≥20% and/or positive mBPT was observed. 30 of 50 patients were diagnosed with asthma. After 1 month, 17 patients were evaluated for treatment outcomes. The sensitivity and specificity of PEF variability for different cut-off values (≥20%, >15% and >10%) were 61.5-83.3, 88.5-62.5 and 100-16.7, respectively. One of the most important findings of our study was the absence of variable airflow limitation or airway hyper reactivity in 39% patients with a previous diagnosis of asthma. Multiple logistic regression analysis revealed that a low baseline FEF25-75 value was an independent predictive factor for the diagnosis of asthma (p= 0.05). The most efficient diagnostic test for asthma is still unclear due to many factors. Our study is one of the few studies on this subject. Although current diagnostic recommendations generally recommend a PEF variability of 10% for the diagnosis of asthma, this threshold may not be appropriate for the BDR-negative patient group. Our results suggest using a threshold value of <15% for PEF variability when excluding asthma and ≥20% when confirming the diagnosis of asthma in patients with clinically suspected but unproven reversibility. Furthermore, FEF25-75 is considered to be an important diagnostic parameter that should be included in diagnostic recommendations for asthma.

Bronchodilator reversibility in the GAN severe asthma cohort.

Positive bronchodilator reversibility (BDR) is a diagnostic criterion for asthma. However, patients with asthma may exhibit negative BDR test.To describe frequency of positive and negative BDR in patients with severe asthma and associations with phenotypic characteristics. Positive BDR was defined as FEV1 increase > 200 ml AND > 12% upon testing with a short-acting beta-agonist (SABA). Out of 2013 patients included in the German Asthma Net (GAN) severe asthma registry, 793 had data on BDR. Hereof, 250 (31.5%) had a positive and 543 (68.5%) had a negative BDR test. Comorbidities significantly associated with negative BDR were gastro-esophageal reflux (GERD) (28.0% vs 40.0%, p<0.01) and EGPA (0.4% vs 3.0%; p<0.05), while smoking history (active: 2.8% vs 2.2%; ex: 40.0% vs 41.7%) and COPD comorbidity (5.2% vs 7.2%) were similar in both groups. Patients with positive BDR had worse asthma control (median ACQ-5 3.4 vs 3.0, p<0.05), reported dyspnea at rest (26.8% vs 16.4%, p<0.001) and chest tightness (36.4% vs 26.2%, p<0.001) more frequently, had more severe airway obstruction at baseline (FEV1% pred: 56 vs 64, p<0.001) and higher FeNO levels (41 vs 33 ppb, p<0.05), while diffusion capacity did not differ (DLCO-SB % pred. 70% vs 71%). Multivariate linear regression analysis identified association of lower baseline FEV1% (p<0.001) and chest tightness (p<0.05) with positive, and GERD (p<0.05) with negative BDR. In this real-life setting the majority of patients with severe asthma exhibited negative BDR. Interestingly, this was not associated with smoking history or COPD, but with lower FeNO and presence of GERD.

COPD Patients with Asthma Features in Vietnam: Prevalence and Suitability for Personalized Medicine.

COPD patients with asthma features usually benefit from inhaled corticosteroids (ICS)-containing regimens, but their burden and diagnostic criteria remain to be established. The aims of this study were to estimate the proportion of patients with asthma features among patients with physician-diagnosed COPD and to investigate differences in clinical characteristics and current medications between COPD patients with asthma features and patients with COPD alone. A cross-sectional study was conducted at two respiratory out-patient clinics at the University Medical Center in Ho Chi Minh City and Bach Mai Hospital in Ha Noi, Vietnam. COPD patients with asthma features were identified by attending physicians following the approach recommended by the GINA/GOLD joint committee. Of the 332 patients screened, 300 were enrolled in the study. The proportion of COPD patients with asthma features was 27.3% (95% confidence interval (95% CI) 22.6-32.6%). COPD patients with asthma features were younger, with higher FEV1 values, a greater proportion of positive bronchodilator reversibility tests, higher blood eosinophil count, and were more often treated with ICS/LABA (ICS/long-acting bronchodilator beta-2 agonist) than patients with COPD alone. The prevalence of COPD patients with asthma features is particularly high in Vietnam thus requiring appropriate action plans in clinical practice.

Role of C-reactive Protein and Mean Platelet Volume in Predicting COPD Severity and its Association with Cardiac Abnormalities among the Southern Indian Population: A Cross-sectional Study

Introduction: Chronic Obstructive Pulmonary Disease (COPD) is one of the leading causes of disease and mortality worldwide. In individuals with mild-to-moderate COPD, serum C-reactive Protein (CRP) corresponds with disease severity and poor health outcomes. Mean Platelet Volume (MPV) is also linked to an elevated degree of inflammation in the body, as well as the severity and acute exacerbation of COPD. Aim: To evaluate the relationship between serum CRP levels and MPV and its association with COPD disease severity and the patient’s cardiac abnormality. Materials and Methods: A cross-sectional study was conducted in the Department of Respiratory Medicine, Chettinad Hospital and Research Institute, Chennai, Tamil Nadu, India, between January 2015 and January 2016. Study was carried out among 55 patients who were diagnosed with COPD in accordance with Global Initiative for Chronic Obstructive Lung Disease 2014 (GOLD) and who were within the age range of 40-70 years were included in the investigation. Severity of airflow obstruction was confirmed by Spirometry using True Flow Easy on PC sensor Pulmonary Function Test (PFT) machine with bronchodilator reversibility testing, as per Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines 2014 and abnormality was evaluated by clinical and radiological assessment. A 3 mL of blood was collected into a clot vial and sent for analysis of CRP using an immunoassay system based on antigen-antibody reaction and fluorescence technology and MPV using the impedance count technique. Receiver Operating Characteristic (ROC) curve was used to find out the sensitivity and specificity of MPV and CRP levels with cardiac abnormality. The study was statistically analysed by Pearson’s Chi-square test. Results: Out of total sample, majority (n=25, 45.5%) were between 51-60 years age group and, there were 35 (63.63%) males and 20 (36.37%) females. The mean CRP levels of mild COPD patients were found to be 6.980±0.7328 mg/dL, moderate and severe COPD patients were found to be 7.243±0.5324 mg/ dL and 7.550±0.4950 mg/dL, respectively and it was statistically significant (p-value &lt;0.0001). In the present study, the mean CRP levels and mean MPV were found to be significantly higher in patients with cardiac abnormality than the patients without cardiac abnormality (p-value &lt;0.0001). Conclusion: Finally, it was concluded that systemic inflammation is common in COPD patients and that CRP and MPV are significant COPD biomarkers for assessing disease severity, predicting cardiac abnormalities, and predicting patient prognosis.

An unusual case of upper airways obstruction: What if it's not asthma?

Tracheal stenosis poses a diagnostic challenge that can mimic other respiratory pathologies, particularly bronchial asthma. It is characterized by a narrowing of the tracheal lumen, leading to respiratory symptoms such as dyspnea, cough, and wheezing. However, these manifestations can overlap with those of bronchial asthma, making the differential diagnosis a challenging yet crucial task for an appropriate therapeutic approach. This study aimsed to underscore the importance of a comprehensive clinical approach, using bronchoscopy and global spirometry with bronchodilator reversibility testing, to differentiate tracheal stenosis from bronchial asthma, thereby contributing to accurate and timely surgical treatment. Bronchoscopy stands as a cornerstone in investigating tracheal stenosis, allowing for a direct assessment of the site, extent, and nature of the stenosis. Endoscopic observation of the morphological characteristics of the stenosis, such as concentric narrowing or mucosal irregularities, can guide precise diagnosis. Asthma, characterized by reversible bronchial obstruction, responds positively to bronchodilators, compared with a minimal response in the context of tracheal stenosis.

Study on Asthma and Chronic Obstructive Pulmonary Disease Overlaps among Patients with Obstructive Airway Diseases

Background and Aim: Although asthma and chronic obstructive pulmonary disease (COPD) are clinically distinct diseases, they represent biologically diverse and overlapping clinical entities and it has been observed that they often co-occur. Some research and theorizing suggest there is a common comorbid condition termed asthmachronic obstructive pulmonary disease overlap (ACO). However, the existence of ACO is controversial.Material and Methods: This is prospective, observational and descriptive study conducted at tertiary care institute of Gujarat for the duration of 1 year. Among chronic airway diseases who were classified into three groups (COPD, asthma and ACO). Patients with COPD and ACO were diagnosed according to GOLD guidelines 2020 and patients with asthma were diagnosed according to Global Initiative for Asthma (GINA) guidelines 2020. Total 150 participants were included in the research. All patients are subjected to full history taking, clinical examination, full laboratory examinations, chest radiography, spirometry and post bronchodilator reversibility test was performed and sputum analysis, where induction of sputum by hypertonic saline or mannitol is done by a trained staff with strict airborne respiratory precautions.Results: We found that 71.42% of ACO group, 79.48% of asthma group and 25% of COPD group had a positive history of atopy. Comparison of study groups regarding sputum eosinophils revealed that 30.15 % of ACO group, 76.92% of asthma group and 31.25% of COPD group had positive sputum eosinophils.Conclusion: ACO addresses an enormous rate among patients with obstructive airway diseases. It shares a few highlights of asthma like atopy and positive sputum eosinophilia, and a few highlights of COPD like old age of shows and positive smoking history

An Investigation into the Factors Associated with Incorrect Use of a Pressurized Metered-Dose Inhaler in Japanese Patients.

Rationale: Inhalation of the correct dose of a short-acting beta 2 agonist (SABA) from a pressurized metered-dose inhaler (pMDI) is essential for the relief of symptoms in patients with asthma and/or chronic obstructive pulmonary disease. The aim of this study was to evaluate the prevalence and factors associated with the incorrect use of a pMDI. Methods: This study retrospectively assessed the electronic medical records of 161 patients with various respiratory diseases. The patients had never used a pMDI and underwent training by pharmacists educated in the use of a pMDI followed by bronchodilator reversibility testing at our hospital. The patients' characteristics and various lung capacity parameters were evaluated for association with the incorrect use of a pMDI. Results: Thirty-nine of the 161 (24.2%) patients, including 46% of 28 patients older than 80 years, used the pMDI incorrectly, mainly because of incoordination between activation of the device and inhalation (n = 11), inadequate strength to manipulate the device (n = 9), too short duration of inhalation (n = 6), and difficulty in breath holding (n = 3). Advanced age; lower height; and decreased lung volumes, including vital capacity (VC), inspiratory capacity, inspiratory reserve volume (IRV), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow rate, were associated with the incorrect use of a pMDI. Neither the body weight, tidal volume, expiratory reserve volume, %FVC predicted, %FEV1 predicted, nor FEV1% was associated with the incorrect use of a pMDI. Multivariate binomial logistic regression analysis identified decreased IRV as the only independent predictor associated with the incorrect use of a pMDI. Conclusions: Physicians should be aware that elderly patients or patients with decreased IRV might be unable to obtain the correct SABA dose from a pMDI. A large-scale prospective study is required to confirm these findings from our retrospective study with a small group of patients.

Association of Asthma with COVID-19 Disease Severity in Pediatric Patients

Background: The impact of COVID-19 on asthmatic patients is still uncertain. Objective: This study intended to examine the associations between the severity of coronavirus dis-ease 2019 (COVID-19), asthma, and some inflammatory markers among pediatric patients. Methods: A retrospective study enrolled pediatric COVID-19 patients who were admitted to Abuzar Hospital (Ahvaz, Iran) during eight months. The diagnosis of COVID-19 was according to the real-time reverse transcription-polymerase chain reaction (RT‐PCR) method. Asthma diagnosis was confirmed by specialists through functional and clinical evaluations (positive bronchodilator reversibility test or positive methacholine challenge test). Demographic and clinical characteristics of the patients were documented. Asthmatic patients with COVID-19 were considered as Group 1 (n= 52) and non-asthmatic COVID-19 patients were assigned as Group 2 (n= 54). Results: The mean age of 106 patients was 71.28 ± 50.09 months (range: 1-16 years). Children with severe and moderate COVID-19 had significantly lower levels of neutrophils and lymphocytes, higher inflammatory markers, and longer hospital length of stay (LOS) than patients with a mild course of COVID-19 (p &lt; 0.001). Patients in Group 1 had significantly longer LOS, higher dry cough, chest radiographic findings, fever, levels of D-dimer, fibrinogen, and C-reactive protein (CRP), as well as lower neutrophil and lymphocyte counts, compared with those in Group 2 (p &lt; 0.001). Conclusion: The presence of asthma in COVID-19 patients was associated with severe COVID-19 in comparison with their non-asthmatic counterparts. Additional studies with large sample sizes are deemed necessary to determine the impact of asthma on the management and incidence of COVID-19 disease.

Bronchodilator reversibility testing in long-term cough and dyspnea after Covid-19 viral infection: a trigger for asthma?

Objective: This study aims to investigate the presence of underlying chronic airway disease in individuals with chronic cough and dyspnea lasting longer than eight weeks and who had previously Coronavirus disease 2019 (COVID-19) and had no known lung disease. Methods: A total of 151 patients admitted to the respiratory diseases outpatient room with the complaint of cough and/or dyspnea that persisted for at least eight weeks following COVID-19 infection were accrued to the study. Demographic characteristics, smoking history, the severity of lung involvement on chest computed tomography in the acute phase of Covid-19 infection, and bronchodilator reversibility test results were recorded. Smoking history and forced expiratory volume in the first second (FEV1) were compared. Results: FEV1 increase ≥ 200 ml was observed in 40 (26.5%) patients. In 24 (15.9%) patients, an increase in FEV1 was found to be 200 ml and above, and the percentage of FEV1 was 12% or more. While 14 (9.3%) patients were diagnosed with asthma, 13 (8.6%) patients were diagnosed with nonreversible airflow obstruction (NRAO), and 1 (0.7%) patient was diagnosed with chronic obstructive pulmonary disease (COPD). Conclusions: COVID-19 infection may play a vital role in initiating asthma pathogenesis. It should be kept in mind that viral infection-related asthma may be the underlying cause of prolonged cough and dyspnea after COVID-19 infection.

Prevalence and Characteristics of Chronic Obstructive Pulmonary Disease in Dairy Farmers

Objective: To assess the prevalence and characteristics of chronic obstructive pulmonary disease (COPD) in dairy farmers, and evaluate the role of job exposure and smoking as predictors for respiratory health impairment. Methods: A cross-sectional study was performed, including 83 dairy farmers (mean age: 52.6±8.7 years; mean exposure duration: 23.7±7.6 years) and 80 office workers as a control group (mean age: 52.7±8.2 years) matched for age, smoking habits, and socioeconomic status. Methods for evaluation of study participants included a questionnaire on respiratory symptoms in the last 12 months, baseline spirometry and bronchodilator reversibility testing, and diagnostic criteria for COPD. Results: The mean post-bronchodilator values of spirometric parameters are significantly lower in subjects among EG with negative bronchodilator test compared to those in CG, while the mean post-bronchodilator values of spirometric parameters are lower in dairy farmers with negative BD tests exposed more than 20 years compared to those with exposure less than 20 years, being statistically significant for FEV1/FVC%, MEF25, MEF50 and MEF75. The COPD prevalence is non-significantly higher in dairy farmers compared to controls, and is significantly associated with age over 40 years in dairy farmers (P=0.035). The risk for COPD development in dairy farmers is about 36 fold higher in subjects exposed more than 20 years (OR = 36.00 (1.21-37.77) CI 95%) compared to those with exposure duration less than 20 years, and is about 6 fold higher in dairy farmers who are current smokers (OR = 6.12 (0.95-37.77) CI 95%). COPD is significantly associated with smoking duration among smokers in both groups, while combined effect of smoking, smoking duration, and number of cigarettes smoked daily has a significant impact on COPD development in dairy farmers. According to the GOLD classification, depending on the degree of airflow limitation, mild and moderate types of COPD are detected in dairy farmers, and only mild type in controls, showing no significant difference between the two groups. Conclusion: The study findings recognized the role of farming exposure, and smoking as well, as predictors for respiratory health impairment, and furthermore confirmed their potential to be a predictive factor in the COPD development. These facts should be helpful in detection of critical points for action, indicate the need of adverse occupational exposures reduction through adequate preventive measures and regular health examinations, implementation of relevant engineering controls, smoking cessation programs, and complete and efficient respiratory health assessment.

Asthma diagnosis using patient-reported outcome measures and objective diagnostic tests: now and into the future.

The global prevalence of asthma continues to increase; however, asthma remains under-diagnosed and under-treated. This results in a significant burden on the healthcare system and preventable patient morbidity and mortality. Over-diagnosis of asthma based on clinical history alone also complicates patient management. This heightens the importance of a prompt and accurate asthma diagnosis. Therefore, a review of the literature was performed regarding both objective diagnostic testing for asthma and using patient-reported outcome measures. The cornerstone of asthma diagnosis remains spirometry with testing for bronchodilator reversibility testing for pediatric and adult populations. This test may need to be repeated at multiple time points due to its low sensitivity. Peak flow measurement, fractional exhaled nitric oxide testing, and allergy testing are useful adjuncts to the diagnosis and phenotyping of asthma. Bronchoprovocation testing is reserved for people with high clinical suspicion for asthma, but negative spirometry. Novel noninvasive testing modalities may play a diagnostic role in the future. The advent of remote digital health monitoring technology has resulted in revisiting patient-reported outcome measures for the diagnosis and monitoring of asthma. Overall, improved diagnostic tools for asthma are crucial for earlier recognition and treatment of the disease and improved patient care outcomes worldwide.

European Respiratory Society Guidelines for the Diagnosis of Asthma in Adults.

Although asthma is very common affecting 5-10% of the population, the diagnosis of asthma in adults remains a challenge in the real world that results in both over- and under-diagnosis. A task force (TF) was set up by the European Respiratory Society to systematically review the literature on the diagnostic accuracy of tests used to diagnose asthma in adult patients and provide recommendation for clinical practice.The TF defined eight PICO (Population, Index, Comparator, and Outcome) questions that were assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach, The TF utilised the outcomes to develop an evidenced-based diagnostic algorithm, with recommendations for a pragmatic guideline for everyday practice that was directed by real-life patient experiences.The TF support the initial use of spirometry followed, and if airway obstruction is present, by bronchodilator reversibility testing. If initial spirometry fails to show obstruction, further tests should be performed in the following order: FeNO, PEF variability or in secondary care, bronchial challenge. We present the thresholds for each test that are compatible with a diagnosis of asthma in the presence of current symptoms.The TF reinforce the priority to undertake spirometry and recognise the value of measuring blood eosinophils and serum IgE to phenotype the patient. Measuring gas trapping by body plethysmography in patients with preserved FEV1/FVC ratio deserves further attention. The TF draw attention on the difficulty of making a correct diagnosis in patients already receiving inhaled corticosteroids, the comorbidities that may obscure the diagnosis, the importance of phenotyping, and the necessity to consider the patient experience in the diagnostic process.

Pulmonary function testing for the diagnosis of asthma in preschool children.

To highlight the recent evidence of the lung function techniques used in preschool children to diagnose asthma. Several techniques are available to measure lung function and airway inflammation in preschool children, including spirometry (from age 5 years), impulse oscillometry (>3 years), whole-body plethysmography (>3 years), fractional exhaled nitric oxide (FeNO) (>5 years), multiple breath washout (>3 years), structured light plethysmography (>1-2 years) and impedance pneumography (>1 years). If applicable, measuring forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio using spirometry is useful (cut-off < 80% predicted or below lower limit of normal [LLN] defined as z-score < -1.64) for diagnosing preschool asthma. For those unable to perform spirometry, whole-body plethysmography (sRaw > 1.6 kPa/s) and impulse oscillometry (Rrs and Xrs at 5 Hz z-score > 2) may be useful. Adding a bronchodilator reversibility test (FEV1 increase > 12%, sRaw decrease > 25-30%, Rrs at 5 Hz decrease > 40%) or a bronchial challenge test, for example, exercise test (FEV1 decrease > 10%), may improve the sensitivity of these tests. Elevated FeNO (>25-35 ppb) is a promising adjunctive test for diagnosing preschool asthma. With trained personnel, lung function testing can be done with high reliability even in children between 2 and 4 years of age. To avoid over and undertreatment of asthma, objective measurement of lung function is clinically important in preschool children.

Interleukin-26 is associated with the level of systemic inflammation and lung functions in obese and non-obese moderate-to-severe asthmatic patients.

Obese asthma is a complex syndrome, which includes different phenotypes of disease. At present, these phenotypes only have started to acquire a sufficient understanding. It was suggested that IL-26 is a potential biomarker of disease severity in asthma without signs of Th2-mediated inflammation. In this study, we investigated the serum and exhaled levels of IL-26 and its associations with the level of systemic inflammation, lung functions, and body weight in obese and non-obese moderate-to-severe asthmatic patients MATERIAL AND METHODS: The study included 10 healthy subjects, 10 obese subjects without lung pathologies, 10 non-obese asthmatics (NOA) (BMI 18.5-24.9 kg/m²), and 40 obese asthmatics (OA) (BMI 25.0-49.9 kg/m²). During the visit, patients' examination and spirometry with the bronchodilator reversibility test were conducted, the exhaled breath condensate (EBC) was obtained, and the blood samples were collected. The level of IL-26, interleukin-1β (IL-1β), interleukin-4 (IL-4), interleukin-6 (IL-6), TNF-α, interleukin-10 (IL-10), total and specific immunoglobulin E (IgE), and high sensitive C reactive protein (hs-CRP) were measured using the ELISA kits. Statistical comparison between 2 groups was analyzed using the Mann-Whitney rank-sum test. Chi-square with Yates' correction was used to compare frequencies. Spearman's rank test was used for correlating nonparametric variables. The Receiver Operating Characteristic (ROC) curve and the area under ROC curve (AUC) were used for evaluating the diagnostic power of IL-26 as a possible biomarker. NOA had a reversible airway obstruction with reduced FEV1, FEV1/FVC, FVC 25/75, and positive post-bronchodilator test (PBT), significantly increased serum levels of IL-10, IL-4, and slightly increased IL-26. NOA had significantly increased exhaled IL-26 in comparison with healthy subjects. The obese subjects had a normal ventilatory pattern without airway obstruction, and differences in serum IL-26, IL-10, and IL-4 concentrations in comparison with healthy subjects. Obese subjects had a significant escalation of hs-CRP and no differences in the levels of exhaled IL-26, IL-10, and hs-CRP as compared with healthy subjects. OA had reduced FEV1, FEV1/FVC, and FEV25-75 in comparison with non-obese asthmatics. OA had elevated IL-26, IL-10, IL-4, and hs-CRP concentrations as compared with healthy subjects. These patients had a partial similarity with both non-obese asthmatics (elevated IL-26, IL-10, and IL-4) and obese subjects (elevated, IL-1β, IL-6, TNF-α, hs-CRP). OA had a reduced concentration of exhaled IL-26 in comparison with NOA and elevated exhaled IL-10 in comparison with obese subjects. Furthermore, OA had an increased concentration of IL-1β and TNF-α in comparison with healthy individuals and NOA. Exhaled IL-26 concentration distinguished non-obese asthmatics from healthy subjects, asthmatic patients from non-asthmatics (healthy and obese subjects), all asthmatic patients from non-asthmatics (healthy and obese subjects). Exhaled IL-26 elevated in obese and non-obese moderate-to-severe asthmatic patients. Exhaled IL-26 might be a perspective biomarker in non-obese and obese asthmatics. The obese asthmatic phenotype comprised the combined systemic and local airway inflammation.

Use of capnography for prediction of obstruction severity in non-intubated COPD and asthma patients

BackgroundCapnography waveform contains essential information regarding physiological characteristics of the airway and thus indicative of the level of airway obstruction. Our aim was to develop a capnography-based, point-of-care tool that can estimate the level of obstruction in patients with asthma and COPD.MethodsTwo prospective observational studies conducted between September 2016 and May 2018 at Rabin Medical Center, Israel, included healthy, asthma and COPD patient groups. Each patient underwent spirometry test and continuous capnography, as part of, either methacholine challenge test for asthma diagnosis or bronchodilator reversibility test for asthma and COPD routine evaluation. Continuous capnography signal, divided into single breaths waveforms, were analyzed to identify waveform features, to create a predictive model for FEV1 using an artificial neural network. The gold standard for comparison was FEV1 measured with spirometry.Measurements and main resultsOverall 160 patients analyzed. Model prediction included 32/88 waveform features and three demographic features (age, gender and height). The model showed excellent correlation with FEV1 (R = 0.84), R2 achieved was 0.7 with mean square error of 0.13.ConclusionIn this study we have developed a model to evaluate FEV1 in asthma and COPD patients. Using this model, as a point-of-care tool, we can evaluate the airway obstruction level without reliance on patient cooperation. Moreover, continuous FEV1 monitoring can identify disease fluctuations, response to treatment and guide therapy.Trial registrationclinical trials.gov, NCT02805114. Registered 17 June 2016, https://clinicaltrials.gov/ct2/show/NCT02805114