Bronchoconstriction In Children Research Articles

Association of temperature and absolute humidity with incidence of exercise-induced bronchoconstriction in children.

Exercise test outdoors is widely used to diagnose asthma in children, but it is unclear how much outdoor air factors affect the results. We analysed 321 outdoor exercise challenge tests with spirometry in children 6-16 years conducted due to suspicion of asthma or for assessing the effect of medication on asthma. We studied the association of FEV1 decrease and incidence of exercise-induced bronchoconstriction (EIB) with temperature, relative humidity (RH) and absolute humidity (AH). Asthma was diagnosed in 57% of the subjects. AH ≥5 g/m3, but not RH or temperature, was associated with the EIB incidence (p = 0.035). In multivariable logistic regression, AH ≥5 g/m3 was negatively associated (OR = 0.51, 95% CI [0.28─0.92], p = 0.026) while obstruction before exercise (OR = 2.11, 95% CI [1.16─3.86], p = 0.015) and IgE-mediated sensitisation were positively associated with EIB (OR = 2.24, 95% CI [1.11─4.51], p = 0.025). AH (r = -0.12, p = 0.028) and temperature (r = -0.13, p = 0.023) correlated with decrease in FEV1. In multivariable linear regression, only AH was associated with FEV1 decrease (coefficient = -0.044, 95% CI [-0.085 to -0.004], p = 0.033). AH of outdoor air associates with occurrence and severity of EIB in outdoor exercise tests in children. Care should be taken when interpreting negative outdoor exercise test results if AH of air is high.

Exercise-Induced Bronchoconstriction in Children: A Comparison between Athletes and Non-Athletes.

Exercise-induced bronchoconstriction (EIB) is a dysfunction of the respiratory tract consisting of transient airflow obstruction. This study is a retrospective analysis of two prospective studies concerning EIB symptoms in two adolescent populations. Our study group included 400 non-athletes and 101 athletes. Due to the similarity of indoor exercise conditions, an analysis was performed on the basis of where training took place. The study aims to assess the EIB prevalence in the following groups of adolescent children: non-athletes and athletes. In "indoor" athletes, the EIB prevalence was 22.4%. Among non-athletes, EIB was diagnosed in 10.2% (p = 0.007). A history of asthma was found in 6.5% of non-athletes and 29.3% of indoor athletes (p < 0.001). The incidence of EIB without asthma was higher in indoor athletes (14.6%) than in non-athletes (9.9%). Athletes achieved higher mean values in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), and maximum expiratory flow rate at 25% (MEF25) parameters. In the group of non-athletes, higher results were observed in forced expiratory volume in one second % of vital capacity (FEV1%VC), MEF50, and MEF75. The findings of the study present the complexity of the EIB diagnosis among children training in an indoor environment.

Impulse oscillometry (IOS) for detection of exercise induced bronchoconstriction in children with asthma ages 6–15 years

Objectives To determine the discriminatory value of various impulse oscillometry (IOS) parameters, and to find the cutoff value of the appropriate parameter for identifying exercise-induced bronchoconstriction (EIB) in children with asthma. Methods This cross-sectional study was conducted in India from October 2016 to March 2018 in children with asthma who were 6–15 years of age. One hundred and five children were enrolled and subjected to pre-exercise IOS and spirometry followed by free running treadmill test as an exercise challenge. All children could achieve minute ventilation >17.5–21 times of FEV1 during the exercise challenge test. Then, IOS and spirometry were performed at 10 ± 2, 20 ± 2, and 30 ± 2 min post-exercise challenge. EIB was defined as reduction of FEV1 ≥10% within 30 min of exercise. For purposes of analysis, the children were grouped into two categories: “EIB Present” or “EIB Absent”. Results The prevalence of EIB in our study was 20.95% (n = 22). ΔR5max percentage within 30 min post-exercise (AUC 0.74; 95% CI: 0.64, 0.84) had the best discriminating capacity among all IOS parameters for identifying EIB. A cutoff value of 14.1% increase in R5 within 30 min post-exercise was obtained for detection of EIB (sensitivity—95.45%, specificity—50.6%, PPV—33.87% and NPV—97.67%). Conclusions A percentage change in R5 with a cutoff value of 14.1% increase post-exercise had the best discriminatory capacity among all IOS parameters for detection of EIB in children with asthma. However, low positive predictive value (PPV) with high negative predictive value (NPV) made this cutoff value more apt to rule out EIB.

The Effect Of Mouth Breathing On Exercise Induced Bronchoconstriction In Children

BACKGROUND: Exercise induced bronchoconstriction (EIB) is a common finding in the pediatric population. Nose breathing is considered to decreases hyper-responsiveness of the airways. Therefore, nose clip (NC) is used during exercise challenge test (ECT) in adults to increase test sensitivity. Data on the need for NC during ECT in children is scarce. Our aim was to evaluate the effect of breathing with and without NC on EIB in children. METHODS: A prospective study evaluating two ECT’s with/without NC within a month period. Demographic, clinical data, Total Nasal Symptoms Score (TNSS) and Asthma Control Test (ACT) were recorded. RESULTS: Fifty-four children (mean age 16.7 ± 1.2 y/o, 39% Female) were evaluated. Forty-four returned to visit 2. At Visit 1 (with NC) baseline FEV1 was 92.8 ± 11.0%pred and 27/44 (61%) had positive ECT (decline≥12% in FEV1) with mean FEV1 drop of 14.7 ± 11.3%pred. At visit 2 ,8.7 ± 7.7 days post visit 1 (without NC), baseline FEV1 was 88.9 ± 11.3%pred (p < 0.001), mean FEV1 drop was 9.0 ± 10.1%pred (p < 0.0001) and only 14/44 (32%) had positive ECT (p < 0.0001). A total of 14/44 (32%) of children with a positive ECT with a NC turned negative without a NC. CONCLUSIONS: Use of NC during ECT increases the rate of positive tests thus possibly improving the yield of EIB diagnosis in children. Optional physiologic mechanisms could be humidification and warming of the inhaled air through the nose cavity. The findings strengthen the recommendation of nasal blockage during ECT. Larger randomized studies are needed to unfold the full effect of nose breathing during exercise.

Exercise-Induced Bronchoconstriction in Children.

Exercise-induced bronchoconstriction (EIB) is a transient airflow obstruction, typically 5–15 min after physical activity. The pathophysiology of EIB is related to the thermal and osmotic changes of the bronchial mucosa, which cause the release of mediators and the development of bronchoconstriction in the airways. EIB in children often causes an important limitation to physical activities and sports. However, by taking appropriate precautions and through adequate pharmacological control of the condition, routine exercise is extremely safe in children. This review aims to raise awareness of EIB by proposing an update, based on the latest studies, on pathological mechanisms, diagnosis, and therapeutic approaches in children.

Outdoor pollen concentration is not associated with exercise-induced bronchoconstriction in children.

Free running exercise test outdoors is an important method to diagnose asthma in children. However, the extent of how much exposure to pollens of outdoor air affects the results of the test is not known. We analyzed all reliable exercise challenge tests with impulse oscillometry in children (n = 799) between January 2012 and December 2014 in Tampere University Hospital. Pollen concentrations at the time of the test were collected from the register of Biodiversity Unit of the University of Turku. We compared the frequency of exercise-induced bronchoconstriction and pollen concentrations. The analyses were restricted to birch and alder pollen as high counts of grass and mugwort pollen were so infrequent. The relative change in resistance at 5 Hz after exercise or the frequency of exercise-induced bronchoconstriction were not related to alder or birch pollen concentrations over 10 grains/m3 (p = 0.125-0.398). In logistic regression analysis comparing the effects of alder or birch pollen concentrations, immunoglobulin E (IgE)-mediated alder or birch allergy and absolute humidity over 10 g/m3 only absolute humidity was independently associated with change in airway resistance (odds ratio [OR]: 0.32, confidence interval [CI]: 0.13-0.67, p: 0.006). In our large clinical sample, outdoor air pollen concentration was not associated with the probability of exercise-induced bronchoconstriction in free running test in children while low absolute humidity was the best predictor of airway obstruction.

The Role of Physical Aerobic Activity in Controlling Exercise-Induced Bronchoconstriction in Children and Adolescents with Asthma

Asthma, one of the major widespread chronic disorders among children and adolescents, has become more prevalent recently. The common manifestations of this disorder are caused by inflammatory airways that lead to airway restriction and lung hypersensitivity causing dry coughing, wheezing, and shortness of breath, all of which are combined with sleep disturbance, impaired physical activity, and reduced quality of life. The main goal of this brief review was to identify the associated variables that affect the management of asthma disease in children and young adolescents and to identify the role of physical aerobic exercise in the treatment of asthmatic children. The current review was based on prior research published in English databases such as Google Scholar, PubMed, and Embase in scientific articles published between January 2010 and October 2021 with the keywords "asthma," "children," "adolescents," "breathing episodes," "physical activity," and "physical exercise." Regular physical aerobic exercise training with moderate intensity has been shown to improve pulmonary functions, life quality, psychological conditions, and reduce asthma symptoms and EIB in children and adolescents with bronchial asthma.

The Effects of Climate Therapy on Cardiorespiratory Fitness and Exercise-Induced Bronchoconstriction in Children with Asthma

We investigated whether a 1-week stay in the mountains may have a positive impact on Exercise-Induced Bronchoconstriction (EIB) and cardiorespiratory endurance in asthmatic children from an urban area. Spirometry was performed before and 10 min after a 20 m shuttle run test (20mSRT) on the first and seventh day of a summer asthma camp in the Italian Alps at 900 m of altitude. Spirometry z-scores were derived from the Global Lung Initiative 2012 prediction equations, and percentiles of the 20mSRT performance were assigned according to De Miguel-Etayo’s and Tomkinson’s predictive equations. A FEV1 decrease ≥10% after the exercise was defined as EIB. Particulate matter pollution was monitored during the camp and in the urban area of provenience. Twenty-four subjects (age range 7–16 years) were included. Frequency of EIB decreased from 58% (14/24) at day-1 to 33% (8/24) at the end of the camp (p = 0.08). Most subjects with a 20mSRT in the lowest quartile at day 1 had EIB (9/11). The proportion of children with a 20mSRT &lt;25° percentile decreased from 45% (11/24) at day-1 to 16% (4/24) at day-7 (p = 0.02). Conclusion: One-week climate therapy in the mountains improved both bronchial hyperreactivity and cardiorespiratory endurance in our cohort of asthmatic children.

Effect of age on exercise-induced bronchoconstriction in children and adolescents with asthma

Objective The relationship between exercise-induced bronchoconstriction (EIB) and exertional dyspnea in children and adolescents is yet to be fully established. This study examined whether indicators of fractional exhaled nitric oxide (FeNO), forced expiratory volume in 1 s (FEV1) percent predicted at baseline, and dyspnea are useful for predicting children and adolescents with EIB. Methods We enrolled 184 children and adolescents diagnosed with asthma (mean age 11.2 years); participants were divided into two groups according to age (12 years) and were subjected to a 6-min exercise challenge test. Lung function tests and modified Borg scale scores were used to examine perceptions of dyspnea at 0, 5 and 15 min after exercise. Results Among children, the maximum percentage drop in FEV1 after exercise correlated significantly with FeNO (adjusted β = 2.3, P < 0.001) and with the perception of dyspnea at 5 min after exercise (adjusted β = 1.9, P < 0.001). Among adolescents, the maximum percentage drop in FEV1 correlated with FeNO (adjusted β = 2.7, P = 0.007) and with lung function (FEV1, percent predicted; adjusted β = −0.28, P = 0.006). Children with EIB had significantly stronger dyspnea after exercise than did children without EIB. Adolescents even without EIB may experience more exertional dyspnea than children without EIB. Conclusions Overall, our findings indicated that EIB was associated with FeNO and exertional dyspnea in asthmatic children. By contrast, EIB was associated with FEV1 percent predicted at baseline and FeNO but not with exertional dyspnea in asthmatic adolescents.

The sensitivity and specificity of the forced oscillation technique in the diagnosis of bronchoconstriction in children

Objective The forced oscillation technique (FOT) is a useful diagnostic respiratory system for children. However, the final value of the FOT in the diagnosis of bronchoconstriction is still open. The aim of the study was to evaluate the sensitivity and specificity of the FOT vs. body plethysmography tests in the measure of bronchoconstriction in asthmatic children. Materials and methods A total of 102 children aged 2 to 6 years diagnosed with early-onset asthma and 52 healthy controls were included in this prospective, randomized study. All asthmatic patients and healthy controls underwent a basic FOT as one measurement, according to the recommendation of the Resmon Pro FOT. Then, the reversibility test was performed 20 min after the administration of 200 mg salbutamol using the FOT and body plethysmography in all patients. Results The mean basic Rrs, Xrs and sRaw in asthmatic patients were, respectively, 11.13 ± 1.28 kPa sL−1, −4.6 ± 1.18 kPa sL−1 and 1.72 ± 0.58 kPa s. Similar parameters were significantly better in the control group (p < 0.05). A total of 73 (71.6%) asthmatic patients had a positive test using the FOT according to Calogero. In 4 (7.7%) patients in the control group, a positive test was obtained. In body plethysmography, similar results were reached, with a positive test in 76 (74.5%) study patients and 5 (9.6%) control patients. Conclusions A bronchial reversibility test with the use of the FOT is useful for the diagnosis of bronchial asthma, especially with the use of an Rrs parameter, such as the body plethysmography test.

The Visual Analog Scale detects exercise-induced bronchoconstriction in children with asthma

Objective: Exercise-induced bronchoconstriction (EIB) is a specific morbidity of childhood asthma and an important sign of uncontrolled asthma. The occurrence of EIB is insufficiently identified by the Childhood Asthma Control Test (C-ACT) and Asthma Control Test (ACT). This study aimed to (1) evaluate the Visual Analog Scale (VAS) for dyspnea as a tool to detect EIB in asthmatic children and (2) assess the value of combining (C-)ACT outcomes with VAS scores. Methods: We measured EIB in 75 asthmatic children (mean age 10.8 years) with a standardized exercise challenge test (ECT) performed in cold and dry air. Children and parents reported VAS dyspnea scores before and after the ECT. Asthma control was assessed by the (C-)ACT. Results: Changes in VAS scores (ΔVAS) of children and parents correlated moderately with fall in forced expiratory volume in 1 second (FEV1), respectively rs=0.57 (p < .001) and rs=0.58 (p < .001). At a ΔVAS cutoff value of ≥3 in children, sensitivity and specificity for EIB were 80% and 79% (AUC 0.82). Out of 38 children diagnosed with EIB, 37 had a (C-)ACT score of ≤19 and/or a ΔVAS of ≥3, corresponding with a sensitivity of 97% and a negative predictive value of 96%. Conclusion: This study shows that the VAS could be an effective additional tool for diagnosing EIB in children. A reported difference in VAS scores of ≥3 after a standardized ECT combined with low (C-)ACT scores was highly effective in detecting and excluding EIB.

Association of air humidity with incidence of exercise-induced bronchoconstriction in children.

The effects of humidity and temperature on results of free running test in children are not known. Assess the relation of outdoor air temperature, relative humidity (RH), and absolute humidity (AH) to airway obstruction in children after free running exercise test. We analyzed all exercise challenge tests with impulse oscillometry in children between January 2012 and April 2015 in the Tampere University Hospital. The associations of AH, RH, and temperature of outdoor air with change in airway resistance were studied using regression analysis and by comparing the frequency of exercise-induced bronchoconstriction (increase ≥40% in resistance at 5 Hz) at different levels of temperature and humidity. Overall, 868 children with reliable results were included (mean age: 5.4 years; range: 3.0-14.1). In regression analysis, the relative change in resistance at 5 Hz after exercise was related to temperature (regression coefficient = -0.223, P = .020) and AH (regression coefficient = -0.893, P = .002), but not to RH. If absolute air humidity was <5 g/m3 , exercise-induced bronchoconstriction (EIB) occurred in 17.6% of study subjects and at AH levels ≥10 g/m3 , it occurred in 5.9% of study subjects (P = .008). In multiple regression analysis comparing the effects of temperature and humidity and adjusting for covariates, only AH was independently associated with change in airway resistance (P = .009). High AH of air is associated with lower incidence of EIB after outdoor exercise test in children. A negative test result at AH ≥10 g/m3 should be interpreted with caution.

Assessing Exercise-Induced Bronchoconstriction in Children; The Need for Testing.

Objective: Exercise-induced bronchoconstriction (EIB) is a specific morbidity of childhood asthma and a sign of insufficient disease control. EIB is diagnosed and monitored based on lung function changes after a standardized exercise challenge test (ECT). In daily practice however, EIB is often evaluated with self-reported respiratory symptoms and spirometry. We aimed to study the capacity of pediatricians to predict EIB based on information routinely available during an outpatient clinic visit.Methods: A clinical assessment was performed in 20 asthmatic children (mean age 11.6 years) from the outpatient clinic of the MST hospital from May 2015 to July 2015. During this assessment, video images were made. EIB was measured with a standardized ECT performed in cold, dry air. Twenty pediatricians (mean years of experience 14.4 years) each evaluated five children, providing 100 evaluations, and predicted EIB severity based on their medical history, physical examination, and video images. EIB severity was predicted again after additionally providing baseline spirometry results.Results: Nine children showed no EIB, four showed mild EIB, two showed moderate, and five showed severe EIB. Based on clinical information and spirometry results, pediatricians detected EIB with a sensitivity of 84% (95% CI 72–91%) and a specificity of 24% (95% CI 14–39%).The agreement between predicted EIB severity classifications and the validated classifications after the ECT was slight [Kappa = 0.05 (95% CI 0.00–0.17)]. This agreement still remained slight when baseline spirometry results were provided [Kappa = 0.19 (95% CI 0.06–0.32)].Conclusion: Pediatricians' prediction of EIB occurrence was sensitive, but poorly specific. The prediction of EIB severity was poor. Pediatricians should be aware of this in order to prevent misjudgement of EIB severity and disease control.

Ventilatory Demand During Stepping and Running: Implications for Exercise-Induced Bronchoconstriction in Children.

Single-step tests have been proposed as simple and inexpensive challenges to diagnose exercise-induced bronchoconstriction (EIB) in the pediatric population. Work performed and the resulting ventilation, however, might be substantially lower in stepping than running. This might decrease the diagnostic yield of step-based challenges. In a cross-sectional study, 53 children with asthma with exercise-related symptoms (34 boys, age 6-18 y) underwent an incremental stepping test, a 6-min constant stepping test, and a treadmill running test on different days. Constant and incremental stepping tests presented with lower metabolic demands (V̇O2 1.42 ± 0.48 and 1.34 ± 0.55 L/min, respectively), ventilatory demands (V̇O2 45 ± 14 and 43 ± 16 L/min, respectively), and cardiovascular demands (160 ± 20 and 161 ± 19 beats/min, respectively) than the treadmill running test (1.65 ± 0.60 L/min, 54 ± 17 L/min, and 172 ± 7 beats/min, respectively) (P < .05). Between-test agreement in diagnosing EIB was poor (kappa 0.217-0.361). Although EIB prevalence was higher after the treadmill running test (60%) compared to constant (53%) and incremental (47%) stepping tests, 7 subjects developed EIB only in stepping. Clinical and resting functional characteristics did not differ in discordant subjects (ie, EIB negative in a given test but positive in another) versus concordant subjects (ie, EIB negative or positive in both tests). EIB was not related to individual test ability in eliciting high to very-high ventilation (≥ 40% or ≥ 60% maximum voluntary ventilation, respectively). Moreover, a negative stepping test but a positive treadmill test (and vice versa) was not associated with greater ventilatory demands. Lower prevalence of EIB in stepping compared to treadmill running is not related to less ventilation demand in the former modality. Although stepping might be useful as a screening EIB test due its portability and low cost, a negative test should be confirmed with a running-based test in symptomatic children.

FeNO and Exercise Testing in Children at Risk of Asthma

Exercise testing is the gold standard for diagnosing exercise-induced bronchoconstriction in children, but requires considerable cooperation and medical resources. Therefore, fraction of exhaled nitric oxide (FeNO) has been proposed as a tool to predict the need for exercise testing. The objective of this study was to investigate the relationship between FeNO, exercise test results, and a history of respiratory symptoms during exercise in children at risk of asthma. FeNO measurement, exercise testing, and interview about respiratory symptoms during exercise were completed in 224 seven-year-old children from the at-risk Copenhagen Prospective Studies on Asthma in Childhood2000 birth cohort. The associations between FeNO, exercise test results, and reported respiratory symptoms during exercise were analyzed adjusting for gender, respiratory infections, and inhaled corticosteroid treatment. The associations were also analyzed stratified by asthma and atopic status. Of the 224 children, 28 (13%) had an established asthma diagnosis and 58 (26%) had a positive exercise test (≥15% drop in forced expiratory volume in 1 second [FEV1] from baseline). FeNO and bronchial obstruction after exercise were linearly associated with a doubling of FeNO corresponding to a 2.4% drop in FEV1 (95% confidence interval, 0.8-4.1; P<.01). However, a receiver operating characteristic curve analysis showed that the best cutoff of FeNO for predicting exercise test outcome among children who reported respiratory symptoms during exercise was 17 ppb, which only had 74% negative predictive value. There was no association between FeNO and reported respiratory symptoms during exercise (odds ratio= 1.3 [0.8-1.9]; P= .29) or reported symptoms during exercise and exercise test results (odds ratio= 1.0 [1.0-1.1]; P= .12). A history of respiratory symptoms during exercise was not associated with either elevated FeNO or a positive exercise test in children at risk of asthma. FeNO and exercise test results were linearly associated traits, but FeNO could not reliably be used dichotomized to predict the need of exercise testing.

Exercise-induced bronchoconstriction in children with asthma: An observational cohort study.

The diagnosis of exercise-induced bronchoconstriction (EIB) was established by changes in lung function after exercise challenge. The prevalence of EIB and factors related to EIB were not fully described in children with asthma. The aim of this study was to investigate the prevalence and predictors of EIB in children with asthma. A total of 149 children with physician-diagnosed asthma above 5 years of age underwent standardized treadmill exercise challenge for EIB and methacholine challenge for airway hyper-responsiveness from October 2015 to December 2016. EIB presented in 52.5% of children with asthma. Compared with children without EIB, there were more patients with atopic dermatitis in children with EIB (p=0.038). Allergic to Dermatohagoides pteronyssinus and Dermatophagoides farinae were also found more in children with EIB (p=0.045 and 0.048 respectively). Maximal decrease in forced expiratory volume in 1s (FEV1) were highest in patients who were most sensitive to methacholine provocation (provocation concentration causing 20% fall in FEV1 [PC20]≤1mg/mL). Patients, who were more sensitive to methacholine challenge (with lower PC20 levels), develop EIB with more decline in FEV1 after exercise challenge (p=0.038). Among patients with EIB, airflow limitation development in patient with methacholine-induced airway hyper-responsiveness was more abrupt and severe compared with patients without airway hyper-responsiveness (p=0.045 and 0.033 respectively). EIB presented in 52.5% of children with asthma. The more severe methacholine-induced hyper-responsiveness, the higher prevalence of EIB as well as the severity.

Exercise intolerance and exercise-induced bronchoconstriction in children.

Respiratory symptoms at rest or during exercise may restrain the physical capabilities required for normal motor and psychosocial development in children. The most frequent cause of exercise intolerance, apart from poor physical fitness, is exercise-induced bronchoconstriction (EIB), which may occur in some healthy children and in children with asthma. It is proposed that hyperventilation during exercise is associated with drying and cooling of airways, which can trigger a proinflammatory response. Several tests are used to confirm EIB, and the exercise-challenge test is the most common. Some nonpharmacologic therapies may induce airway refractoriness; warm-up exercise can result in the attenuation of EIB in more than half of the people with EIB. Prophylactic intermittent treatment with short-acting bronchodilators is the most commonly used treatment, but the conventional pharmacologic therapy for patients with uncontrolled asthma is the regular use of inhaled corticosteroids, with or without long-acting beta-agonists and montelukast. Therapy should result in optimal control of exercise-induced symptoms during habitual physical activity and also allow participation in sports activity in athletes.

Comparison on the profiles of a modified Borg scale and the pediatric dyspnea scale during an induced bronchoconstriction in children with clinical asthma

Purpose: Dyspnea is the cardinal symptom of asthma, but it is difficult to quantify clinically. Although modified Borg (mBorg) scale has been successfully used in adult, but there has been some difficulties to apply in children. Recently, Pediatric Dyspnea Scale (PDS) was adequately designed and has been widely used. The aim of this study is to compare 2 evaluating scales of dyspnea provoked by induced-bronchoconstriction in childhood asthma. Methods: Seventy-three clinically suspected children with asthma were enrolled in this study. Each ‘fractional exhaled nitric oxide (FeNO)’ was documented. Forced expiratory volume in 1 second (FEV1), mBorg score and PDS score were recorded during metha-choline provocation test. Results: Mapping using canonical plot demonstrated global similarity between 2 scales with some distinctive features. Whereas mBorg score showed more diverse categories in low level of dyspnea, PDS score did in medium level of it. A distribution of dyspnea perception score at a 20% decrease in FEV1 relative to baseline (PS20), a perception score of dyspnea at 20% fall in FEV1 of 2 scales represented similar wide, biphasic feature. Statistical relevance was verified with spearman correlation (Rs=0.903, P<0.001) and Bland-Altman analysis. PS20 of both scores and FeNO had no statistical relationship. While relationship between PS20 by mBorg score and the concentration of methacholine at 20% fall in FEV1 (PC20) was not significant (Rs=0.224, P=0.154), that between PS20 by PDS and PC20 was weak positive (Rs=0.29, P=0.063). Conclusion: PDS had similar pattern to assess the dyspnea with the mBorg scale suggesting adequacy of PDS in evaluating pediat-ric clinical asthma. We expect these scales to help clinical practice in complementary ways. (Allergy Asthma Respir Dis 2017;5:262-268)

A novel method for detecting airway narrowing using breath sound spectrum analysis in children.

Using a breath sound analyzer, we investigated new clinical parameters that are rarely affected by airflow in young children. A total of 65 children with asthma participated in this study (mean age 9.6 years). In Study 1, the intra- and inter-observer variability was measured. Common breath sound parameters, frequency at 99%, 75%, and 50% of the maximum frequency (F99, F75, and F50) and the highest frequency of inspiratory breath sounds were calculated. In addition, new parameters obtained using the ratio of sound spectra parameters, i.e., the spectrum curve indexes including the ratio of the third and fourth area to the total area and the ratio of power and frequency at F75 and F50, were calculated. In Study 2, 51 children underwent breath sound analyses. In Study 3, breath sounds were studied before and after methacholine inhalation. In Study 1, the data showed good inter- and intra-observer reliability. In Study 2, there were significant relationships between the airflow rate, age, height, and spirometric and common breath sound parameters. However, there were no significant relationships between the airflow rate and the spectrum curve indexes. Moreover, the spectrum curve indexes showed no relationships with age, height, or spirometric parameters. In Study 3, all parameters significantly changed after methacholine inhalation. Some spectrum curve indexes are not significantly affected by the airflow rate at the mouth, although they successfully indicate airway narrowing. These parameters may play a role in the assessment of bronchoconstriction in children.

The role of leukotriene receptor antagonists in exercise induced bronchoconstriction in children.

Exercise induced bronchoconstriction (EIB) may complicate childhood asthma. Leukotriene receptor antagonists (LTRAs), such as montelukast, may be beneficial in protecting against EIB. Our aim was to systematically review the role of LTRAs in the treatment of asthmas complicated by exercise induced bronchoconstriction and to assess various clinical factors which may influence the therapeutic outcome. Electronic searches were performed in the following databases: PubMed, CENTRAL, and the US National Institutes of Health Clinical Trial database. Following selection according to clearly defined inclusion and exclusion criteria and in accordance with the PRISMA statement; 5 double-blind, randomized, placebo-controlled trials of montelukast as monotherapy or add-on therapy in childhood asthma and 2 review articles were analysed in this systematic review. Treatment with LTRAs provides protection from EIB, when used as both monotherapy and add-on therapy. However, disease variables and aetiological factors may impact on the extent of clinical improvement. Genetic variability may influence leukotriene production and subsequent response to LTRAs. This issue could be addressed in further studies.