Exercise-induced Bronchospasm In Children Research Articles

EFFECT OF PHYSICAL TRAINING ON EXERCISE-INDUCED BRONCHOSPASM IN YOUNG ASTHMATICS

ABSTRACT Introduction: Asthma is the most common chronic disease in childhood and its prevalence has increased in recent years. Although regular physical activity (PA) is considered to be beneficial for the health of asthmatics, especially children and adolescents, it can also be one of the elements that triggers asthma. This is known as exercise-induced bronchospasm (EIB), and is considered one of the factors that limits asthmatics’ participation in PA. Objective: This study aims to review the effects of physical conditioning on EIB in asthmatic children and adolescents. Methods: A systematic review was carried out on the Pubmed, Bireme and Web of Science databases, considering publications from 1998 to April 2019. Results: Eight articles were retrieved; five of the articles presented no significant difference in EIB parameters after physical training, and three demonstrated significant benefits in EIB. Conclusion: There is insufficient evidence that physical training helps reduce the frequency and severity of EIB in young asthmatics. There are still few studies that seek to show the effect of a physical training program on the improvement of EIB in children and adolescents. It is suggested that further randomized clinical trials be conducted, to investigate the effects of physical training on EIB parameters in children and adolescents. Level of Evidence II; Systematic review.

Exercise-induced bronchospasm in children and adolescents with allergic rhinitis by treadmill and hyperventilation challenges.

Respiratory complaints after exercise are common in patients with rhinitis. Exercise-induced bronchospasm (EIB) may be one of the causes. To evaluate EIB prevalence in a group of children and adolescents with allergic rhinitis, to compare the treadmill running (TR) and eucapnic voluntary hyperventilation (EVH) challenge methods as diagnostic tools and to assess the association between respiratory complaints on exercise and EIB. Patients aged between 10 and 20 years were studied at the Pulmonology Department of the Hospital das Clínicas -UFPE- Recife, Brazil. The severity of symptoms of rhinitis and exercise-related respiratory complaints in the past year were evaluated. Challenges were performed in random sequence, no more than 72 h apart and followed international guidelines. Forced expiratory volume in the first second (FEV1) was determined before and 3, 5, 7, 10, 15 and 30 min after each challenge. A >10% reduction in FEV1 from baseline at two points after the challenge was considered sufficient to diagnose EIB. Of the thirty-five subjects evaluated, thirteen (37%) showed EIB, six by both methods, three only after TR and four only after EVH (Coens' Kappa = 0.489). There was no association between respiratory complaints after exercise and EIB (p = 0.74). A high prevalence of EIB was found in this population but only moderate agreement between the challenges used to diagnose EIB. Caution should be adopted when comparing these methods or interpreting their results interchangeably. There was no association between reported respiratory symptoms after exercise and EIB.

The association between endotoxin in house dust with atopy and exercise-induced bronchospasm in children with asthma

BackgroundStudies have reported protective and adverse associations between microbial exposure and childhood asthma. However, among children with asthma the relationships between endotoxin and exercise-induced bronchospasm (EIB) is less clear. ObjectiveWe investigated the association between exposure to endotoxin in house dust with atopy and EIB in children with asthma. MethodsA cross-sectional survey was conducted among schoolchildren (aged 7–17 years) in the province of Saskatchewan, Canada. A subpopulation with asthma (n = 116) were identified from 335 participants using a validated asthma algorithm. We determined atopy among the asthma subpopulation by skin prick testing (SPT) while EIB was evaluated using exercise challenge testing (ECT). Dust samples were collected from mattress and play area floors, and endotoxin was measured in dust extracts. Logistic regression analyses were used to explore associations between endotoxin with atopy and EIB. ResultsAmong the 116 children with asthma, 99 completed SPT and all had completed ECT. Of these, 71/99 (71.7%) were atopic and 26/116 (22.4%) had EIB. Exposure to high play area endotoxin concentration [adjusted odds ratio (aOR) = 0.15, 95% CI: 0.03–0.85] and load (aOR = 0.11, 95% CI: 0.02–0.73) were negatively associated with atopy. In contrast, EIB was positively associated with high mattress endotoxin concentration (aOR = 6.01, 95% CI: 1.20–30.13). ConclusionIndoor microbial endotoxin exposure has varied associations with atopy and exercise-induced bronchospasm among children with asthma.

The association of forced expiratory volume in one second and forced expiratory flow at 50% of the vital capacity, peak expiratory flow parameters, and blood eosinophil counts in exercise-induced bronchospasm in children with mild asthma.

BackgroundExercise-induced bronchoconstriction (EIB), which describes acute airway narrowing that occurs as a result of exercise, is associated with eosinophilic airway inflammation, bronchial hyperresponsiveness. The forced expiratory volume in one second (FEV1) is the most commonly used spirometric test in the diagnosis of EIB in exercise challenge in asthma. Other parameters such as forced expiratory flow at 50% of the vital capacity (FEF50%) and peak expiratory flow (PEF) are used less often in the diagnosis of EIB.ObjectiveThe purpose of this study is to evaluate the association of FEV1 and FEF50%, PEF parameters, blood eosinophil counts in EIB in children with mild asthma.MethodsSixty-seven children (male: 39, female: 28) with mild asthma were included in this study. Pulmonary functions were assessed before and at 1, 5, 10, 15, and 20 minutes after exercise. The values of spirometric FEV1, FEF50%, PEF, and blood eosinophil counts were evaluated in EIB in children with mild asthma.ResultsThere was a positive correlation between FEV1 with FEF50% and PEF values (p<0.05; FEF50%, r=0.68; PEF, r=0.65). Also, a positive correlation was found between blood eosinophil counts and the values of spirometric FEV1, FEF50%, and PEF (p<0.05; FEV1, r=0.54; FEF50%, r=0.42; PEF, r=0.26). In addition to these correlations, in the exercise negative group for FEV1, the FEF50% and PEF values decreased more than the cutoff values in 3, and 2 patients, respectively.ConclusionAccording to the presented study, eosinophil may play a major role in the severity of EIB in mild asthma. FEF50% and PEF values can decrease in response to exercise without changes in FEV1 in mild asthmatic patients.

Pranlukast hydrate in the treatment of pediatric bronchial asthma

Pranlukast hydrate in the treatment of pediatric bronchial asthma Shigemi Yoshihara Department of Pediatrics, Dokkyo Medical University, Tochigi, Japan Abstract: Pranlukast hydrate is a potent, selective, orally active, cysteinyl leukotriene antagonist that binds at the type 1 receptor. It is used as a 10% dry syrup to treat asthma and allergic rhinitis in pediatric patients. In a 4-week, dose-finding study, a dose-dependent improvement in lung function was observed in pediatric patients with asthma at an optimal dose of 5.1&ndash;10 mg/kg/day. In a comparative, randomized, double-blind, 4-week multicenter trial, pranlukast dry syrup 7 mg/kg/day achieved significantly better final overall improvement (71.4%) versus oxatomide 1 mg/kg/day (37.2%) in pediatric patients older than one year with asthma. In two 12-week, open-label trials and in a long-term open-label trial of treatment for up to 24 months, pranlukast dry syrup improved asthma control over baseline values. In a prospective post-marketing surveillance study and a long-term follow-up study, the safety and efficacy of pranlukast dry syrup was confirmed in infants younger than one year with bronchial asthma. In a 4-week, open-label trial, pranlukast dry syrup improved overall health-related quality of life and physical and emotional domain scores over baseline in pediatric patients with asthma. In a randomized, multicenter, double-blind, placebo-controlled, two-period crossover trial, pranlukast dry syrup significantly inhibited exercise-induced bronchospasm in children with asthma compared with placebo. In a modified Childhood Asthma Control Test, pranlukast dry syrup was significantly more effective in controlling asthma in patients younger than 4 years with the common cold. These findings show that pranlukast is useful and beneficial for treating pediatric patients with bronchial asthma. Keywords: pranlukast, leukotriene receptor antagonist, pediatric asthma

Exhaled RANTES and interleukin 4 levels after exercise challenge in children with asthma

BackgroundDespite the universality and clinical significance of exercise-induced bronchospasm (EIB), the mechanisms responsible for it are incompletely understood. ObjectiveTo investigate the role of exhaled RANTES (regulated on activation, normal T-cell expressed and secreted) and interleukin (IL) 4 in EIB in children with asthma. MethodsFifty-six children with asthma were evaluated with exercise challenge and exhaled RANTES and IL-4 levels. Exhaled breath condensate was collected before and 30 minutes after exercise challenge. RANTES and IL-4 concentrations were determined using a specific immunoassay kit. ResultsA significant increase was found in RANTES levels after exercise challenge in the asthmatic children (P<.001). A statistically significant increase in RANTES levels was noted after exercise challenge in both the asthmatic children with EIB (n=25, P=.007) and in the non-EIB asthmatic group (n=31, P=.005). Our study revealed that exhaled RANTES level correlates significantly well with percentage of forced expiratory volume in 1 second (FEV1), exacerbation frequency, serum IgE, and body mass index. No statistically significant increase was found in IL-4 levels after exercise challenge. The maximal postexercise decrease in FEV1 strongly correlated with total eosinophil count (P<.001, r=−0.61) and baseline ratio of FEV1 to forced vital capacity (FVC) (P=.002, r=0.40). Results from multivariate regression analysis adjusted for age, sex, and atopy as covariates showed that eosinophil count and FEV1/FVC ratio were significantly associated with EIB. ConclusionWe found that exercise challenge, leading to hyperosmolar stimulus, may increase exhaled RANTES levels in children with asthma. In addition, exhaled RANTES levels correlate well with serum IgE, severity of asthma, FEV1/FVC ratio, and body mass index. RANTES and IL-4 may not be independent predictors for EIB. Furthermore, eosinophil count and FEV1/FVC ratio may predict the presence and severity of EIB in asthmatic children.

Exercise-induced bronchospasm in children with asthma in the United States: Results from the Exercise-Induced Bronchospasm Landmark Survey

Despite the availability of effective therapies, uncontrolled asthma remains a common problem. Previous large surveys suggest that exercise-related respiratory symptoms may be a significant element of uncontrolled asthma. The Exercise-Induced Bronchospasm (EIB) Landmark Survey is the first comprehensive, national survey evaluating EIB awareness and impact among the general public, asthma patients, and health care providers. This study was designed to evaluate the prevalence and impact of exercise-related respiratory symptoms in children (aged 4-17 years) with asthma. A national survey was conducted with parents of 516 children diagnosed with asthma or taking medications for asthma in the prior year. The majority of parents reported that their child experienced one or more exercise-related respiratory symptom and almost one-half (47.4%) experienced four or more symptoms. Most commonly reported symptoms were coughing, shortness of breath, and wheezing. Respondents reported that asthma limited their child's ability to participate either "a lot" or "some" in sports (30%), other outdoor activities (26.3%), and normal physical exertion (20.9%). Only 23.1% of children with exercise-related respiratory symptoms were reported to take short-acting beta-agonists such as albuterol "always" or "most of the time" before exercising. Exercise-related respiratory symptoms among pediatric asthma patients are common and substantially limit the ability of children to participate normally and perform optimally in physical activities. Such symptoms may reflect uncontrolled underlying asthma that should be evaluated and treated with appropriate controller medications. Despite the availability of preventative therapy, many children do not use short-acting bronchodilators before exercise as recommended in national guidelines.

Helminth Parasites and Allergic Disease in Vietnam: Do Gut Worms Protect against Allergic Sensitisation, Asthma, Eczema, and Hay Fever?

Helminth Parasites and Allergic Disease in Vietnam: Do Gut Worms Protect against Allergic Sensitisation, Asthma, Eczema, and Hay Fever?

Effect of Different Antiasthmatic Treatments on Exercise-Induced Bronchoconstriction in Children With Asthma

Stelmach I, Grzelewski T, Majak P, Jerzynska J, Stelmach W, Kuna P. J Allergy Clin Immunol. 2008;121(2):383–389 PURPOSE OF THE STUDY. To compare the effectiveness of different patterns of antiasthmatic treatments to protect children from exercise-induced bronchospasm (EIB). STUDY POPULATION. This was a randomized, double-blind, placebo-controlled study of 100 children aged 6 to 18 years with atopic asthma sensitive only to house dust mites and EIB. Subjects must have had a resting forced expiratory volume in 1 second (FEV1) of ≥70% predicted and at least a 20% drop in FEV1 after exercise to qualify for the study. METHODS. Participants were randomly assigned to a 4-week double-blind, placebo-controlled trial to receive 1 of the following treatments: (1) budesonide 100 μg + formoterol 4.5 μg twice daily; (2) budesonide 100 μg twice daily + montelukast 5 or 10 mg at bedtime; (3) montelukast 5 or 10 mg at bedtime; (4) budesonide 100 μg twice daily; or (5) placebo alone. All study arms had matching placebo medications from which active drugs were omitted (eg, group 1 had placebo tablets in place of montelukast, etc). At randomization and after 4 weeks on the study medication(s), a treadmill exercise test was performed to evaluate the effectiveness of treatment. RESULTS. Ninety-one subjects with a median age of 11.3 to 12.2 among the groups completed the study. Preexercise FEV1 and EIB, as represented by the area under the curve of time-response curve and by maximum percentage decrease in FEV1 after exercise, did not differ at baseline between the groups. EIB was diminished with all treatments when compared with placebo. The effect of treatment with budesonide plus montelukast and with montelukast alone were greater than budesonide alone or budesonide plus formoterol (P &amp;lt; .001). The budesonide-plus-formoterol group was also better than budesonide alone, but these results did not reach significance (P = .59). CONCLUSIONS. Budesonide plus montelukast or montelukast alone were the most effective treatments for EIB in children. REVIEWER COMMENTS. This was the first study in asthmatic children that evaluated both monotherapy and combination therapy for the reduction of EIB. This study highlights the importance of controller therapy in childhood asthma and the effects on EIB between therapeutic options recommended for childhood asthma. In particular, consideration for the use of montelukast as monotherapy or in combination therapy with inhaled corticosteroids is indicated for EIB in children with similar asthmatic phenotypes.

Management of Exercise-Induced Bronchospasm in Children:Role of Long-Acting β2-Adrenergic Receptor Agonists

Management of Exercise-Induced Bronchospasm in Children:Role of Long-Acting β₂-Adrenergic Receptor Agonists

Management of Exercise-Induced Bronchospasm in Children:Role of Long-Acting β2-Adrenergic Receptor Agonists

Exercise-induced bronchospasm (EIB) is a common, often unrecognized and undiagnosed, condition in children. The goal of treatment for EIB is to allow children and adolescents to maintain activity levels similar to those of their peers. Patients who develop symptoms only after strenuous activity can be treated prophylactically and do not require continuous treatment. Whereas short-acting β2-adrenergic receptor agonists (SABAs; e.g., albuterol) can protect against the symptoms of EIB in 80-95% of cases, these agents may not always be a practical treatment option. Results from small, randomized, placebo-controlled, single-dose studies comparing long-acting β2-adrenergic receptor agonists (LABAs) with SABAs in children and/or young adults have demonstrated that occasional dosing with formoterol or salmeterol provides significantly greater protection against EIB for a longer time than do SABAs. The onset of action of formoterol is comparable to that of albuterol (3 minutes), whereas the onset of action of salm...

Pretreatment with Albuterol versus Montelukast for Exercise‐Induced Bronchospasm in Children

To compare pretreatment with albuterol versus montelukast added to the current asthma regimen for protection against exercise-induced bronchospasm in children with mild-to-moderate asthma, and to determine whether cysteinyl leukotriene (Cys-LT) concentrations measured in the exhaled breath condensate correlated with response to montelukast. Prospective, randomized, double-blind, double-dummy, crossover study. Asthma clinic at a university-affiliated medical center. Eleven children aged 7-17 years with physician-diagnosed mild-to-moderate asthma for at least 6 months and with self-reported exercise-induced bronchospasm (defined as > or = 15% decrease in forced expiratory volume in 1 sec [FEV(1)] at screening and baseline visit). Patients were randomly assigned to receive 3-7 days of oral montelukast 5-10 mg/day or 2 puffs of an albuterol metered-dose inhaler just before an exercise challenge and then were crossed over to the alternate therapy for the last visit. Serial spirometry was performed before and at 0, 5, 10, 15, 30, 45, and 60 minutes after the exercise challenge at each visit. Measurement of exhaled breath condensate was performed at the screening visit and study visits 1 and 2. The primary outcome was the maximum change in FEV(1) after exercise. Secondary outcomes were the area under the curve for FEV(1) (expressed as percentage decrease from baseline) during the first 60 minutes (AUC(0-60)) after exercise and the proportion of patients in whom exercise-induced bronchospasm was prevented (defined as < 15% decrease in FEV(1) after exercise challenge). The mean +/- SD maximum decrease in FEV(1) was 27.5 +/- 7.9% at baseline. Patients receiving montelukast had an 18.3 +/- 13.7% decrease in FEV(1) compared with 0.7 +/- 1.6% in patients receiving albuterol (p=0.002, paired t test). Exercise-induced bronchospasm was prevented in 100% of the patients receiving albuterol compared with 55% receiving montelukast (p<0.05, McNemar's test). The AUC(0-60) was significantly smaller with albuterol compared with montelukast (p<0.001, Wilcoxon signed rank test). No correlations were found between Cys-LT concentration and the severity of exercise-induced bronchospasm or the response to montelukast. Pretreatment with albuterol is more effective than montelukast for prevention of exercise-induced bronchospasm in children with asthma.

Formoterol dry-powder inhaler for the treatment of asthma and chronic obstructive pulmonary disease

Formoterol, a long-acting β2-adrenergic agonist, is used as an inhaled bronchodilator therapy for patients with asthma or for the prevention of exercise-induced bronchospasm in children and in chronic obstructive pulmonary disease. Formoterol has unique characteristics of rapid onset and sustained duration of action compared with other bronchodilators. In addition to its effectiveness as regular maintenance therapy in asthma and chronic obstructive pulmonary disease, formoterol is also reported to be effective as an as-needed reliever therapy in patients with asthma. Formoterol is available in several different types of dry-powder inhalers and pressurized metered-dose inhalers.

Exercise-induced Bronchospasm In Children

This review will encompass definition, history, epidemiology, pathogenesis, diagnosis, and management of exercise -induced bronchospasm in the pediatric individual with and without known asthma. Exercise induced asthma is the conventional term for transient airway narrowing in a known asthma in association with strenuous exercise usually lasting 5-10 minutes with a decline in pulmonary function by at least 10%. Exercise induced asthma will be referred to as exercise induced bronchospasm in an asthmatic. Exercise-induced bronchospasm (EIB ) is the same phenomenon in an individual without known asthma. EIB can be seen in healthy individuals including children as well as defense recruits and competitive or elite athletes. The diagnosis with objective exercise challenge methods in conjunction with history is delineated. Management is characterized with pharmacotherapy and non pharmacotherapeutic measures for underlying asthma as well as exercise induced bronchospasm and inhalant allergy. Children can successfully participate in all sports if asthma is properly managed.

Broncoespasmo induzido pelo exercício em crianças e adolescentes com diagnóstico de asma

INTRODUÇÃO: A broncoconstrição temporária após o exercício físico tem elevada prevalência em crianças e adolescentes asmáticos. OBJETIVO: Determinar a freqüência e gravidade do broncoespasmo induzido pelo exercício em crianças e adolescentes, com diagnóstico clínico de asma leve, moderada e grave. MÉTODO: Foi realizado um estudo descritivo, tipo transversal, não controlado. A amostra constituiu-se de 40 indivíduos asmáticos, de ambos os sexos, com idade entre 7 e 18 anos, que não utilizavam regularmente medicação anti-inflamatória. Foi realizado teste padronizado de provocação brônquica com exercício de corrida em esteira rolante. A espirometria foi padronizada em seis manobras expiratórias, realizadas antes e aos 1, 5, 10, 15, 20 e 30 minutos após o término do exercício, sendo escolhida a de maior valor. O volume expiratório forçado no primeiro segundo (VEF1) foi utilizado para o diagnóstico e classificação da gravidade do broncoespasmo. Os pacientes asmáticos apresentavam condições clínicas e espirométricas adequadas para os testes (VEF1 &gt; 70% do valor previsto). Foi utilizada como critério de positividade para o broncoespasmo induzido pelo exercício queda &gt;10% em relação ao VEF1 prévio ao exercício. RESULTADOS: Vinte e seis (65%) pacientes desenvolveram broncoespasmo após o exercício. Dos pacientes com asma leve 44%, e dos com asma moderada e grave, 100% desenvolveram broncoespasmo. Houve associação significativa entre a freqüência do broncoespasmo induzido pelo exercício e a gravidade da asma (p&lt; 0,05), e diferença significativa entre a sua gravidade (confirmada por uma queda no VEF1) e a gravidade da asma (p &lt; 0,05). CONCLUSÃO: A freqüência e gravidade do broncoespasmo induzido pelo exercício estiveram relacionadas com a gravidade clínica da asma.

Management of exercise-induced bronchospasm in children: the role of leukotriene antagonists.

This review assesses the evidence on the efficacy of leukotriene antagonists in the management of exercise-induced bronchospasm (EIB) in children. Only two randomized, double-blind, placebo-controlled, crossover studies have examined the effect of leukotriene antagonists in EIB in a pediatric setting. All other studies, including those comparing leukotriene antagonists with other agents such as beta(2)-adrenoceptor agonists (beta(2)-agonists) and inhaled corticosteroids, primarily involve adult patients. In children, not receiving other asthma medication, leukotriene antagonists can offer statistically significant protection from EIB compared with placebo. However, protection is not complete, as a significant proportion of children will continue to experience a >15% reduction in FEV(1). None of the studies involved children treated concurrently with other asthma medications; therefore, comments on additive therapy cannot be made. Despite evidence from only a few studies, leukotriene antagonists are seen to be well tolerated, efficacious, and of benefit to some children. In addition, current management for EIB with short-acting beta(2)-agonists is less than ideal. It is therefore concluded that in children with EIB, leukotriene antagonists are indicated on a trial basis with individualized therapy and follow-up to evaluate treatment response.

Management of Exercise-Induced Bronchospasm in Children

Bronchospasm precipitated by exercise is often indistinguishable from bronchospasm produced by other stimuli. Symptoms result from airflow limitation and include wheezing, cough, chest tightness, dyspnea and sometimes hypoxemia. The prevalence of exercise-induced bronchospasm varies from 30%-90%, but virtually all patients with current asthma will experience a decrease in lung function if the exercise is sufficiently vigorous, especially in cold, dry environmental conditions. Exercise-induced bronchospasm is more prevalent in children than in adults, probably because children are physically more active. It is also more prevalent among elite winter sports athletes. The pathogenesis of exercise-induced bronchospasm involves a defect in respiratory heat exchange that probably triggers mast cell and eosinophil release of bronchoconstricting mediators. The goal of therapy is prevention of symptoms. This may be accomplished by pre-treating patients with isolated exercise-induced bronchospasm using an inhaled rapid-onset β2-adrenergic agonist before a scheduled activity or by treating the underlying inflammation when exercise-induced bronchospasm is part of the clinical syndrome of persistent asthma. In the later instance, either an inhaled corticosteroid, an oral leukotriene modifier, or a combination of both, depending on severity, may be required to prevent exercise-induced bronchospasm associated with activities of daily living. In addition, some of these patients may still require pre-treatment with a short-acting inhaled β2-agonist before a scheduled vigorous activity, especially in very cold ambient temperatures. Because the duration of bronchoprotection decreases with daily use (tachyphylaxis), long acting β2-adrenergic agonists (e.g., formoterol, salmeterol) have a limited role in treating exercise-induced bronchospasm.

Exercise-induced bronchospasm in children: effects of asthma severity.

The prevalence of exercise-induced bronchospasm (EIB) in asthmatic individuals has been reported to vary from 40% to 90%. There are, however, few studies addressing the effects of asthma severity on airway responsiveness to exercise. The purpose of the present study was to investigate the effects of asthma severity on EIB in children. We studied 164 children classified as having intermittent (n = 63), mild persistent (n = 30), moderate persistent (n = 40), and severe persistent asthma (n = 31) according to the Global Initiative for Asthma classification. Subjects exercised for 6 min on a cycle ergometer at 80% of their maximum heart rate, and spirometry was performed before and 5, 10, and 20 min after exercise challenge. The prevalence of EIB in children with moderate or severe persistent asthma was significantly greater than in children with intermittent asthma (p < 0.001). EIB-positive children with intermittent asthma exhibited smaller changes in FEV1 than children in the other three groups (p < 0.001). There was no significant relationship between baseline FEV1 and the decline in FEV1 after exercise. We conclude that the prevalence of EIB is greater in children with more severe asthma, and that the intensity of response to exercise is not consistently related to the clinical severity of asthma.

Montelukast Reduces Exercise-Induced Bronchospasm in Children.

A recent study examined the effect of the leukotriene receptor antagonist montelukast in young adults with exercise-induced bronchospasm (EIB) (see JW , Aug 15 1998, p. 126, accession number 98080402, and N Engl J Med 1998; 339:147). Now a double-blind, placebo-controlled, crossover …

Exercise-induced bronchospasm in children: effects and therapies.

Exercise-induced bronchospasm in children: effects and therapies.