Exercise-induced bronchoconstriction, allergy and sports in children.

Exercise-induced bronchoconstriction (EIB) is characterized by the narrowing of airways during or after physical activity, leading to symptoms such as wheezing, coughing, and shortness of breath. Distinguishing between EIB and exercise-induced asthma (EIA) is essential, given their divergent therapeutic and prognostic considerations. EIB has been increasingly recognized as a significant concern in pediatric athletes. Moreover, studies indicate a noteworthy prevalence of EIB in children with atopic predispositions, unveiling a potential link between allergic sensitivities and exercise-induced respiratory symptoms, underpinned by an inflammatory reaction caused by mechanical, environmental, and genetic factors. Holistic management of EIB in children necessitates a correct diagnosis and a combination of pharmacological and non-pharmacological interventions. This review delves into the latest evidence concerning EIB in the pediatric population, exploring its associations with atopy and sports, and emphasizing the appropriate diagnostic and therapeutic approaches by highlighting various clinical scenarios.

Feasibility of Constant Work Rate Testing to Detect Exercise-Induced Laryngeal Obstruction.

INTRODUCTION: Exercise-induced laryngeal obstruction (EILO) is a condition in which laryngeal structures inappropriately obstruct the upper airway during exercise. The standard diagnostic test for EILO is the continuous laryngoscopy during exercise (CLE) test, usually performed with an incremental work rate protocol regardless of the nature of the triggering event. Typically, laryngeal obstruction occurs only briefly at the end of an incremental test, near peak work capacity. We aimed to investigate constant work rate (CWR) protocols for CLE testing to expand diagnostic test modalities and improve the understanding of EILO. METHODS: In this prospective, self-controlled feasibility study, 10 patients with EILO performed both an incremental and a CWR CLE test at 70%, 80%, and 90% of maximal exercise capacity. Laryngoscopic video data were recorded and compared, and we evaluated the ability of CWR to reproduce the symptoms and laryngeal obstruction seen in incremental testing. RESULTS: In 70%-90% of cases, CWR testing induced at least the same severity of obstruction as incremental testing and CLE scores remained comparable across test modalities. CWR at 70% allowed observation of laryngeal obstruction for a significantly longer duration than in incremental testing (158 s; 95% confidence interval, 25-291 s; P = 0.027). Dyspnea intensity appeared higher during CWR testing compared with incremental testing. CONCLUSIONS: Submaximal CWR CLE testing is feasible and able to induce EILO equivalent to the standard incremental CLE test. This is the first step toward tailored CLE exercise protocols, and further studies are now needed to establish the utility of CWR in clinical and research settings.

[Exercise-induced laryngeal obstruction†: diagnosis and management]. / Obstruction laryngée induite à l'effort: méthodes diagnostiques et prise en charge.

Exercise-induced laryngeal obstruction (EILO) is a condition characterized by temporary narrowing or closure of the larynx during physical activity, in particular during intense physical exertion. It generally affects teenagers and young adults and is often misdiagnosed as exercise-induced asthma. Symptoms include dyspnea, wheezing and a feeling of throat tightness during exercise. The aim of this article is to review this often underrecognized condition, its diagnosis and its management.

L'obstruction laryngée induite à l'effort (EILO) est une affection caractérisée par le rétrécissement ou la fermeture temporaire du larynx au cours d'une activité physique, en particulier lors d'un effort physique intense. Elle touche généralement les adolescents et les jeunes adultes et est souvent diagnostiquée à tort comme de l'asthme d'effort. Les symptômes comprennent une dyspnée, une respiration sifflante et une sensation d'oppression au niveau de la gorge pendant l'exercice. Cet article passe en revue cette pathologie souvent méconnue, son diagnostic et sa prise en charge.

Asthma and exercise-induced bronchoconstriction in athletes: Diagnosis, treatment, and anti-doping challenges.

Athletes often experience lower airway dysfunction, such as asthma and exercise-induced bronchoconstriction (EIB), which affects more than half the athletes in some sports, not least in endurance sports. Symptoms include coughing, wheezing, and breathlessness, alongside airway narrowing, hyperresponsiveness, and inflammation. Early diagnosis and management are essential. Not only because untreated or poorly managed asthma and EIB potentially affects competition performance and training, but also because untreated airway inflammation can result in airway epithelial damage, remodeling, and fibrosis. Asthma and EIB do not hinder performance, as advancements in treatment strategies have made it possible for affected athletes to compete at the highest level. However, practitioners and athletes must ensure that the treatment complies with general guidelines and anti-doping regulations to prevent the risk of a doping sanction because of inadvertently exceeding specified dosing limits. In this review, we describe considerations and challenges in diagnosing and managing athletes with asthma and EIB. We also discuss challenges facing athletes with asthma and EIB, while also being subject to anti-doping regulations.

Exercise-induced bronchoconstriction assessed by a ratio of surface diaphragm EMG to tidal volume.

Exercise-induced bronchoconstriction (EIB) is usually assessed by changes in forced expiratory volume in 1 s (FEV1 ) which is effort dependent. The purpose of this study was to determine whether the diaphragm electromyogram (EMGdi ) recorded from chest wall surface electrodes could be used to reflect changes in airway resistance during an exercise challenge test and to distinguish patients with EIB from those without EIB. Ninety participants with or without asthma history were included in the study. FEV1 was recorded before and 5, 10, 15, and 20 min after exercise. EIB was defined as an FEV1 decline greater than 10% after exercise. A ratio of root mean square of EMGdi to tidal volume (EMGdi /VT ) was used to assess changes in airway resistance. Based on changes in FEV1 , 25 of 90 participants exhibited EIB; the remainder were defined as non-EIB participants. EMGdi /VT in EIB increased by 124% (19%-478%) which was significantly higher than that of 21% (-39% to 134%) in non-EIB participants (p < 0.001). At the optimal cutoff point (54% in EMGdi /VT ), the area under the ROC curve (AUC) for detection of a positive test was 0.92 (p < 0.001) with sensitivity 92% and specificity 88%. EMGdi /VT can be used to assess changes in airway resistance after exercise and could be used to distinguish participants with EIB from those without EIB.

Is there cardiac autonomic dysfunction in children and adolescents with exercise-induced bronchospasm?

BACKGROUND: The pulmonary impairment in patients with bronchoconstriction induced by eucapnic voluntary hyperpnea(EVH) goes beyond the respiratory system, also impairing autonomic nervous modulation. This study aimed to evaluate the behavior of cardiac autonomic modulation in young asthmatics with and without EIB after the EVH test. RESEARCH DESIGN AND METHODS: A cross-sectional study design using 54 asthmatics(51.9% female), aged between 10 and 19 years, investigated with the EVH test. Forced expiratory volume in one second(FEV1) was measured at 5, 10, 15, and 30 min after EVH. Heart rate variability(HRV) measures of time were assessed pre and 30 min-post EVH. The diagnosis of Exercise-Induced bronchoconstriction with underlying clinical asthma(EIBA) was confirmed by a fall in FEV1 ≥10% compared to baseline. RESULTS: Thirty(55.5%) asthmatics had EIBA. Subjects with EIBA have reduced mean of the R-R intervals in relation to baseline until 15 minutes after EVH. Individuals without EIBA had increased parasympathetic activity compared to baseline(rMSSD) from 5 min after EVH(p < 0.05). This parasympathetic activity increase in relation to baseline was seen in individuals with EIBA after 25 minutes (rMSSD = 49.9 ± 5.3 vs 63.5 ± 7.2, p < 0.05). CONCLUSION: Young asthmatics with EIBA present a delay in the increase of the parasympathetic component after EVH when compared to asthmatics without EIBA.

The effect of nose clip on exercise-induced bronchoconstriction in adolescents.

BACKGROUND: Oral breathing is considered to increase hyper-responsiveness of the airways. Data on the need for nose clip (NC) during exercise challenge test (ECT) in children and adolescents is scarce. Ouraim was to evaluate the role of NC during ECT in children and adolescents. METHODS: A prospective, cohort study; children referred for ECT were evaluated on two separate visits, with and without a NC. Demographic, clinical data and measurements of lung functions were recorded. Allergy and asthma control were evaluated by Total Nasal Symptoms Score (TNSS) and Asthma Control Test (ACT) questionnaires. RESULTS: Sixty children and adolescents (mean age 16.7 ± 1.1 years, 38% Female,) performed ECT with NC and 48 (80%) completed visit 2 (ECT without NC), 8.7 ± 7.9 days after visit 1. Following exercise, 29/48 patients (60.4%) with NC had a decline of ≥12% in forced expiratory volume in the first second (FEV1 ) (positive ECT) compared to only 16/48 (33.3%) positive tests without NC (p = 0.0008). Test result was changed in 14 patients from positive ECT (with NC) to negative ECT (no NC) and in only one patient from negative to positive. The use of NC resulted in greater FEV1 decline (median 16.3% predicted, IQR 6.0-19.1% predicted vs. median 4.5% predicted, IQR 1.6-18.4% predicted, p = 0.0001), and better FEV1 increase after bronchodil at or inhalation compared to ECT without NC. Higher TNSS scores did not predict higher probability to positive ECT. CONCLUSIONS: The use of NC during ECT increases detection rate of exercise induced bronchoconstriction during ECT in the pediatric population. These findings strengthen the recommendation of nasal blockage during ECT in children and adolescents.

Exercise Induced Bronchospasm and associated factors in primary school children: a cross-sectional study.

BACKGROUND: Exercise Induced Bronchospasm(EIB) is not equivalent to asthma. As many as 20%of school aged children are estimated to have EIB. In Nigeria, there is still a dearth of information on EIB as a clinical entity. This study determined the presence of EIB(using pre and post-exercise percentage difference in peak expiratory flow rate(PEFR) and associated factors such as age, gender, social class and nutritional status in primary school children in Nnewi, Anambra state, South-East Nigeria. The study also grouped those with EIB into those with asthma(EIBA) and those without asthma(EIBWA). METHODS: This was a community based cross-sectional study involving 6-12 year olds. The PEFR was taken at rest and after a 6 min free running test on the school play-ground using a Peak Flow Meter. A diagnosis of EIB was made if there was a decline of ≥ 10%. Those who had EIB were grouped further based on the degree of decline in post-exercise PEFR (a decline ≥ 10% < 25% → Mild EIB, ≥ 25% < 50% → Moderate EIB and ≥ 50% → Severe EIB) and then categorized as those with EIBWA/EIBA. RESULTS: EIB in the various minutes post-exercise was as follows: 19.2%(1stmin), 20.9%(5thmin), 18.7%(10thmin), 10%(20thmin), 0.7%(30thmin). Mild EIB accounted for the greater proportion in all minutes post-exercise and none of the pupils had severe EIB. Using values obtained in the 5thmin post-exercise for further analysis, EIBWA/EIBA = 84.1%/15.9% respectively. Mean difference in the post-exercise PEFR of EIB/no EIB and EIBWA/EIBA was -48.45(t = -7.69, p = < 0.001) and 44.46(t = 3.77, p = 0.01) respectively. Age and gender had a significant association to the presence of EIB and 58% of the pupils with EIB were of high social class. The BMI for age and gender z-scores of all study subjects as well as those with EIB was -0.34 ± 1.21, -0.09 ± 1.09 respectively. Other features of allergy(history of allergic rhinitis: OR-5.832, p = 0.001; physical findings suggestive of allergic dermatitis: OR-2.740, p = 0.003)were present in pupils diagnosed with EIB. CONCLUSION: EIB has a high prevalence in primary school children in Nnewi and the greater proportion of those with EIB had EIBWA. EIB therefore needs to be recognized as a clinical entity and stratified properly based on the presence or absence of asthma. This will help the proper management and prognostication.

Diagnostic approach to lower airway dysfunction in athletes: a systematic review and meta-analysis by a subgroup of the IOC consensus on 'acute respiratory illness in the athlete'.

OBJECTIVES: To compare the performance of various diagnostic bronchoprovocation tests (BPT) in the assessment of lower airway dysfunction (LAD) in athletes and inform best clinical practice. DESIGN: Systematic review with sensitivity and specificity meta-analyses. DATA SOURCES: PubMed, EBSCOhost and Web of Science (1 January 1990-31 December 2021). ELIGIBILITY CRITERIA: Original full-text studies, including athletes/physically active individuals (15-65 years) who underwent assessment for LAD by symptom-based questionnaires/history and/or direct and/or indirect BPTs. RESULTS: In 26 studies containing data for quantitative meta-analyses on BPT diagnostic performance (n=2624 participants; 33% female); 22% had physician diagnosed asthma and 51% reported LAD symptoms. In athletes with symptoms of LAD, eucapnic voluntary hyperpnoea (EVH) and exercise challenge tests (ECTs) confirmed the diagnosis with a 46% sensitivity and 74% specificity, and 51% sensitivity and 84% specificity, respectively, while methacholine BPTs were 55% sensitive and 56% specific. If EVH was the reference standard, the presence of LAD symptoms was 78% sensitive and 45% specific for a positive EVH, while ECTs were 42% sensitive and 82% specific. If ECTs were the reference standard, the presence of LAD symptoms was 80% sensitive and 56% specific for a positive ECT, while EVH demonstrated 65% sensitivity and 65% specificity for a positive ECT. CONCLUSION: In the assessment of LAD in athletes, EVH and field-based ECTs offer similar and moderate diagnostic test performance. In contrast, methacholine BPTs have lower overall test performance. PROSPERO REGISTRATION NUMBER: CRD42020170915.

The continuous laryngoscopy exercise test in severe or in difficult-to-treat asthma in adults: a systematic review.

OBJECTIVE: A systematic review was performed to determine if the continuous laryngoscopy exercise test (CLE) has been used in the diagnostics of exercise dyspnea in adults with asthma, and whether inducible laryngeal obstruction (ILO) is found in those with asthma or with severe or difficult-to-treat asthma. DATA SOURCES: We used Scopus and PubMed databases. The articles published up to 13 August 2019 were considered. STUDY SELECTIONS: We excluded manuscripts that did not contain information about adult patients with asthma. We included six studies from 59 search results in Scopus and none from the 17 search results in PubMed. RESULTS: The articles included 455 study individuals. Of these, 229 (50.3%) had diagnosed asthma or were treated with asthma medication. Altogether 31/229 (13.5%) subjects with diagnosis of asthma or previous asthma treatment had exercise-induced laryngeal obstruction (EILO) as comorbidity. The CLE test was performed on 229 patients with asthma. The method was used only for differential diagnosis of exercise-induced dyspnea to confirm EILO. At least 10/455 (2.2%) out of the 455 subjects experienced adverse events. CONCLUSIONS: This systematic review revealed that only a small proportion of patients with asthma had undergone the CLE test to assess exercise-induced dyspnea. None of the selected manuscripts reported severity of asthma. Whether CLE provides a valuable diagnostic tool for patients with severe or difficult-to-treat asthma cannot be determined according to this review.

Exercise-Induced Dyspnea in Collegiate Athletes: Are We Missing the Diagnosis?

OBJECTIVES: Exercise-induced dyspnea (EID) can disrupt an athlete's participation and performance in their given sport. Differential diagnosis of EID is often completed using subjective report and may be inaccurate, therefore increasing the frustration and stress of the athlete. This nonexperimental research study was used to determine prevalence of EID and related respiratory symptoms in athletes at a small, Division I university. METHODS: An anonymous survey was provided to athletes at Murray State University as they registered for participation in sports for the 2020-2021 school year. Data from this survey was analyzed as to reported physician-given diagnosis of a respiratory disorder as well as reported symptoms of EID. RESULTS: Results showed that athletes with a physician-given diagnosis often did not report symptoms or responses to medications that support that diagnosis. Additionally, athletes frequently reported symptoms of EID without a formal diagnosis of a respiratory disorder. CONCLUSIONS: These findings provide preliminary insight and pilot data that may be used to understand the prevalence of EID in collegiate athletes and the need for improved methods of diagnosis for etiologies of EID.

Diagnostic work-up of exercise-induced laryngeal obstruction.

PURPOSE: Exercise-induced laryngeal obstruction (EILO) is suspected when dyspnea associated with upper airway symptoms is triggered by exercise. This condition affects mainly adolescent athletes. Visualization of the obstruction, while the patient is experiencing the symptoms during continuous laryngoscopy during exercise (CLE-test) is the gold standard for diagnosing EILO. Our study aims to evaluate the prevalence of EILO in a population presenting exercise-induced inspiratory symptoms (EIIS) or uncontrolled asthma with exertional symptoms. The second objective was to evaluate the diagnostic strength of laryngology consultation (LC) and pulmonary function tests (PFTs). METHODS: All patients referred to our center for EIIS or uncontrolled asthma with exertional symptoms were included. EILO diagnosis was made if Maat score was > 2 for patients with CLE-test or if there were inspiratory anomalies on PFTs and LC. The sensitivity and specificity of LC and PFTs as diagnostic tools were calculated considering CLE-test as the gold standard. RESULTS: Sixty two patients were referred to our center for EIIS or uncontrolled asthma with exertional symptoms. EILO was diagnosed in 28 patients (56%) with associated asthma in 9 patients (18%). The sensibility and specificity of LC for supraglottic anomalies were 75% and 60%, respectively. The sensibility and specificity of PFTs were 61% and 89%, respectively. CONCLUSIONS: There was a high prevalence of EILO among patients with EIIS and uncontrolled asthma. Some clinical characteristics might guide the diagnosis. Nevertheless, CLE-test remained the gold standard for EILO diagnosis and identification of the dysfunctional upper airway site to provide specific management.

Can physical exercise assist in controlling and reducing the severity of exercise-induced bronchospasm in children and adolescents? A systematic review.

OBJECTIVE: The aim of this study was to analyze whether physical exercise can contribute to improving the control and severity of exercise-induced bronchospasm (EIB) in children and adolescents. METHOD: This is a systematic review that used PubMed/Medline and Scopus databases as a search source, and using descriptors indexed to DeCS/Mesh. The articles were analyzed in three stages in the selection process. Methodological quality was assessed using the TESTEX scale. RESULT AND DISCUSSION: A total of 5867 articles were filtered in the initial search; however, only eight of these were included after the eligibility criteria. All presented improvements in cardiorespiratory fitness. Only two followed the international EIB diagnostic guidelines. Of these, only one described a reduction in FEV1 and considered that this improvement may influence the EIB response in children and adolescent athletes with a non-asthmatic sample. CONCLUSION: The studies analyzed in this review did not enable drawing a conclusion regarding the influence of physical exercise on EIB in asthmatics. The lack of clinical trials on EIB and physical exercise, as well as the difficulty in methodological standardization for EIB diagnosis evidence the lack of scientific knowledge in this area, serving as a stimulus for researchers to find more consolidated answers.

Exercise-induced bronchoconstriction in elite athletes: a narrative review.

Exercise-induced bronchoconstriction (EIB) is the most common chronic disease among elite athletes and when left untreated, can impact both respiratory health and sports performance. In recent years, there has been an increase in the awareness and detection of EIB in elite athletes. This narrative review aims to evaluate the risk, prevention, diagnosis, medication, and anti-doping policies of EIB in elite athletes, and to provide more references for athletes with EIB. The results showed that athletes of endurance, winter, and water sports generally have a higher prevalence of EIB than athletes of other sports. Adaptive warm-up before formal exercise and using heat exchange masks at low temperatures are effective ways for athletes to prevent EIB. For physicians, the exercise challenge test and eucapnic voluntary hyperpnea are the recommended diagnostic methods for EIB in athletes. The treatment of athletes with EIB is medication-based, such as inhaled corticosteroids and beta-2 agonists, but current anti-doping policies should be considered when used.

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.

Adolescent Athletes at Risk of Exercise-Induced Bronchoconstriction: A Result of Training or Pre-Existing Asthma?

Exercise may trigger bronchoconstriction, especially in a group of athletes in whom bronchospasm during exercise is reported to occur more frequently than in nonathletes. The aim of this study was to determine the prevalence and environmental risk factors contributing to exercise-induced bronchoconstriction (EIB) in adolescent athletes. A prospective study was conducted among a group of 101 adolescent athletes who underwent spirometry, exercise challenge, fractional exhaled nitric oxide (FeNO) measurements, and allergy assessment. The study group was divided into three subgroups of athletes based on the most common sports environments: swimmers, "indoor" athletes, and "outdoor" athletes. The clinical evaluation demonstrated a high frequency of EIB in the study group. Moreover, a large proportion of the athletes in whom EIB was observed reported no pre-existing symptoms suggestive of bronchospasm or asthma. Among patients without a previous diagnosis of asthma, clinical evaluation confirmed 22% with positive exercise challenges, compared with 77% of adolescents with negative test results. Moreover, among the athletes with a history of asthma, 39% had positive exercise challenges. Both EIB and asthma are common conditions that affect adolescent athletes. Physicians should pay particular attention to this group, as the symptoms can lead to under- and overdiagnosis.

Cut-off value for exercise-induced bronchoconstriction based on the features of the airway obstruction.

The current cut-off value for diagnosing exercise-induced bronchoconstriction (EIB) in adults-percent fall in FEV1 (ΔFEV1) ≥ 10% after exercise challenge test (ECT)-has low specificity and weak evidences. Therefore, this study aimed to identify the cut-off value for EIB that provides the highest diagnostic sensitivity and specificity. Participants who underwent the ECT between 2007 and 2018 were categorized according to ΔFEV1: definite EIB (ΔFEV1 ≥ 15%), borderline (10% ≤ ΔFEV1 < 15%), and normal (ΔFEV1 < 10%). Distinct characteristics of the definite EIB group were identified and explored in the borderline EIB group. A receiver operating characteristic curve was plotted to determine the optimal cut-off value. Of 128 patients, 60 were grouped as the definite EIB group, 23 as the borderline group, and 45 as the normal group. All participants were men, with a median age of 20 years (interquartile range [IQR:] 19-23 years). The definite EIB group exhibited wheezing on auscultation (P < 0.001), ΔFEV1/FVC ≥ 10% (P < 0.001), and ΔFEF25-75% ≥ 25% (P < 0.001) compared to other groups. Eight (8/23, 34.8%) patients in the borderline group had at least one of these features, but the trend was more similar to that of the normal group than the definite EIB group. A cut-off value of ΔFEV1 ≥ 13.5% had a sensitivity of 98.5% and specificity of 93.5% for EIB. Wheezing on auscultation, ΔFEV1/FVC ≥ 10%, and ΔFEF25-75% ≥ 25% after ECT may be useful for the diagnosis of EIB, particularly in individuals with a ΔFEV1 of 10-15%. For EIB, a higher cut-off value, possibly ΔFEV1 ≥ 13.5%, should be considered as the diagnostic criterion.

Evaluating Children and Adolescents with Suspected Exercise Induced Asthma: Real Life Data.

OBJECTIVE: Exercise-induced bronchoconstriction (EIB) occurs frequently in children and adolescents and may be a sign of insufficient asthma control. EIB is often evaluated by respiratory symptoms, spirometry, eNO measurement and methacholine testing (MCT) instead of time consuming exercise test. Aim of this study was to analyse the amount of patients for which an exercise challenge in a cold chamber (ECC) was needed for a clear EIB diagnosis, to characterize EIB phenotypes and the incidence of exercise induced laryngeal obstruction (EILO) in a large cohort of patients with EIB. METHODS: A retrospective analysis was performed in 595 children and adolescents (mean age 12.1 years) with suspected EIB from January 2014 to December 2018. Complete data sets of skin prick test, spirometry, eNO and MCT were available from 336 patients. RESULTS: An ECC to confirm the EIB diagnosis was performed in 125 (37.2%) of patients. Three EIB phenotypes were detected: group 1: EIB without allergic sensitization (n=159); group 2: EIB with other than house dust mite (HDM) sensitization (n=87) and group 3: EIB with HDM sensitization (n=90). MCT and eNO showed significant differences between the subgroups: An eNO>46 ppb and/or a MCT<0.1 mg was found in 23.9% vs. 50.6% vs. 57.8% in group 1-3, respectively. Significantly more patients suffered from EILO in group 1 compared to group 2 and 3 (n=13 vs. n=1). CONCLUSION: EIB without sensitization is as often as EIB with sensitization. In patients without sensitization, EILO has to be considered as a possible cause of symptoms during exercise.

Ventilation Rates Achieved in Eucapnic Voluntary Hyperpnea Challenge and Exercise-Induced Bronchoconstriction Diagnosis in Young Patients with Asthma.

PURPOSE: Exercise-induced bronchoconstriction (EIB) affects approximately 50% of young asthma patients, impairing their participation in sports and physical activities. Eucapnic voluntary hyperpnea (EVH) is an approved surrogate challenge to exercise for objective EIB diagnosis, but the required minimum target hyperventilation rates remain unexplored in this population. This study aimed to evaluate the association between the achieved ventilation rates (VRs) during a challenge and EIB-compatible response (EIB-cr) in young asthma patients. METHODS: This cross-sectional study included 72 asthma patients aged 10-20 years. Forced expiratory volume in the first second (FEV1) was measured before and 5, 15, and 30 min after the EVH. The target VR was set at 21 times the individual's baseline FEV1. A decrease of > 10% in FEV1 after the challenge was considered an EIB-cr. The challenge was repeated after 48-72 h in those without an EIB-cr. RESULTS: Thirty-six individuals had an EIB-cr at initial evaluation. The median VRs achieved was not different between individuals with and without an EIB-cr (19.8 versus 17.9; p = 0.619). The proportion of individuals with an EIB-cr was nor different comparing those who achieved (12/25) or not (24/47) the calculated target VRs (p = 0.804). At the repeated EVH challenge an EIB-cr was observed in 14/36 individuals with a negative response in the first evaluation, with no differences in achieved VRs between the two tests (p = 0.463). CONCLUSION: Irrespective of the achieved VR, an EIB-compatible response after an EVH challenge must be considered relevant for clinical and therapeutic judgment and negative tests should be repeated.