RESUMO
AIM: Exercise test outdoors is widely used to diagnose asthma in children, but it is unclear how much outdoor air factors affect the results. METHODS: 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). RESULTS: 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 [0.28â0.92], p = 0.026) while obstruction before exercise (OR = 2.11, 95% CI [1.16â3.86], p = 0.015) and IgE-mediated sensitisation were positively associated with EIB (OR = 2.24, 95% CI [1.11â4.51], 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). CONCLUSION: 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.
Assuntos
Asma Induzida por Exercício , Umidade , Temperatura , Humanos , Criança , Masculino , Feminino , Asma Induzida por Exercício/epidemiologia , Asma Induzida por Exercício/diagnóstico , Asma Induzida por Exercício/fisiopatologia , Adolescente , Incidência , Teste de Esforço , BroncoconstriçãoRESUMO
OBJECTIVE: To compare the thermographic pattern of regions of interest (ROI) of respiratory muscles in young asthmatics with and without bronchospasm induced by eucapnic voluntary hyperpnea (EVH). MATERIALS AND METHODS: Cross-sectional study carried out with 55 young (55% male and 45% females) aged 12.5 ± 3.3 years, divided in nine nonasthmatics, 22 asthmatics without exercise-induced bronchospasm compatible response (EIB-cr) and 24 asthmatics with EIB-cr. The diagnosis of EIB was given to subjects with a fall in forced expiratory volume in the first second (FEV1) ≥ 10% compared to baseline. Thermographic recordings of respiratory muscles were delimited in ROI of the sternocleidomastoid (SCM), pectoral, and rectus abdominis intention area. Thermal captures and FEV1 were taken before and 5, 10, 15 and 30 min after EVH. RESULTS: Twenty-four (52.1%) of asthmatics had EIB-cr. There was a decrease in temperature at 10 min after EVH test in the SCM, pectoral and rectus abdominis ROIs in all groups (both with p < 0.05). There was a decrease in temperature (% basal) in asthmatic with EIB-cr compared to nonasthmatics in the rectus abdominis area (p < 0.05). CONCLUSION: There was a decrease in temperature in the ROIs of different muscle groups, especially in asthmatics. The greater drop in FEV1 observed in individuals with EIB-cr was initially associated with a decrease in skin temperature, with a difference between the nonasthmatics in the abdominal muscle area. It is likely that this decrease in temperature occurred due to a temporary displacement of blood flow to the most used muscle groups, with a decrease in the region of the skin evaluated in the thermography.
Assuntos
Valor Preditivo dos Testes , Músculos Respiratórios , Termografia , Humanos , Masculino , Feminino , Estudos Transversais , Criança , Adolescente , Músculos Respiratórios/fisiopatologia , Volume Expiratório Forçado , Termografia/métodos , Estudos de Casos e Controles , Fatores de Tempo , Asma Induzida por Exercício/fisiopatologia , Asma Induzida por Exercício/diagnóstico , Pulmão/fisiopatologia , Fatores Etários , Asma/fisiopatologia , Asma/complicações , Asma/diagnóstico , Hiperventilação/fisiopatologia , Espasmo Brônquico/fisiopatologia , Espasmo Brônquico/etiologiaRESUMO
We determined the effect of exercise-induced bronchoconstriction (EIB) on the shape of the maximal expiratory flow-volume (MEFV) curve in asthmatic adults. The slope-ratio index (SR) was used to quantitate the shape of the MEFV curve. We hypothesized that EIB would be accompanied by increases in SR and thus increased curvilinearity of the MEFV curve. Adult asthmatic ( n = 10) and non-asthmatic control subjects ( n = 9) cycled for 6-8 min at 85% of peak power. Following exercise, subjects remained on the ergometer and performed a maximal forced exhalation every 2 min for a total 20 min. In each MEFV curve, the slope-ratio index (SR) was calculated in 1% volume increments beginning at peak expiratory flow (PEF) and ending at 20% of forced vital capacity (FVC). Baseline spirometry was lower in asthmatics compared to control subjects (FEV1 % predicted, 89.1 ± 14.3 vs. 96.5 ± 12.2% [SD] in asthma vs. control; p < 0.05). In asthmatic subjects, post-exercise FEV1 decreased by 29.9 ± 13.2% from baseline (3.48 ± 0.74 and 2.24 ± 0.59 [SD] L for baseline and post-exercise nadir; p < 0.001). At baseline and at all timepoints after exercise, average SR between 80 and 20% of FVC was larger in asthmatic than control subjects (1.48 ± 0.02 vs. 1.23 ± 0.02 [SD] for asthma vs. control; p < 0.005). This averaged SR did not change after exercise in either subject group. In contrast, post-exercise SR between PEF and 75% of FVC was increased from baseline in subjects with asthma, suggesting that airway caliber heterogeneity increases with EIB. These findings suggest that the SR-index might provide useful information on the physiology of acute airway narrowing that complements traditional spirometric measures.
Assuntos
Asma Induzida por Exercício , Curvas de Fluxo-Volume Expiratório Máximo , Adulto , Humanos , Asma/etiologia , Asma/fisiopatologia , Broncoconstrição/fisiologia , Exercício Físico/efeitos adversos , Exercício Físico/fisiologia , Expiração , Volume Expiratório Forçado , Curvas de Fluxo-Volume Expiratório Máximo/fisiologia , Asma Induzida por Exercício/fisiopatologiaRESUMO
BACKGROUND: There is conflicting data regarding the role of transforming growth factor-ß1 (TGF-ß1) in the pathogenesis of airway hyper-reactivity and asthma exacerbation. OBJECTIVE: To investigate the role of exhaled-TGF-ß1 in exercise-induced bronchospasm (EIB) in asthmatic and nonasthmatic healthy children, and in asthma exacerbation and asthma control. METHODS: The exhaled-TGF-ß1 levels of 56 stable asthmatic children and 15 nonasthmatic healthy children were evaluated before and 30 min after an exercise challenge. The exhaled-TGF-ß1 levels of 20 additional children with asthma exacerbation were evaluated. RESULTS: While no significant difference in the exhaled-TGF-ß1 levels was found at the baseline, exhaled-TGF-ß1 levels after the exercise challenge were significantly higher in the non-EIB (n = 31) asthmatics when compared to the asthmatic children with EIB (n = 25) (p = 0.04). Although there was a statistically significant increase in the concentration of the exhaled-TGF-ß1 after the exercise challenge in the non-EIB asthmatics (p = 0.008), the concentration of the TGF-ß1 was not increased after the exercise challenge in EIB + asthmatics. The exhaled-TGF-ß1 was significantly correlated with the ACT score (p = 0.01, r = 0.49) and the baseline FEV1 level (p = 0.02, r = 0.35). The exhaled-TGF-ß1 levels were significantly higher in the stable asthmatic children when compared to the nonasthmatic children (p < 0.0001). There was no significant difference in exhaled-TGF-ß1 levels after the exercise challenge in the nonasthmatics. The exhaled-TGF-ß1 levels were significantly lower in those children with asthma exacerbation when compared to the stable asthmatic children (p = 0.0003). CONCLUSION: Our results suggest that TGF-ß1 may play a role in suppressing airway reactivity and its deficiency is associated with asthma exacerbation.
Assuntos
Asma Induzida por Exercício/fisiopatologia , Asma/fisiopatologia , Testes Respiratórios/métodos , Fator de Crescimento Transformador beta1/análise , Adolescente , Asma/epidemiologia , Biomarcadores , Criança , Eosinófilos/citologia , Feminino , Humanos , Hipersensibilidade/epidemiologia , Hipersensibilidade/fisiopatologia , Imunoglobulina E/sangue , Masculino , Testes de Função Respiratória , Índice de Gravidade de DoençaRESUMO
Asthma is one of the most common respiratory disorders, characterized by fully or largely reversible airflow limitation. Asthma symptoms can be triggered or magnified during exertion, while physical activity limitation is often present among asthmatic patients. Cardiopulmonary exercise testing (CPET) is a dynamic, non-invasive technique which provides a thorough assessment of exercise physiology, involving the integrative assessment of cardiopulmonary, neuromuscular and metabolic responses during exercise. This review summarizes current evidence regarding the utility of CPET in the diagnostic work-up, functional evaluation and therapeutic intervention among patients with asthma, highlighting its potential role for thorough patient assessment and physician clinical desicion-making.
Assuntos
Asma/diagnóstico , Teste de Esforço/métodos , Asma/fisiopatologia , Asma/terapia , Asma Induzida por Exercício/diagnóstico , Asma Induzida por Exercício/fisiopatologia , Broncoconstrição , Exercício Físico , HumanosRESUMO
OBJECTIVE: To review the pathogenesis and evaluation of exercise-induced bronchoconstriction pertaining to the elite or endurance athlete, as well as propose a diagnostic algorithm based on the current literature. DATA SOURCES: Studies were identified using Ovid MEDLINE and reference lists of key articles. STUDY SELECTIONS: Randomized controlled trials were selected when available. Systematic reviews and meta-analyses of peer-reviewed literature were included, as were retrospective studies and observational studies of clinical interest. RESULTS: Exercise-induced bronchoconstriction (EIB) is the physiologic entity in which exercise induces acute narrowing of the airways and occurs in patients both with and without asthma. It may present with or without respiratory symptoms, and the underlying cause is likely attributable to environment stressors to the airway encountered during exercise. These include the osmotic effects of inhaled dry air, temperature variations, autonomic nervous system dysregulation, sensory nerve reactivity, and airway epithelial injury. Deposition of allergens, particulate matter, and gaseous pollutants into the airway also contribute. Elite and endurance athletes are exposed to these stressors more frequently and in greater duration than the general population. CONCLUSION: A greater awareness of EIB among elite and endurance athletes is needed, and a thorough evaluation should be performed if EIB is suspected in this population. We propose an algorithm to aid in this evaluation. Symptoms should not be solely relied on for diagnosis but should be taken into the context of bronchoprovocative challenges, which should replicate the competitive environment as closely as possible. Further research is needed to validate these tests' predictive values.
Assuntos
Algoritmos , Asma Induzida por Exercício/diagnóstico , Asma Induzida por Exercício/fisiopatologia , Atletas , HumanosRESUMO
Asthma is a common disease in paediatrics and adults with a significant morbidity, mortality, and financial burden worldwide. Asthma is now recognized as a heterogeneous disease and emerging clinical and laboratory research has elucidated understanding of asthma's underlying immunology. The future of asthma is classifying asthma by endotype through connecting discernible characteristics with immunological mechanisms. This comprehensive review of the immunology of asthma details the currently known pathophysiology and clinical practice biomarkers in addition to forefront biologic and targeted therapies for all of the asthma endotypes. By understanding the immunology of asthma, practitioners will be able to diagnose patients by asthma endotype and provide personalized, biomarker-driven treatments to effectively control patients' asthma.
Assuntos
Asma/imunologia , Citocinas/imunologia , Leucotrienos/imunologia , Células Th1/imunologia , Células Th2/imunologia , Asma/classificação , Asma/fisiopatologia , Asma/terapia , Asma Induzida por Aspirina/imunologia , Asma Induzida por Aspirina/fisiopatologia , Asma Induzida por Aspirina/terapia , Asma Induzida por Exercício/imunologia , Asma Induzida por Exercício/fisiopatologia , Asma Induzida por Exercício/terapia , Produtos Biológicos , Biomarcadores , Eosinofilia/imunologia , Eosinofilia/fisiopatologia , Eosinofilia/terapia , Humanos , Aspergilose Pulmonar Invasiva/imunologia , Aspergilose Pulmonar Invasiva/fisiopatologia , Aspergilose Pulmonar Invasiva/terapia , Terapia de Alvo Molecular , Obesidade/imunologia , Obesidade/fisiopatologia , Estresse Oxidativo/imunologia , Fenótipo , Hipersensibilidade Respiratória/imunologia , Hipersensibilidade Respiratória/fisiopatologia , Hipersensibilidade Respiratória/terapia , Sons RespiratóriosRESUMO
BACKGROUND: Given the high prevalence of asthma and obesity in minority children, there is a need to identify targets for intervention to decrease the impact of these conditions on children's functioning in this high-risk group. OBJECTIVE: To examine in urban children with persistent asthma, 1) differences in asthma indicators (eg, FEV1% predicted) by weight status, and by ethnic group/weight status, 2) caregivers' fears about their child's asthma by weight status, and by ethnic group/weight status, and 3) the proportion of children who qualified for exercise-induced bronchospasm (EIB) via exercise challenge test among those whose caregivers endorse exercise as a trigger for asthma. METHODS: In this sample of urban children (aged 7-9; Nâ¯=â¯147), subjective measures included child/caregiver daily report of asthma symptoms and caregiver fears about their child's asthma. Objective lung function was measured twice daily via handheld spirometer and EIB was confirmed via exercise challenge test. RESULTS: In the overall sample, a greater proportion of normal-weight children reported asthma symptoms compared to overweight/obese children. Caregiver fears about asthma were more prevalent among Latino caregivers. Non-Latino White children whose caregivers were afraid their child may die when having asthma reported more days with asthma symptoms. Very few children had confirmed EIB compared to the proportion of caregivers who endorsed exercise as a dangerous trigger for asthma. CONCLUSIONS: Caregiver fear about asthma and misperceptions of exercise as a dangerous trigger for asthma should be addressed during health care visits with families of children with asthma and interventions including urban children with asthma.
Assuntos
Asma/etnologia , Asma/fisiopatologia , Peso Corporal , População Urbana/estatística & dados numéricos , Asma/epidemiologia , Asma Induzida por Exercício/epidemiologia , Asma Induzida por Exercício/etnologia , Asma Induzida por Exercício/fisiopatologia , Cuidadores/psicologia , Criança , Teste de Esforço , Medo , Feminino , Humanos , Masculino , Testes de Função Respiratória , Rhode Island/epidemiologia , Fatores SocioeconômicosRESUMO
Objective: Exercise-induced bronchoconstriction (EIB) is an acute, transient narrowing of the airway as a result of exercise. Diurnal variation in asthma is well-established, however, few studies have investigated diurnal variability in EIB; no study has used eucapnic voluntary hyperpnea (EVH). The aim of this study was to examine circadian variability in EIB using EVH.Methods: Fourteen recreationally-active males with mild to moderate asthma and nine healthy controls were randomized to first complete either an AM (07:00-08:00) or PM (17:00-18:00) EVH challenge, followed by the alternate test 34 h to 7 days later. The EVH protocol comprised of six-minutes of hyperventilation of a 5% CO2 gas at a minimum ventilation rate of 21 × FEV1 min-1. The primary outcome measure was FEV1 pre- and post-EVH.Results: We observed no diurnal effect on EIB in the asthma group. The minimum observed post-EVH FEV1 in the asthma cohort was 3.58 ± 0.95 L in AM and 3.62 ± 0.87 L in PM tests, corresponding to a 15.0 ± 15.3% vs. 14.9 ± 14.7% reduction from baseline, respectively. The asthma group showed similar baseline FEV1 before AM (4.21 ± 0.79 L) and PM (4.25 ± 0.65 L) tests. No difference was observed in minute ventilation between AM (26.1 ± 3.4 × FEV1 min-1) and PM (25.6 ± 3.8 × FEV1 min-1) tests for the asthma cohort. Controls displayed no significant changes in FEV1 or minute ventilation between tests.Conclusions: When baseline pulmonary function is similar, this study suggests that time-of-day has no effect on EIB in mild to moderate asthma.
Assuntos
Asma Induzida por Exercício/fisiopatologia , Ritmo Circadiano/fisiologia , Hiperventilação/fisiopatologia , Adolescente , Adulto , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Função Respiratória , Adulto JovemRESUMO
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.
Assuntos
Asma Induzida por Exercício/diagnóstico , Broncoconstrição/fisiologia , Dispneia/diagnóstico , Escala Visual Analógica , Adolescente , Asma Induzida por Exercício/etiologia , Asma Induzida por Exercício/fisiopatologia , Criança , Estudos Transversais , Dispneia/etiologia , Dispneia/fisiopatologia , Teste de Esforço , Feminino , Humanos , MasculinoRESUMO
Objective: To investigate whether once-daily (OD) fluticasone furoate (FF)/vilanterol (VI) provides greater long-term protection from postexercise fall in forced expiratory volume in 1 s (FEV1) than twice-daily (BD) fluticasone propionate (FP) in patients with asthma and exercise-induced bronchoconstriction. Methods: A randomized, double-blind, crossover study was conducted in patients (aged 12-50 years) on low-/mid-dose maintenance inhaled corticosteroid. Following a 4-week run-in period (FP 250 µg BD), patients with a ≥ 20% decrease in postexercise FEV1 received FF/VI 100/25 µg OD or FP 250 µg BD for 2 weeks. Exercise challenges were carried out 23 h after the first dose of study medication, and 12 and 23 h after evening clinic dose at the end of the 2-week treatment period. After a 2-week washout period (FP 250 µg), patients crossed over treatments, with procedures and tests repeated. The primary endpoint was mean maximal percentage decrease from pre-exercise FEV1 following exercise challenge 12-h postevening dose on Day 14. Results: The mean maximal percentage decrease from pre-exercise FEV1 after the 12-h exercise challenge (Day 14) was 15.02% with FF/VI, and 16.71% with FP (difference, -1.69; 95% confidence interval, -3.76 to 0.39; p = 0.109). After the 23-h exercise challenge (Day 14), respective mean maximal decreases were 11.90% and 14.05% (difference, -2.15; 95% confidence interval, -4.31 to 0.01). Conclusion: The study failed to show a difference between FF/VI and FP at providing long-term protection from exercise-induced bronchoconstriction.
Assuntos
Androstadienos/administração & dosagem , Asma Induzida por Exercício/tratamento farmacológico , Álcoois Benzílicos/administração & dosagem , Broncoconstrição/efeitos dos fármacos , Clorobenzenos/administração & dosagem , Fluticasona/administração & dosagem , Administração por Inalação , Adolescente , Adulto , Asma Induzida por Exercício/diagnóstico , Asma Induzida por Exercício/fisiopatologia , Broncoconstrição/fisiologia , Criança , Estudos Cross-Over , Método Duplo-Cego , Esquema de Medicação , Combinação de Medicamentos , Exercício Físico/fisiologia , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto JovemRESUMO
Asthma is a chronic obstructive respiratory disease with high prevalence in children. Several factors may trigger asthma symptoms, including exercise, which can lead to exercise-induced bronchoconstriction (EIB). Although physical exercise may represent a risk factor for triggering bronchial obstruction in asthmatics, studies have also indicated several positive effects. Thus, this article aimed to summarize current evidence on the effects of exercise training in children with asthma. There is substantial available evidence on the topic. Most of the findings show that exercise induce positive effects, including the increase of aerobic fitness, decrease of EIB levels, as well as an increase in both disease control and quality of life levels in asthmatic children. As for possible influencing factors in order to obtain exercise-induced positive effects, an adequate prescription of exercise intensity highlights and should be personalized, as well as established close to the anaerobic threshold. Thus, considering the evidence showing beneficial effects and the fact that the practice of physical exercise consists of a low cost and safe non-pharmacological therapy, supervised, personalized and individual recommendation of exercise training by health professionals are indicated to asthmatic children.
El asma es una enfermedad respiratoria obstructiva crónica con alta prevalencia en niños. Varios factores pueden desencadenar síntomas de asma, incluido el ejercicio, que puede conducir a la broncoconstricción inducida por el ejercicio (BIE). Aunque el ejercicio físico puede representar un factor de riesgo para desencadenar la obstrucción bronquial en los asmáticos, estudios también han indicado varios efectos positivos. Este artículo tiene como objetivo resumir la evidencia actual sobre los efectos del entrenamiento físico en niños con asma. Hay evidencia sustancial disponible sobre el tema. La mayoría de los hallazgos muestran que el ejercicio induce efectos positivos, incluido el aumento de la aptitud aeróbica, la disminución de los niveles de la BEI, así como un aumento tanto en el control de la enfermedad como en los niveles de calidad de vida en niños asmáticos. Se destaca la importancia de una prescripción de la intensidad del ejercicio adecuada y personalizada, cerca del umbral anaeróbico, para obtener los efectos positivos inducidos por el ejercicio. Por lo tanto, considerando la evidencia que muestra efectos beneficiosos y el hecho de que la práctica del ejercicio físico consiste en una terapia no farmacológica, segura y de bajo costo, el entrenamiento físico supervisado, personalizado e individualizado por parte de profesionales de la salud es recomendado para niños asmáticos.
Assuntos
Humanos , Criança , Asma/terapia , Asma Induzida por Exercício/etiologia , Exercício Físico/fisiologia , Qualidade de Vida , Testes de Função Respiratória , Asma/fisiopatologia , Asma Induzida por Exercício/fisiopatologiaRESUMO
BACKGROUND: The relative scale adjusts for baseline variability and therefore may lead to findings that can be generalized more widely. It is routinely used for the analysis of binary outcomes but only rarely for continuous outcomes. Our objective was to compare relative vs absolute scale pooled outcomes using data from a recently published Cochrane systematic review that reported only absolute effects of inhaled ß2-agonists on exercise-induced decline in forced-expiratory volumes in 1 s (FEV1). METHODS: From the Cochrane review, we selected placebo-controlled cross-over studies that reported individual participant data (IPD). Reversal in FEV1 decline after exercise was modeled as a mean uniform percentage point (pp) change (absolute effect) or average percent change (relative effect) using either intercept-only or slope-only, respectively, linear mixed-effect models. We also calculated the pooled relative effect estimates using standard random-effects, inverse-variance-weighting meta-analysis using study-level mean effects. RESULTS: Fourteen studies with 187 participants were identified for the IPD analysis. On the absolute scale, ß2-agonists decreased the exercise-induced FEV1 decline by 28 pp., and on the relative scale, they decreased the FEV1 decline by 90%. The fit of the statistical model was significantly better with the relative 90% estimate compared with the absolute 28 pp. estimate. Furthermore, the median residuals (5.8 vs. 10.8 pp) were substantially smaller in the relative effect model than in the absolute effect model. Using standard study-level meta-analysis of the same 14 studies, ß2-agonists reduced exercise-induced FEV1 decline on the relative scale by a similar amount: 83% or 90%, depending on the method of calculating the relative effect. CONCLUSIONS: Compared with the absolute scale, the relative scale captures more effectively the variation in the effects of ß2-agonists on exercise-induced FEV1-declines. The absolute scale has been used in the analysis of FEV1 changes and may have led to sub-optimal statistical analysis in some cases. The choice between the absolute and relative scale should be determined based on biological reasoning and empirical testing to identify the scale that leads to lower heterogeneity.
Assuntos
Agonistas de Receptores Adrenérgicos beta 2/uso terapêutico , Asma Induzida por Exercício/prevenção & controle , Asma Induzida por Exercício/fisiopatologia , Estatística como Assunto , Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Broncoconstrição/efeitos dos fármacos , Volume Expiratório Forçado , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Revisões Sistemáticas como AssuntoRESUMO
The eucapnic voluntary hyperpnea (EVH) challenge is used to determine the presence of exercise-induced bronchoconstriction (EIBC) by monitoring changes in forced expiratory volume in 1 s (FEV1). However, the predictability of the post-EVH decline in FEV1 on post-exercise FEV1 remains unclear. Participants completed an EVH challenge to confirm EIBC and completed a continuous exercise (CONT; n = 21), high-intensity interval exercise (HI; n = 13), and sprint interval exercise (SPRT; n = 8) sessions on separate days. FEV1 was assessed pre- and post exercise. A 1% decline in FEV1, post EVH was associated with 0.44%, 0.85%, and 0.56% declines in FEV1 post CONT, post HI, and post SPRT, respectively. The decline in FEV1 following the EVH challenge was associated with the decline in FEV1 following all exercise conditions, with the strongest association being observed following HI. These findings may have implications for exercise prescription and asthma education for recreationally active adults with EIBC.
Assuntos
Asma Induzida por Exercício/diagnóstico , Broncoconstrição , Teste de Esforço , Treinamento Intervalado de Alta Intensidade/efeitos adversos , Pulmão/fisiopatologia , Adolescente , Adulto , Asma Induzida por Exercício/etiologia , Asma Induzida por Exercício/fisiopatologia , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Valor Preditivo dos Testes , Ensaios Clínicos Controlados Aleatórios como Assunto , Medição de Risco , Fatores de Risco , Fatores de Tempo , Adulto JovemRESUMO
BACKGROUND: The effects of humidity and temperature on results of free running test in children are not known. OBJECTIVE: Assess the relation of outdoor air temperature, relative humidity (RH), and absolute humidity (AH) to airway obstruction in children after free running exercise test. METHODS: 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. RESULTS: 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). CONCLUSION: 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.
Assuntos
Asma Induzida por Exercício/epidemiologia , Umidade , Resistência das Vias Respiratórias , Asma Induzida por Exercício/fisiopatologia , Broncoconstrição , Criança , Pré-Escolar , Teste de Esforço , Feminino , Humanos , Incidência , Inalação , Masculino , TemperaturaRESUMO
INTRODUCTION: Exercise-induced bronchoconstriction (EIB) is very common in athletes. Cardiopulmonary exercise tests (CPET) have traditionally been used for the diagnosis of EIB. However, alternative indirect bronchoprovocation tests have recently been used as surrogate tests. One of these is the eucapnic voluntary hyperventilation (EVH). This meta-analysis studied the agreement between the two tests. METHODS: An extensive search in PubMed and Medline was conducted for studies where participants underwent both CPET and EVH with measurement of forced expiratory volume in 1-second (FEV1). After extracting data using two-by-two contingency tables, pooled positive and negative agreements were first calculated between the two tests, with EVH benchmarked against CPET, and then, pooled positive and negative agreements were calculated with CPET benchmarked against EVH. RESULTS: The pooled positive and negative agreements between EVH and CPET (with CPET as the reference) were 0.62 [(95% confidence interval 0.54-0.70), I2 77%] and 0.61 [(0.56-0.65)), I2 81%]. The pooled positive and negative agreements between CPET and EVH (with EVH as the reference) were 0.36 [(0.30-0.42), I2 93%] and 0.82 [(0.77-0.86), I2 78%]. The average of positive test results with EVH across all studies was greater than that of CPETs (58.84% vs. 39.51%). CONCLUSIONS: Results of this meta-analysis show poor positive agreement between the two tests but high negative agreement (specifically using EVH as reference), suggesting that either test can be used for correctly identifying those without EIB. Results also suggest that the chances of a test resulting positive are higher with EVH than with CPET.
Assuntos
Asma Induzida por Exercício/diagnóstico , Broncoconstrição , Teste de Esforço , Hiperventilação/fisiopatologia , Pulmão/fisiopatologia , Adolescente , Adulto , Asma Induzida por Exercício/fisiopatologia , Criança , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto JovemRESUMO
BACKGROUND: The exercise challenge is the gold standard for diagnosing exercise-induced bronchoconstriction (EIB). Airway obstructions appear up to 30â¯min after the challenge, with a maximum decrease in spirometry and a maximum increase in airway resistance. There is evidence that changes in body plethysmography parameters are more sensitive to the exercise challenge and precede those in spirometry. PURPOSE: To compare changes in body plethysmography and spirometry parameters after exercise challenges and to verify the cut-off values of sReff in EIB. PROCEDURES: In 82 subjects with suspected EIB, a total of 473 lung function tests were measured at baseline and at 5, 10, 15, and 30â¯min after exercise challenges at different stages of bronchial obstruction. FINDINGS: The maximum changes in the body plethysmography parameter sReff significantly preceded the maximum changes in the spirometry parameter FEV1 (sReff: 12.2â¯min⯱8.8, FEV1: 15.2â¯min⯱9.3, pâ¯<â¯0.005). The parameters of sReff and FEV1 had a strong negative correlation (râ¯=â¯-0.63, pâ¯<â¯0.0001) with a nonlinear, polynomial relationship. Furthermore, sReff and Reff had a strong linear correlation (râ¯=â¯0.86, pâ¯<â¯0.001), and Reff and Rtot had a perfect linear correlation (râ¯=â¯0.99, pâ¯<â¯0.001). Based on baseline values and on quantile regression, an increase of 0.25â¯kPaâ¯s in sReff was defined as significant. Using this cut-off value, FEV1 and sReff almost equally detected EIB. CONCLUSION: The changes in sReff were more sensitive and better indicated lung impairment than did the changes in FEV1, which underestimated the degree of hyperinflation.
Assuntos
Asma Induzida por Exercício/fisiopatologia , Pletismografia Total/métodos , Espirometria/métodos , Adolescente , Adulto , Obstrução das Vias Respiratórias/fisiopatologia , Resistência das Vias Respiratórias/fisiologia , Testes de Provocação Brônquica/instrumentação , Criança , Feminino , Volume Expiratório Forçado/fisiologia , Humanos , Masculino , Pletismografia Total/estatística & dados numéricos , Espirometria/estatística & dados numéricos , Adulto JovemRESUMO
BACKGROUND: Recurrent wheezing in early life is transient in most children. The significance of airway hyperresponsiveness (AHR) in persistence of respiratory symptoms from infancy to early childhood is controversial. OBJECTIVE: We evaluated whether AHR in wheezy infants predicts doctor-diagnosed asthma (DDA) or AHR at the age of 6 years. METHODS: Sixty-one wheezy infants (age 6-24 months) were followed up to the median age of 6 years. Lung function and AHR with methacholine challenge test were assessed at infancy and 6 years. The exercise challenge test was performed at the age of 6 years. Atopy was assessed with skin prick tests. RESULTS: At 6 years, 21 (34%) of the children had DDA. Children with DDA had higher logarithmic transformed dose-response slope (LOGDRS) to methacholine in infancy than children without DDA (0.047 vs 0.025; P = .033). Furthermore, AHR to methacholine in infancy and at 6 years were associated with each other (r = 0.324, P = .011). Children with exercise-induced bronchoconstriction (EIB) at 6 years were more reactive to methacholine in infancy than those without EIB (P = .019). CONCLUSION: Increased AHR in symptomatic infants was associated with increased AHR, DDA, and EIB at median the age of 6 years, suggesting early establishment of AHR.
Assuntos
Asma Induzida por Exercício/diagnóstico , Asma/diagnóstico , Hipersensibilidade Respiratória/diagnóstico , Sons Respiratórios/fisiopatologia , Asma/fisiopatologia , Asma Induzida por Exercício/fisiopatologia , Testes de Provocação Brônquica , Broncoconstrição , Criança , Pré-Escolar , Teste de Esforço , Feminino , Seguimentos , Humanos , Lactente , Masculino , Cloreto de Metacolina/administração & dosagem , Estudos Prospectivos , Hipersensibilidade Respiratória/fisiopatologia , Testes CutâneosRESUMO
BACKGROUND: 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. METHODS: 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. RESULTS: Constant and incremental stepping tests presented with lower metabolic demands (VÌO2 1.42 ± 0.48 and 1.34 ± 0.55 L/min, respectively), ventilatory demands (VÌO2 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. CONCLUSIONS: 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.