Reproducibility of eucapnic voluntary hyperpnoea for exercise-induced bronchoconstriction diagnosis in asthmatic children and adolescents.

BACKGROUND: Respiratory symptoms after exercise are frequently reported by asthmatic patients, and exercise-induced bronchoconstriction (EIB) is a frequent cause, which requires objective testing for diagnosis. Eucapnic voluntary hyperpnea (EVH) is recommended as a surrogate stimulus for this purpose. Its short-term reproducibility is not yet established in children and young adolescents with asthma. OBJECTIVE: To evaluate the short-term test-retest agreement and reproducibility of FEV1 changes after EVH in this population. METHODS: Asthmatic patients aged between 10 and 20 years underwent EVH for EIB diagnosis on two occasions 2-4 days apart at a specialized university clinic. FEV1 was measured at 5, 15, and 30 min after EVH with a target ventilation rate 21 times the baseline FEV1 . EIB was diagnosed as a decrease ≥10% in FEV1 from baseline. RESULTS: A total of 26 of 62 recruited individuals tested positive for EIB on both visits (positive group) and 17 on one visit only (divergent group), while 19 tested negative on both visits (negative group). The overall agreement was 72.5% (95%CI 61.6%, 83.6%), and Cohen's kappa coefficient was 0.452. Low bias (0.87%) and high intra-class correlation coefficient (0.854, 95%CI 0.758,0.912; p < .001) for FEV1 response between test days were found, but with wide limits of agreement (±20.72%). There were no differences in pre-challenge FEV1 or achieved ventilation rate between visits either between groups (p = .097 and p = .461) or within groups (p = .828 and p = .780). There were no safety issues. CONCLUSIONS: More than one EVH test should be performed in children and young adolescents with asthma to exclude EIB and minimize misdiagnosis and mistreatment.

Maximum phonation time in the pulmonary function assessment / Tempo máximo de fonação para avaliação da função pulmonar

ABSTRACT Purpose: to evaluate the reliability of the maximum phonation time (MPT) and Vital Capacity intra and inter-examiner, by means of the single-breath counting test (CT) and the sustained /a/ phoneme, and the slow vital capacity (SVC). Methods: a reliability study carried out in three groups of healthy individuals, each group with 30 volunteers, allocated according to age. SVC was measured using a spirometer, while the MPT was assessed by the phoneme /a/ and CT. The data were analyzed using SPSS version 20.0. Initially, descriptive statistics were used and for data reliability, the intraclass correlation coefficient (ICC). Results: the Intraclass Correlation Coefficients (ICC) were considered excellent, with significant results above 0.92 for SVC and greater than 0.79 for CT and phoneme /a/. Regarding the inter-examiner evaluation, the ICCs were also significant for both SVC with values greater than 0.96, and for CT and the phoneme /a/ with values greater than 0.85. The error inherent in the technique was assessed using the standard error of the measurement for intra and inter-examiner analyses with values ranging from 1.79 to 3.29 for phoneme /a/, 3.20 to 6.58 for CT and 65, 05 to 206.73 for SVCml. Conclusion: phonation techniques with the phoneme /a/ and CT, as well as SVC, have an excellent reliability, due to intra and inter-examiner agreement measures.

RESUMO Objetivo: avaliar a concordância do tempo máximo de fonação (TMF) com a Capacidade Vital, intra e interexaminador, por meio da técnica de contagem numérica em uma única respiração (TC) e do fonema /a/ sustentado e da capacidade vital lenta (CVL). Métodos: trata-se de um estudo de concordância realizado em três grupos de indivíduos saudáveis, cada grupo com 30 voluntários, alocados de acordo a idade. A CVL foi mensurada por meio do espirômetro, enquanto o TMF foi avaliado pela emissão do fonema/a/ e da TC. Os dados foram analisados pelo programa SPSS versão 20.0. Inicialmente utilizou-se estatística descritiva e para concordância dos dados foi utilizado o coeficiente de correlação intraclasse (CCI). Resultados: os Coeficientes de Correlação Intraclasse (CCI) intraexaminadores foram considerados excelentes, com resultados significantes acima de 0,92 para a CVL e maiores que 0.79 para a TC e fonema/a/. Em relação à avaliação interexaminadores, os CCIs também foram significantes tanto para a CVL com valores maiores que 0,96 quanto para a TC e o fonema/a/ com valores maiores que 0,85. O erro inerente a técnica foi avaliada por meio do erro padrão da medida para as analises intra e interexaminadores com valores que variaram de 1,79 a 3,29 para fonema/a/, 3,20 a 6,58 para TC e 65,05 a 206,73 para CVLml. Conclusão: as técnicas de fonação com o fonema /a/ e TC, assim como a CVL, demonstraram uma excelente concordância intra e interexaminadores.