Objective: To evaluate criteria for the diagnosis of asthma in an epidemiological survey. Methods: Adolescents (13-14 years of age) and legal guardians of schoolchildren (6-7 years of age) in the city of Santo André, Brazil, completed the International Study of Asthma and Allergies in Childhood (ISAAC) standard written questionnaire. Affirmative responses regarding wheezing within the last 12 months, asthma ever, bronchitis ever (question added at the end of the questionnaire), as well as the overall ISAAC score above the predefined cutoff points, were considered indicative of asthma. Results: The legal guardians of 2,180 schoolchildren and 3,231 adolescents completed the questionnaires properly. Depending on the criterion adopted, the prevalence of asthma ranged from 4.9% to 26.8% for the schoolchildren and from 8.9% to 27.9% for the adolescents. The criteria with the lowest and highest prevalences were, respectively, physician-diagnosed asthma and physician-diagnosed bronchitis. When compared with other criteria, physician-diagnosed bronchitis showed concordance levels between 71.9% and 79.4%, positive predictive values between 0.16 and 0.63 and poor concordance (kappa: 0.21-0.46). Strong concordance levels were found only between wheezing within the last 12 months and the overall ISAAC score (kappa: 0.82 and 0.98). Conclusions: The prevalence of asthma varied significantly, depending on the criterion adopted, and there was poor concordance among the criteria. Wheezing within the last 12 months and the overall ISAAC score are the best criteria for the diagnosis of asthma, whereas the question regarding bronchitis ever did not improve the questionnaire. Modifications in this instrument can make it difficult to draw comparisons and should therefore be carefully evaluated.

Keywords: Asthma; Bronchitis; Diagnosis; Epidemiology; Child; Adolescent.

Objective: To determine the prevalence and severity of wheezing in infants, using the standardized protocol devised for the "Estudio Internacional de Sibilancias en Lactantes" (EISL, International Study of Wheezing in Infants), as well as to determine the relationship between such wheezing and physician-diagnosed asthma, in the first year of life. Methods: Between March of 2005 and August of 2006, the EISL questionnaire was administered to the parents or legal guardians of infants undergoing routine procedures or immunization at public primary health care clinics in the southern part of the city of São Paulo, Brazil. Results: Our sample comprised 1,014 infants (mean age = 5.0 ± 3.0 months), 467 (46.0%) of whom had at least one wheezing episode, 270 (26.6%) having three or more such episodes, in their first year of life. The use of inhaled β2 agonists, inhaled corticosteroids, or antileukotrienes, as well as the occurrence of nocturnal symptoms, difficulty breathing, pneumonia, emergency room visits, and hospitalization due to severe wheezing, was significantly more common among those with recurrent wheezing (p < 0.05). Physician-diagnosed asthma was reported for 35 (7.5%) of the 467 wheezing infants and was found to be associated with the use of inhaled corticosteroids, difficulty breathing during the attacks, and six or more wheezing episodes in the first year of life. However, less than 40% of those infants were treated with inhaled corticosteroids or antileukotrienes. Conclusions: In this study, the prevalence of wheezing episodes among infants in their first year of life was high and had an early onset. The proportion of infants diagnosed with and treated for asthma was low.

Keywords: Asthma/diagnosis; Asthma/epidemiology; Respiratory sounds.

Objetivo: Avaliar as alterações da mecânica respiratória e do volume corrente (VC) em lactentes sibilantes em ventilação espontânea após a realização da técnica de expiração lenta e prolongada (ELPr). Métodos: Foram incluídos no estudo lactentes com história de sibilância recorrente e sem exacerbações nos 15 dias anteriores. Para a avaliação da função pulmonar, os lactentes foram sedados e posicionados em decúbito dorsal com máscara facial acoplada a um pneumotacógrafo. As variáveis da respiração corrente - VC e FR - e da mecânica respiratória - complacência do sistema respiratório (Csr), resistência (Rsr) e constante de tempo (psr) - foram mensuradas antes e após a realização de três sequências consecutivas de ELPr. Resultados: Foram avaliados 18 lactentes, com média de idade de 32 ± 11 semanas. Houve um aumento significante no VC após ELPr (79,3 ± 15,6 mL vs. 85,7 ± 17,2 mL; p = 0,009), assim como uma redução na FR (40,6 ± 6,9 ciclos/min vs. 38,8 ± 0,9 ciclos/min; p = 0,042). Entretanto, não houve alterações significantes nos valores da mecânica respiratória (Csr: 11,0 ± 3,1 mL/cmH2O vs. 11,3 ± 2,7 mL/cmH2O; Rsr: 29,9 ± 6,2 cmH2O  mL−1  s−1 vs. 30,8 ± 7,1 cmH2O  mL−1  s−1; e psr: 0,32 ± 0,11 s vs. 0,34 ± 0,12 s; p > 0,05 para todos). Conclusões: Essa técnica de fisioterapia respiratória é capaz de induzir alterações significativas no VC e na FR de lactentes com sibilância recorrente, mesmo na ausência de exacerbações. A manutenção das variáveis da mecânica respiratória indica que a técnica é segura para ser aplicada nesse grupo de pacientes. Estudos com lactentes sintomáticos são necessários para quantificar os efeitos funcionais da técnica.

Keywords: Modalidades de Fisioterapia; Mecânica Respiratória; Lactente; Testes de Função Respiratória.