Objective: To describe the pulmonary function in children and adolescents with postinfectious bronchiolitis obliterans (PIBO), as well as to evaluate potential risk factors for severe impairment of pulmonary function. Methods: The pulmonary function of 77 participants, aged 8-18 years, was assessed by spirometry and plethysmography. The following parameters were analyzed: FVC; FEV 1 ; FEF 25-75% ; FEV 1 /FVC; RV; TLC; RV/TLC; intrathoracic gas volume; and specific airway resistance (sRaw). We used Poisson regression to investigate the following potential risk factors for severe impairment of pulmonary function: gender; age at first wheeze; age at diagnosis; family history of asthma; tobacco smoke exposure; length of hospital stay; and duration of mechanical ventilation. Results: The mean age was 13.5 years. There were pronounced decreases in FEV 1 and FEF 25-75% , as well as increases in RV and sRaw. These alterations are characteristic of obstructive airway disease. For the parameters that were the most affected, the mean values (percentage of predicted) were as follows: FEV 1 = 45.9%; FEF 25-75% = 21.5%; RV = 281.1%; RV/TLC = 236.2%; and sRaw = 665.3%. None of the potential risk factors studied showed a significant association with severely impaired pulmonary function. Conclusions: The patients with PIBO had a common pattern of severe pulmonary function impairment, characterized by marked airway obstruction and pronounced increases in RV and sRaw. The combination of spirometric and plethysmographic measurements can be more useful for assessing functional damage, as well as in the follow-up of these patients, than are either of these techniques used in isolation. Known risk factors for respiratory diseases do not seem to be associated with severely impaired pulmonary function in PIBO.
Keywords:Respiratory function tests; Airway obstruction; Bronchiolitis obliterans.
ResumoObjetivo: Descrever a função pulmonar de crianças e adolescentes com bronquiolite obliterante pós-infecciosa (BOPI) e avaliar potenciais fatores de risco para pior função pulmonar. Métodos: A função pulmonar de 77 participantes, com idades de 8-18 anos, foi avaliada por meio de espirometria e pletismografia. Os seguintes parâmetros foram analisados: CVF, VEF 1 , FEF 25-75%, VEF 1 /CVF, VR, CPT, VR/CPT, volume de gás intratorácico e specific airway resistance (sRaw, resistência específica das vias aéreas). Foi utilizada a regressão de Poisson para investigar os seguintes potenciais fatores de risco para pior função pulmonar: sexo, idade do primeiro sibilo, idade ao diagnóstico, história familiar de asma, exposição ao tabaco, tempo de hospitalização e tempo de ventilação mecânica. Resultados: A idade média foi de 13,5 anos. Houve uma diminuição importante de VEF 1 e FEF 25-75% , assim como um aumento de VR e sRaw, característicos de doença obstrutiva das vias aéreas. Os parâmetros mais afetados e as médias percentuais dos valores previstos foram VEF 1 = 45,9%; FEF 25-75% = 21,5%; VR = 281,1%; VR/ CPT = 236,2%; e sRaw = 665,3%. Nenhum dos...