Capnografia volumétrica na avaliação de crianças e adolescentes com asma persistente / Volumetric capnography for the avaliation of children and adolescents with persistent asthma

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Objective: To study changes in the variables of volumetric capnography in children and adolescents with persistent asthma compared with controls, and investigate their changes with the use of bronchodilators and in response to bronchial provocation test. Methods: Hundred-three asthmatics and 40 healthy volunteers (aged 6-15 years) were serially enrolled. Spirometric test and volumetric capnography were performed. All asthmatics have repeated the tests after bronchodilator use. Thirty-three asthmatic patients also underwent methacholine challenge testing and measurements were recorded on three occasions: before and after methacholine provocation and after bronchodilator. Results: Compared with controls, asthmatics had higher phase 3 slope normalized for tidal volume (slope3/VT) and smaller tidal volume (VT), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC and expiratory flow between 25 and 75% of FVC (FEF25-75). However, in asthmatics with and without obstruction classified by spirometry, no differences were found in slope3/VT. After bronchodilator, patients had higher dead space volume (VDaw), higher VDaw/VT and lower phase 2 slope normalized for tidal volume (slope2/VT). After methacholine, patients had higher slope3/VT, with lower after bronchodilator. Conclusions: The slope3/VT increased in asthmatics reflects the inhomogeneity of ventilation in the distal air spaces, regardless of the presence or absence of obstructive and may reflect either structural disorders such as chronic airway changes seen in reversible acute bronchial provocation test

ASSUNTO(S)

asma pediatria dióxido de carbono asthma pediatrics carbon dioxide pulmonar physiology spirometry fisiologia pulmonar espirometria

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