OBJECTIVETo study the changes in pulmonary function and fractional exhaled nitric oxide in exhaled breath (FeNO) in asthmatic children who have different responses to regular treatment.

METHODSA total of 52 asthmatic children who had a good compliance with regular stepped control treatment were selected as subjects. They were followed up every three months to evaluate the asthma control level, pulmonary ventilation function, and FeNO for 9 months. Besides, medications for asthma control were recorded.

RESULTSAt three follow-up points (months 3, 6, and 9), the percentage of asthmatic children who used the first or the second level of control treatment in the stable group (with stable response to the treatment) was significantly higher than in the unstable group (with unstable response to the treatment) (P<0.05), while the percentage of asthmatic children who used the third level of control treatment in the stable group was significantly lower than in the unstable group (P<0.05). At the three follow-up points, the stable group had a significantly higher ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) than the unstable group (P<0.05); at the 3-month and 9-month follow-up points, the stable group had a significantly higher percentage of predicted maximum mid-expiratory flow (MMEF%) than the unstable group (P<0.05); at the initial evaluation and 3-month follow-up point, the stable group had a significantly higher FeNO than the unstable group (P<0.05).

CONCLUSIONSContinuously monitoring FEV1/FVC, MMEF% and FeNO is useful in the early evaluation of the responses to treatment in children with asthma.