目的　探讨儿童哮喘发作时支气管舒张试验中大小气道功能指标变化的临床意义。方法　选择2012年10月至2014年4月哮喘初次发作患儿51例，采用Master Screen肺功能仪，在雾化吸入硫酸沙丁胺醇前、后进行肺功能检测；比较用力肺活量(FVC)、呼气峰流速(PEF)、1秒用力肺活量(FEV1)、1秒率(FEV1/FVC)、最大呼气中段流量(MMEF)、用力呼气流速(FEF)25、FEF50、FEF75的变化。结果　51例患儿的平均年龄(7.30±2.33)岁。患儿哮喘发作时支气管舒张试验总阳性率58.8%，并有随病情加重而升高的趋势；与舒张试验前比较，舒张试验后大小气道各指标的绝对值、占预计值百分比均明显增加，差异有统计学意义(P均<0.01)；以代表大气道指标的FEV1改善率≥12% 判定为舒张试验阳性，阳性率58.8%；以代表小气道指标的MMEF改善率≥25%判定为舒张试验阳性，阳性率70.6%，两者比较差异无统计学意义(P=0.214)。结论　哮喘发作患儿FEV1基础值>70%亦可行支气管舒张实验，同时结合大、小气道指标以判断气道可逆性可以更全面反映哮喘的病情严重程度。

　Objective　To investigate the clinical significance of changes of the airway size and its function indicators in asthmatic children using dilation test. Methods　From October 2012 to April 2014, 51 children with initial attack of asthma were selected. Master Screen spirometer were used before and after nebulized albuterol sulfate pulmonary function testing; forced vital capacity (FVC), peak expiratory flow (PEF), one second forced vital capacity (FEV1), 1 second ratio (FEV1 / FVC), peak expiratory flow in the middle (MMEF), forced expiratory flow (FEF)25, FEF50, FEF75 changes were compared. Results　The average age of 51 children included in this study was (7.30 ± 2.33) years. The positive rate of dilation test was 58.8% in children with asthma onset, and increased with severity of the disease. The size of the airway absolute value of each index, percentage predicted after the test increased significantly than that before the test (P<0.05); FEV1 positive rate was 58.8%, and MMEF positive rate was 70.6%, which showed no statistically significant difference (P>0.05). Conclusions　Asthmatic children with baseline FEV1>70% can be given relaxation experiments, and indicators of large and small airways could be combined to determine the airway reversibility, which can be a better reflection of the severity of asthma.