目的 探讨学龄前哮喘肺通气功能分布特征，并进一步分析其特点。方法 回顾性收集2019年1月—2020年12月门诊首次诊断为哮喘的学龄前儿童的临床信息及肺通气功能资料。使用潜在剖面分析法分析肺通气功能分布类别特征，对不同类别组间资料行差异性分析，最后应用有序多分类logistic回归分析组间差异性因素与肺通气功能类别特征关系。结果 本研究共纳入学龄前哮喘患儿851例，中位年龄4.3岁，对肺通气功能参数FEV₁、FEV₁/FVC、PEF、FEF₅₀、FEF₇₅、FEF_25~75的实测值占预计值百分比（%pred）行潜在剖面分析，拟合出四类肺通气功能分布特征曲线：高于正常肺通气功能组118例（13.9%）、肺通气功能正常组269例（31.6%）、小气道功能下降组297例（34.9%）、小气道功能障碍组167例（19.6%）。这四类别组间肺通气功能参数值呈下降趋势，其中小气道功能参数在各组间差异均有统计学意义（P<0.001）。同高于正常肺通气功能组及肺通气功能正常组相比，小气道功能障碍组年龄更大（P<0.001），嗜酸性粒细胞增多症占比更高（P=0.040），达到支气管激发试验阳性时所需乙酰甲胆碱浓度更低（P<0.001）。有序多分类logistic回归分析显示，血嗜酸性粒细胞增多（P=0.036）、中度（P=0.008）及重度气道高反应（P<0.001）与学龄前哮喘患儿发生小气道功能障碍呈正相关。结论 学龄前哮喘肺通气功能分布特征可分为：高于正常肺通气功能、肺通气功能正常、小气道功能下降、小气道功能障碍四类。血嗜酸性粒细胞增多、气道高反应性与学龄前哮喘患儿小气道功能障碍相关。

Objective To investigate the distribution characteristics of spirometry in preschool asthmatic children and further analyze its characteristics. Methods The clinical information and lung function results of preschool asthmatic children who were initial diagnosed from January 2019 to December 2020 were retrospectively collected. Latent profile analysis (LPA) was applied to analyze the category features of spirometry parameters distribution. The ordinal logistic regression analysis was used to analyze the relationship between the difference factors and category features of spirometry. Results A total of 851 preschool asthmatic children were included in this study, with a median age of 4.3 years. Latent profile analysis of spirometry parameters (FEV₁, FEV₁/FVC, FEF₅₀, FEF₇₅ and FEF_25~75, %pred) fitted four categories of spirometry parameters distribution curves: above-normal lung ventilation function group (118 cases, 13.9 %), normal lung ventilation function group (269 cases, 31.6 %), small airway function decreased group (297 cases, 34.9 %) and small airway dysfunction group (167 cases, 19.6 %). Spirometry parameters values showed a downward trend among the four category groups, with statistically significant differences in small airway function parameters among groups (P<0.001). Compared with the above-normal lung ventilation function group and the normal lung ventilation function group, patients in the small airway dysfunction group were older (P<0.001), had a higher proportion of eosinophilia (P=0.040) and severe airway hyperresponsiveness (AHR, P<0.001). The ordinal logistic regression analysis showed blood eosinophilia (P=0.036), moderate airway hyperresponsiveness (P=0.008), and severe airway hyperresponsiveness (P<0.001) were positively correlated with small airway dysfunction in preschool asthmatic children. Conclusions The distribution characteristics of spirometry parameters in preschool asthmatic children can be categorized into four types: above-normal lung ventilation function, normal lung ventilation function, small airway function decreased and small airway dysfunction. Blood eosinophilia and airway hyperresponsiveness are associated with small airway dysfunction in preschool children with asthma.