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Respir Med. 2010 Jul;104(7):966-71. doi: 10.1016/j.rmed.2010.01.015. Epub 2010 Feb 10.
While lung hyperinflation is frequent in asthma, measurement of lung volumes is not recommended in current guidelines. The aim of this descriptive functional study was to assess whether systematic measurement of volumes by plethysmography may detect isolated hyperinflation with normal expiratory flows.
One hundred sixty asthmatic children (mean age + or - SD: 10.8 + or - 2.7 years; 50 girls) receiving inhaled corticosteroid underwent lung function tests before and after bronchodilation (BD). To avoid the problem of dysanaptic lung growth on predicted values in childhood, airflow limitation and hyperinflation were defined by ratios (FEV(1,%pred)/FVC(%pred) for the former, RV/TLC for the latter) and values below and above the 5th or 95th percentiles of reference values, were chosen as cut-off values.
Different functional phenotypes were evidenced, mainly normal lung function (142/160 [89%] after BD), but also isolated airflow limitation (35/160 [22%] before and 7/160 [4%] after BD) and isolated hyperinflation (17/160 [11%] before and 11/160 [7%] after BD), while the combination of both impairments before BD (13/160 [8%]) was never observed after BD. There was no statistical relationship between airflow limitation and hyperinflation, either before or after BD. Indices of spirometry (FEV(1), FEF(50%)) were unable to predict isolated hyperinflation that corresponds to small airway obstructive syndrome.
Isolated hyperinflation is not infrequent in asthmatic children (7-11%) and small airway obstruction is not detected by forced expiratory flows.
虽然在哮喘中肺过度充气很常见，但目前的指南并不建议测量肺容积。本描述性功能研究的目的是评估通过体描仪系统测量容积是否可以检测到伴有正常呼气流速的孤立性过度充气。
160 名接受吸入皮质激素治疗的哮喘儿童（平均年龄+或-标准差：10.8+或-2.7 岁；50 名女性）接受了支气管扩张前后的肺功能测试。为了避免儿童时期预测值中肺生长失同步的问题，气流受限和过度充气通过比值（FEV1%/FVC% 用于前者，RV/TLC 用于后者）和参考值的第 5 或 95 百分位数以下和以上的值来定义，选择这些值作为截断值。
表现出不同的功能表型，主要是正常的肺功能（支气管扩张后 142/160 [89%]），但也有孤立的气流受限（支气管扩张前 35/160 [22%]和支气管扩张后 7/160 [4%]）和孤立性过度充气（支气管扩张前 17/160 [11%]和支气管扩张后 11/160 [7%]），而支气管扩张前两者同时受损（13/160 [8%]）的情况在支气管扩张后从未出现过。支气管扩张前后，气流受限和过度充气之间均无统计学关系。肺量计指数（FEV1，FEF50%）无法预测对应于小气道阻塞综合征的孤立性过度充气。
在哮喘儿童中（7-11%）孤立性过度充气并不少见，并且强制呼气流量无法检测到小气道阻塞。
