呼气相气道内负压法检测呼气流速受限应用于儿童支气管激发试验的可行性

目的 观察支气管哮喘(简称哮喘)患儿支气管组胺激发试验前、后呼气流速受限(EFL)情况,并与常规的以第1秒用力呼气容积(FEV1)作为判断指标的支气管激发试验结果进行比较,探讨EFL作为支气管激发试验判断指标的可行性.方法 非急性发作期哮喘30例患儿,采用呼气相气道内负压(NEP)法检测患儿支气管组胺激发试验前、后EFL情况.结果 30例非急性发作期哮喘息儿中,支气管组胺激发试验阳性者(BPT阳性组)19例,阴性者(BPT阴性组)11例.BPT阳性患儿激发前、后FEV1分别为(1.71±0.52)L和(1.21±0.34)L,FEV1下降率为(29.04±7.49)%,19例BPT阳性患儿激发前和激发后分别有1例和3例出现卧位EFL,坐位时均无EFL,患儿3分法EFL和5分法EFL激发前(分别为1.05±0.23和0.05±0.22)与激发后(分别为1.16±0.37和0.26±0.65)比较差异均无统计学意义(t分别为1.455和1.714,P分别为0.163和0.104).BPT阴性患儿激发前、后FEV1分别为(1.89±0.80)L和(1.79±0.78)L,FEV1下降率为(6.09±5.29)%,11例BPT阴性患儿激发前与激发后均无EFL.结论 NEP法检测EFL不能敏感反映传统支气管激发试验阳性判断标准(FEV1下降≥20%)的变化,其在支气管激发试验中的可行性和阳性判断标准尚有待进一步研究探讨.

Feasibility of expiratory flow limitation detected by negative expiratory pressure for airway hyperreactivity in children with asthma

Objective To detect expiratory flow limitation (EFL)before and after histamine bronchoprovocation test in children with asthma,and compared with the most commonly used lung function parameter FEV1, so that to examine the feasibility of EFL in the assessment of bronchoprovocation test.Methods Thirty stable asthmatic children were included. EFL was measured by applying negative expiration pressure(NEP) at the mouth before and after histamine bronchoprovocation test. Results Histamine bronchoprovocation test was positive in 19 (BPT-positive group) cases and negative in 11 (BPT-negative group) cases of 30 asthmatic children. In BPT-positive group, the mean FEV1 before and after bronchoprovocation test was (1.71±0. 52) L and (1.21±0. 34) L respectively, the mean descending rate was (29.04±7.49)% after histamine provocation. EFL was detected only in 1 case and 3 cases of the 19 asthmatic children with positive, bronchoprovocation test before and after histamine provocation. The difference in three-point EFL(EFL-3) or five-point EFL(EFL-5) before.and after bronchoprovocation test was not significant (EFL-3:1. 05±0.23 vs 1. 16±0. 37, t=1.455, P =0. 163;EFL-5:0. 05±0. 22 vs 0. 26± 0. 65, t = 1. 714, P = 0. 104). In BPT-negative group, the mean FEV1 before and after bronehoprovocation test was (1.89±0.80) L and (1.79±0. 78)L respectively,the mean descending rate was (6. 09±5.29)%.None of the 11 asthmatic children in BPT-negative group presented EFL before and after histamine bronchoprovocation test. Conclusions EFL detected by NEP does not sensitively reflect the positive criteria (FEV1 falling ≥20% ) for bronehoprovoeation test. The feasibility and criterion of EFL detected by NEP in the assessment of bronchoprovocation test await further studies.