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目的探讨在使用脉冲振荡肺功能(IOS)检测时,如何判断支气管舒张试验阳性。方法随机抽取发作期哮喘患儿156例,均进行最大呼气流量-容积和IOS测定,然后进行支气管舒张试验。以第一秒用力呼气容积(FEV1)和最大呼气中段流量(MMEF)作为金标准,分别计算IOS主要参数,即呼吸总阻抗(Zrs)、气道总粘性阻力(R5)、电抗(X5)在不同改善率水平时其对诊断的敏感度与特异度,并计算两种肺功能主要参数间的回归方程。结果吸入支气管舒张剂后,患儿肺功能显著改善,两种肺功能主要参数的改善率均存在显著相关(P<0.01),其中X5改善率与最大呼气流量-容积曲线参数改善率相关性最强(相关系数分别为0.676、0.571),Zrs次之。无论使用FEV1改善率≥15%,还是使用MMEF改善率≥30%作参照,IOS参数以Zrs、R5下降≥20%,X5下降≥30%作为舒张试验阳性有着较高的敏感度和特异度。回归方程结果显示,与FEV1改善15%、MMEF改善30%对应的Zrs、R5、X5的降低率分别为21.7%、21.3%;19.9%、19.5%;30.1%、29.6%。结论用IOS进行支气管舒张试验,只有在Zrs、R5下降≥20%,X5下降≥30%时,才能考虑作为试验阳性。
Objective To explore how to judge the positive bronchodilator test when using pulsed oscillatory pulmonary function test (IOS). Methods A total of 156 children with asthma were randomly selected. The maximal expiratory flow-volume and IOS were measured. Bronchodilator test was then performed. The main parameters of IOS were the total respiratory impedance (Zrs), airway total viscous resistance (R5), reactance (X5), airway total resistance ) At different rates of improvement of its diagnostic sensitivity and specificity, and calculate the two main parameters of pulmonary function regression equation. Results After bronchodilator inhalation, pulmonary function was significantly improved in both groups, and there was a significant correlation between the improvement rate of the two main parameters of lung function (P <0.01). Correlation between the improvement rate of X5 and the improvement rate of maximum expiratory flow volume-volume curve Strongest (correlation coefficient of 0.676,0.571 respectively), followed by Zrs. No matter using FEV1 improvement rate ≥15%, or using MMEF improvement rate ≥30% as reference, the IOS parameters were reduced by ≥20% with Zrs, R5 and ≥30% by X5. As the diastolic test positive, IOS parameters had higher sensitivity and specificity. The regression equation showed that the reduction rates of Zrs, R5 and X5 corresponding to 15% improvement of FEV1 and 30% improvement of MMEF were 21.7%, 21.3%, 19.9%, 19.5%, 30.1% and 29.6% respectively. Conclusions The bronchodilator test with IOS was considered positive only if the Zrs, R5 decreased ≥20% and X5 decreased ≥30%.