Bridge P D, Lee H, Silverman M
Dept of Paediatrics and Neonatal Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Eur Respir J. 1996 Jul;9(7):1368-73. doi: 10.1183/09031936.96.09071368.
A new device for measuring airway resistance following brief airflow interruption (Microlab 4000; Micromedical Ltd, UK) was evaluated in 25 asthmatic school children in comparison with well-established methods. Airway resistance was measured during brief airflow interruption (Rint), before and after administration of salbutamol 200 micrograms by metered-dose inhaler, and in the spirometric parameters, forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), and total respiratory system resistance at 6 Hz (Rrs,6) measured by the forced oscillation technique (FOT). The sensitivity index (SI) (mean change/baseline standard deviation) was calculated for each subject. At baseline, interrupter conductance, the reciprocal of Rint, correlated well with FEV1 (r = 0.837; p < 0.001) and PEF (r = 0.773; p < 0.001), and Rint correlated highly with Rrs,6 (r = 0.942; p < 0.001). The median intrasubject coefficient of variation of the interrupter method was higher than the FOT or either spirometric parameter; Rint 11%, Rrs,6 9%, FEV1 5% and PEF 5%. However, the sensitivity to detect change after bronchodilator, expressed as the median SI, did not differ significantly between measurements: Rint 3.5, Rrs,6 3.6, FEV1 2.4 and PEF 3.0. A significant response (SI > 2) was shown by the interrupter in 22 of the subjects compared with 16 by FEV1. The interrupter technique is useful for assessing changes in airway calibre in asthmatic school children, with a sensitivity at least as good as standard methods. Such a device could be of particular value in those too young to perform spirometry.
一种用于在短暂气流中断后测量气道阻力的新设备（Microlab 4000；英国Micromedical有限公司），与成熟方法相比，在25名哮喘学龄儿童中进行了评估。在短暂气流中断期间测量气道阻力（Rint），在通过定量吸入器给予200微克沙丁胺醇之前和之后，以及在肺量计参数、一秒用力呼气量（FEV1）和呼气峰值流量（PEF）以及通过强迫振荡技术（FOT）测量的6 Hz时的总呼吸系统阻力（Rrs,6）。为每个受试者计算敏感性指数（SI）（平均变化/基线标准差）。在基线时，中断器传导率（Rint的倒数）与FEV1（r = 0.837；p < 0.001）和PEF（r = 0.773；p < 0.001）相关性良好，并且Rint与Rrs,6高度相关（r = 0.942；p < 0.001）。中断器方法的受试者内变异系数中位数高于FOT或任何一个肺量计参数；Rint为11%，Rrs,6为9%，FEV1为5%，PEF为5%。然而，以中位数SI表示的支气管扩张剂后检测变化的敏感性在测量之间没有显著差异：Rint为3.5，Rrs,6为3.6，FEV1为2.4，PEF为3.0。中断器在22名受试者中显示出显著反应（SI > 2），而FEV1为16名。中断器技术对于评估哮喘学龄儿童气道口径的变化很有用，其敏感性至少与标准方法一样好。这样的设备对于那些太小而无法进行肺量计检查的儿童可能具有特别的价值。
