INTRODUCTION: The upper airway shunt attenuates measurements of respiratory system impedance (Zrs), with greater impact in young children. Changes in respiratory system admittance, Ars (or Zrs(-1)), are theoretically independent of the shunt. This study compared the ability of Ars, to standard oscillatory outcomes, to determine respiratory disease and differentiate responses to inhaled bronchial challenges in the clinical setting. METHODS: The forced oscillation technique (FOT) was used to establish reference equations for Ars in healthy preschool children, compare the change in Ars to standard oscillatory outcomes during bronchial challenge with inhaled adenosine-5'-monophosphate (AMP) and to inhaled bronchodilator in healthy children and those with respiratory disease. RESULTS: Children with respiratory disease had lower baseline Ars than healthy children (P < 0.05). However, there was no improved ability for Ars to differentiate between bronchodilator responses in healthy and disease populations. In contrast, the response to inhaled AMP occurred at a lower concentration, [25 (3.12-400) mg ml(-1); median (10th-90th centile)], as measured by Ars when compared to respiratory system resistance [225 (6.25-400) mg ml(-1); P = 0.016]. CONCLUSION: This study supports the use of Ars during inhaled challenges, but not in response to bronchodilation.
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机译：简介：上呼吸道分流器减弱了对呼吸系统阻抗（Zrs）的测量，对幼儿的影响更大。呼吸系统导纳Ars（或Zrs（-1））的变化在理论上与分流无关。这项研究比较了Ars与标准振荡结果在临床环境中确定呼吸系统疾病和区分对吸入支气管挑战的反应的能力。方法：采用强迫振荡技术（FOT）建立健康学龄前儿童Ars的参考方程，比较吸入式5'-单磷酸腺苷（AMP）和吸入性支气管扩张剂时Ars与标准振荡结果的变化。健康的儿童和患有呼吸系统疾病的儿童。结果：呼吸系统疾病儿童的基线Ars低于健康儿童（P <0.05）。但是，在健康人群和疾病人群中，Ars不能更好地区分支气管扩张剂反应。相反，对吸入的AMP的反应发生在较低的浓度[25（3.12-400）mg ml（-1）;中位数（第10-90个百分位数）]，通过Ars与呼吸系统阻力的比较[225（6.25-400）mg ml（-1）; P = 0.016]。结论：本研究支持在吸入性挑战中使用Ars，但不响应支气管扩张。
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