Clinical Implications of Oscillatory Lung Function during Methacholine Bronchoprovocation Testing of Preschool Children.
BIOMED RESEARCH INTERNATIONAL 2017;
2017:9460190. [PMID:
28740854 PMCID:
PMC5504923 DOI:
10.1155/2017/9460190]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/21/2017] [Accepted: 05/07/2017] [Indexed: 12/21/2022]
Abstract
OBJECTIVE
To investigate the repeatability and safety of measuring impulse oscillation system (IOS) parameters and the point of wheezing during bronchoprovocation testing of preschool children.
METHODS
Two sets of methacholine challenge were conducted in 36 asthma children. The test was discontinued if there was a significant change in reactance (Xrs5) and resistance (Rrs5) at 5 Hz (Condition 1) or respiratory distress due to airway obstruction (Condition 2). The repeatability of PC80_Xrs5, PC30_Rrs5, and wheezing (PCw) was assessed. The changes in Z-scores and SD-indexes from prebaseline (before testing) to postbaseline (after bronchodilator) were determined.
RESULTS
For PC30_Rrs5, PC80_Xrs5, and PCw for subjects, PC80_Xrs5 showed the highest repeatability. Fifteen of 70 tests met Condition 2. The changes from pre- and postbaseline values varied significantly for Rrs5 and Xrs5. Excluding subjects with Z-scores higher than 2SD, we were able to detect 97.1% of bronchial hyperresponsiveness during methacholine challenge based on the change in Rrs5 or Xrs5. A change in IOS parameters was associated with wheezing at all frequencies.
CONCLUSION
Xrs5 and Rrs5 have repeatability comparable with FEV1, and Xrs5 is more reliable than Rrs5. Clinicians can safely perform a challenge test by measuring the changes in Rrs5, Xrs5, and Z-scores from the prebaseline values.
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