PURPOSE: Lung function is considered abnormal via impulse oscillometry (IOS) if the airway resistance (AR) is greater than 150 percent of the predicted value. The purpose of our study was to determine if new percent of predicted values needed to be set for airway resistance in children.
METHODS: We retrospectively reviewed 957 IOS studies performed in a pediatric pulmonology clinic. We evaluated the airway resistance percent predicted values at 5, 10, 15, and 20Hz. The children ranged in age from 4 to 19 years of age. We calculated the mean percent of predicted value at each of these resistances and compared them to the current standard of 150 percent. We also reviewed FVC and FEV1 that were performed at the same visit at the clinic.
RESULTS: For all patients, the mean AR percent predicted value at 5Hz was 115.5%, 94.31% at 10Hz, 80.7% at 15Hz, and 72.35% at 20Hz. The mean spirometry was within normal range with a FEV1 of 86.27% and a FVC of 100.6%.
CONCLUSIONS: In the pediatric population the standard of greater than 150 percent of the predicted value via IOS has been suggestive of abnormal lung function. This standard may need to be adjusted to a lower percentage. This percentage may have many false negatives and miss patients with abnormal lung function.
CLINICAL IMPLICATIONS: The normal percent predicted values of airway resistance via impulse oscillometry at 5, 10, 15, and 20 Hz may need to be reassessed. The true percentage to detect abnormal lung function may be less than 120 percent of the predicted value instead of 150 percent.
DISCLOSURE: The following authors have nothing to disclose: Stamatio Alexiou, Sneha Taylor, Glenn Hildreth, Kevin Maupin
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