Validation of commercial devices for measurement of lung clearance index (LCI) and functional residual capacity (FRC) in school-aged children

Short-Term Effect of Autogenic Drainage on Ventilation Inhomogeneity in Adult Subjects With Stable Non-Cystic Fibrosis Bronchiectasis

“…34 How- ever, it is also admitted that the commercial multiplebreath nitrogen washout device used in this study overestimates true FRC to such an extent that some authors even report higher FRC washout than FRC pleth . [35][36][37][38] The mechanism behind this remains unclear, but because we found a small positive bias toward higher FRC pleth , we assume that substantial volumes of gas were trapped in a number of our subjects. The relatively high values observed in RV and RV/TLC, both markers also traditionally utilized to represent gas trapping, 34,39 and their positive associations with the magnitude of the bias (ie, FRC pleth Ϫ FRC washout ) further support this hypothesis.…”