Further evidence for an association between LCI and FEV1 in patients with PCD

We have taken keen interest in the current discussion on the meaning of the lung clearance index (LCI) in patients with primary ciliary dyskinesia (PCD). In patients with cystic fibrosis (CF), LCI from the nitrogen multiple-breath gas washout (N2-MBW) test has become a sensitive marker for detection of ventilation inhomogeneity with a good correlation between LCI and FEV1.1 However, in patients with PCD, two studies failed to find a correlation for the FEV1 and LCI.1 ,2 This difference in functional measures between CF and PCD was recently challenged by Boon et al ,3 showing a robust correlation between LCI and FEV …