LAUSR

Introduction: Nasal NO is recommended to be used in the diagnostic work-up of PCD. Objective: To determine whether nNO measurements using portable electrochemical device NIOX VERO ® could distinguish subjects with PCD from healthy subjects. The primary endpoint was mean nNO measurements in subjects with at least 2 measurements. Method: A multi-center, single visit, non-randomised study involved subjects ≥5 years with known PCD vs. age matched healthy controls (HC). Subjects attempted nNO using both tidal breathing method (TB-nNO) and expiration against resisitance method (ER-nNO). Descriptive analyses were performed, including a Receiver Operating Characteristic curve analysis to assess optimal cut-off values. Results: In this study, 98.1% (49 PCD [mean age 17.5 (SD 11.66)/105 HC 19.4 (SD 14.22)] completed at least one measurement in both methods; 96.8% completed at least two measurements from one nostril using either method. Mean TB-nNO values were 50.7 (SD 50.28) ppb and 575.3 (SD 236.88) ppb in PCD vs HC and mean ER-nNO values were 80.5 (SD 101.73) ppb and 915.9 (SD 391.68) ppb in PCD vs HC. In subjects with two measurements from both nostrils using either method, opitimal cut-off values were 171 ppb (51.3 nL/min) for TB-nNO (AUC 99.8%; specificity 100%; sensitivity 98.0%) and 356 ppb (106.8 nL/min) for ER-nNO (AUC 98.7%; specificity 96.3%; sensitivity 97.8%). Conclusions: The new NIOX VERO ® nasal application can be used to differentiate patients with PCD from healthy individuals. The obtained cut-off TB-nNO and ER-nNO values show that both methods in NIOX VERO ® can be used in children and adult patients as part of the diagnostic work-up of PCD.