Abstract
Background Variable thresholds of nasal nitric oxide (nNO) are proposed to screen children for primary ciliary dyskinesia (PCD) without taking age into account. But very few young children have been studied in whom false positive were tests were found.
Objectives 1) to study the relationship between age and nNO measured using apnea (AP) or expiration against resistance (ExRe), and the tidal breathing (VT) techniques in non PCD children.
Methods Multicentre online nNO measurements study (chemiluminescence, Seres, France, Aerocrine, Sweden, flow sample 0.3L.min-1) in children with suspected PCD. Values recorded were the best value of AP or ExRe, and means of 5 maximal peaks, 10s during controlled regular VT, and last 30s during VT measurement.
Results 79 children with complete diagnosis procedure (47 with PCD, age, median [range] 11.0 [3.2-17.8]y) were studied. In non PCD children, nNO measurement was correlated with age (AR or ExRe p=0.0002, r2 = 0.38; 5 peaks p<0.03, r2 = 0.17; 10s p<0.02, r2 = 0.22) (Figure). nNO values according to techniques are shown in table.
Conclusion
nNO thresholds value to discriminate for PCD cannot be independent of age in children whichever the nNO technique of measure used.
- © 2013 ERS