TY - JOUR T1 - Nasal NO measurement in preschool children: Feasibility and validation of a novel tidal breathing technique JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p1126 AU - Andreas Jung AU - Christian Geidel AU - Irmela Heinrichs AU - Alexander Moeller AU - Guenter Menz AU - Roger Lauener Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p1126.abstract N2 - Background: Screening for primary ciliary dyskinesia (PCD) in preschool children by measurement of nasal nitrite oxide (nNO) is difficult due to a lack of standardization and reference values. This study aimed to compare a conventional nNO measurement technique with a tidal breathing technique through a straw.Methods: nNO was assessed by the Niox Flex system in children and adults with chronic rhino-sinusitis (CRS), confirmed PCD and in healthy controls. Measurements consisted of 2 tests with subjects holding their breath (BH), followed by 2 tests with tidal breathing through a straw (TB).Results: 88 subjects were recruited. 71 (81%) or 77 (88%) subjects performed either a valid BH or a valid TB test, respectively. In the preschool age group (n=22), 19 subjects (86%) had a valid TB test with only 10 individuals (45%) performing a valid BH test. A high correlation between TB and BD values were observed (r2=0.954, p<0.001). Bland-Altman analysis showed that both methods were comparable for PCD and CRS groups, while a bias towards higher nasal NO levels using the TB technique was observed in healthy control subjects. When controls were stratified for age (<6 yrs n=9, 6-15 yrs n=18, 16 ≥yrs n=21), there was a trend towards lower NO levels for younger children in the preschool age group (r2=0.341, p<0.1).Conclusion: Nasal NO measurement by TB with a straw is a feasible and valid method in all age groups. Results correlate well with nNO levels measured by conventional techniques. Almost all preschool children were able to perform a valid TB test. A larger study is on the way to determine reference values in preschool children using the established TB method with a straw. ER -