PT  - JOURNAL ARTICLE
AU  - Waldemar Tomalak
AU  - Jakub Radlinski
TI  - A comparison of two analysers measuring exhaled nitric oxide concentration
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P1157
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P1157.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P1157.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - The measurements of the concentration of nitric oxide in exhaled air (FeNO) has been introduced in 90's of XXth century. FeNO appeared to be a useful marker of inflammation activity and is used as a tool in controlling asthma and its treatment.The aim of the work was to compare two analysers measuring FeNO: Sievers 280i (Sievers, USA) and HypAir (Medisoft, B). The Sievers analyser works on-line and uses ozone transducer to measure FeNO. Hypair analyses the sample off-line (time of analysis ∼25s) and uses electrochemical transducer. In 76 patients (12.6±6.0 years) we have made measurements using both analysers in random order according to ERS/ATS recommendations. The subjects exhaled air through flow restrictor. At least three measurements that did not differ much than 5% were taken in each subject using both analysers, and the mean was taken as a result. The data were then analysed using Bland-Altman approach.Mean value of FeNO for Sievers was 35.0±33.9 ppb (range 5-172 ppb) and 31.5±30.4 ppb (5-162) for HypAir respectively. The mean difference was 3.5±8.5 ppb; both measurements did not differ between them (paired t-test p=0.25). The measurements were strongly related to each other with r=0.971 and FeNO(HypAir) = 1.07+0.87*FeNO(SIEVERS).Bland-Altman analysis showed, that correlation between difference and the mean was statistically significant (r=0.42, P<0.001) and positive. That means that the difference has a systematic character and cannot be omitted. When using results from both apparatuses the correction formula should be applied.