Fractional Exhaled Nitric Oxide in the Interpretation of Specific Inhalational Challenge Tests for Occupational Asthma

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• 作者：Gareth I. Walters (1)
  Vicky C. Moore (1)
  Emmet E. McGrath (1)
  Sherwood Burge (1)
  
• 关键词：Occupational asthma ; Bronchial challenge ; Exhaled nitric oxide ; Specific inhalational challenge ; Asthma ; Eosinophilic inflammation
• 刊名：Lung
• 出版年：2014
• 出版时间：February 2014
• 年：2014
• 卷：192
• 期：1
• 页码：119-124
• 全文大小：204 KB
• 作者单位：Gareth I. Walters (1)
  Vicky C. Moore (1)
  Emmet E. McGrath (1)
  Sherwood Burge (1)
  
  1. Occupational Lung Disease Unit, Birmingham Heartlands Hospital, Bordesley Green, Birmingham, B9 5SS, UK
  
• ISSN：1432-1750

文摘

Purpose Fractional exhaled nitric oxide (FENO) measurements are recommended for the assessment of eosinophilic airway inflammation in asthma. Clinically relevant increases in FENO have been reported 24?h after positive specific inhalational challenge (SIC) tests in occupational asthma. We aimed to determine whether positive SICs could be discriminated from control tests, on the basis of change in FENO. Methods We reviewed all positive SICs to a variety of agents performed at our institution 2008-012 and gathered data on age, sex, asthmatic response (immediate/dual/late), smoking status, inhaled corticosteroid usage, and FENO pre- and 24-h postcontrol and positive SIC from each worker. Changes in FENO after positive SICs were compared with control SICs from each worker, by using paired Student’s t tests. Results In 16 workers, negative control challenges were associated with mean changes in FENO of 9?% (95?% CI ?.14 to 19.01) or 1.1?ppb (95?% CI ?.59 to 5.84); 2 of 16 (13?%) workers tested showed increases in FENO that were clinically relevant based on recent guidelines. Subsequent positive SICs were associated with mean changes in FENO of 7?% (95?% CI ?5.73 to 29.6) or 2.1?ppb (95?% CI ?.07 to 10.19), which were not significantly different to controls; only 2 of 16 (13?%) workers had FENO changes that were clinically relevant. Conclusions FENO changes above the upper confidence limits of ?0?% or ??ppb may be considered to be outside the range of normality. However, the majority of workers who had clearly positive SICs to common low molecular weight agents also had no statistically or clinically relevant increase in FENO. Therefore, change in FENO does not predict a positive SIC in this group.