Changes in exhaled nitric oxide after inhalation challenge with occupational agents

Area of Science:

• Occupational Medicine
• Pulmonary Medicine
• Allergy and Immunology

Background:

• Fractional exhaled nitric oxide (FeNO) is explored as a marker for airway response to specific inhalation challenge (SIC).
• Occupational asthma diagnosis often involves SIC with specific agents.
• FeNO monitoring post-SIC is investigated for its utility in occupational settings.

Purpose of the Study:

• To evaluate FeNO measurements for monitoring airway responses to occupational agents during SIC.
• To determine the diagnostic and predictive capacity of FeNO in the context of SIC.

Main Methods:

• Recruitment of workers with suspected occupational asthma.
• Performance of SIC with occupational agents.
• Measurement of FeNO at baseline and 24 hours post-challenge.

Main Results:

• A significant FeNO increase (1.25 ratio) was observed 24 hours post-SIC in positive cases (P=.01).
• FeNO variations showed a 4% increased probability of positive SIC per unit increase.
• A baseline FeNO of 25 ppb offered 60% sensitivity and 80% specificity; a 41% FeNO increase yielded 50% sensitivity and 95% specificity.

Conclusions:

• Asthmatic reactions to occupational agents in SIC correlate with increased FeNO.
• FeNO measurements demonstrate limited predictive diagnostic capacity for SIC.
• FeNO may assist SIC interpretation but is not a general surrogate marker for occupational agent challenges.