Airspace Dimension Assessment (AiDA) for early detection of lung function impairment in the peripheral airways of firefighters

Introduction Firefighters have increased risk of chronic respiratory disease. Standard clinical techniques used in medical checkups may not detect the earliest microstructural changes in peripheral airways. A new technique called Airspace Dimension Assessment (AiDA) has been shown to enable early detection of emphysema in chronic obstructive pulmonary disease. This method may be useful in the occupational setting to detect early pulmonary changes and enable prevention.

Aim To evaluate whether AiDA detects changes in the most peripheral airways of firefighters.

Methods AiDA, measuring the effective airspace radius (r_AiDA) and zero-second recovery (R₀), was used as a complement to other standardised lung function measures in 21 male firefighters and 16 age-matched male controls.

Results There were significant differences in r_AiDA and R₀ between firefighters (mean r_AiDA 0.301 mm, standard deviation (sd) 0.024; mean R₀ 0.336 arbitrary units, sd 0.116 and controls (mean r_AiDA 0.276 mm, sd 0.044; mean R₀ 0.576 arbitrary units, sd 0.168), p=0.03 and p<0.001, respectively. Higher forced vital capacity was found in firefighters (mean 101% of predicted) than in controls (mean 93% of predicted; p=0.03). No significant differences were found with regard to either the ratio between forced expiratory volume in 1 s and forced vital capacity or forced expiratory volume in 1 s. The majority of firefighters had diffusing capacity for carbon monoxide, oscillometry and single-breath nitrogen washout values within the normal ranges.

Conclusion AiDA parameters can provide information on early pulmonary peripheral changes that may not be seen with standard techniques used in screening of pulmonary function.