The role of impulse oscillometry in detecting airway dysfunction in athletes

Abstract

Background: Impulse oscillometry (IOS) has previously been proposed to provide greater sensitivity than spirometry when employed with indirect bronchoprovocation testing for the diagnosis of airway dysfunction in athletes. However, this recommendation is based on a highly selected population of symptomatic patients. Objective: To compare IOS, spirometry and respiratory symptoms following indirect bronchoprovocation in a screened cohort of athletes. Methods: One hundred and one recreational athletes were recruited. Respiratory symptoms were assessed via the Dyspnoea-12 questionnaire. Spirometry and IOS were performed pre and post a eucapnic voluntary hyperpnoea (EVH) challenge. Results: Ninety-four athletes completed the study. Sixteen athletes (17%) were positive for airway dysfunction based on spirometry (i.e. ≥10% fall in FEV₁) and 17 athletes (18%) based on IOS (i.e. ≥50% increase in R₅). Only nine athletes (10%) met both diagnostic thresholds. A poor relationship was observed between respiratory symptoms (i.e. Dyspnoea-12 score) and all spirometry and IOS variables. A direct relationship was observed between percentage change in R₅ (r = 0.65), Z₅ (r = 0.68), R_F (r = 0.65), A_X (r = 0.69) and the maximum fall in FEV₁ (ΔFEV₁max; p < 0.001). A weak relationship was observed between R₂₀ (r = 0.27), X₅ (r = 0.37) and ΔFEV₁max (p < 0.01). Conclusion: Impulse oscillometry and spirometry do not concur precisely following indirect bronchoprovocation. However, IOS detects additional cases of airway dysfunction in athletes and therefore may provide diagnostic value in this population. Further work is required to establish diagnostic thresholds and fully determine the place of IOS in screening athletes for airway dysfunction.

• Asthma
• diagnosis
• eucapnic voluntary hyperpnoea
• exercise-induced bronchoconstriction
• respiratory symptoms

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.