LAUSR

An exercise challenge test (ECT) that follows American Thoracic Society (ATS) guidelines is the criterion that surrogate tests for exercise-induced bronchoconstriction (EIB) should be compared (Stickland, M. et al. Annals of Allergy, Asthma & Immunology 2011; 107:229-234). Studies that have compared eucapnic voluntary hyperventilation (EVH) with ECT often fail to follow ATS guidelines. The aim of this study was to compare the airway response to EVH with the response elicited by an ECT that complied with ATS guidelines. Seventeen participants completed an ECT and an EVH test on separate days. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV 1 ), FEV 1 /FVC, and peak expiratory flow (PEF) were compared to baseline to determine the response to each challenge. Bland & Altman plot analysis was used to evaluate the bias between the mean differences for ΔFEV 1 , and to estimate a limit of agreement (LoA) within which 95% of the differences fell. The bias was 2.2% (95% CI -0.8-5.0%) indicating that ECT tended to give a ΔFEV 1 between 0.8% lower and 5% higher than EVH. The upper and lower LoA (13.7 and -9.3%, respectively) were large indicating that the ECT may result in a ΔFEV 1 ­ between 13.7% higher and 9.3% lower than EVH. Further, the confidence intervals for the upper and lower LoA (8.5 to 18.6% and -14.5 to -4.4%, respectively) were wide, also indicating poor agreement. These data do not support the use of EVH as a suitable alternative to ECT for the detection of EIB. More data is needed to fully evaluate the utility of EVH as an airway challenge.