Document resource
Introduction Eucapnic voluntary hyperpnoea (EVH) is a validated surrogate for exercise in the objective diagnosis of exercise-induced bronchoconstriction (EIB) ( figure 1) 1. However, its validity traditionally depends on achieving a minimum hyperventilation target, defined as ventilation (VE) ≥80% of maximum voluntary ventilation (MVV)2.This strict threshold can lead to invalid tests for individuals unable to meet it due to physiological or technical limitations. This case series explores the use of a novel validity criterion (VE ≥60% of MVV) in three diverse participants, demonstrating its ability to preserve diagnostic integrity.Methods Three participants (M:2, F:1; aged 17–27 years) underwent EVH testing at using a Jaeger CPX system. Hyperventilation breath by breath data was captured continual for six minutes. Entrained directly into the circuit was a gas mix consisting of 21% O2 5% CO2 and 74% Nitrogen.Baseline and post-EVH FEV1 values were recorded at 3,5,7,10,15,20 minutes. Post 20-minute time a 2.5 mg Salbutamol nebuliser was administered.VE as a percentage of MVV was calculated, with test validity determined using traditional (≥80%) and novel (≥60%) thresholds.Results Subject 1 (M, 27 years): VE = 54.54% MVV, 7.6% FEV 1 reduction (normal response).Subject 2 (M, 17 years): VE = 76.20% MVV, 8.9% FEV1 reduction (normal response).Subject 3 (F, 19 years): VE = 65.15% MVV, 13% FEV1 reduction (mild airway hyperresponsiveness).Abstract P64 Figure 1Conclusion For participants with suboptimal ventilatory performance, such as those with lower fitness levels achieving 80% of MVV may not be feasible, leading to the invalidation of their tests. Subject 1, for instance, achieved only 54.54% of MVV yet demonstrated a normal post-test FEV 1 reduction of 7.6%, indicative of a valid negative response. Similarly, Subject 3 achieved 65.15% of MVV, with a 13% FEV1 reduction consistent with mild airway hyperresponsiveness. Both cases would have been excluded under the traditional criteria, potentially delaying or misdirecting clinical care.Expanding test validity criteria balances methodological rigour with practical applicability. These findings emphasise the need for further research to evaluate the impact of ventilatory thresholds on EVH outcomes across diverse populations and settings. Additional studies are warranted to confirm broader applicability.