A Protocol for Validation of Novel AI-Based Framework for Dyspnoea Investigation with CPET

Background Exertional dyspnoea largely represents the sensory translation of an ever-growing dynamic mismatch between ventilatory demand and capacity as exercise intensifies. This fundamental tenet, however, has not been formally incorporated into data display and clinical interpretation of incremental cardiopulmonary exercise testing (CPET). Objectives To validate a novel framework ( Dy namic Assessment of Dy spnoea and Ve ntilation on E x ercise, DyVe-X) to quantify the severity of exertional dyspnoea while exposing its mechanical-ventilatory underpinnings across progressively higher exercise intensities in subjects showing varied pre-test likelihood of abnormality. Methods Incremental CPET data from 3 large cohorts of tobacco-exposed subjects: smokers and ex-smokers at risk for, or at different stages of, COPD (N=1161). Based on recently published normative data, a homonymous software (DyVe-X 1.0.0 Kingston, ON, Canada) uses an AI-based algorithm to establish the burden of a) exertional dyspnoea versus work rate and ventilation, b) excessive breathing (low submaximal ventilatory reserve, high dyspnoea-work rate but preserved dyspnoea-ventilation), and c) constrained breathing (reduced inspiratory reserve, high dyspnoea-work rate and dyspnoea-ventilation). We hypothesize that categories of progressive mechanical-ventilatory abnormalities, based on DyVe-X, would exhibit progressively worse physiological and sensory CPET outcomes. Using the current key criterion to indicate ventilatory limitation to exercise (peak breathing reserve ≤15%) as the comparator, we anticipate a superior performance of DyVe-X in exposing dyspnoea-generating mechanical-ventilatory abnormalities across cohorts. Implications This study may validate an original framework for investigating dyspnoea using CPET, characterized by continuous assessment of symptom intensity and time course, in light of the rate of dynamic depletion of mechanical-ventilatory reserves.