Quantification of breathing irregularity for the diagnosis of dysfunctional breathing using proportional tidal volume variation: a cross-sectional, retrospective real-world study

Abstract

ObjectivesTo develop a statistical approach that provides a quantitative index measuring the magnitude of the irregularity of the breathing response to exercise for the diagnosis of dysfunctional breathing.DesignCross-sectional, retrospective, real-world study.SettingSingle-centre study.ParticipantsA population of 209 patients investigated with cardiopulmonary exercise testing in our institution for unexplained or disproportionate exertional dyspnoea between January and July 2022.Primary and secondary outcome measuresA novel statistical approach providing a quantitative index—proportional tidal volume variation (PTVV)—was developed to measure the magnitude of the irregularity of the breathing response to exercise.ResultsPTVV provided a reliable statistical readout for the objective assessment of DB with a prediction accuracy of 78% (95% CI: 72 to 83%). The prevalence of DB in the investigated population was high with more than half of the patients affected by moderate-to-severe DB.ConclusionsPTVV can easily be implemented in the clinical routine. Our study suggests a possible further simplification for the diagnosis of DB with two objective criteria including PTVV and one single criterion for hyperventilation.