Evaluation Of Inter-rater Agreement For Identifying Dysfunctional Breathing In Cardiopulmonary Exercise Testing

PURPOSE: Dysfunctional breathing (DB) during exercise describes alterations in the breathing pattern that contributes to dyspnea and impairs quality of life. There are presently no gold standard criteria to define DB, but erratic depth (VT) and rate (Rf) are defining features. Here we examine agreement among three ACSM Certified Clinical Exercise Physiologists (CEPs) in identifying DB during maximal cardiopulmonary exercise testing (CPET). METHODS: Breath-by-breath CPET data were retrospectively analyzed from 64 adults (6 female; 40.8 ± 9.0 years) who volunteered for a research study. VT and Rf (y-axes) were plotted against minute ventilation (x-axis) for each individual and independently reviewed and coded (DB present or not). Blinded results were sent to a colleague and aggregated for analysis. Interrater reliability analysis using the Fleiss kappa statistic (two-way mixed; absolute agreement) was performed to assess consistency among the three CEPs in identifying DB. CPET performance (VO2 peak, VE/VCO2 slope, PetCO2) was also compared between those with and without DB via independent t-tests. RESULTS: There was moderate agreement between CEPs for determination of DB, К = 0.52 (95%CI: 0.38, 0.66), p < 0.001. Using the mode, DB was present in 60% of our sample. Overall, subjects endorsed ‘severe’ (Borg: 5.5 ± 1.8) shortness of breath at peak exercise. CPET performance was similar in those with and without DB for each of the measured parameters, VO2 peak, VE/VCO2 slope, PetCO2 (p > 0.05). CONCLUSIONS: Three CEPs displayed moderate agreement in identifying DB in our sample when employing a standard definition. Despite the subjective nature of determining DB, the identification of its presence in 60% of our sample may warrant greater attention in the interpretation of CPET in individuals with unexplained dyspnea; especially when other parameters appear normal. Supported by: VA I01CX001515 and DoD W81XWH-19-2-0059