Validity, reliability and minimum detectable change of COSMED K5 portable gas exchange system in breath-by-breath mode

• DOI: 10.1371/journal.pone.0209925
• Publication Date: 2018-12-31T18:48:22Z
• Authors: Laura Guidetti; Marco Meucci; Francesco Bolletta; Gian Pietro Emere...; Maria Chiara Gall...; Carlo Baldari
• Keywords: Pulmonary Gas Exchange; Science; Q; R; Carbon Dioxide; Oxygen; 03 medical and health sciences; Oxygen Consumption; 0302 clinical medicine; Breath Tests; Medicine; Humans; Breath Tests; Carbon Dioxide; Humans; Oxygen; Oxygen Consumption; Pulmonary Gas Exchange; Research Article

Purpose This study aimed to examine the validity, reliability and minimum detectable change (MDC) of Cosmed K5 in breath by (BxB) mode, against VacuMed metabolic simulator. Intra inter-units was also assessed. Methods Fourteen rates (from 0.9 4 L.min-1) were reproduced a system pulmonary ventilation (VE), oxygen consumption (VO2) carbon dioxide production (VCO2) measured two different units. Validity assessed ordinary least products (OLP) regression analysis, Bland-Altman plots, intraclass correlation coefficients (ICC), mean percentage differences, technical errors (TE) MDC for VE, VO2, VCO2. Intra- inter-K5 evaluated absolute differences between measurements (MAPE), ICCs, TE, MDC. Results analysis from OLP data Bland- Altman plots indicated high agreement ICC values excellent all variables (>0.99). Mean VE (-0.50%, p = 0.11), VO2 (-0.04%, 0.80), VCO2 (-1.03%, 0.09) showed no significant bias. The error ranged 0.73% 1.34% (VE respectively). lower than 4% 2.0%, 3.8%, 3.7%). intra inter assessment reveled ICCs (>0.99), MAPE <2% (no trials), TE < or around 1%, <or 3%. Conclusions BxB mode is valid reliable measurements. first assessing accounting only variability reporting intra- MDCs <3.3%.