title: Comparison of 2 portable respiratory gas analysers.
abstract: The aim of this study was to compare respiratory measures taken simultaneously using the Cosmed K4b(2) and Cortex Metamax II portable metabolic systems. 10 trained male cyclists performed a graded exercise cycle test to exhaustion (40w.3 min (- 1)) under standardized conditions. The measured respiratory variables were significantly correlated between both devices: r=0.97 and 0.98 (n=10, p<0.01) for oxygen uptake ( V˙O(2)) and ventilation (VE), respectively. Further Bland and Altman plots revealed a good level of agreement for measures of V˙O(2) expressed in mL.min (- 1) [- 670 to 486] (mean bias of - 91.7, i. e., - 3.1%) or in mL.min (- 1).kg (- 1) [- 7.3 to 9.0] (mean bias of 0.85, i. e., 2.3%) and V(E) [- 23.1 to 18.2] (L.min (- 1), mean bias of - 2.4, i. e. - 4.1%). However, poor agreement was found for measures of carbon dioxide (VCO(2), mL.min (- 1)) [- 280 to 1 394] (mean bias of 671 i.e., 20.3%). VCO(2) at maximal exercise intensity was also significantly (p<0.01) greater in the Cortex compared to the Cosmed system. The higher measured CO(2) concentrations led to significantly (p<0.01) higher calculated respiratory exchange ratio (RER) values with the Cortex device. In conclusion, there was satisfactory agreement between the Cosmed K4b(2) and Cortex Metamax II systems for most respiratory measures; however there was a poor level of agreement between VCO(2) and calculated RER measurements between the 2 systems.
authors.affiliation: Laboratoire de Recherche Adaptations Physiologiques à l'Exercice et -Réadaptation à l'Effort Université de Picardie Jules Verne, AMIENS, France. pierre-marie.lepretre@u-picardie.fr
authors.forename: P M
authors.initials: PM
authors.lastname: Leprêtre
authors.forename: T
authors.initials: T
authors.lastname: Weissland
authors.forename: C
authors.initials: C
authors.lastname: Paton
authors.forename: M
authors.initials: M
authors.lastname: Jeanne
authors.forename: S
authors.initials: S
authors.lastname: Delannaud
authors.forename: S
authors.initials: S
authors.lastname: Ahmaidi
mesh_terms: D056352:Athletes; D001642:Bicycling / Q000502:physiology*; D002245:Carbon Dioxide / Q000032:analysis* / Q000502:physiology; D004867:Equipment Design; D005080:Exercise Test; D006801:Humans; D008297:Male; D010100:Oxygen / Q000032:analysis* / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen