Validity of four commercially available metabolic carts for assessing resting metabolic rate and respiratory exchange ratio in nonventilated humans Alcántara Alcántara, Juan Manuel Jurado Fasoli, Lucas Dote Montero, Manuel Merchán Ramírez, Elisa Ruiz Ruiz, Jonatan Sánchez Delgado, Guillermo Indirect calorimetry Reliability Basal metabolic rate Supported by the Spanish Ministry of Economy and Competitiveness via Retos de la Sociedad grant DEP2016-79512-R (to JRR), and European Regional Development Fund (ERDF); Spanish Ministry of Education grant (FPU15/04059 to JMAA; FPU19/01609 to LJF; and FPU18/03357 to MD-M); the University of Granada Plan Propio de Investigacion 2016-Excellence actions: Unit of Excellence on Exercise and Health (to JRR) -Plan Propio de Investigacion 2018 Programa Contratos-Puente and Programa Perfeccionamiento de Doctores (to GS-D); Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades grant SOMM17/6107/UGR (to JRR) via the ERDF; and the Fundacion Alfonso Martin Escudero (to GS-D); Funding for open access charge: Universidad de Granada/CBUA. Background & aims: The validity of most commercially available metabolic cart is mostly unknown. Thus, we aimed to determine the accuracy, precision, within-subject reproducibility, and concordance of RMR and RER measured by four commercially available metabolic carts [Cosmed Q-NRG, Vyaire Vyntus CPX, Maastricht Instruments Omnical, and Medgraphics Ultima CardiO2]. Further, we studied whether a previously proposed simulation-based post-calorimetric calibration of cart readouts [individual calibration control evaluation (ICcE)] modify the RMR and RER reproducibility and concordance. Methods: Three experiments simulating different RMR and RER by controlled pure gas (N-2 and CO2) infusions were conducted on 5 non-consecutive days. Moreover, 30-min methanol burns were performed on 3 non-consecutive days. Lastly, the RMR and RER of 29 young non-ventilated adults (11 women; 25 +/- 4 years-old; BMI: 24.1 +/- 3.2 kg/m(2)) were assessed twice using each instrument, 24 hours apart, under standardized conditions. Results: The Omnical presented the lowest measurement error for RER (Omnical = 1.7 +/- 0.9%; Vyntus = 4.5 +/- 2.0%; Q-NRG = 6.6 +/- 1.9%; Ultima = 6.8 +/- 6.5%) and EE (Omnical = 1.5 +/- 0.5%; Q-NRG = 2.5 +/- 1.3%; Ultima = 10.7 +/- 11.0%; Vyntus = 13.8 +/- 5.0%) in all in vitro experiments (controlled pure gas infusions and methanol burns). In humans, the 4 metabolic carts provided discordant RMR and RER estimations (all P < 0.001). No differences were detected in RMR within-subject reproducibility (P = 0.058; Q-NRG inter-day coefficient of variance = 3.6 +/- 2.5%; Omnical = 4.8 +/- 3.5%; Vyntus = 5.0 +/- 5.6%; Ultima = 5.7 +/- 4.6%), although the Ultima CardiO2 provided larger RER inter-day differences (4.6 +/- 3.5%) than the others carts (P = 0.001; Omnical = 1.9 +/- 1.7%; Vyntus = 2.1 +/- 1.3%; Q-NRG = 2.4 +/- 2.1%). The ICcE procedure did not modify the RMR or RER concordance and did not reduce the inter-day differences in any of the carts. Conclusions: The 4 metabolic carts provided discordant measurements of RMR and RER. Overall, the Omnical provides more accurate and precise estimations of RMR and RER than the Q-NRG, Vyntus and Ultima CardiO(2), and might be considered the best for assessing RMR and RER in non-ventilated humans. Finally, our results do not support the use of an ICcE procedure. 2022-04-04T07:24:00Z 2022-04-04T07:24:00Z 2022-02-04 info:eu-repo/semantics/article J.M.A. Alcantara... [et al.]. Validity of four commercially available metabolic carts for assessing resting metabolic rate and respiratory exchange ratio in non-ventilated humans, Clinical Nutrition, Volume 41, Issue 3, 2022, Pages 746-754, ISSN 0261-5614, [https://doi.org/10.1016/j.clnu.2022.01.031] http://hdl.handle.net/10481/74059 10.1016/j.clnu.2022.01.031 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España Elsevier