Reliability of, and Agreement Between, two Breath‐by‐Breath Indirect Calorimeters at Varying Levels of Inspiratory Oxygen. (4th February 2019)

• Record Type: Journal Article
• Authors: Poulsen, Mathias Krogh; Thomsen, Lars Pilegaard; Kjærgaard, Søren; Rees, Stephen Edward; Karbing, Dan Stieper
• Is Part Of: Nutrition in clinical practice. Volume 34:Number 5(2019)
• Page Start: 767
• Page End: 774
• Publication Date: 2019-02-04
• Subjects: bias -- indirect calorimetry -- mechanical ventilation -- reproducibility of results -- resting energy expenditure; Nutrition -- Periodicals; Diet therapy -- Periodicals; Artificial feeding -- Periodicals; 615.854
• DOI: 10.1002/ncp.10250
• Languages: English
• ISSNs: 0884-5336

Abstract

Abstract: Background: Indirect calorimetry (IC) is considered the accurate way of measuring energy expenditure (EE). IC devices often apply the Haldane transformation, introducing errors at inspiratory oxygen fraction (FiO2 ) >60%. The aim was to assess measurement reliability and agreement between an unevaluated IC (device 2) (Beacon Caresystem, Mermaid Care A/S, Noerresundby, Denmark) not using Haldane transformation and an IC that does (device 1) (Ecovx, GE, Helsinki, Finland) at varying FiO2 . Methods: Twenty healthy male subjects participated, with 16 completing the study (33 ± 9 years, 83.3 ± 16 kg, 1.83 ± 0.08 m). Subjects were mechanically ventilated in pressure support (3cmH2 O; positive end‐expiratory pressure: 3cmH2 O) at FiO2 of 21%, 50%, 85%, and 21% for 15 minutes at each FiO2 . Mean EE, oxygen consumption (VO2 ), and CO2 production (VCO2 ) were compared within and between devices across FiO2 levels. Results: Device 2 showed within‐device EE significant differences at 21% vs 50% FiO2 and device 1 for VCO2 at 50% vs. 85% FiO2 . For all variables, both devices showed reliable measurements at 21% and 50% FiO2, but at 85%, FiO2 bias and limits of agreement increased. Between devices, there were significant differences for EE at both 21% and 85% FiO2 for VO2 and for VCO2 at 85% FiO2 . Conclusion: Both systems measured EE, VO2, and VCO2 at 21%–85% FiO2 reliably but with bias at 85% FiO2 . The devices were in agreement at 21% and 50% FiO2, but further studies need to confirm accuracy at high FiO2 .