Multiple propane gas flow rates procedure to determine accuracy and linearity of indirect calorimetry systems : An experimental assessment of a method.
- Published
- Accepted
- Subject Areas
- Bioengineering, Nutrition, Metabolic Sciences
- Keywords
- indirect calorimetry, propane gas, energy production, Accuracy, linearity
- Copyright
- © 2019 Ismail et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Multiple propane gas flow rates procedure to determine accuracy and linearity of indirect calorimetry systems : An experimental assessment of a method. PeerJ Preprints 7:e27550v1 https://doi.org/10.7287/peerj.preprints.27550v1
Abstract
Objective: Indirect calorimetry (IC) systems measure the fractions of expired carbon dioxide (FECO2) and oxygen (FEO2) recorded at the mouth in order to estimate whole body energy production (EP). The fundamental principal of IC relates to oxidative mechanisms, expressed as rate of oxygen uptake (V̇O2) and carbon dioxide production (V̇CO2). From these volumes we calculate energy production and respiratory exchange ratio which is used to estimate substrate utilization rates. The accuracy of IC systems is critical to detect small changes in respiratory gas exchanges. The aim of this technical report was to assess the accuracy and linearity of IC systems using multiple propane gas flow rates procedure. Approach: A series of propane gas with different flow rates and ventilation rates were run on three different IC systems. The actual experimental V̇O2 and V̇CO2 were calculated and compared to stoichiometry theoretical values. Results: showed a linear relationship between gas volumes (V̇O2 and V̇CO2) and propane gas flows (99.6%, 99.2%, 94.8% for the Sable, Moxus, and Jaeger metabolic carts, respectively). In terms of system error, Jaeger system had significantly (p < 0.001) greater V̇O2 (M = -0.057, SE = 0.004), and V̇CO2 (M = -0.048, SE = 0.002) error compared to either the Sable (V̇O2, M = 0.044, SE = 0.004; V̇CO2, M = 0.024, SE = 0.002) or the Moxus (V̇O2, M = 0.046, SE = 0.004; V̇CO2, M = 0.025, SE = 0.002) metabolic carts. There were no significant differences between the Sable or Moxus metabolic carts. Conclusion: The multiple flow rates approach permitted the assessment of linearity of IC systems in addition to determining the accuracy of fractions of expired gases.
Author Comment
This method article describes a complementary propane gas calibration procedure to assess accuracy and linearity of indirect calorimetry (IC) systems. The IC systems output must yield accurate fraction of gases for the computation of V̇O2 and V̇CO2 and EP in the field of medicine, nutrition, and exercise sciences. We recommend using the described propane gas mass flow calibration procedure to assess the linearity of IC sensors responses.