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Determining the Accuracy and Reliability of Indirect Calorimeters Utilizing the Methanol Combustion Technique

Kaviani, Sepideh ; Schoeller, Dale A. ; Ravussin, Eric ; Melanson, Edward L. ; Henes, Sarah T. ; Dugas, Lara R. ; Dechert, Ronald E. ; Mitri, George ; Schoffelen, Paul F.M. and Gubbels, Pim , et al. (2018) In Nutrition in Clinical Practice 33(2). p.206-216
Abstract

Background: Several indirect calorimetry (IC) instruments are commercially available, but comparative validity and reliability data are lacking. Existing data are limited by inconsistencies in protocols, subject characteristics, or single-instrument validation comparisons. The aim of this study was to compare accuracy and reliability of metabolic carts using methanol combustion as the cross-laboratory criterion. Methods: Eight 20-minute methanol burn trials were completed on 12 metabolic carts. Respiratory exchange ratio (RER) and percent O2 and CO2 recovery were calculated. Results: For accuracy, 1 Omnical, Cosmed Quark CPET (Cosmed), and both Parvos (Parvo Medics trueOne 2400) measured all 3 variables within 2%... (More)

Background: Several indirect calorimetry (IC) instruments are commercially available, but comparative validity and reliability data are lacking. Existing data are limited by inconsistencies in protocols, subject characteristics, or single-instrument validation comparisons. The aim of this study was to compare accuracy and reliability of metabolic carts using methanol combustion as the cross-laboratory criterion. Methods: Eight 20-minute methanol burn trials were completed on 12 metabolic carts. Respiratory exchange ratio (RER) and percent O2 and CO2 recovery were calculated. Results: For accuracy, 1 Omnical, Cosmed Quark CPET (Cosmed), and both Parvos (Parvo Medics trueOne 2400) measured all 3 variables within 2% of the true value; both DeltaTracs and the Vmax Encore System (Vmax) showed similar accuracy in measuring 1 or 2, but not all, variables. For reliability, 8 instruments were shown to be reliable, with the 2 Omnicals ranking best (coefficient of variation [CV] < 1.26%). Both Cosmeds, Parvos, DeltaTracs, 1 Jaeger Oxycon Pro (Oxycon), Max-II Metabolic Systems (Max-II), and Vmax were reliable for at least 1 variable (CV ≤ 3%). For multiple regression, humidity and amount of combusted methanol were significant predictors of RER (R2 = 0.33, P <.001). Temperature and amount of burned methanol were significant predictors of O2 recovery (R2 = 0.18, P <.001); only humidity was a predictor for CO2 recovery (R2 = 0.15, P <.001). Conclusions: Omnical, Parvo, Cosmed, and DeltaTrac had greater accuracy and reliability. The small number of instruments tested and expected differences in gas calibration variability limits the generalizability of conclusions. Finally, humidity and temperature could be modified in the laboratory to optimize IC conditions.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
accuracy, energy metabolism, indirect calorimetry, metabolic cart, methanol, reliability
in
Nutrition in Clinical Practice
volume
33
issue
2
pages
11 pages
publisher
Wiley-Blackwell
external identifiers
  • pmid:29658183
  • scopus:85045530724
ISSN
0884-5336
DOI
10.1002/ncp.10070
project
Träning och tester inom idrott och hälsa
language
English
LU publication?
yes
id
2bbd178c-0025-46c0-999b-f0e3d6a8ffd9
date added to LUP
2018-04-27 14:09:43
date last changed
2024-03-01 18:17:56
@article{2bbd178c-0025-46c0-999b-f0e3d6a8ffd9,
  abstract     = {{<p>Background: Several indirect calorimetry (IC) instruments are commercially available, but comparative validity and reliability data are lacking. Existing data are limited by inconsistencies in protocols, subject characteristics, or single-instrument validation comparisons. The aim of this study was to compare accuracy and reliability of metabolic carts using methanol combustion as the cross-laboratory criterion. Methods: Eight 20-minute methanol burn trials were completed on 12 metabolic carts. Respiratory exchange ratio (RER) and percent O<sub>2</sub> and CO<sub>2</sub> recovery were calculated. Results: For accuracy, 1 Omnical, Cosmed Quark CPET (Cosmed), and both Parvos (Parvo Medics trueOne 2400) measured all 3 variables within 2% of the true value; both DeltaTracs and the Vmax Encore System (Vmax) showed similar accuracy in measuring 1 or 2, but not all, variables. For reliability, 8 instruments were shown to be reliable, with the 2 Omnicals ranking best (coefficient of variation [CV] &lt; 1.26%). Both Cosmeds, Parvos, DeltaTracs, 1 Jaeger Oxycon Pro (Oxycon), Max-II Metabolic Systems (Max-II), and Vmax were reliable for at least 1 variable (CV ≤ 3%). For multiple regression, humidity and amount of combusted methanol were significant predictors of RER (R<sup>2</sup> = 0.33, P &lt;.001). Temperature and amount of burned methanol were significant predictors of O<sub>2</sub> recovery (R<sup>2</sup> = 0.18, P &lt;.001); only humidity was a predictor for CO<sub>2</sub> recovery (R<sup>2</sup> = 0.15, P &lt;.001). Conclusions: Omnical, Parvo, Cosmed, and DeltaTrac had greater accuracy and reliability. The small number of instruments tested and expected differences in gas calibration variability limits the generalizability of conclusions. Finally, humidity and temperature could be modified in the laboratory to optimize IC conditions.</p>}},
  author       = {{Kaviani, Sepideh and Schoeller, Dale A. and Ravussin, Eric and Melanson, Edward L. and Henes, Sarah T. and Dugas, Lara R. and Dechert, Ronald E. and Mitri, George and Schoffelen, Paul F.M. and Gubbels, Pim and Tornberg, Asa and Garland, Stephen and Akkermans, Marco and Cooper, Jamie A.}},
  issn         = {{0884-5336}},
  keywords     = {{accuracy; energy metabolism; indirect calorimetry; metabolic cart; methanol; reliability}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{2}},
  pages        = {{206--216}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Nutrition in Clinical Practice}},
  title        = {{Determining the Accuracy and Reliability of Indirect Calorimeters Utilizing the Methanol Combustion Technique}},
  url          = {{http://dx.doi.org/10.1002/ncp.10070}},
  doi          = {{10.1002/ncp.10070}},
  volume       = {{33}},
  year         = {{2018}},
}