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VCO2 calorimetry: stop tossing stones, it’s time for building!

The Original Article was published on 22 October 2015

We followed with interest the discussion [1, 2] fueled by the study of Stapel et al. [3] who reported fairly accurate assessment of energy expenditure (EE) in critically ill patients based on ventilator-derived carbon dioxide production (VCO2). The proposed technique is elegant and valid but has inherent limitations. It is applicable in patients who are in one way or another ventilator-dependent but not in spontaneously breathing yet oxygen-dependent subjects. We concur that VO2 is the most relevant variable for EE measurement. However, the most accurate and precise estimation of EE in a critically ill population can only be obtained by sampling of inspired and expired oxygen/carbon dioxide concentrations and measuring expired gas flow. This is the core task of indirect calorimetry [4].

Initiative has been undertaken to develop a ‘full option’, easy-to-use, accurate, and affordable indirect calorimeter. The project is supported by the European Society of Intensive Care Medicine and the European Society of Parenteral and Enteral Nutrition [5] and has actually reached Technology Readiness Level. It is probably only a matter of time before such a device will render all current mathematical uproar obsolete.



Energy expenditure

VCO2 :

Carbon dioxide production


  1. 1.

    Singer P. Simple equations for complex physiology: can we use VCO2 for calculating energy expenditure? Crit Care. 2016;20:72.

    Article  PubMed  PubMed Central  Google Scholar 

  2. 2.

    Pielmeier U, Andreassen S. VCO2 calorimetry is a convenient method for improved assessment of energy expenditure in the intensive care unit. Crit Care. 2016;20:224.

    Article  PubMed  PubMed Central  Google Scholar 

  3. 3.

    Stapel SN, de Grooth HJS, Alimohamad H, Elbers PW, Girbes AR, Weijs PJ, et al. Ventilator-derived carbon dioxide production to assess energy expenditure in critically ill patients: proof of concept. Crit Care. 2015;19:370.

    Article  PubMed  PubMed Central  Google Scholar 

  4. 4.

    Frankenfield DC. On heat, respiration, and calorimetry. Nutrition. 2010;26(10):939–50.

    Article  PubMed  Google Scholar 

  5. 5.

    Oshima T, Berger MM, De Waele E, Guttormsen AB, Heidegger CP, Hiesmayr M, et al., A position paper by the ICALIC study group. Indirect calorimetry in nutritional therapy. Clin Nutr. 2016;(16):30142-X.

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EDW designed the paper; EDW, PMH, and HDS participated in drafting the manuscript, and have read and approved the final version.

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The authors declare that they have no competing interests.

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Correspondence to Elisabeth De Waele.

Additional information

See related research by Stapel et al.

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De Waele, E., Honoré, P.M. & Spapen, H.D. VCO2 calorimetry: stop tossing stones, it’s time for building!. Crit Care 20, 399 (2016).

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  • Energy expenditure
  • Nutrition
  • Intensive care unit