Evaluation of three indirect calorimetry devices in mechanically ventilated patients: Which device compares best with the Deltatrac II®? A prospective observational study

Background & aims: Indirect calorimetry (IC) is the gold standard to measure energy expenditure (EE) in hospitalized patients. The popular 30 year-old Deltatrac II(R) (Datex) IC is no more commercialized, but other manufacturers have developed new devices. This study aims at comparing for the first time simultaneously, two new IC, the CCM express(R) (Medgraphics) and the Quark RMR(R) (Cosmed) with the Deltatrac II(R) to assess their potential use in intensive care unit (ICU) patients. Methods: ICU patients on mechanical ventilation, with positive end-expiratory pressure <9 cm H2O and fraction of inspired oxygen <60%, underwent measurements by the three IC simultaneously connected during 20 min to the ventilator (Evita XL, Drager). Patients' characteristics, VO2 consumption, VCO2 production, respiratory quotient and EE were recorded. Data were presented as mean (SD) and compared by linear regression, repeated measure one-way ANOVA and Bland & Altman diagrams. Results: Forty patients (23 males, 60(17) yrs, BMI 25.4(7.0) kg/m(2)) were included. For the Deltatrac II(R), VO2 was 227(61) ml/min, VCO2 189(52) ml/min and EE 1562(412) kcal/d. VO2, VCO2, and EE differed significantly between Deltatrac II(R) and CCM express(R) (p < 0.001), but not between Deltatrac II(R) and Quark RMR(R). For EE, diagrams showed a mean difference (2SD) of 25.2(441) kcal between Deltatrac II(R) vs. the Quark RMR(R), and -273 (532) kcal between Deltatrac II(R) vs CCM express(R). Conclusion: Quark RMR(R) compares better with Deltatrac II(R) than CCM express(R), but it suffers an EE variance of 441 kcal, which is not acceptable for clinical practice. New indirect IC should be further improved before recommending their clinical use in ICU. (C) 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.