A Validation and Comparison Study of Two Metabolic Monitors

Two portable metabolic cart systems of indirect calorimetry (Deltatrac Metabolic Monitor, 2900 MMC System) were validated. CO 2 and N 2 were delivered at precise rates into a constructed lung model to simulate CO 2 production (VCO 2 ) and O 2 consumption (VO 2 ). VCO 2 (200–400 ml/min) and VO 2 (250–750 ml/min) were measured at varying combinations of minute ventilation (VE) (6, 10, 20 liter/min) and FiO 2 (0.21, 0.30, 0.60, 0.80). VCO 2 was measured with overall errors of 1.5% and 2.4% for the Deltatrac and 2900 monitors, respectively. VO 2 was measured with overall errors of 1.9% and 3.2% by the Deltatrac and 2900 monitors, respectively. Both monitors performed equally well for measurement of VO 2 at FiO 2 up to 0.6, but the Deltatrac had less error for measurements of VO 2 at FiO 2 of 0.8. (Journal of Parenteral and Enteral Nutrition 14: 259–261, 1990)