Indirect Calorimetry VO2 (mL/min) VCO2 (mL/min) Energy Expenditure kCal/d Respiratory Quotient NB : precision is limited when FiO2>0.5. Estimation of Qualitative Expenditure : Carbohydrates g/d Lipids g/d Estimations based on Single Parameter : Expenditure estimated from VO2 kCal/d Expenditure estimated from VCO2 kCal/d