Fig. 2

Correlation and agreement between the methods used to assess energy expenditure (EE) and gold standard indirect calorimetry. a Regression plots showing the correlation between the different methods used to assess EE and gold standard indirect calorimetry. b Bland–Altman plots showing the agreement between the methods used to assess EE and gold standard indirect calorimetry. The solid lines indicate the bias (mean difference with indirect calorimetry). The thick dashed lines indicate the limits of agreement (bias ±2 standard deviations). Every dot represents 1 of 84 patients. The x-axis represents the mean of the method used to assess EE and gold standard indirect calorimetry. The y-axis represents the difference in EE in kilocalories per 24 h between the method used and gold standard indirect calorimetry. EE:Esp25, Energy expenditure calculated with the European Society for Clinical Nutrition and Metabolism guideline equation of 25 kcal/kg/day; EE:Faisy, Energy expenditure calculated with the Faisy equation; EE:HB, Energy expenditure calculated with the Harris–Benedict equation; EE:PSU, Energy expenditure calculated with the Penn State University 2003b equation; EE:VCO₂, Energy expenditure from ventilator-derived volume of carbon dioxide and nutritional respiratory quotient