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Table 3 Comparison of EE estimates to IC including sensitivity of EE(VCO2) reliance on RQ

From: Energy expenditure in critically ill patients estimated by population-based equations, indirect calorimetry and CO2-based indirect calorimetry

Equation Mean EE (bias) (kcal/day) SF Range of estimation differences RMSE of EE difference # Of patients with accurate EE estimates (%)
ACCP 1889 (−20 %)* NA [−49 %; 22 %] 28 % 6 (33 %)
Harris–Benedict 2347 (0 %) 1.55 [−20 %; 61 %] 16 % 9 (50 %)
Harris–Benedict, IBM 2347 (0 %) 1.67 [−23 %; 76 %] 18 % 8 (35 %)
Mifflin St Jeor 2347 (0 %) 1.59 [−18 %; 68 %] 15 % 9 (50 %)
Penn State 1 1782 (−24 %)* NA [−41 %; 0 %] 27 % 1 (6 %)
Penn State 2 1572 (−33 %)* NA [−49 %; −10 %] 35 % 1 (6 %)
Penn State 3 1637 (−30 %)* NA [−43 %; −9 %] 32 % 1 (6 %)
EE(VCO2) RQ = 0.81 2332 (−1 %) NA [−13 %; 14 %] 7 % 16 (89 %)
EE(IC) 2347 (0 %) NA
Sensitivity analysis of RQ      
 EE(VCO2) RQ = 0.70 2626 (12 %)* NA [−2 %; 30 %] 12 % 9 (50 %)
 EE(VCO2) RQ = 0.76 2455 (5 %)* NA [−8 %; 20 %] 8 % 14 (78 %)
 EE(VCO2) RQ = 0.85 2244 (−4 %) NA [−16 %; 10 %] 6 % 16 (89 %)
 EE(VCO2) RQ = 0.89 2163 (−8 %)* NA [−19 %; 6 %] 10 % 10 (56 %)
 EE(VCO2) RQ = 1.00 1976 (−16 %)* NA [−26 %; −3 %] 17 % 4 (22 %)
  1. The bias in percent is relative to the mean EE(IC). The range of estimation differences is the maximum and minimum difference between the equations and individual mean EE(IC). The RMSE of EE difference is the root mean square error of EE difference between the equations and the IC measurements. Accurate EE estimates are defined as per-patient mean EE within ±10 % of EE(IC)
  2. * Significantly different from mean EE(IC)
  3. Significantly greater variance than EE(VCO2) RQ = 0.81
  4. Significantly different from EE(VCO2) RQ = 0.81