Table 1.
Predictive equations for REE
| Equations | Formula |
|---|---|
| ACCP equation | = 25 × weight If BMI is in the range of 16–25 kg/m2, use usual BW If BMI > 25 kg/m2, use IBW If BMI < 16 kg/m2, use existing BW for the first 7–10 d, and then use IBW |
| HBE | Men: kcal/d = 66.47 + 13.75 (w) + 5 (h) − 6.75 (a) Women: kcal/d = 655.1 + 9.56 (w) + 1.85 (h) − 4.68 (a) w = actual weight (kg); but if >125% IBW, use ABW ABW = [(actual body weight − IBW) × (0.25 to 0.5)] + IBW |
| MSJ equation | Men: kcal/d = 10 (w) + 6.25 (h) − 5 (a) + 5 Women: kcal/d = 10 (w) + 6.25 (h) − 5 (a) − 161 |
| Ireton-Jones 1992 equation | 1925 − 10 (a) + 5 (w) + 281 (S) + 292 (T) + 851 (B) |
| Ireton-Jones 2002 equation | 1784 − 11 (a) + 5 (w) + 244 (S) + 239 (T) + 804 (B) |
| Penn State 2003 equation | Harris–Benedict: kcal/d = 0.85 (HBE) + 175 (Tmax) + 33 (Ve) − 6433 Mifflin: kcal/d = 0.96 (MSJ) + 167 (Tmax) + 31 (Ve) − 6212 |
| Penn State 2010 equation | MSJ (0.71) + Ve (64) + Tmax (85) − 3085 |
| Swinamer 1990 equation | (945 × BSA) − (6.4 × age) + (108 × BT) + (24.2 × RR) + (817 × VT) − 4349 |
| Faisy equation | 8 (w) + 14 (h) + 42 (Ve) + 94 (BT) − 4834 |
| Brandi 1999 equation | 0.96 (HBE) + 7 (HR) + 48 (Ve) − 702 |
| Equation commonly used in critical illness | 25 kcal/kg actual body weight including 1–1.5 g protein/kg |
[i] The clinical variables such as HR, minute ventilation, BT, etc. were chosen from the same period of measured REE.
[ii] a, age; ABW, adjusted body weight; ACCP, American College of Chest Physicians; B, burn (yes = 1, no = 0); BMI, body mass index; BSA, body surface area; BT, body temperature; h, height; HBE, Harris–Benedict equation; HR, heart rate; IBW, ideal body weight; MSJ, Mifflin–St. Jeor; RR, respiratory rate; REE, resting energy expenditure; S, sex (male = 1, female = 0); T, trauma (yes = 1, no = 0); Tmax, maximal body temperature; Ve, minute ventilation; VT, tidal volume; w, weight.
Figure 1.
Flow of participants.
Table 2.
Baseline characteristics of the patients
| Baseline characteristics | |
|---|---|
| Sex n (%) | |
| Male | 12 (50) |
| Age | |
| Median (years) | 64.5 [43.50, 75.50] |
| Height | |
| Median (cm) | 160 [151.0, 167.0] |
| Median (kg) | |
| Median (cm) | 62.5 [47.75, 85.50] |
| BMI n (%) | 27 (100) |
| Underweight (<18.5 kg/m2) | 6 (25) |
| Normal (18.5–22.9 kg/m2) | 7 (29.2) |
| Overweight (23–24.9 kg/m2) | 0 (0) |
| Obese 1 (25–29.9 kg/m2) | 1 (4.2) |
| Obese 2 (>30 kg/m2) | 10 (41.7) |
| BSA (Dubois) median (m2) | 1.7 [1.46, 1.86] |
| Cause of respiratory failure n (%) | |
| Pneumonia | 4 (16.7) |
| Post ARDS | 3 (12.5) |
| COPD | 2 (8.3) |
| Chronic lung disease | 1 (4.2) |
| Sepsis | 2 (8.3) |
| Cardiac arrest | 1 (4.2) |
| Heart failure | 2 (8.3) |
| Tetanus | 1 (4.2) |
| Others | 8 (33.3) |
| Ventilator mode n (%) | |
| Volume control | 3 (10) |
| Pressure control | 6 (20) |
| Pressure support | 20 (66.7) |
| Proportional assist ventilation | 1 (3.3) |
| Measured REE median (kcal/d) | |
| Total | 1553.0 [1126.75, 2065.75] |
| Underweight (<18.5 kg/m2) | 1044.0 [884.50, 1591.50] |
| Normal (18.5–22.9 kg/m2) | 1545.0 [1125.75, 1981.00] |
| Overweight (23–24.9 kg/m2) | – |
| Obese 1 (25–29.9 kg/m2) | 1475.0 [1475.00, 1475.00] |
| Obese 2 (>30 kg/m2) | 2043.5 [1525.25, 2329.50] |
| Average measured calories per actual BW (kcal/kg) | 23.5 |
| Average measured calories per BW (kcal/kg) | 27 |
| Use actual BW if BMI <30 kg/m2 | |
| Use adjusted BW if BMI ≥ 30 kg/m2 | |
| Average measured calories per IBW (kcal/kg) | 29.5 |
| REE calculated by predictive equations median (kcal/d) | |
| ACCP | 1255.0 [1050.00, 1423.00] |
| HBE | 1180.5 [1078.89, 1518.95] |
| 1.2×HBE | 1424.3 [1292.80, 1752.98] |
| 1.5×HBE | 1780.4 [1615.99, 2191.23] |
| MSJ | 1250.0 [1012.25, 1522.50] |
| Ireton-Jones 1992 | 1688.0 [1585.00, 2042.25] |
| Ireton-Jones 2002 | 1479.5 [1373.25, 1957.00] |
| Penn State 2003 (HBE) | 1523.5 [1270.24, 1734.94] |
| Penn State 2003 (MSJ) | 1516.5 [1182.04, 1905.00] |
| Penn State 2010 | 1542.4 [1310.89, 1846.61] |
| Swinamer 1990 | 1740.0 [1502.28, 2115.50] |
| Faisy | 1840.4 [1576.60, 2155.20] |
| Brandi 1999 | 1547.3 [1302.86, 1794.43] |
| Equation commonly used in critical illness (25 kcal/kg) | 1562.5 [1225.00, 2400.00] |
[i] ACCP, American College of Chest Physicians equation; ARDS, acute respiratory distress syndrome; BMI, body mass index; BSA, body surface area; BW, body weight; COPD, chronic obstructive pulmonary disease; HBE, Harris–Benedict equation; IBW, ideal body weight; MSJ, Mifflin–St. Jeor; REE, resting energy expenditure.
Table 3.
Accuracy of predictive equations
| Mean | Minimum | Maximum | ||||||
|---|---|---|---|---|---|---|---|---|
| ACCP | 30 | 23.3 | 60.0 | 16.7 | −13.0 | −320 | −1257 | 617 |
| HBE | 30 | 30.0 | 60.0 | 10.0 | −4.0 | −99 | −1063 | 930 |
| 1.2×HBE | 30 | 31.8 | 21.3 | 40.9 | 3.2 | −49 | −742 | 631 |
| 1.5×HBE | 30 | 18.2 | 9.1 | 72.7 | 29.0 | 322 | −476 | 979 |
| MSJ | 30 | 33.3 | 50.0 | 16.7 | −10.8 | −200 | −1172 | 919 |
| Ireton-Jones 1992 | 30 | 6.7 | 23.3 | 70.0 | 22.2 | 233 | −812 | 923 |
| Ireton-Jones 2002 | 30 | 26.7 | 23.3 | 50.0 | 8.0 | 43 | −1018 | 665 |
| Penn State 2003 (HBE) | 24 | 25.0 | 50.0 | 25.0 | 1.6 | −88 | −740 | 837 |
| Penn State 2003 (MSJ) | 27 | 37.0 | 22.2 | 40.7 | 9.6 | 100 | −502 | 1056 |
| Penn State 2010 | 27 | 48.1 | 14.8 | 37.0 | 11.6 | 98 | −472 | 1089 |
| Swinamer 1990 | 27 | 18.5 | 11.1 | 70.4 | 25.9 | 295 | −336 | 1191 |
| Faisy equation | 27 | 25.9 | 0.0 | 74.1 | 31.8 | 366 | −176 | 1397 |
| Brandi 1999 | 22 | 22.7 | 27.3 | 50.0 | 13.6 | 74 | −549 | 1115 |
| 25 kcal/kg | 30 | 30.0 | 20.0 | 50.0 | 25.2 | 440 | −933 | 4030 |
[i] ACCP, American College of Chest Physicians equation; Accurate prediction%, percentage of patients who had predictive values within 90% and 110% of measured values; Bias%, mean percentage error between predictive equations and measured value; HBE, Harris–Benedict equation; Mean bias, difference between predictive and measured values; MSJ, Mifflin–St. Jeor; Overestimation%, percentage of patients who had predictive values of more than 110% of measured values; Underestimation%, percentage of patients who had predictive values of less than 90% of measured values.
Table 4.
Sensitivity analysis for the accuracy of predictive equations
| Mean | Minimum | Maximum | |||||
|---|---|---|---|---|---|---|---|
| ACCP | 22.7 | 54.5 | 22.7 | −10.2 | −272.4 | −1091.0 | 617.0 |
| HBE | 27.3 | 59.1 | 13.6 | 14.02 | 296.7 | −987.1 | 399.7 |
| 1.2×HBE | 31.8 | 27.3 | 40.9 | 3.18 | −49.1 | −742.1 | 631.3 |
| 1.5×HBE | 18.2 | 9.1 | 72.7 | 29.0 | 322.3 | −475.7 | 978.6 |
| MSJ | 36.4 | 50.0 | 13.6 | −9.3 | −183.3 | −773.0 | 490.8 |
| Ireton-Jones 1992 | 9.1 | 18.2 | 72.7 | 25.0 | 275.5 | −421.0 | 923.0 |
| Ireton-Jones 2002 | 22.7 | 27.3 | 50.0 | 8.8 | 53.4 | −662.0 | 665.0 |
| Penn State 2003 (HBE) | 22.7 | 50.0 | 27.3 | 2.6 | −76.1 | −739.9 | 837.1 |
| Penn State 2003 (MSJ) | 27.3 | 27.3 | 45.5 | 9.6 | 73.0 | −501.7 | 944.4 |
| Penn State 2010 | 40.9 | 18.2 | 40.9 | 12.1 | 82.6 | −471.9 | 1088.6 |
| Swinamer 1990 | 18.2 | 13.6 | 68.2 | 25.9 | 276.6 | −335.2 | 1190.8 |
| Faisy equation | 27.3 | 0.0 | 72.7 | 32.4 | 353.5 | −176.0 | 1397.2 |
| Brandi 1999 | 23.5 | 29.4 | 47.1 | 14.1 | 61.4 | −548.6 | 1115.4 |
| 25 kcal/kg | 31.8 | 18.2 | 50.0 | 20.6 | 318.5 | −933.0 | 1867.0 |
[i] ACCP, American College of Chest Physicians equation; Accurate prediction%, percentage of patients who had predictive values within 90% and 110% of measured values; Bias%, mean percentage error between predictive equations and measured value; HBE, Harris–Benedict equation; Mean bias, difference between predictive and measured values; MSJ, Mifflin–St. Jeor; Overestimation%, percentage of patients who had predictive values of more than 110% of measured values; Underestimation%, percentage of patients who had predictive values of less than 90% of measured values.
Figure 2.
Accuracy of predictive equations for estimating REE in obese and non-obese patients. REE, resting energy expenditure.
Figure 3.
Bland–Altman plots of differences between predictive REE calculated by 14 equations and measured REE (predictive REE – measured REE) in 24 mechanically ventilated Thai patients. The solid lines at the middle part of each picture represent mean differences of compared values and the upper and lower solid lines represent upper and lower limits of agreement (LOA) (±1.96 SD from mean). The points on these plots non-uniformly and widely scatter around mean differences, indicating poor agreement and bias. REE, resting energy expenditure; SD, standard deviation.
Table 5.
Correlation and agreement between measured REE and predictive REE
| Mean bias | SD | Lower LOA Mean – 1.96 (SD) | Upper LOA Mean + 1.96 (SD) | ||
|---|---|---|---|---|---|
| ACCP | 0.445 | −320 | 457 | −1217 | 576 |
| HBE | 0.675 | −99 | 464 | −1008 | 810 |
| 1.2×HBE | 0.566 | −49 | 355 | −744 | 646 |
| 1.5×HBE | 0.566 | 322 | 358 | −379 | 1023 |
| MSJ | 0.736 | −200 | 429 | −1041 | 641 |
| Ireton-Jones 1992 | 0.624 | 233 | 427 | −603 | 1070 |
| Ireton-Jones 2002 | 0.666 | 43 | 402 | −745 | 831 |
| Penn State 2003 (HBE) | 0.714 | −88 | 367 | −807 | 631 |
| Penn State 2003 (MSJ) | 0.767 | 100 | 369 | −623 | 823 |
| Penn State 2010 | 0.771 | 98 | 312 | −513 | 709 |
| Swinamer 1990 | 0.708 | 295 | 335 | −363 | 952 |
| Faisy equation | 0.778 | 366 | 333 | −287 | 1019 |
| Brandi 1999 | 0.587 | 74 | 394 | −698 | 846 |
| 25 kcal/kg | 0.675 | 439 | 1019 | −4377 | 2457 |
[i] ACCP, American College of Chest Physicians equation; HBE, Harris–Benedict equation; LOA, limits of agreement; MSJ, Mifflin–St. Jeor; REE, resting energy expenditure; SD, standard deviation.
Table 6.
The ICC of 14 equations
| Lower bound | Upper bound | |||
|---|---|---|---|---|
| ACCP | 0.324 | −0.338 | 0.692 | 0.136 |
| HBE | 0.608 | −0.023 | 0.845 | 0.003 |
| 1.2×HBE | 0.764 | 0.430 | 0.902 | <0.001 |
| 1.5×HBE | 0.686 | 0.017 | 0.886 | <0.001 |
| MSJ | 0.809 | 0.515 | 0.923 | <0.001 |
| Ireton-Jones 1992 | 0.723 | 0.204 | 0.894 | <0.001 |
| Ireton-Jones 2002 | 0.800 | 0.519 | 0.917 | <0.001 |
| Penn State 2003 (HBE) | 0.672 | 0.217 | 0.863 | 0.007 |
| Penn State 2003 (MSJ) | 0.843 | 0.626 | 0.934 | <0.001 |
| Penn State 2010 | 0.814 | 0.561 | 0.922 | <0.001 |
| Swinamer 1990 | 0.715 | 0.155 | 0.893 | <0.001 |
| Faisy equation | 0.643 | −0.123 | 0.873 | <0.001 |
| Brandi 1999 | 0.608 | −0.104 | 0.859 | 0.039 |
| 25 kcal/kg | 0.701 | 0.295 | 0.875 | 0.002 |
[i] ACCP, American College of Chest Physicians equation; HBE, Harris–Benedict equation; ICC, Intraclass correlation coefficient; MSJ, Mifflin–St. Jeor. The ICC values of less than 0.5, between 0.5 and 0.75, between 0.75 and 0.9, and greater than 0.90 are indicative of poor, moderate, good, and excellent reliability, respectively.