Critical Illness

CI: Best Method to Estimate RMR (2010)

Predictive Equation Formulas Used in Critically Ill Adults

Brandi Equation

HBE(0.96) + HR(7) + V_E(48) – 702

V_E = expired minute ventilation

Faisy Equation

W (8)+H (14)+V_E (32)+T (94)-4,834
 

Equation uses weight (W) in kilograms (kg) and height (H) in centimeters (cm). V_E is expired minute ventilation and T is body temperature in degrees centigrade.
 

Fick Equation
 

RMR=CO x Hb(SaO₂-SvO₂)95.18
 

Equation uses cardiac output (CO) in liters per minute (L/min), hemoglobin concentration (Hb) in mg/L, oxygen saturation of arterial blood (SaO₂) and oxygen saturation of mixed venous blood (SvO₂).
 

Harris-Benedict Equations (HBE)  
 

Men: RMR = 66.47 + 13.75 (W) + 5 (H) - 6.76 (A)
Women:  RMR = 655.1 + 9.56 (W) + 1.7 (H) - 4.7 (A)
 

Equation uses weight (W) in kilograms (kg), height (H) in centimeters (cm), and age (A) in years.
 

Ireton-Jones, 1992 Equations

Spontaneously breathing IJEE (s) = 629 - 11 (A) + 25 (W) - 609 (O)

Ventilator dependent IJEE (v) = 1925 - 10 (A) + 5 (W) + 281 (S) + 292 (T) + 851 (B) 
 

Equations use age (A) in years, body weight (W) in kilograms (kg), sex (S, male = 1, female = 0), diagnosis of trauma (T, present = 1, absent = 0), diagnosis of burn (B, present = 1, absent = 0), obesity >30% above initial body weight from 1,959 Metropolitan Life Insurance tables or body mass index (BMI) more than 27kg/m² (present = 1, absent = 0).

Ireton-Jones, 1997 Equations

Spontaneously breathing IJEE (s) = 629 - 11 (A) + 25 (W) - 609 (O)

Ventilator dependent IJEE (v) = 1784 - 11 (A) + 5 (W) + 244 (S) + 239 (T) + 804 (B) 

Equations use age (A) in years, body weight (W) in kilograms (kg), sex (S, male=1, female=0), diagnosis of trauma (T, present=1, absent=0), diagnosis of burn (B, present=1, absent=0), obesity more than 30% above initial body weight from 1959 Metropolitan Life Insurance tables or BMI higher than 27kg/m² (present=1, absent=0).

Penn State Equations (PSU)

• PSU(1998) - Invalidated in 2009

RMR = HBE(1.1) + V_E (32) + T_max (140) - 5340
[use adjusted body weight in HBE for patients with BMI>30kg/m²]
 

• PSU(2003a) - Invalidated in 2007 and 2009

RMR = HBE(0.85) + V_E (33) + T_max (175) - 6433
           [use actual weight in all patients]

• PSU(2003b) - Validated in 2009 and also referred to as Penn State Equation

RMR = Mifflin(0.96) + V_E (31) + T_max (167) - 6212

• PSU(2010) - Validated in 2010 and also referred to as Modified Penn State Equation

RMR = Mifflin(0.71) +  V_E (64) + T_max(85) - 3085
 

Mifflin-St. Jeor Equation (MSJE)

Men: RMR = (9.99 X weight) + (6.25 X height) – (4.92 X age) + 5

Women: RMR = (9.99 X weight) + (6.25 X height) – (4.92 X age) – 161
 

Equations use weight in kilograms (kg), height in centimeters (cm).

Swinamer Equation

EE = 945 (BSA) - 6.4 (age) + 108 (T) + 24.2 (breaths per minute) + 81.7 (VT) - 4,349

Equation uses body surface area (BSA) in squared meters (m²), temperature (T) in degrees Celsius, and tidal volume (VT) in liters per minute (L per minute).
 

• Assessment
  If indirect calorimetry is unavailable or impractical, what is the best way to estimate resting metabolic rate (RMR) in non-obese adult critically ill patients?

  • Conclusion

    Twenty-two papers (17 positive and five neutral research quality studies) evaluating nine predictive equations were reviewed for this evidence analysis question. Four equations were precise and unbiased in the non-obese patients. These equations and their accuracy rates in patients younger 60 years and those 60 years or older, respectively, were: PSU(2003b) (69%, 77%); Brandi equation (61%, 61%), MSJE x 1.25 (54%, 54%) and Faisy equation (65%, 37%).

    Click here to see all Predictive Equation Formulas.

  • Grade: II
    • Grade I means there is Good/Strong evidence supporting the statement;
    • Grade II is Fair;
    • Grade III is Limited/Weak;
    • Grade IV is Expert Opinion Only;
    • Grade V is Not Assignable.
    • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
    • Moderate (B) means we are moderately confident in the effect estimate;
    • Low (C) means our confidence in the effect estimate is limited;
    • Very Low (D) means we have very little confidence in the effect estimate.
    • Ungraded means a grade is not assignable.
  • Evidence Summary: If indirect calorimetry is unavailable or impractical, what is the best way to estimate resting metabolic rate (RMR) in non-obese adult critically ill patients?
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • Alexander E, Susla GM, Burstein AH, Brown DT, Ognibene FP. Retrospective evaluation of commonly used equations to predict energy expenditure in mechanically ventilated, critically ill patients. Pharmacotherapy. 2004; 24(12): 1,659-1,667.
      • Boullata J, Williams J, Cottrell F, Hudson L, Compher C. Accurate determination of energy needs in hospitalized patients. J Am Diet Assoc. 2007; 107: 393-401.
      • Casati A, Colombo S, Leggieri C, Muttini S, Capocasa T, Gallioli G. Measured versus calculated energy expenditure in pressure support ventilated ICU patients. Minerva Anestesiol. 1996; 62 (5): 165-170.
      • Cheng CH, Chen CH, Wong Y, Lee BJ, Kan MN, Huang YC. Measured versus estimated energy expenditure in mechanically ventilated critically ill patients. Clin Nutr. 2002; 21 (2): 165-172.
      • Epstein CD, Peerless JR, Martin JE, Malangoni MA. Comparison of methods of measurements of oxygen consumption in mechanically ventilated patients with multiple trauma: The Fick method vs. indirect calorimetry. Crit Care Med. 2000; 28(5): 1,363-1,369. 
      • Faisy C, Guerot E, Diehl JL, Labrousse J, Fagon JY.  Assessment of resting energy expenditure in mechanically ventilated patients. Am J Clin Nutr. 2003; 78: 241-249. 
      • Frankenfield DC, Coleman A, Alam S, Cooney R. Analysis of estimation methods for resting metabolic rate in critically ill adults. J Parenter Enteral Nutr. 2009; 33: 27.
      • Savard JF. Faisy C. Lerolle N. Guerot E. Diehl JL. Fagon JY. Validation of a predictive method for an accurate assessment of resting energy expenditure in medical mechanically ventilated patients. Critical Care Medicine. 2008; 36(4): 1,175-1,183.
      • Stucky CC, Moncure M, Hise M, Gossage CM, Northrop D. How accurate are resting energy expenditure prediction equations in obese trauma and burn patients? J Parenter Enteral Nutr. 2008 Jul-Aug; 32(4): 420-426.
  • Search Plan and Results: CI: Determination of RMR 2009
     
  If indirect calorimetry is unavailable or impractical, what is the best way to estimate resting metabolic rate (RMR) in obese adult critically ill patients?

  • Conclusion

    Eight studies (five positive quality and three neutral quality) compared measured resting metabolic rate (RMR) with RMR predicted by several equations in critically ill patients with obesity.  The Penn State equation [PSU(2003b)] worked best and predicted RMR with 70% accuracy in obese patients. For a subset of obese critically ill patients ≥60 years old, a modified Penn State equation [PSU(2010)] predicted RMR with 74% accuracy. All other predictive equations tested had lower accuracy rates.

    Click here to see all Predictive Equation Formulas.

     

  • Grade: II
    • Grade I means there is Good/Strong evidence supporting the statement;
    • Grade II is Fair;
    • Grade III is Limited/Weak;
    • Grade IV is Expert Opinion Only;
    • Grade V is Not Assignable.
    • High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
    • Moderate (B) means we are moderately confident in the effect estimate;
    • Low (C) means our confidence in the effect estimate is limited;
    • Very Low (D) means we have very little confidence in the effect estimate.
    • Ungraded means a grade is not assignable.
  • Evidence Summary: If indirect calorimetry is unavailable or impractical, what is the best way to estimate resting metabolic rate (RMR) in obese adult critically ill patients?
    • Detail
    • Quality Rating Summary
      For a summary of the Quality Rating results, click here.
    • Worksheets
      • Anderegg BA, Worrall C, Barbour E, Simpson KN, Delegge M. Comparison of resting energy expenditure prediction methods with measured resting energy expenditure in obese, hospitalized adults. J Parenter Enteral Nutr. 2009 Mar-Apr; 33(2): 168-175.
      • Boullata J, Williams J, Cottrell F, Hudson L, Compher C. Accurate determination of energy needs in hospitalized patients. J Am Diet Assoc. 2007; 107: 393-401.
      • Frankenfield David. Validation of an equation for resting metabolic rate in older obese critically ill patients. JPEN. 2010 (in press).
      • Frankenfield DC, Coleman A, Alam S, Cooney R. Analysis of estimation methods for resting metabolic rate in critically ill adults. J Parenter Enteral Nutr. 2009; 33: 27.
  • Search Plan and Results: CI: Determination of RMR 2009