Estimation of Energy ExpendituresManual of Clinical Nutrition Management II- 13 Copyright © 2013 Compass Group, Inc.
The formulas described below are considered the most reliable and valid formulas used for patients in the
critical care and hospital setting (2,3,9,10). These equations have easily measured variables (height, weight, age,
gender, diagnosis, presence of obesity, and ventilatory status) that are used in the equation to estimate RMR.
. The variables in these some of the equations take into account the health,mobility status, and ventilator
status of a critical care patient. The common practice of multiplying additional physical activity level (PAL)
factors or injury factors is not validated with these formulas unless specified (3,10). All equations described
below were developed using actual weight (3). At this time there is no evidence that substituting adjusted or
ideal weight in these calculations results in improved accuracy (2, 3, 9).
Penn State equations (3):
The latest version referred to as Penn State Equation (PSU 2003b) was validated in 2009 (Grade II) (3). This
version of the formula is currently recommended for critically patients of any age with BMI below 30, or for
patients who are younger than 60 years with BMI over 30 (Grade II) (^) (3). The Penn State equation originated in
1998 and was modified again in 2003. The PSU 1998 version used the Harris-Benedict equation and was
replaced with the Mifflin St Jeor equation using actual weight in 2003 to improve accuracy (3, 10). The equation
was further revised to improve performance for the older adult obese population (10). The 1998 and 2003a
versions should no longer be used and were invalidated in 2007 and 2009 by the Academy Evidence Analysis
Library (3):
PSU 2003 b: RMR = Mifflina (0.96) + VE (31) + Tmax (167)- 6212
aMifflin = resting energy expenditure calculated using the Mifflin St. Jeor Equation (5)
VE = minute ventilation (L/min)
Tmax = maximum temperature (degrees Celsius)
Modified Penn State Equation, also known as PSU 2010 was validated in 2010 by the Academy (Grade II) (3).
This formula is recommended to be used for patients with BMI over 30 and older than 60 years of age (3).
PSU 2010: RMR = Mifflina (0.71) + VE (64) + Tmax (85) – 3085
aMifflin = resting energy expenditure calculated using the Mifflin St. Jeor Equation (5)
VE = minute ventilation (L/min)
Tmax = maximum temperature (degrees Celsius)
Brandi Equation (3, 12)
Upon evaluation by the Academy Evidence-Based Library, the Brandi equation was shown to be unbiased
toward non-obese patients with an accuracy of 61% (Grade III) (3). It was biased for obese patients with accuracy
of 48% (Grade III) (3, 12).
HBE (0.96) + HR (7) + Ve (48)- 702
HBE = Harris Benedict Equation
VE = Expired minute ventilation
Harris-Benedict equation (4) for use in Brandi equation or otherwise specified:
kcal/day (male) = 66 +13.8 (W) + 5.0(H) – (6.8 x A)
kcal/day (female) = 655 + 9.6 (W) + 1.8 (H) – (4.7 x A), where
W = actual weight (kg)
H = height (cm)
A = age (years)
Faisey Equation (3,12, 13)
In the two studies evaluating the Faisey equation it was shown the equation was unbiased but inaccurate (Grade
III)^ (3). The equation predicted RMR +/-^ in 53% of subjects (Grade III) (3).^
W (8) + H (14) + VE (32) + T (94) -4,834
Equation uses weight (W) in kilograms and height (H) in centimeters. VE is expired minute ventilation and T is body temperature in
degrees centigrade (3).