Calculating Energy Needs

Basal Metabolic Rate:

Men          BMR = 66 + (1.37 x W) + (5 x H) - 6.8 x A)

Women     BMR = 655 + (9.6 x W) + (1.7 x H) - (4.7 x A)

BMR - basal metabolic rate W - actual weight in kilograms

H - height in centimeters A - age in years

Just for fun, calculate your BMR.

Caloric Needs

To determine the number of calories your patient needs, we calculate the basal energy
expenditure (BEE):

Men         BEE = 879 + (10.2 x weight)

Women    BEE = 795 + (7.18 x weight)

The BEE is then multiplied by the appropriate stress factor:

Type of stress	Factor
Fever	1 + 0.13/ C elevation       above norm
Pneumonia	1.2
Major injury	1.3
Severe sepsis,     burn 15-30% TBSA	1.5
Burn 31-49% TBSA	1.5-2
Burn >  50% TBSA	1.8-2.1

Practice Problem:  Nancy Ames, age 52, is admitted with sepsis. Her weight is 84 kg and height is 1.7 m.   What is her caloric requirement?

Protein needs:

Protein needs also vary with the degree of stress and malnutrition. To calculate the protein needs we multiple the body weight by one of the following factors:

Condition	Factor
Healthy person, or well-nourished    elective surgery	0.8-1.0 g protein
Malnourished or catabolic state    (sepsis, major injury)	1.2 to 2 g protein
Burns  15-30% TBSA	1.5 g protein
Burns 31-49% TBSA	1.5-2 g protein
Burns > 505 TBSA	2-2.5g protein

Practice problem: Calculate Nancy Ames' protein requirements. 
Click here for answers.

How much nutrition is your patient actually getting?

Enteral feeding: Just look on the label to find out how much protein and calories are present. You will have to find out how much of the feeding the patient receives daily.

Parenteral feeding:  If you are lucky, a dietician has calculated this for you or it is on the label.  If not, you will have to do some math.  Let's say Nancy is receiving TPN at 85 ml/hr.  At 80 ml/hr she is receiving 1920 ml per day

The bag label states it contains
               D70W 500 ml
               Amino acids 10% 400 ml
               Intralipids 20% add 200 ml to one bag per day

She will need one bag with intralipids (1100 ml) and one without (900 ml).  To make the calculations easier we will give her all of the second bag.

Dextrose has 3.4 calories per gram.
   Multiply 1000 ml x 0.70 x 3.4 cal/ml = 2380 calories from 
   carbohydrates
   ( I got the 1000 ml by adding the two bags together)

Fat has 9 calories per gram
   Multiply 200 ml x 0.20 x 9 cal/ml = 360 calories from fat
     (She only gets 200 ml per day)

Protein has 4 calories per gram
   Multiply 800 ml x 0.10 x 4 cal/ml = 320 calories from protein
    (I got the 800 ml by adding the two bags together)

Total calories = 2380 + 360 + 320 = 3060

Total Protein - she is getting 800 ml of 10% solution = 80 gm protein.

Practice Problem:  Is she getting enough calories and protein?  
                                         Check your answer

Sharon Kumm, University of Kansas School of Nursing, October2004