Thursday, March 21, 2013

Variability in Energy Needs

By Nikki Bolduc

Energy needs are different depending on the population you are working with, such as if the patient is critically ill, elderly, or an infant.  In addition, the protocol on calculating energy needs for one population may differ between hospitals.  I have experienced the functioning of three different hospitals during my internship and I can appreciate variables in procedure.

I completed my main clinical internship experience at the DC Veteran’s Affairs Medical Center in a 12-week rotation.  A typical patient consisted of a middle-aged male with multiple chronic conditions.  Dietitians most often used Mifflin St. Jeor to estimate resting energy expenditure (REE) plus an energy and activity factor to calculate energy needs.  Protein was calculated using dietary reference intakes (DRI) grams/kg depending on their nutrition status and fluid was often calculated using 1 mL/kcal or per doctors order.

Mifflin St. Jeor (ages 19-78):
REE (female) = 10(weight in kg) + 6.25(height in cm) – 5(age) – 161
            REE (male)    = 10(weight in kg) + 6.25(height in cm) – 5(age) + 5

DRI for protein:
0.5 g/kg = minimal requirement
0.8-1.0 g/kg = normal maintenance
1.5-2.5 g/kg = increased protein demands

1 mL/kcal
per MD orders

This week I completed a two-week rotation at Children’s National Medical Center in Washington, DC.  During my experience, I concentrated on gastroenterology, hematology, and oncology pediatric patients.  Dietitians often used estimated energy expenditure (EER) plus an activity factor and basal metabolic rate (BMR) plus an activity factor to calculate calorie needs.  Protein was calculated using dietary reference intakes (DRI) grams/kg based on pediatric guidelines and fluid was calculated using the Holliday Segar equation.

(ranges are further broken down by age)
(ranges are further broken down by gender and weight)
Infants (0-35 months)
80-102 kcal/kg/day
Age 1 wk-10 mo
202-593 kcal/day
Boys (ages 3-8)
59-85 kcal/kg/day
Age 11-36 mo
509-816 kcal/day
Girls (ages 3-8)
59-82 kcal/kg/day
Age 3-16 yr
799-1980 kcal/day
Boys (ages 9-18)
36-49 kcal/kg/day

Girls (ages 9-18)
34-42 kcal/kg/day

DRI for protein:
                Infants (0-35 months): 1.05-1.52 g/kg/day
                Boys & Girls (ages 3-8): 0.95-1.05 g/kg/day
                Boys & Girls (ages 9-18): 0.8-0.95 g/kg/day

Holliday Segar:
                1st 10 kg          -> 100 mL/kg
                2nd 10 kg         -> 50 mL/kg
                each addtl kg   -> 20 mL/kg (≤ 50 yo)
                                             15 mL/kg (> 50 yo)

It is important to understand the protocol of calculating energy needs at your hospital as well as the reasons why they use what they do.  Dietetics is grounded in scientific research, so although protocols at hospitals vary there most certainly is a reason for each approach.   There are many resources available to dietetic interns, such as the Nutrition Care Manual, the American Society for Parenteral and Enteral Nutrition (ASPEN), and the Evidence Analysis Library.  I hope the above equations will help get you started!

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