Unformatted text preview: ESTIMATING ENERGY
AND PROTEIN NEEDS
FOR HOSPITAL PATIENTS Consequences
of Underfeeding Loss of muscle
mass
Reduced immune
response
Impaired organ
function
Poor wound healing
and increased
infection Consequences
of Overfeeding Hyperglycemia Insulin resistance Fatty liver Hypertriglyceridemia
yp
gy Failure to wean from
mechanical
ventilation Assessing Hospital Energy Needs Direct measurement using indirect calorimetry
g
y Calculation from pulmonary artery catheter
measurement
t Fick equation Estimation using equations based on body size degree
size,
of injury or inflammatory response Weir equation MifflinSt. Jeor
Harris Benedict
HarrisBenedict
IretonJones
Penn State Rule f thumb
R l of th b Estimating Hospital Energy Needs using: Indirect Calorimetry
Pulmonary gas exchange measurements are used to
determine cellular metabolism (energy expenditure)
Energy usage calculated by measuring: CO2 exhaled
O2 consumed
urea nitrogen (rarely) Relies on known constant energy expenditure associated
with all ratios of O2 consumption and CO2 production Indirect Calorimetry
Abbreviated Weir Formula
REE = [3.94 (VO2) + 1.11 (VCO2)] 1.44
VO2 = oxygen consumption (mL/min)
VCO2 = carbon dioxide production (mL/min) Indirect Calorimetry Advantages “Gold Standard” Most accurate method for establishing energy
needs Disadvantages Expensive equipment Requires trained personnel Some patients can’t be measured Recommended Energy Intake for Hospital
Patients using Indirect Calorimetry Nonambulatory Patients EER = REE x 1.2 Ambulatory Patients EER = REE x 1.4 Pulmonary Artery Catheter
(Swan Ganz Catheter) Bedside measurement
of pressure and flow
within the cardiocardio
pulmonary system
Used to characterize
fluid status in complex
patients and evaluate
response t therapeutic
to th
ti
manipulations Estimating Hospital Energy Needs using: PAC (Fisk Equation)
VO2 = cardiac output x 10 (CaO2 – CvO2)
REE = VO2 x 7 Calculation based on d t
C l l ti b
d
determination of wholei ti
f h l
body oxygen consumption
Method of opportunity Invasive nature precludes its use of anything
other than its intended purpose
th th it i t d d One study demonstrated this method was
accurate (± 20% of IC) in only 30% of subjects Estimating Hospital Energy Needs using: MifflinSt.
MifflinSt Jeor Equations
Male: REE = 10(W) + 6.25 (H) – 5(A) + 5
Female: REE = 10(W) + 6.25 (H) – 5(A) – 161 W = weight in kg (2.2 lb/kg) H = height in cm (2.54 cm/in) A = age in years Estimating Hospital Energy Needs using: MifflinSt.
MifflinSt Jeor Equations Equations estimate basal requirement only (REE)
EER = REE x Activity Weight Gain/Loss Must adjust by: multiplying by an stress factor May l
M also adjust b
dj t by: adding for pregnancy or lactation adding for weight gain
weight loss is not a suitable goal for hospital patients No research to validate in hospital p p
p
population Effect of various stresses on REE
in hospitalized patients Adjustment for
Stress/Activity/Hypermetabolism
Condition Degree of Increase Stress Factor Elective Surgery/
Serious Medical
Problems 110 – 120% REE 1.1 – 1.2 Trauma 135 – 150% REE 1.35 – 1.5 Sepsis 150%  170% REE 1.5 – 1.7 ASPEN, 2007 Estimating Hospital Energy Needs using: HarrisHarris Benedict Equations
H i B
di t E
ti Males:
Females: BEE/REE = 66.5 + 13.8(W) + 5(H) – 6.8(A)
BEE/REE = 655 + 9.6(W) + 1.9(H) – 4.7(A) W = weight in kg (2.2 lb/kg)
H = height in cm (2.54 cm/in)
A = age in years Research listed formula as estimating BEE
Conditions more consistent with measuring REE
Adjust for stress, weight gain, pregnancy/lactation EAL Evaluation of
HarrisHarrisBenedict Equations Without added factors (13 papers)
( p p ) One study reported 97% results were more than 15%
above/below RMR
Mean difference between RMR and predicted value range
from 250900 kcal/day With added factors (13 papers) Using stress factor of 1.3 21% were within 10% of measured values
56% were more than 15% above/below RMR Using stress factor of 1.6 51% were within 10% of measured values
27% were more than 15% above/below RMR Estimating Hospital Energy Needs using: IretonIretonJones Equations 1992 Formula for ventilator dependent patients:
IJEEV = 1925  10(A) + 5(W) + 281(S) + 292(T) + 851(B) 1997 Formula for ventilator dependent patients:
IJEEV = 1784  11(A) + 5(W) + 244(S) + 239(T) + 804(B)
A = age in years
W = actual weight in kg
S = sex (male = 1 female = 0)
1,
T = trauma (present = 1, absent = 0)
B = burns (present = 1, absent = 0) EAL Evaluation of
IretonIretonJones Equations 1992 formula (7 papers)
MacDonald & Hildebrandt reported 52% of nonobese
subjects fell within 10% RMR and 34% were >15%
RMR above or b l
b
below RMR Frankenfield reported 28% within ±10% RMR and
57% were >15% RMR above/below RMR 1997 formula (3 papers) Only
O l one study reported accuracy rates: 36% within
t d
t d
t
ithi
±10% RMR and 40% >15% above/below RMR Estimating Hospital Energy Needs using: Penn State Equation
PSU (BMI<30) = HBE (0.85) + Tmax (175) + Ve (33) – 6344
(
)
(
)
(
)
( )
Use actual weight in HarrisBenedict Equation PSU (BMI ≥30) = HBE (1.1) + Tmax (140) + Ve (32) – 5340
Use adjusted weight in HarrisBenedict Equation
Harris Benedict PSU (BMI<30) = Mifflin (0.96) + Tmax (167) + Ve (31) – 6212
Use actual weight in MifflinSt. Jeor Equation Tmax – maximum b d t
T
i
body temperature i previous 24 h
t
in
i
hr.
Ve – minute ventilation at the time of measurement, read from
ventilator, not calorimeter Developed from a mixed ICU population (19921997)
Based on variables related to body size (HBE MSJ)
(HBE, MSJ),
inflammatory response (temperature, minute ventilation) Limitations of Predictive Equations Normal physiologic range of individual variations in RMR
p y
g
g Typical factors (sex, height, weight, age) account for
only about 80% of energy expenditure Differences in body composition accounts some of the
individual variation Variation in the effect of trauma and disease on RMR Small increase due to diseases (except
hyperthyroidism ) Increase due to traumatic injury can be very large Estimating Hospital Energy Needs using: “Rule of Thumb
Rule Thumb” Healthy,
H l h nonhospitalized
h
i li d 30 k l/k
kcal/kg Adjust for activity and weight loss/gain No stress 2025 kcal/kg Mild stress 25 30
2530 kcal/kg Pneumonia, elective surgery Moderate t
M d t stress 3035 kcal/kg
30 35 k l/k Major surgery, longbone fractures ASPEN, 2007 Assessing Hospital Protein Needs Grams per kilogram Kcal:N ratio Effect of various stresses on urinary
nitrogen excretion in hospitalized patients Estimating Protein Needs using: grams/kg
Protein
Stress Condition (g/day) Normal Hospitalized without stress 1.0 Mild g y,
Minor surgery, mild infection 1.0 – 1.2 Moderate Major surgery, moderate infection,
moderate skeletal trauma 1.2 – 1.5 Severe Severe infection, multiple injuries,
severe trauma major burns
trauma, 1.6 – 2.0 Estimating Protein Needs using: Kcal:N Ratio
Kcal requirement
= g N x 6.25 = g protein
Desired ratio
Ratio for anabolism:
150:1 100:1 standard recommendation
when limiting energy intake Assessing Hospital Fluid Needs Energy Age/Weight Estimating Fluid Needs based on: Energy Needs 1 mL fluid per 1 kcal estimated energy Estimating Fluid Needs using: Age/Weight Method Age Fluid Requirement 16 – 30 years, active 40 mL/kg/day 20 – 55 years 35 mL/kg/day 55 – 75 years
y 30 mL/kg/day
g y > 75 years 25 mL/kg/day Factors Increasing
Fluid Requirements
Factors
F t Increase
I Fever 12% per 1° C Sweating 10 – 25% Hyperventilation 10 – 60% Hyperthyroidism 25 – 50% Elevated GI losses Replace mL/mL based on
24 hr output Elevated renal losses p
Replace mL/mL based on
24 hr output Feeding Recommendations
for ICU patients Begin feeding within 24o if possible
Use enteral feeding rather than parenteral if at
all possible
ll
ibl
Consider limiting energy in most critical p
g
gy
patients ...
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 Spring '09
 southworth
 Calorimetry, Basal Metabolic Rate, Hospital Energy Needs

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