1. health and fitness
2. nutrition

MNT for Metabolic Stress:
Sepsis, Trauma, Burns, Surgery
Metabolic Stress
 Sepsis (infection)
 Trauma (including burns)
 Surgery
 Once the systemic response is activated, the
physiologic and metabolic changes that follow are
similar and may lead to septic shock.
Immediate Physiologic and Metabolic
Changes after Injury or Burn
ADH, Antiduretic hormone; NH3, ammonia.
Metabolic Response to Stress
 Involves most metabolic pathways
 Accelerated metabolism of LBM
 Negative nitrogen balance
 Muscle wasting
Ebb Phase
 Immediate—hypovolemia, shock, tissue




hypoxia
Decreased cardiac output
Decreased oxygen consumption
Lowered body temperature
Insulin levels drop because glucagon is
elevated.
Flow Phase
 Follows fluid resuscitation and O2 transport
 Increased cardiac output begins
 Increased body temperature
 Increased energy expenditure
 Total body protein catabolism begins
 Marked increase in glucose production, FFAs,
circulating insulin/glucagon/cortisol
Hormonal and Cell-Mediated
Response
 There is a marked increase in glucose
production and uptake secondary to
gluconeogenesis, and
—Elevated hormonal levels
—Marked increase in hepatic amino acid
uptake
—Protein synthesis
—Accelerated muscle breakdown
Skeletal Muscle Proteolysis
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
Metabolic Changes in
Starvation
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
Starvation vs. Stress
 Metabolic response to stress differs from the
responses to starvation.
 Starvation = decreased energy expenditure, use
of alternative fuels, decreased protein wasting,
stored glycogen used in 24 hours
 Late starvation = fatty acids, ketones, and
glycerol provide energy for all tissues except
brain, nervous system, and RBCs
Starvation vs. Stress—cont’d
 Hypermetabolic state—stress causes
accelerated energy expenditure, glucose
production, glucose cycling in liver and
muscle
 Hyperglycemia can occur either from insulin
resistance or excess glucose production via
gluconeogenesis and Cori cycle.
 Muscle breakdown accelerated also
Hormonal Stress Response
 Aldosterone—corticosteroid that causes
renal sodium retention
 Antidiuretic hormone (ADH)—
stimulates renal tubular water absorption
 These conserve water and salt to support
circulating blood volume
Hormonal Stress
Response—cont’d
 ACTH—acts on adrenal cortex to
release cortisol (mobilizes amino acids
from skeletal muscles)
 Catecholamines—epinephrine and
norepinephrine from renal medulla to
stimulate hepatic glycogenolysis, fat
mobilization, gluconeogenesis
Cytokines
 Interleukin-1, interleukin-6, and tumor
necrosis factor (TNF)
 Released by phagocytes in response to
tissue damage, infection, inflammation,
and some drugs and chemicals
Systemic Inflammatory Response
Syndrome
 SIRS describes the inflammatory response
that occurs in infection, pancreatitis,
ischemia, burns, multiple trauma, shock,
and organ injury.
 Patients with SIRS are hypermetabolic.
Multiple Organ Dysfunction
Syndrome
 Organ dysfunction that results from direct
injury, trauma, or disease or as a response to
inflammation; the response usually is in an
organ distant from the original site of
infection or injury
Diagnosis of Systemic Inflammatory
Response Syndrome (SIRS)
 Site of infection established and at least two of the
following are present
—Body temperature >38° C or <36° C
—Heart rate >90 beats/minute
—Respiratory rate >20 breaths/min (tachypnea)
—PaCO2 <32 mm Hg (hyperventilation)
—WBC count >12,000/mm3 or <4000/mm3
—Bandemia: presence of >10% bands (immature
neutrophils) in the absence of chemotherapyinduced neutropenia and leukopenia
 May be caused by bacterial translocation
Bacterial Translocation
 Changes from acute insult to the
gastrointestinal tract that may allow entry of
bacteria from the gut lumen into the body;
associated with a systemic inflammatory
response that may contribute to multiple
organ dysfunction syndrome
 Well documented in animals, may not occur
to the same extent in humans
 Early enteral feeding is thought to prevent
this
Bacterial Translocation across Microvilli
and How It Spreads into the Bloodstream
Hypermetabolic Response to
Stress—Cause
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
Hypermetabolic Response to
Stress—Pathophysiology
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000.
Hypermetabolic Response to Stress—
Medical and Nutritional Management
Algorithm content developed by John Anderson, PhD, and Sanford C. Garner, PhD, 2000. Updated by Maion F. Winkler and
Ainsley Malone, 2002.
Factors to Consider in Screening
an ICU Patient
 ICU medical admission
—Diagnosis, nutritional status, organ function,
pharmacologic agents
 Postoperative ICU admission
—Type of Surgery, intraoperative
complications, nutritional status, diagnosis,
sepsis/SIRS
 Burn or trauma admission
—Type of trauma, extent of injury, GI
function
ASPEN
 American Society of Parenteral and Enteral
Nutrition
ASPEN
 Objectives of optimal metabolic and
nutritional support in injury, trauma,
burns, sepsis:
1. Detect and correct preexisting malnutrition
2. Prevent progressive protein-calorie
malnutrition
3. Optimize patient’s metabolic state by
managing fluid and electrolytes
ASPEN’s Strength of Evidence
Evaluation (adapted from AHRQ)
 A: there is good research-based evidence to
support the guideline (prospective,
randomized trials).
 B: There is fair research-based evidence to
support the guideline (well-designed studies
without randomization).
 C: The guideline is based on expert opinion
and editorial consensus
ASPEN Practice Guidelines for
Critical Care
 Patients with critical illnesses are at nutrition risk
and should undergo nutrition screening to identify
those who require formal nutrition assessment
with development of a nutrition care plan. (B)
 Specialized nutrition support (SNS) should be
initiated when it is anticipated that critically ill
patients will be unable to meet their nutrient needs
orally for a period of 5-10 days. (B)
 EN is the preferred route of feeding in critically ill
patients requiring SNS. (B)
 PN should be reserved for those patients requiring
SNS in whom EN is not possible. ( C )
ASPEN BOD. JPEN 26;S92SA, 1992
NUTRITIONAL ASSESSMENT
 Traditional methods not adequate/reliable
 Urine urea nitrogen (UUN) excretion in
gms per day may be used to evaluate degree
of hypermetabolism:
–
–
–
–
0 –5 = normometabolism
5 – 10 = mild hypermetabolism (level 1 stress)
10 – 15 = moderate (level 2 stress)
>15 = severe (level 3 stress)
NUTRITIONAL ASSESSMENT
 Clinical judgment must play a major role in
deciding when to begin/offer nutrition
support
Determination of Nutrient
Requirements
 Energy
 Protein
 Vitamins, Minerals, Trace Elements
 Nonprotein Substrate
– Carbohydrate
– Fat
Energy
 Enough but not too much
 Excess calories:
– Hyperglycemia
• Diuresis – complicates fluid/electrolyte balance
– Hepatic steatosis (fatty liver)
– Excess CO2 production
• Exacerbate respiratory insufficiency
• Prolong weaning from mechanical ventilation
Indirect Calorimetry
 Better estimate in critically ill
hypermetabolic patient
 The “gold standard” in estimating energy
needs in critical care
 Can be used in both mechanically ventilated
and spontaneously breathing patients
(ventilated patients most accurate)
 Equipment is expensive and not readily
available in many facilities
GUIDELINES: Indirect Calorimetry
in Critical Care
 R.16.1. Indirect calorimetry is the standard for
determination of RMR in critically ill patients
since RMR based on measurement is more
accurate than estimation using predictive
equations. Strong, Imperative
 When indirect calorimetry cannot be performed,
predictive formulas may be necessary (Grade I)
– ADA Evidence Analysis Library, accessed 10-06
Indirect Calorimetry
 Requires appropriate calibration of
equipment, attainment of a steady state for
measurement, and appropriate timing of
measurement
 Requires interpretation by trained clinician
 Inaccurate in patients requiring inspired
oxygen (FiO2>60%), and with air leaks via
the entrotracheal tube cuff, chest tubes or
bronchopleural fistula
Respiratory Quotient
 Respiratory quotient (RQ) is the ratio of vCO2 and
vO2 and is a function of the mix of substrates
being utilized for metabolism.
 An RQ of <0.7 or > 1.0 may identify unusual
metabolic or respiratory conditions, failure to
adhere to the fasting requirement of the
measurement protocol, and/or operator or
equipment error.
 A repeated measurement should be considered if
an RQ value is outside the range of 0.70 to 1.0.
– ADA Evidence Analysis Library, 10-06
Indications for Indirect Calorimetry
 Patients with altered body composition
(underweight, obese, limb amputation, peripheral
edema, ascites)
 Difficulty weaning from mechanical ventilation
 Patients s/p organ transplant
 Patients with sepsis or hypercatabolic states
(pancreatitis, trauma, burns, ARDS)
 Failure to respond to standard nutrition support
Malone AM. Methods of assessing energy expenditure in the intensive
care unit. Nutr Clin Pract 17:21-28, 2002.
Predictive Equations for Estimation of
Energy Needs in Critical Care
 Harris-Benedict x 1.3-1.5 for stress
 ASPEN Guidelines:
– 25 – 30 calories per kg per day*
 Ireton-Jones Equations**
 Penn State equations
 Swinamer equation
*ASPEN Board of Directors. JPEN 26;1S, 2002
** Ireton-Jones CS, Jones JD. Why use predictive equations for energy
expenditure assessment? JADA 97(suppl):A44, 1997.
**Wall J, Ireton-Jones CS, et al. JADA 95(suppl):A24, 1995.
Harris-Benedict Equation
 Monograph in 1919 described results of indirect
calorimetry on 239 healthy men and women of
varying body sizes up to a BMI of 56 in men and
40 in women
 Predicts BMR (RMR) with systematic
overestimation of 5-15%
 Random error greater in women than in men
 Stress and activity factors must be applied to
estimate total energy expenditure
 HB RMR X 1.3-1.5 used in critically ill patients
Ireton-Jones 1997 Equations
Ventilator-Dependent Patients:
 EEE = 1784 – 11(A) + 5(W) + 244(G) +
239(T) = 804(B)
Spontaneously-Breathing Patients:
 EEE = 629 – 11(A) + 25(W) – 609(O)
Ireton-Jones Equations
Where:
 A = age in years
 W = weight (kg)
 O = presence of obesity >30% above IBW (0 =
absent, 1 = present)
 G = gender (female = 0, male = 1)
 T = diagnosis of trauma (absent = 0, present = 1)
 B = diagnosis of burn (absent = 0, present = 1)
 EEE = estimated energy expenditure
Ireton-Jones 1997 Equations
 Three studies comparing RMR and the updated
Ireton-Jones 1997 equations report similar mean
values
 However, only 36% of subjects were predicted
within 10% of RMR.
 Further research in the critically ill population is
needed regarding the Ireton-Jones 1997 equations
(Grade III)
– ADA Evidence Analysis Library,
accessed 10-06
Ireton-Jones 1992 Equations
Spontaneously-breathing patients:
 IJEE (s) = 629 – 11(A) + 25(W) – 609 (O)
Ventilator-dependent patients:
 IJEE (v) = 1925 – 10(A) + 5(W) + 281 (S) +
292 (T) + 851 (B)
Ireton-Jones Equations 1992
Where:
 A = age in years
 W = weight (kg)
 O = presence of obesity >30% above IBW from
1959 Metropolitan ht/wt tables or BMI >27 (0 =
absent, 1 = present)
 G = gender (female = 0, male = 1)
 T = diagnosis of trauma (absent = 0, present = 1)
 B = diagnosis of burn (absent = 0, present = 1)
 EEE = estimated energy expenditure
Ireton-Jones Equations 1992
 Seven studies comparing RMR and the
Ireton-Jones 1992 equations report similar
mean values
 However, for an individual, energy
predictions may be different by as much as
500 kcals (60% of subjects predicted within
10% of RMR). (Grade III)
• ADA Evidence Analysis Library, accessed 10-06
Penn State Equation
 1998 version: RMR = BMR (1.1) + VE (32)
+ Tmax (140) - 5340
 2003a version: RMR = BMR (0.85) + VE
(33) + Tmax (175) – 6433
 Equations use BMR calculated using the
Harris-Benedict equation, minute
ventilation (VE) in liters per min (L/min),
and maximum temperature (Tmax) in
degrees Celsius.
Penn State Equations
 Two studies comparing RMR and the Penn
State equation report adequate precision
(80% of non-obese subjects predicted
within 10% of RMR).
 Further research in the critically ill
population is needed regarding the Penn
State equation (Grade III)
– ADA Evidence Analysis Library accessed 1006
Swinamer Equation
 EE = 945 (BSA) - 6.4 (age) + 108 (T) +
24.2 (breaths/min) + 81.7 (VT) - 4349
 Equation uses body surface area (BSA) in
squared meters (m2), temperature (T) in
degrees Celsius, and tidal volume (VT) in
liters per minute (L/min).
Swinamer Equation
 In one positive quality cross-sectional study by
MacDonald and Hildebrandt, 2003, 24-hour
indirect calorimetry was performed on 76
critically ill patients with a mean APACHE II
score of 12.6 +/- 7.5.
 The Swinamer formula correlated with 24-hour
measured RMR, with an r = 0.791 and r2 = 0.62 (P
< 0.0001). The Swinamer equation predicted RMR
within 20% of IC values 88% of the time for the
entire population studied
Estimation of RMR in Obesity
 Harris-Benedict using actual weight x 1.2 (60% of
subjects predicted within 10% of RMR) or an
adjusted weight x 1.3 (67% of subjects predicted
within 10% of RMR) resulted in the most accurate
predictions.
 Penn State 2003a equation predicts within 10% of
RMR in 61% of subjects, the Penn State 1998
equation predicts within 10% of RMR in 67% of
subjects
 Ireton-Jones, 1992 equations predict within 10%
of RMR in 72% of subjects.
 Further research is needed in critically ill patients
with obesity.
Recommendations for Predicting
RMR in Critically Ill Pts
 HBE should not be used to predict RMR in
critically ill patients (Grade I)
 Ireton-Jones 1997 should not be used to
predict RMR in critically ill patients (Grade
II)
 Ireton-Jones 1992 may be used to predict
RMR in critically ill pts but errors will
occur. (Grade III)
– ADA Evidence Analysis Library, 10-06
Recommendations for Predicting
RMR in Critically Ill Pts
 Penn State 2003 may be used in critically ill
patients, but errors will occur. (Grade III)
 Penn State 2003 or Ireton-Jones 1992 may
be used to predict RMR in critically ill
OBESE patients, but errors will occur.
(Grade III)
– ADA Evidence Analysis Library, 10-06
GUIDELINES: Determining RMR
in Critical Illness
 R.16.1. Indirect calorimetry is the standard
for determination of RMR in critically ill
patients since RMR based on measurement
is more accurate than estimation using
predictive equations. Strong, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Determining RMR
in Critical Illness
 R.16.2. If predictive equations are needed in
critically ill patients, consider using one of
the following, as they have the best
prediction accuracy of equations studied:
Ireton-Jones, 1992, Penn State, 2003a or
Swinamer. In some individuals, errors
between predicted and actual energy needs
will result in under- or over-feeding. Fair,
Conditional
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Determining RMR
in Critical Illness
 R.16.3. The Harris-Benedict (with or without
activity and stress factors), the Ireton-Jones, 1997,
and the Fick equation should not be considered for
use in RMR determination in critically ill patients,
as these equations do not have adequate prediction
accuracy. In addition, the Mifflin-St. Jeor equation
should not be considered for use in critically ill
patients, as it was developed for healthy people
and has not been well researched in the critically
ill population. Strong, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Determining RMR
in Critical Illness
 R.16.4. If predictive equations are needed
for critically ill mechanically ventilated
individuals who are obese, consider using
Ireton-Jones, 1992, or Penn State, 1998,
as they have the best prediction accuracy
of equations studied. In some individuals,
errors between predicted and actual
energy needs will result in under- or overfeeding. Fair, Conditional
Critical Illness ADA Evidence Based Guidelines, 10-06
What Weight Do You Use?
 Actual weight may be inaccurate in trauma and
burn patients who have been fluid resuscitated
 Usual weights may not be available
 There is no validation for the common practice of
using an “adjusted” body weight for obese patients
when using Harris-Benedict since Harris-Benedict
equations were derived from studies done on
healthy people of all sizes
 Ireton-Jones uses actual weight in her equations
and then adjusts for obesity
What Weight Do You Use?
 Lean body mass is highly correlated with actual
weight in persons of all sizes
 Studies have shown that determination of energy
needs using adjusted body weight becomes
increasingly inaccurate as BMI increases
 However, some studies suggest that high protein
hypocaloric feedings in obese patients may be
therapeutically useful
 Because overfeeding is more problematic than
underfeeding, could possibly use adjusted weight
or 20-21 kcal/kg actual BW in obese pts
Objectives
 First, fluid resuscitation and treatment of
cause of hypermetabolism
 When hemodynamically stable, begin
nutrition support
 Nutrition support may not result in +N
balance – may slow loss of protein
 Undernutrition can lead to protein
synthesis, weakness, MODS, death
Nutrient Guidelines: Carbohydrate
 Should provide 60 – 70% calories
 Maximum rate of glucose oxidation =
~5 – 7 mg/kg/min or 7 g/kg/day*
 Blood glucose levels should be monitored
and nutrition regimen and insulin adjusted
to maintain glucose below 150 mg/dl
*ASPEN BOD. JPEN 26;22SA, 1992
Nutrient Guidelines: Fat
 Can be used to provide needed energy and
essential fatty acids
 Should provide 15 – 40% of calories
 Limit to 2.5g/kg/day or possibly 1 g/kg/day
IV*
 Caution with use of fats in stressed &
trauma pts
– There is evidence that high fat feedings
(especially LCT) cause immunosuppression
– New formulas focus on omega-3s
*ASPEN BOD. JPEN 26;22SA, 1992
Nutrient Guidelines: Protein
 1.5 – 2.0 g/kg/day to start; monitor response
 Nonprotein calorie/gram of nitrogen ratio
for critically ill = 100:1
 Giving exogenous aa’s decreases negative N
balance by supplying liver aa’s for protein
synthesis
ASPEN BOD. JPEN 26;22SA, 1992
Nutrient Guidelines: Protein
 No studies were found in generalized critical care
populations that demonstrated a significant
difference in mortality based on level of protein
intake or delivery. In critically ill patients
undergoing continuous renal replacement therapy,
a single study indicates that protein intake > 2.0 g
per kg per day is more likely to promote positive
N balance (P=0.0001). And, while a more positive
N balance is associated with decreased mortality, a
higher protein intake was not associated with
mortality.—ADA EAL 11-27-07
Nutrient Guidelines: Protein
 To date, adequately powered studies have not been
conducted to demonstrate a significant difference
in rate of infectious complications when
comparing critically ill patients with positive or
negative N balance.
 To date, no studies were found that demonstrated a
significant difference in LOS or ICU length of
stay based on level of protein intake or protein
delivery.
– ADA EAL, 11-27-07
Fluid and Electrolytes
Fluid
 30-40 mL/kg or
 1 to 1.5mL/kcal expended
Electrolytes/Vitamins/Trace Elements
 Enteral feedings: begin with RDA/AI values
 PN: use PN dosing guidelines
ASPEN BOD. JPEN 26;23SA, 1992
Specialized Nutrients in Critical
Care
 Include supplemental branched chain amino acids,
glutamine, arginine, omega-3 fatty acids, RNA,
others
 Most studies used more than one nutrient, making
assessment of efficacy of specific supplements
impossible
 Immune-enhancing formulas may reduce
infectious complications in critically ill pts but not
alter mortality
 Mortality may actually be increased in some
subgroups (septic patients)
ASPEN BOD. JPEN 26;91SA, 1992
Immune-Enhancing EN in Critical
Care
 The addition of immune-enhancing EN to enteral
feeding of severely ill ICU patients may be
associated with increased mortality, though
adequately powered trials have not been
conducted (Grade III)
 The addition of immune-enhancing EN to enteral
feeding of moderate or less severely ill ICU
patients demonstrates no effect on mortality
(Grade II)
– ADA Evidence Analysis Library Accessed 10-06
Immune-Enhancing EN in Critical
Care
 The addition of immune-enhancing EN to enteral
feeding of critically ill ICU patients is not
associated with fewer infectious complications
(Grade III)
 The addition of immune-enhancing EN to enteral
feeding of critically ill ICU patients has limited
impact on LOS (Grade II)
ADA Evidence Analysis Library Accessed 10-06
Immune-Enhancing EN in Critical
Care
 The addition of immune-enhancing EN to enteral
feeding of critically ill ICU patients is not
associated with reduced number of days on
mechanical ventilation (Grade II).
 The addition of immune-enhancing EN to enteral
feeding of critically ill ICU patients is not
associated with reduced cost of medical care
(Grade III)
– ADA Evidence Analysis Library Accessed 10-06
GUIDELINES: Immune-Enhancing
EN in Critical Care
 R.3 Immune-enhancing EN is not recommended for
routine use in critically ill patients in the ICU. Immuneenhancing EN is not associated with reduced infectious
complications, LOS, reduced cost of medical care, days on
mechanical ventilation or mortality in moderately to less
severely ill ICU patients. Their use may be associated with
increased mortality in severely ill ICU patients, although
adequately-powered trials evaluating this have not been
conducted. For the trauma patient, it is not recommended
to routinely use immune-enhancing EN, as its use is not
associated with reduced mortality, reduced LOS, reduced
infectious complications or fewer days on mechanical
ventilation. Fair, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
Supplemental Glutamine (GLN) in
Critical Care
 Alterations in glutamine metabolism can occur in
critical care, possibly affecting gut function
 PN solutions traditionally have not contained
glutamine because of instability in solution
 Animal and human studies suggest that
supplemental GLN in PN may have beneficial
effects
 Those benefits have not been demonstrated in EN
Glutamine Metabolism
NH2, Amine; NH3, ammonia.
From Simmons RL, Steed DL: Basic science review for surgeons, Philadelphia, 1992, WB Saunders.
EN vs PN in Critical Care
 Adequately powered trials have not been found to
enable evaluation of the impact of EN versus PN
on mortality in critically ill patients (Grade V)
 Enteral nutrition is associated with reductions in
infectious complications in critically ill patients,
when compared to PN (Grade I)
– ADA Evidence Analysis Library, accessed 10-06
EN vs PN in Critical Care
 Adequately powered trials have not been found to
enable evaluation of the impact of EN versus PN
on LOS in critically ill patients (Grade V)
 Enteral nutrition is associated with reduced cost of
medical care in critically ill patients, when
compared to PN (Grade II)
– ADA Evidence Analysis Library, accessed 10-06
GUIDELINES: EN vs PN in Critical
Care
 R.1. If the critically ill ICU patient is
hemodynamically stable with a functional GI tract,
then EN is recommended over PN. Patients who
received EN experienced less septic morbidity and
fewer infectious complications than patients who
received PN. In the critically ill patient, EN is
associated with significant cost savings when
compared to PN. There is insufficient evidence to
draw conclusions about the impact of EN or PN
on LOS and mortality. Strong, Conditional
Critical Illness ADA Evidence Based Guidelines, 10-06
[Potential] Beneficial Effects of Postburn
Early Enteral Nutrition
 Nutrient needs satisfied
 Improved nitrogen balance
 Improved tube feeding
 Reduced urinary
tolerance
 Decreased incidence of
bacterial translocation
 Decreased number of
infectious episodes
 Decreased antibiotic
therapy
catecholamines
 Diminished serum
glucagon
 Suppressed
hypermetabolic response
 Enhanced visceral protein
status
*Mayes and Gottslich, Burns and Wound Healing. In The science and practice of
nutrition support: A core curriculum. ASPEN 2001, p. 401
Early Enteral Nutrition (ADA EAL)
 To date, adequately powered studies have not been
conducted to demonstrate a significant difference
in mortality when comparing early versus late EN
in critically ill patients (Grade V)
 In fluid-resuscitated, critically ill patients, EN
started within 24-48 hours following injury or
admission to the ICU reduces the incidence of
infectious complications (Grade I)
• ADA Evidence Analysis Library, accessed 10-06
Early Enteral Nutrition (ADA EAL)
 In fluid-resuscitated, critically ill patients,
EN started within 24-48 hours following
injury or admission to the ICU may reduce
LOS (Grade II)
• ADA Evidence Analysis Library, accessed 10-06
GUIDELINES: Timing of Enteral
Nutrition and Critical Illness
 R.2. If the critically ill patient is adequately
fluid resuscitated, then EN should be started
within 24 to 48 hours following injury or
admission to the ICU. Early EN is
associated with a reduction in infectious
complications and may reduce LOS. The
impact of timing of EN on mortality has not
been adequately evaluated. Strong,
Conditional
Critical Illness ADA Evidence Based Guidelines, 10-06
Cautions Re/ Early Enteral Feeding
in Critically Ill Patients
 Benefits cited are theoretical; many based on
animal studies
 During sepsis, the GI tract and liver are
susceptible to ischemia due to increased oxygen
consumption and decreased blood flow
 Enteral nutrition delivered to septic patients given
vasoactive drugs may exacerbate this
 EN should be initiated cautiously after
hemodynamic stability is established
Brantley. Support Line; 24:10, 2003
Feeding Tube Placement in
Critically Ill Patients
 R.4. Enteral Nutrition (EN) administered into the
stomach is acceptable for most critically ill
patients.
 Consider placing feeding tube in the small bowel
when patient is in supine position or under heavy
sedation.
 If your institution's policy is to measure GRV, then
consider small bowel tube feeding placement in
patients who have more than 250ml GRV or
formula reflux in two consecutive measures. Fair,
Conditional A DA EAL accessed 11-27-07
Feeding Tube Placement in
Critically Ill Patients
 Small bowel tube placement is associated with
reduced GRV.
 Adequately-powered studies have not been
conducted to evaluate the impact of GRV on
aspiration pneumonia.
 There may be specific disease states or conditions
that may warrant small bowel tube placement
(e.g., fistulas, pancreatitis, gastroporesis), however
they were not evaluated at this phase of the
analysis.
 ADA EAL Guidelines accessed 11-27-07
Relationship Between Wt and
Outcomes in Critically Ill Pts
 There is fair evidence that mortality is increased in
critically ill trauma patients with BMI > 30. Grade
II
 There is limited evidence that BMI > 30 is not
associated with increased rate of infection in
critically ill trauma patients.
Grade III
 There is fair evidence that LOS is increased in
critically ill trauma patients with BMI > 30.
Grade II
– ADA EAL 11-27-07
Monitoring Response to MNT in
Critical Care Pts: Blood Glucose
 Hyperglycemia (up to 200-220 mg/dl) in critically
ill patients was once considered acceptable
 Recent studies suggest hyperglycemia is
associated with infection, morbidity, mortality
 New goal is to keep BG as close to normal as
possible. Target: <150 mg/dl
 Use insulin drip and sliding scale; convert to
subcutaneous insulin as possible
 Can use intermediate insulins morning and
evening once feedings are tolerated and stable
Charney P. Glycemic control in the ICU. In Sharpening Your Skills as a
Nutrition Support Dietitian. DNS, 2003, p. 210
Glucose Control in Critical Illness
 Survival is decreased in critically ill patients with
hyperglycemia (Grade I)
 Controlling BG is associated with fewer infectious
complications in critically ill patients (Grade I)
 There is fair evidence that controlling BG values
in critically ill patients leads to a decrease in ICU
LOS (Grade II)
– ADA Evidence Analysis Library Accessed 10-06
Glucose Control in Critical Illness
 There is fair evidence that controlling BG values
in critically ill patients is associated with reduced
number of days on mechanical ventilation (Grade
II)
 There is limited evidence that controlling BG
values in critically ill patients leads to a decrease
in the cost of medical care (Grade III)
– ADA Evidence Analysis Library Accessed 10-06
GUIDELINES: Blood Glucose
Control in Critical Illness
 R.8.1 Evidence indicates that blood glucose under
140mg/dL is associated with decreased mortality,
LOS and infectious complications in critically ill
patients. Dietitians should promote attainment of
these levels for BG control. Strong, Imperative
 R.8.2 Dietitians should promote attainment of
strict glycemic control (80-110mg/dL) to reduce
time on mechanical ventilation in critically ill
medical ICU patients. Strong, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
MNT in Selected Populations in
Critical Care
Traumatic Brain Injury (TBI)
 Severely hypermetabolic and catabolic
 The more severe the head injury, the greater
the release of catecholamines
(norepinephrine and epinephrine) and
cortisol and the greater the hypermetabolic
response.
ASPEN Practice Guidelines:
Neurological Impairment
 Patients with neurologic impairment are at
nutrition risk and should undergo nutrition
screening to identify those who require
formal nutrition assessment with
development of a nutrition care plan. (B)
 SNS should be initiated early in patients
with moderate or severe TBI. (B)
 When SNS is required, EN is preferred if it
is tolerated. ( C )
ASPEN BOD. JPEN 26;91SA, 1992
ASPEN Practice Guidelines:
Neurological Impairment



PN should be administered to patients with TBI
if SNS is indicated and EN does not meet the
nutritional requirements. ( C )
Indirect calorimetry should be utilized, if
available, to accurately determine nutrition
requirements in patients with TBI and CVAs. (B)
Swallowing function should be evaluated to
determine the safety of oral feedings and risk of
aspiration before the initiation of an oral diet.
(B)
ASPEN BOD. JPEN 26;91SA, 1992
Traumatic Brain Injury (TBI)
 Use indirect calorimetry when available
 Use H/B x 1.4 stress factor
 Protein requirements estimated at 1.5 – 2.2
g/kg of body weight
Acute Spinal Cord Injury
Source: www.spinal-cord-injury-resources.com/ spinal-i...
Acute Spinal Cord Injury (SCI)
 Energy requirement for SCI = H/B x 1.1 x
1.2 (Barco et al, NCP 17;309-313, 2002)
 Pt with multi-traumas in addition to SCI
may have higher needs
 Protein needs: 2 g/kg (Rodriguez DJ et al,
JPEN 15:319-322, 1991
Nutrition Support in Surgery/Trauma
Graphic source www.nlm.nih.gov/.../ gallery/image/surgery.gif
ASPEN Practice Guidelines
Perioperative Nutrition Support
 Preoperative SNS should be administered to
moderately-severely malnourished pts undergoing
major gastrointestinal surgery for 7 to 14 days if
the operation can be safely postponed. (A)
 PN should not be routinely given in the immediate
postoperative period to patients undergoing major
gastrointestinal procedures. (A)
 Postoperative SNS should be administered to
patients who will be unable to meet their nutrient
needs orally for a period of 7 to 10 days. (B)
ASPEN BOD. JPEN 26;96SA, 1992
Postoperative Nutrition Support
 Introduction of solid foods depends on condition
of GI
 Oral feeding may be delayed for first 24 – 48
hours post surgery until return of bowel sounds,
passage of flatus or soft abdomen
 Traditional practice has been to progress from
clear liquids, to full liquids, to solid foods
 However, there is no physiological reason not to
initiate solid foods once small amounts of liquids
are tolerated
Energy Requirements in Surgery
or Trauma
 Will vary with type of surgery, degree of trauma
 Use Ireton-Jones 1992 or Penn State if data is
available*
 Can use estimate of 25-30 kcals/kg to begin and
monitor response to therapy**
 Indirect calorimetry yields most accurate
estimates, particularly in pts difficult to assess
*ADA Evidence Analysis Library, accessed 10-06
**ASPEN Nutrition Support Practice Manual, 2nd Edition, p. 278
Hypocaloric Feedings
 Hypocaloric feedings have been
recommended in specific patient
populations
 Aggressive protein provision (1.5-2.0
gm/kg/day
ASPEN Nutrition Support Practice Manual, 2nd Edition, p.
279
Zaloga GD. Permissive underfeeding. New Horizons 1994
Hypocaloric Feedings Have Been
Recommended in:
 Class III obesity (BMI>40
 Refeeding syndrome
 Severe malnutrition
 Trauma patients following shock
resuscitation
 Hemodynamic instability
 Acute respiratory distress syndrome or
COPD
 MODS, SIRS or sepsis
Protein or Nitrogen
Requirements in Surgery
 1.2 to 1.5 g protein/kg BW
for anabolism mild or moderate stress
 Nitrogen requirement estimated from
energy requirements
Monitoring Response to MNT in
Critical Care Pts
 Weight: may be difficult to obtain and
inaccurate d/t fluid shifts, dressings
 Indirect calorimetry: if available. Adjust
support as needed; use RQ to evaluate
adequacy of support
 Nitrogen balance: labor intensive. Can be
used to assess metabolic state
 Prealbumin: can reflect repletion once acute
phase response has diminished
Monitoring Response to MNT in
Critical Care
 R.6.1 Evaluating patient position should be
part of an EN monitoring plan. To decrease
the incidence of aspiration pneumonia and
reflux of gastric contents into the esophagus
and pharnyx, critically ill patients should be
placed in a 45-degree head of bed elevation,
if not contraindicated. Strong, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Monitoring
Response to MNT in Critical Care
 R.6.2 Evaluating GRV in critically ill patients is an
optional part of a monitoring plan to assess tolerance of
EN. Enteral nutrition should be held when a GRV
greater than or equal to 250ml is documented on two or
more consecutive occasions. Holding EN when GRV is
less than 250ml is associated with delivery of less EN.
Gastric residual volume may not be a useful tool to
assess the risk of aspiration pneumonia. Adequatelypowered studies have not been conducted to evaluate
the impact of GRV on aspiration pneumonia.
Consensus, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Monitoring
Response to MNT in Critical Care
 R.6.3 If the patient exhibits a history of
gastroparesis or repeated high GRVs, then
consider the use of a promotility agent in
critically ill ICU patients, if there are no
contraindications. The use of a promotility
agent (e.g., Metoclopramide) has been
associated with increased GI transit, improved
feeding tolerance, improved EN delivery and
possibly reduced risk of aspiration. Strong,
Conditional
Critical Illness ADA Evidence Based Guidelines, 10-06
GUIDELINES: Blue Dye Use and
Critical Illness
 R.5. Blue dye should not be added to EN for
detection of aspiration. The risk of using
blue dye outweighs any perceived benefit.
The presence of blue dye in tracheal
secretions is not a sensitive indicator for
aspiration. Strong, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06
Monitoring Response to MNT in
Critical Care Pts
 Intake and output: stooling, fluid balance
 Tolerance of feeding regimen (abdominal
exam, gastric residuals)
 Amount of nutrition prescription delivered;
support is often interrupted due to surgeries,
dressing changes, intolerance, and therapy.
GUIDELINES: Monitoring
Response to MNT in Critical Care
 R.7. Monitoring plan of critically ill patients must
include a determination of daily actual EN intake.
Enteral nutrition should be initiated within 48
hours of injury or admission and average intake
actually delivered within the first week should be
at least 60-70% of total estimated energy
requirements as determined in the assessment.
Provision of EN within this time frame and at this
level may be associated with a decreased LOS,
days on the mechanical ventilation and infectious
complications. Fair, Imperative
Critical Illness ADA Evidence Based Guidelines, 10-06