Nutritional Assessment and Support

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Nutritional AssessmentandSupport
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Outline

• Malnutrition
• definition
• types
• Physiology
• fasting
• starvation
• effects of stress trauma
• Nutritional Assessment
• presence degree of malnutrition
• Nutritional Support
• who benefits
• proper timing
• enteral vs. parenteral
• simple calculations

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Nutrition

• intake of nutrients to provide energy for
• performance of mechanical work
• maintenance of organ/tissue function
• heat production
• maintenance of metabolic homeostasis
• TEE (total energy expenditure)
• REE or BEE (fasting resting or basal energy
  expenditure) 70(1 kcal/kg/hr)
• activity expenditure 20 avg. but very variable
• thermic effect of feeding 10 (intake increases
  the metabolic rate)

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Malnutrition

• estimated that gt50 of hospitalized patients
  exhibit malnutrition
• results in the catabolism of energy stores
• adipose (oxidation of triglycerides) 13kg in
  average person
• glycogen (glucose) 0.5kg, mostly in muscle
• protein (not stored - in use by the body)
• skeletal muscle 6-12 kg
• other protein stores (organs, visceral proteins,
  nerve tissue) few hundred grams

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Types of Malnutrition

• Marasmus
• cachexia
• chronic calorie malnutrition relatively
  balanced diet, but too little for too long
• usually the result of a longstanding problem
  (months)
• see wasting of fat, skeletal muscle (weakness)
• visceral protein stores less affected
• Kwashiorkor (West African term disease of the
  displaced child)
• malnourished African child (after weaning) with
  edema and protuberant abdomen
• more rapid development and worse prognosis
• chronic protein malnutrition (unbalanced diet)
  and the presence of physiologic stress
• fat skeletal muscle reserves are less depleted
  (carbohydrates drive insulin)
• visceral protein stores immunity are affected
  early
• Marasmic kwashiorkor
• combined features usually what is seen in ICU /
  ill patients
• malnurished person with stress of illness
  (hypermetabolic state)
• worst prognosis nutritional support tends to
  only increase fat mass unless the underlying
  stressors are reversed

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Early Fasting Human(Day One)
fuelsupply
consumption
Circulatingglucose
CNS
Liver
glycogen
glucose
Muscle glycogen protein
amino acids
PNSMedulla Marrow Eyes
gluconeogenesis
lactatepyruvate
glycerol
AdiposecirculatingFFA TG
FFA oxidationin mitochondria
MuscleHeartKidney
fatty acids
ketones
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Early Fasting Human(Days 2-14)
fuelsupply
consumption
CNS
Liver
Muscle75 g/d
amino acids
glucose
Renal Marrow PNSEyes
gluconeogenesis
lactatepyruvate
glycerol
Adipose
FFA oxidationin mitochondria
MuscleHeartKidney
fatty acids
ketones
lose 5 body protein stores per week
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Adapted Fasting Human(2 to 6 weeks)
fuelsupply
consumption
CNS
Liver
Muscle20 g/d
amino acids
glucose
Renal Marrow PNSEyes
gluconeogenesis
lactatepyruvate
glycerol
Adipose
FFA oxidation in mitochondria
MuscleHeartKidney
fatty acids
ketones
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Traumatized Human
fuelsupply
consumption
ReparativeProcess
CNS
Visceral MuscleProtein250 g/d
Liver
amino acids
glycogen
glucose
Renal Marrow PNSEyes
gluconeogenesis
lactatepyruvate
glycerol
Adipose
FFA oxidation in mitochondria
MuscleHeartKidney
fatty acids
ketones
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Nutritional Assessment
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Normal Nutrition

• Calories
• US standard diet for 70kg active man contains
  2700 kcal
• protein 325 kcal (81 grams)
• fat 1125 kcal (125 grams)
• carbohydrates 1250 kcal (312 grams)
• amount needs to be decreased for inactivity
• Protein
• US standard diet 80 grams/d (12 of caloric
  intake)
• protein-free diets result in negative nitrogen
  balance
• lose .34 grams protein/kg/d (nitrogen in urine,
  feces, skin, breath, sputum, etc.)
• titrate dietary protein to just keep a positive
  nitrogen balance
• need .38 to .52 grams protein/kg/d (higher
  estimate b/o inefficiency in utilization)
• most use .43 as a minimum and 0.5 - 0.8 gm/kg/d
  as average
• amount needs to be increased for stress
  (hypercatabolic)

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Nutritional Assessment

• Every patient should prompt three questions
• Does pre-existing malnutrition exist?
• Is malnutrition likely to occur?
• When and how to correct the situation?

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Does malnutrition exist?

• poor intake
• weight loss last 6 months (25 false positive,
  33 false negative)
• lt5 considered mild malnutrition 10 is a useful
  cut-off in nutritional support decisions
• gt20 considered severe malnutrition
• GI symptoms of anorexia, N/V, diarrhea,
  malabsorption, obstruction
• hypercatabolic pre-admission
• infection, sepsis
• trauma, burns
• major surgery or pulmonary disease
• anthropometric changes
• loss of SQ fat, muscle wasting, BMI lt 18
• functional changes
• muscle weakness, respiratory effort, daily
  activity performance
• lab studies
• albumin, transferrin, prealbumin, RBP,
  cholesterol, immune function
• affected by by critical illness and become less
  useful in stressed pts

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Does malnutrition exist?

• Subjective Global Assessment Scale (SGA Scale)
• graded on 6 features
• weight change
• intake
• GI symptoms
• functional capacity
• physiologic stress
• physical alterations
• each feature is rated
• A no deficit
• B mild deficit
• C severe deficit
• scored overall
• A well nourished 16 septic complications
• B mild to moderate malnutrition 43 septic
  complications
• C severe malnutrition 69 septic
  complications

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Is Malnutrition Likely to Occur?

• poor intake
• NPO for more than 5 days
• GI symptoms of anorexia, N/V, diarrhea,
  malabsorption, obstruction
• hypercatabolic
• infection, sepsis
• trauma, burns
• major surgery or pulmonary disease

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Nutritional Support

• Theoretical goals of improving the nutritional
  status of hospitalized patients
• improve wound healing
• decrease infectious complications (in the
  severely malnourished)
• decrease non-septic complications
• decrease ventilator weaning time
• shorten hospital stays
• decrease mortality rate

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Enteral vs Parenteral Nutritional Support

• Acute critical illness see catabolismgtgtanabolism,
  fat mobilization is impaired. Enteral and
  parenteral support confer DIFFERENT clinical
  outcomes in critically ill patients.
• Enteral nutrition when started early in the
  disease (first 48 hrs) may decrease risk of
  infection compared to delayed initiation (day 8
  or gt). Barely reaches statistical significance in
  meta-analyses. Mortality reduction trends lower,
  but never reaches significance in meta-analyses.
  Benefit gt harm, but positive trials mostly in
  SICU, not MICU, pts.
• Parenteral nutrition no evidence of benefit by
  early initiation vs late. There is good evidence
  of harm
• 69 trial meta-analysis with 3750 pts comparing
  early TPN vs none found higher infection rates
  and no diff in other outcomes or mortality.
• 2 studies adding TPN (1 early and 1 late) to
  enteral nutrition (hyperalimentation) found
  increased infection rates, days on vent, days in
  hosp, and mortality in 1 trial.
• Head to head studies, mostly SICU (TPN vs
  enteral) lower infection rate (RR 0.61) and no
  mortality difference with enteral support.
• Studies are needed to define roles of each in
  medical pts (more pre-existing malnutrition) vs
  surgical (acute illness with less pre-existing
  malnutrition).

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Simplified Approach

• severe burn or trauma ? early enteral NS within
  24-36 hours
• severe physiologic stress and diet will be
  compromised ? early enteral
• well-nourished on admit, no hurry
• malnourished (remember wt loss, BMI lt18.5, alb lt
  3.2, TLC lt 1500 can be from catabolism) use
  decision chart

patient status days before tube feeding days before TPN
no malnutrition and no stress 7-10 ? (gt10-14)
malnourished only 1-7 ? (gt7)
stressed only (critically-ill) 2-3 ? (gt10, never)
both 1-3 ? (gt10, never)
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Nutritional Support
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Route of Administration

• Enteral
• more physiologic (doesnt bypass gut mucosa and
  liver)
• less complicated (supplements, NG tube, PEG, DHT,
  naso-jejunal tube)
• less costly (especially cyclic, intermittent, or
  bolus feeding)
• fewer infectious and other complications
• better at preserving gut mucosal integrity and
  preventing microbial translocation
• Parenteral
• use only if you cannot use the gut
• bowel leak (not just bowel surgery enteral
  feeding may help fresh anastomosis)
• bowel obstruction
• prolonged ileus
• short bowel / severe malabsorption
• mesenteric ischemia
• no gut access

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Estimate Needs (weight based)

• If malnourished (BMI lt18.5), use actual body
  weight to avoid refeeding syndrome
• Devine formula, 1974
• males IBW 50 kg 2.3 kg for each inch over 5
  feet
• females IBW 45.5 kg 2.3 kg for each inch
  over 5 feet
• underestimates IBW for short women
• Robinson formula, 1983
• males IBW 52 kg 1.9 kg for each inch over 5
  feet
• females IBW 49 kg 1.7 kg for each inch over
  5 feet
• better estimate for females
• Obesity correction (BMI 30)
• adjusted IBW IBW (ABW - IBW)/4

for pts with BMI between 18.5 and 29,most
useABW edema weight
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Estimate Needs

• calories
• basal or resting energy expenditure (BEE or REE)
• men 66 (13.7 x kg wt) (5 x cm ht) (6.8 x
  age) or 879 (10.2 x kg wt)
• women 665 (9.6 x kg wt) (1.7 x cm ht) (4.7
  x age) or 795 (7.18 x kg wt)
• activity factor
• bed rest 5-10 light activity 50
• ambulatory 20-30 moderate activity 75
• stress factor
• minor surgery 10 appendicitis, long bone
  fracture 20
• major infection 30-40 multiple trauma
  60 burns 30-70
• special cases (unstable sepsis, hypotension)
• reduce or hold caloric support to avoid
  hyperglycemia (lt110, NEJM 2001) and immune
  suppression
• protein
• basal
• 0.5 - 0.8 gm/kg/d
• adjust for stress/illness

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Estimate Needs(Practical Method)

• calories per kg/day
• critically ill 15-20 (18)
• bed rest/mod ill 25
• mild stress or activity 30
• for weight gain 35
• burn patient 40
• protein grams per kg/day
• no stress 0.8
• mild stress 1.0
• dialysis 1.3
• moderate stress 1.2
• severe stress 1.5
• burn patient 2.0

80 kg patient 2400 kcal 100 grams protein
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TPN Calculations
carboD70 lipidF20 proteinAA10
80 kg patient 2400 kcal 100 grams protein
protein4 kcal/gram AA1010 grams/dl AA10 40
kcal/dl AA10 0.4 kcal/cc
protein 100x4400 kcal 480/0.41000 cc
2400-4002000 kcal
fat9 kcal/gram F2020 grams/dl F20180
kcal/dl F201.8 kcal/cc
lipid 2400x30720 kcal 720/1.8400 cc
2000-7201280 kcal
dextrose3.45 kcal/gram D7070 grams/dl D70241
kcal/dl D702.4 kcal/cc
carbo 1280/2.4530 cc
propofol is F10 1 kcal/cc
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Monitoring Nutritional Status/Support

• correct osmolality, volume, glucose and
  electrolyte abnormalities first
• watch for refeeding syndrome (fluid
  retention/CHF, low phos, K, Mg, high glucose)
• if serum glucose is hard to control, increase
  lipid ratio (up to 50-66 of calories), but
  remember that lipid is less nitrogen preserving
  than dextrose (below 150 g/d dextrose)
• if triglycerides are hard to control, lower the
  lipid ratio (can be removed for periods)
• follow weights daily, consider prealbumin weekly,
  and UUN occasionally (rare)

N balance (grams protein intake/6.25) - (grams
UUN 4) grams N deficit x 6.25 extra grams
protein needed
albumin rise prealbumin rise transferrin rise
sensitivity 61 88 67
specificity 41 70 55
PPV 86 93 87
NPV 17 56 27