Nutrition provision

Question 1

Aims of artificial nutrition

Answer 1

to maintain/restore body composition with nutritionally rational and balanced intakes (research is looking at best way to maintain/restore/modulate cell and organ function with specific AAs, antioxidants, micronutrients and PUFAs -> immuno-nutrition to optimize outcome)

Question 2

Energy requirements

Answer 2

in healthy subjects = food energy intake which balances total energy expenditure

Question 3

Feeding objectives

Answer 3

minimalize losses (provide energy = provide energy => TEE)

Question 4

Avoid

Answer 4

underfeeding (tissue energy mobilization development of malnutrition), overfeeding (excessive deposition/obesity and re-feeding syndrome -> metabolic complications of hyperalimentation)

Question 5

Food energy

Answer 5

stored 5kcals/g weight gain (rehabilitation and growth), consumed -> releases heat & work (TEE), CO2 and urea

Question 6

Maintenance energy requirements

Answer 6

= total energy expenditure -> calculate by adding BMR (prediction equations +/- 10% for weight/age/gender) +all other output (physical activity level/PAL and thermogenesis); TEE = BMR x PAL

Question 7

BMR

Answer 7

while PAL value is low, this is increased due to diseased state (pyrexia increases 13%/degree increase in temperature, generalized hypermetabolism) -> fall in activity may be balanced by this increase (maintenance needs may be similar to or greater than normal subjects)

Question 8

Energy needs of patients

Answer 8

healthy young adult male -> BMR is 24kcal/kg, PAL is 1.6 -> need 2660kcal/day -> TEE may vary between 1700-2500kcal (30-35kcal/kg/day)

Question 9

Males

Answer 9

need 25-30kcal/kg/day of non-protein energy and 30-35kcal/kg/day of total energy

Question 10

Females

Answer 10

need 20-25kcal/kg/day of non-protein energy and 25-30kcal/kg/day of total energy

Question 11

Malnourished patient

Answer 11

aim for an additional 5kcal/kg expected weight gain

Question 12

Food protein

Answer 12

used to replete tissues and replace nitrogen losses (maintenance of AA metabolism)

Question 13

Nitrogen losses

Answer 13

surfaces (skin/hair growth, sweat and secretions), urine (urea, NH4, creatinine), feces ->

Question 14

Healthy subject

Answer 14

protein losses vary with protein intake at average requirement intake (minimum intake for balance) -> 100mgN/kg = .63gprotein/kg/day

Question 15

ICU patients

Answer 15

need protein >200mgN/kg = 1.3gprotein/kg/day

Question 16

Protein needs

Answer 16

depends on metabolic status (catabolic state/normal metabolism) and nutritional status (depleted body composition or normal body composition)

Question 17

Catabolic state, normal or depleted body composition

Answer 17

If you give them nothing they will be in negative nitrogen balance -> cannot replace all nitrogen losses until you fix catabolic state (excess protein comes straight out) -> curve rises to a plateau that is still in negative balance -> minimalize losses of LBM -> use up to 1.5g/kg (.25gN) to reduce negative balance

Question 18

Normal metabolism, severe depletion

Answer 18

high protein feeds provide 1.9-2.2kg per day -> protein puts them in a significantly positive balance

Question 19

Normal metabolism, normal body composition

Answer 19

maintain balance in normal patients -> RDA = .83 g/kg (.13gN)

Question 20

Protein needs increase

Answer 20

with catabolism associated with SIRS and with tissue depletion in malnutrition -> aim to minimalize losses in catabolic patients and maintain balance in normal patients and replete losses in malnourished depleted patients

Question 21

Normal feeds

Answer 21

1.3-1.5g/kg protein

Question 22

High protein feeds

Answer 22

1.9-2.2g/kg protein

Question 23

Carbohydrates

Answer 23

may have lactose intolerance, may have problems with osmolality/diarrhea -> use polysaccharides -> used to satisfy glucose requirements of tissues, to maintain moderate insulin levels

Question 24

50% of energy needs!

Answer 24

How much carbohydrates are needed

Question 25

CO2 production problem (limit use of carbohydrates)

Answer 25

better to use fat than carbohydrates because of this problem -> 42% more CO2 from carbohydrates than from fat -> potential for respiratory failure and/or respiratory acidosis

Question 26

Lipids

Answer 26

minimum requirements are 3-5% as EFAs, maximum is all non-protein energy (may cause high plasma NEFA levels in catabolic patients -> need for restraint)

Question 27

20-30% of non-protein calories!

Answer 27

How much lipids are needed

Question 28

Types of lipids

Answer 28

medium chain TGs are best for ease of absorption and tissue consumption -> usually soybean oil = intralipid-> n-6 PUFAs (linoleic acid -> 52%), n-3 PUFAs (alpha-linoleic acid -> 7%) -> may be too much n-6 compared to n-3

Question 29

N-6 fatty acid (linoleic acid -> 18:2)

Answer 29

produces arachidonic acid -> 2-series PG and 4 series LT -> inflammation and dysregulated immunity

Question 30

N-3 fatty acids (alpha-linoleic acids -> 18:3)

Answer 30

produces EPA (DHA in fish oil) -> reduces production of arachidonic acid products; produces 3-series PG and 5 series LT -> less inflammation and improved immunity

Question 31

Alternatives to soybean oil

Answer 31

MC TGs, olive oil (oleic acid -> MUFA -> reduce excessive n-6 FA), fish oil (reduce high n-6: n-3 ratios)

Question 32

Nutritional implications for therapy

Answer 32

no quantitative data on requirements -> enteral feeds usually replete but TPN solutions may require supplementation prior to use -> cocktails of key vitamins are given enterally in many centers during severe catabolic stress

Question 33

Vitamins and trace elements for IV nutrition

Answer 33

catabolic patients have increased requirements -> prior malnutrition (depleted levels), increased needs with increased metabolic rate (B vitamins -> thiamine, riboflavin and niacin), increased needs for antioxidants (vitamin C, E, selenium, B6, riboflavin)

Question 34

B6

Answer 34

cofactor for cysteine/glutathione synthesis,

Question 35

Riboflavin

Answer 35

cofactor for glutathione reductase

Question 36

Trace elements (Fe, Cu, Mn, Zn)

Answer 36

100% utilization with IV route compared to with enteral route (no regulation of absorption so give much less -> 15-45% of usual)

Question 37

Immuno-nutrition (post-surgery, critical illness, burns)

Answer 37

improved barrier function, improved immune function, decreased hyperinflammation, improved wound healing -> all lead to better clinical outcome -> this is a research area rather than established practice

Question 38

Immunonutrients

Answer 38

AA (glutamine, arginine, cysteine), antioxidants, fish oils -> not always available at hospitals

Question 39

Glutamine

Answer 39

especially parental route -> has benefit in both post-surgery and critically ill patients

Question 40

Arginine

Answer 40

enteral feeds have benefit in post-surgery patients -> use in critically ill patients is controversial

Question 41

Very-long chain n-3 PUFAs from fish oil

Answer 41

emerging as having a potentially beneficial immunomodulatory actions