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Flashcards in Chapter 10: Nutrition Deck (120):
1

Caloric need

Approximately 20-25 cal/kg/d

2

Calories/gram: fat

9 Calories/gram

3

Calories/gram: protein

4 calories / gram

4

Calories/gram: oral carbohydrates

4 calories / gram

5

Calories/gram: dextrose

3.4 calories / gram

6

Nutritional requirements for average healthy male

- 20% protein calories (1g protein/kg/d; 20% should be essential amino acids)
- 30% fat calories - important for essential fatty acids
- 50% carbohydrate calories

7

% kcal requirement increase: trauma, surgery, or sepsis

20% - 40%

8

kcal/day requirement: pregnancy

300 kcal / day

9

kcal/day requirement: lactation

500 kcal / day

10

Calculation: calorie requirement in burns

25 kcal/kg/d + (30 kcal/d x % burn)

11

Calculation: protein requirement in burns

1-1.5 g/kg/d + (3g x %burn)

12

What is much of energy expenditure used for?

Heat production

13

How does fever affect basal metabolic rate?

Fever increased BMR 10% for each degree above 38.0 degrees Celsius

14

Calculation: caloric need in obesity

Weight = [(actual weight - ideal body weight) x 0.25] + IBW

15

Calculates basal energy expenditure based on weight, height, age, and gender

Harris-Benedict Equation

16

Glucose goals central line TPN

Glucose based
- Maximum glucose administration -> 3 g/kg/h

17

Fat based central nutrition

Peripheral line parenteral nutrition (PPN) - fat based

18

Fuel for colonocytes

Short-chain fatty acids (e.g., butyric acid)

19

Fuel for small bowel enterocytes

Glutamine

20

- MC amino acid in bloodstream and tissue
- Releases NH4 in kidney, thus helping with nitrogen excretion
- Can be used for gluconeogenesis

Glutamine

21

Primary fuel for most neoplastic cells

Glutamine

22

Half-life: albumin

18 days

23

Half-life transferrin

10 days

24

Half-life prealbumin

2 days

25

Normal protein level

6.0 - 8.5

26

Normal albumin level

3.5 - 5.5

27

Acute indicators of nutritional status

Retinal binding protein.
Prealbumin.
Transferrin.

28

Ideal body weight:
- Men
- Women

- Men = 106lb + 6lb for each inch over 5ft
- Women = 100lb + 5lb for each inch over 5 ft

29

Preoperative signs of poor nutritional status

- Acute weight loss > 10% in 6 months
- Weight

30

Strong risk factor for morbidity and mortality after surgery

Low albumin (

31

Ratio of CO2 produced to O2 consumed

Respiratory quotient - measurement of energy expenditure

32

Def: RQ > 1

Lipogenesis (overfeeding)
Tx: decreased carbohydrates and caloric intake.
- High carbohydrate intake can lead to CO2 buildup and ventilator problems

33

Def: RQ

Ketosis and fat oxidation (starving)
- Tx: increased carbohydrates and caloric intake

34

RQ: pure fat utilization

RQ = 0.7

35

RQ: pure protein utilization

RQ = 0.8

36

RQ: pure carbohydrate utilization

RQ = 1.0

37

Post op: diuresis phase

Post op days 2-5

38

Post op: catabolic phase

Post op days 0 -3

39

RQ: pure carbohydrate utilization

RQ = 1.0

40

What is the degree of injury proportional to?

The magnitude of metabolic response

41

When does glycogen deplete?

Depleted after 24-36 hours of starvation on (2/3 in skeletal muscle, 1/3 in liver) -> body then switches to fat.

42

Where is glucose-6-phosphatase found?

Only in the liver.
None in skeletal muscle: G6P stays in muscle after breakdown from glycogen and is utilized.

43

Gluconeogenesis precursors (x4)

Amino acids (esp alanine).
Lactate.
Pyruvate.
Glycerol.

44

Simplest amino acid precursor for gluconeogenesis.
- Primary substrate for gluconeogenesis

Alanine

45

Only amino acids to increase during times of stress

Alanine and phenylalanine

46

Where does gluconeogenesis occur in late starvation?

Kidney

47

Why do protein-conserving mechanisms not happen after trauma?

Secondary to catecholamines and cortisol.

48

Main source of energy in starvation and in trauma

Fat (ketones)
- In trauma, energy is more mixed (fat and protein)

49

% weight loss: pt can tolerate without complications

15%

50

When do you consider Dobhoff tube or TPN?

After about 7 days without eating.

51

Why do you want to feed gut?

To avoid bacterial translocation (bacterial overgrowth, increased permeability due to starved enterocytes, bacteremia) and TPN complications

52

Consider when regular feeding not possible (e.g., CVA) or predicted to not occur for > 4 weeks

PEG tube

53

Utilizes ketones with progressive starvation (normally uses glucose)

Brain

54

Obligate glucose users

Peripheral nerves.
Adrenal medulla.
Red blood cells.
White blood cells.

55

- Occurs when feeding after prolonged starvation / maturation.
- Results in decreased K, Mg, PO4-.
- Causes cardiac dysfunction, profound weakness, encephalopathy.

Refeeding syndrome

56

How do you prevent referring syndrome?

10 - 15 kcal/kg/d

57

- Anorexia, weight loss, wasting
- Thought to be mediated by TNF-alpha
- Glycogen breakdown, lipolysis, protein catabolism

Cachexia

58

Kawshiorkor

Protein deficiency

59

Marasmus

Starvation

60

gram protein = gram nitrogen

6.25g protein = 1g nitrogen

61

Calculate nitrogen balacne

Nin-Nout =
([protein/6.25] - [24hr urine N + 4g])

62

More protein ingested than excreted (anabolism)

Positive N balance

63

More protein excreted than taken in (catabolism)

Negative N balance

64

g/d: total protein synthesis for a healthy, normal 70kg male

250 g/d

65

- Responsible for amino acid production and breakdown
- Urea production is used to get rid of ammonia from amino acid breakdown

Liver

66

Amino acids: majority of protein breakdown from skeletal muscle

Glutamine and alanine

67

Broken down by pancreatic lipase, cholesterol esterase, and phospholipase to micelles and free fatty acids

Triacylglycerides (TAGs), cholesterol, and lipids

68

Aggregates of bile salts, long-chain free fatty acids, and monoacylglycerides
- Enter enterocyte by fusing with membrane

Micelles

69

Increase absorption area for fats, helping form micelles

Bile salts

70

Used to synthesize bile salts

Cholesterol

71

Fat soluble vitamins, absorbed in micelles

A, D, E, K

72

Enter enterocyte by simple diffuse

Medium and short chain fatty acids

73

Composition of chylomicrons

90% TAGS
10% phospholipids / proteins / cholesterol

74

Where do chylomicrons go after they are formed (form micelles and other fatty acids when they enter the enterocytes)?

Lymphatics by way of the thoracic duct

75

Enter lymphatics along with chylomicrons

Long-chain fatty acids

76

Fatty acids: enter the portal system (same as amino acids and carbohydrates)

Medium- and short-chain fatty acids

77

On endothelium in liver and adipose tissue; clears chylomicrons and TAGs from the blood, breaking them down to fatty acids and glycerol

Lipoprotein lipase

78

On endothelium in the liver and adipose tissue; binds short and medium-chain fatty acids

Free fatty acid-binding protein

79

Used for fuel by cardiac and skeletal muscles

Saturated fatty acids

80

Preferred source of energy for colonocytes, liver, heart, and skeletal muscle

Fatty acids (ketones - acetoacetate, beta-hyroxybutyrate)

81

Used as structural components for cells

Unsaturated fatty acids

82

In fat cells; breaks down TAGS (storage form of fat) to fatty acids and glycol, which are released into the bloodstream; sensitive to growth hormone, catecholamines, glucocorticoids

Hormone-sensitive lipase (HSL)

83

Essential fatty acids

Linolenic, linoleic

84

- Needed for prostaglandin synthesis (long-chain fatty acids)
- Important for immune cells

Essential fatty acids (linolenic, linoleum)

85

What does carbohydrate digestion start with?

Begins with salivary amylase, then pancreatic amylase and disaccharidases

86

Carbs: absorbed by secondary active transport; released into portal vein

Glucose and galactose

87

Carbs: facilitated diffusion, released into portal vein

Fructose

88

Fructose + glucose

Sucrose

89

Galactose + Glucose

Lactose

90

Glucose + Glucose

Maltose

91

What does protein digestion begin with?

Stomach pepsin, then trypsin, chymotrypsin, and carboxypeptidase

92

Released from pancreas and activated by enterokinase, which is release from the duodenum

Trypsinogen

93

What releases enterokinase?

Duodenum

94

Activates trypsinogen

Enterokinase

95

- Activates pancreatic protein enzymes
- Can auto activate other trypsinogen molecules

Trypsin

96

Broken down to amino acids, dipeptides, and tripeptides by proteases

Protein

97

How is protein absorbed?

Secondary active transport

98

Where are free amino acids released after protein digestion?

Into portal vein

99

Why limit protein intake in liver and renal failure?

To avoid ammonia buildup and possible worsening encephalopathy

100

Branched chain amino acids

Leucine, isoleucine, valine ("LIV")

101

- Metabolized in muscle
- Possibly important in patients with liver failure
- Are essential amino acids

Branched-chain amino acids (LIV: leucine, isoleucine, valine)

102

Essential amino acids

Leucine, isoleucine, valine, arginine, histidine, lysine, methionin, phenylalanine, threonine, and tryptophan

103

General composition TPN

-10% amino acid
-50% dextrose
-Electrolyes (Na, Cl, K, Ca, -Mg, PO4, Acetate)
-Mineral and vitamine
-Lipids (given separately from TPN)

104

Deficiency: Chromium

Hyperglycemia, encephalopathy, neuropathy

105

Deficiency: Selenium

Cardiomyopathy, weakness

106

Deficiency: Copper

Pancytopenia

107

Deficiency: Zinc

Poor wound healing

108

Deficiency: Phosphate

Weakness (failure to wean off ventilator), encephalopathy, decreased phagocytosis

109

Deficiency: Thiamine (B1)

Wernicke's encephalaopthy, cardiomyopathy

110

Deficiency: Pyridoxine (B6)

Sideroblastic anemia, glossitis, peripheral neuropathy

111

Deficiency: Cobalamin (B12)

Megaloblastic anemia, peripheral neuropathy, beefy tongue

112

Deficiency: Folate

Megaloblastic anemia, glossitis

113

Deficiency: Niacin

Pellagra (diarrhea, dermatitis, dementia)

114

Deficiency: Essential fatty acids

Dermatitis, hair loss, thrombocytopenia

115

Deficiency: Vitamin A

Night blindness

116

Deficiency: Vitamin K

Coagulopathy

117

Deficiency: Vitamin D

Rickets, osteomalacia, osteoporosis

118

Deficiency: Vitamin E

Neuropathy

119

Glucose is utilized and converted to lactate in muscle

Cori Cycle

120

Goes to liver and is converted back to pyruvate and eventually glucose via gluconeogenesis

Lactate