Nutrition and Intensive Care part 2

Question 1

What are the aims of artificial nutrition?

Answer 1

1. Maintain/restore body composition with nutritionally rational and balanced intakes
2. Maintain/restore/modulate cell and organ function with use of specific amino acids, antioxidants, micronutrients, specific polyunsaturated fatty acids

Question 2

What are the energy requirements in a healthy subject?

Answer 2

Food Energy intake which balances Total Energy Expenditure (TEE)
note: energy requirement= TEE kcal/day

Question 3

For patients what are the feeding objectives?

Answer 3

1. Minimization of losses (Severely ill ICU patients): provide as much energy as is safe but will probably be = less than the TEE
2. Energy balance (must normal patients) provide energy = TEE
3. Repletion (malnourished patients): provide energy equal to or greater than TEE

Question 4

What are some consequences if patients are underfed or overfed?

Answer 4

Underfed:
—tissue energy mobilization/development of malnutrition
Overfeeding:
–excessive deposition/obesity
–refeeding syndrome (metabolic complications of over feeding)

Question 5

For repletion of malnourished patients what is the aim?

Answer 5

additional 5kcals/g wt gain

–rehabilitation and growth

Question 6

What is the TEE (total energy expenditure) equation?

Answer 6

TEE= BMR x physical activity level (PAL)

Question 7

Maintenance energy requirements equal what?

Answer 7

Total energy expenditure (TEE)

Question 8

What are the associated PAL values and lifestyle patterns?

Answer 8

Sedentary ------ 1.4 
Average ----- 1.6 
Active ----- 1.8 
Very active -------- less than or equal to 2 
Elite Athlete ------ 2.5

Question 9

Patients: what is energy expenditure?

Answer 9

physical activity is low: less than 20% BMR

BMR is higher in diseased states

Question 10

A fall in physical activity may be balanced by what?

Answer 10

Increased metabolic rate

–maintenance needs may be similar to or even greater than normal subjects

Question 11

What are the target energy intakes for males and females?

Answer 11

Males: 30-35 kcal/kg per day
Females: 25-30 kcal/kg per day

Question 12

What are the protein requirements in a patient?

Answer 12

to replace nitrogen losses and replete tissues

Question 13

What are the total nitrogen losses in a healthy patient?

Answer 13

Losses vary with protein intakes at average requirement intakes, (minimum intake for balance) = 100mgN/kg = 0.63gprotein/kg/day

Question 14

What are the total nitrogen losses in ICU patients?

Answer 14

greater than or equal to 200mgN/kg = greater than or equal to 1.3g protein/kg/day

Question 15

The protein needs of patients depend on what?

Answer 15

1. Metabolic Status: either catabolic state (increased N losses) or normal metabolism (usual N losses)
2. Nutritional Status: Any additional needs for tissue repletion: either depleted lean tissue (more protein needed) or normal lean tissue (No additional needs)

Question 16

What is the protein intake requirement for enterally-fed catabolic patients?

Answer 16

1.3-1.5g/kg with normal feeds

Question 17

What is the protein intake requirement for rehabilitation?

Answer 17

1.9-2.2g.kg with high protein feeds

Question 18

What are potential problems in providing non protein energy such a carbs to patients?

Answer 18

1. Development of secondary lactose intolerance
2. Osmolality/diarrhea
   Use polysaccharides to solve problems 1 and 2
3. CO2 production problem (potential for respiratory failure and/or respiratory acidosis therefore limit use of carbs when feeding patients)
   Limit use of carbs to solve problem 3

Question 19

How much carbs are needed to provide the necessary amount to patients?

Answer 19

1. To satisfy glucose requirements of tissues
2. To maintain moderate insulin levels
   so about 50% of energy needs
   Bottom line: maintain blood glucose at 100-200mg/dl with moderate carb intakes

Question 20

The next non protein energy source are lipids. So how much lipids should be included in the diet of a critically ill patient?

Answer 20

1. Minimum requirements small: 3-5% energy as essential fatty acids

Question 21

What are potential problems of excess intake of lipids for these critically ill patients?

Answer 21

1. High plasma non essential fatty acid levels in catabolic patient

Question 22

What sorts of lipids are recommended for critically ill patients?

Answer 22

1. Ease of absorption/tissue consumption —- medium chain triglycerides best
2. Immune/metabolic aspects of long chain PUFAs: usually soybean oil: this is a high n-6 PUFA oil

Question 23

What are examples of n-6 PUFAs and n-3 PUFAs?

Answer 23

n-6 PUFAs — linoleic acid —- arachidonic acid —-inflammation and dysregulated immunity
n-3 PUFAs — alpha linolenic acid —- EPA and DHA — less inflammation and improved immunity

Question 24

What are ways to reduce n-6 content in the diet as well as the n-6:n-3 PUFA ratio?

Answer 24

reduce n-6 content with olive oil
reduce high n-6:n-3 PUFA ratio with fish oil
—this reduces n-6 prostaglandin and leukotriene synthesis

Question 25

As stated earlier, soybean oil is high in n-6 PUFA oil so what are some alternatives soybean oil?

Answer 25

Medium chain triglycerides
Olive Oil
Fish Oil

Question 26

Lipids can safely provide what percent non protein energy?

Answer 26

20-30%

Question 27

The type of fatty acid available in parental and enteral mixtures can influence what?

Answer 27

1. absorption/tissue utilization

2. patients response to infections and to inflammatory stimuli

Question 28

New lipid mixtures are becoming available and replacing n-6 PUFA with what?

Answer 28

n-6 PUFA with MUFA (oleic acid)

n-6 PUFA with n-3 PUFA from fish oil

Question 29

Provide about _____ % of energy needs as carbs

Answer 29

50%

• -use polysaccharides for enteral feeds
• –avoid respiratory acidosis (Not too much carbs)
• -aim to maintain normal blood glucose levels