Flashcards in Nutrition and Intensive Care part 2 Deck (29)
What are the aims of artificial nutrition?
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
What are the energy requirements in a healthy subject?
Food Energy intake which balances Total Energy Expenditure (TEE)
note: energy requirement= TEE kcal/day
For patients what are the feeding objectives?
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
What are some consequences if patients are underfed or overfed?
---tissue energy mobilization/development of malnutrition
--refeeding syndrome (metabolic complications of over feeding)
For repletion of malnourished patients what is the aim?
additional 5kcals/g wt gain
--rehabilitation and growth
What is the TEE (total energy expenditure) equation?
TEE= BMR x physical activity level (PAL)
Maintenance energy requirements equal what?
Total energy expenditure (TEE)
What are the associated PAL values and lifestyle patterns?
Sedentary ------ 1.4
Average ----- 1.6
Active ----- 1.8
Very active -------- less than or equal to 2
Elite Athlete ------ 2.5
Patients: what is energy expenditure?
physical activity is low: less than 20% BMR
BMR is higher in diseased states
A fall in physical activity may be balanced by what?
Increased metabolic rate
--maintenance needs may be similar to or even greater than normal subjects
What are the target energy intakes for males and females?
Males: 30-35 kcal/kg per day
Females: 25-30 kcal/kg per day
What are the protein requirements in a patient?
to replace nitrogen losses and replete tissues
What are the total nitrogen losses in a healthy patient?
Losses vary with protein intakes at average requirement intakes, (minimum intake for balance) = 100mgN/kg = 0.63gprotein/kg/day
What are the total nitrogen losses in ICU patients?
greater than or equal to 200mgN/kg = greater than or equal to 1.3g protein/kg/day
The protein needs of patients depend on what?
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)
What is the protein intake requirement for enterally-fed catabolic patients?
1.3-1.5g/kg with normal feeds
What is the protein intake requirement for rehabilitation?
1.9-2.2g.kg with high protein feeds
What are potential problems in providing non protein energy such a carbs to patients?
1. Development of secondary lactose intolerance
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
How much carbs are needed to provide the necessary amount to patients?
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
The next non protein energy source are lipids. So how much lipids should be included in the diet of a critically ill patient?
1. Minimum requirements small: 3-5% energy as essential fatty acids
What are potential problems of excess intake of lipids for these critically ill patients?
1. High plasma non essential fatty acid levels in catabolic patient
What sorts of lipids are recommended for critically ill patients?
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
What are examples of n-6 PUFAs and n-3 PUFAs?
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
What are ways to reduce n-6 content in the diet as well as the n-6:n-3 PUFA ratio?
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
As stated earlier, soybean oil is high in n-6 PUFA oil so what are some alternatives soybean oil?
Medium chain triglycerides
Lipids can safely provide what percent non protein energy?
The type of fatty acid available in parental and enteral mixtures can influence what?
1. absorption/tissue utilization
2. patients response to infections and to inflammatory stimuli
New lipid mixtures are becoming available and replacing n-6 PUFA with what?
n-6 PUFA with MUFA (oleic acid)
n-6 PUFA with n-3 PUFA from fish oil