Parenteral Nutrition Support Flashcards
Clinical nutrition support routes of supply
Nasogastric (NG)
Nasojejunal (NJ)
Percutaneous endoscopic- gastrostomy (PEG)
Percutaneous endoscopic- jejunal (PEJ)
Parenteral nutrition- ingredients
Amino acids Carbohydrates Lipids Electrolytes Trace elements Vitamins Water
Indications for parenteral nutrition
Post-operative states where oral or tube feeding is contra-indicated for more than four or five days Short bowel syndrome GI fistulae Acute pancreatitis Multiple injuries involving viscera Major sepsis Severe burns
Nutrition, nutrition science and nutrients definitions
Nutrition: the science of food and its relationship to health
Nutrition science: the nature and distribution of nutrients in foods and their metabolic effects
Nutrients: chemical compounds in foods that are absorbed and utilised to promote health
Essential nutrient
One that is required by an organism, yet cannot be synthesised; failure to do so leading to a deficiency disease
Classifications of nutrients
Can be divided into 2 classes
Macronutrients: proteins, fats, carbohydrates and some mineral salts- supply energy for growth and activity
Micronutrients: vitamins and trace elements- catalyse the utilisation of the macronutrients
Pathophysiology of nutritional disease
Occurs by virtue of:
A dietary inadequacy
GI malabsorption
Abnormal systemic loss of nutrients through haemorrhage, diarrhoea or excessive sweating
Failure to reabsorb and retain nutrients by the kidneys
Primary malnutrition- marasmus
Insufficient energy to match requirements so body draws on its own stores Severe wasting No oedema Subcutaneous fat minimal Severe muscle wasting Albumin near normal
Primary malnutrition- kwashiorkor
Insufficient protein intake so decreased visceral protein synthesis Little wasting, muscle wasting variable Oedema Subcutaneous fat present Low serum albumin Enlarged fatty liver Skin/hair fragility
What are the sequence of events leading to a deficiency disease?
Nutrient not received or retained- plasma and tissue levels decline
Loss of cellular stores of nutrient, followed by reduction in all functions that depend on given nutrient
If deficiency persists, biochemical changes are followed by impairment of physiologic functions in given cells and their organs- leading to mortality
Metabolic pathways in first 24 hours of starvation
Glycogen from the liver is converted into glucose for the heart, muscles, kidney and brain
Metabolic pathways in early/late starvation
Amino acids from muscle and glycerol from fat stores are taken up by the liver and turned into glucose, ketones and fatty acids
The difference between metabolic reactions to short term and long term starvation
Increased glycogenolysis becomes depleted glycogen stored
Glucose oxidation leads to decreased glucose oxidation
Increased lipolysis leads to greatly increased lipolysis
Ketogenesis in the liver leads to greatly increased ketogenesis in the liver
Energy expenditure transiently elevated, becomes decreased
Primary and secondary effects of malnutrition
Increased tendency of infection, delayed wound healing, hypoproteinemia, muscle weakness
Increased morbidity, prolonged hospitalization, prolonged convalescence, increased mortality, increased costs
Effect of malnutrition on respiratory function
Decreased inspiratory force
Reduced vital capacity
Reduced functional residual capacity
Oxygenation decreased
Nutritional assessment
Nausea Obese Underweight Respiration Intake Swallow History Elderly Disease
Malnutrition screening
MUST- Malnutrition Universal Screening Tool
Developed by MAG (malnutrition advisory group) or BAPEN (British association of parenteral and enteral nutrition)
Malnutrition tests
Simple tests- patient height and weight
Anthropometric tests- skinfold thickness, mid-arm circumference
Biochemical tests- complete blood tests, urinary and stool output
Nutritionally at risk patients
Gross underweight or overweight
Recent loss of 10% or more of usual body weight
High alcohol intake
Increased metabolic needs e.g. excessive burns, infection, trauma
Amino acid solutions
Comprise of a solution of crystalline L-amino acids
They provide amino acids for protein synthesis
Have a balance of essential and non-essential amino acids
There is no excessive levels of any one particular amino acid
Carbohydrates
Usually a solution of glucose in water at various concentrations (5-70%)
Major source of energy (minimum requirement of 200g/day for an adult male to avoid ketosis and protein catabolism)
Solutions of fructose, maltose, sucrose, xylitol, sorbitol and even ethanol have been looked at
Definition of an emulsion
A dispersion of one immiscible liquid in another as small droplets. It is a thermodynamically unstable system, which will separate into its original states over time
A barrier to instability can be produced by the use of an emulsifying agent. this generate a mechanical barrier and or an electrostatic barrier.
IV lipid emulsions and chylomicrons
The particle in IV emulsions have similar properties to natural chylomicrons, so that they are cleared from the body with similar kinetics
Fluid and electrolyte balance
Fluid requirements usually in the range of 2-3L/day
Weight increases greater than 1kg/week could be due to water fluid retention
Signs of water depletion
Thirst, dry tongue, low urine volume, concentrated urine, weight loss, inelastic skin, mental confusion
Signs of water intoxication
Drowsiness, loss of concentration, giddiness, confusion, anorexia, loss of muscle power, subcutaneous oedema
