Special nutritional needs

Nutrition support A prepared nutrient formulation/solution that can meet the patient’s nutritional needs. Enteral nutritional support Utilised when patient’s GI tract is still functional; especially refers to tube feedings but include oral diets and supplements. Parenteral nutritional support Utilised in absence of ability to digest and/or absorb nutrients. Typically refer to intravenous feedings.

Understanding normal & clinical nutrition, 8th Edition

Enteral nutrition Four types Standard (polymeric) – contain protein extracted from milk or soybeans or isolated from a combination of blended foods. Elemental (hydrolysed, chemically defined or monomeric)– compromised digestive and/or absorption. Require little to no digestion e.g. MCFA in persons with Chylomicron syndrome or Type I hyperlipidemia. Specialised (disease specific) – designed specifically to treat person with specific illness. Expensive & controversial. Modular – Macronutrients are individually packaged (modules) and then combined to supply patient with the nutrients to meet their individual needs. Modules are sometimes combined with one of the other types.

Macronutrient Composition – 12-20% protein, 40-60% CHO, 30-40% kcal from fat depending on formula type; Metabolic stress =high protein, kidney disease = protein restrictions Energy Density – high energy density = minimize amount of liquid, 0.5-2.0kcal/ml; 1-1.2kcal = usually adequate Fiber Content – important to afford good GI health. Contraindicated in pancreatitis & acute intestinal disorders Osmolality

Where do these macronutrients come from?

Parenteral nutrition Must provide nutrients in a form that is safe to inject directly into bloodstream e.g. amino acids, glucose, fluid & electrolytes, TAGs. May be Peripheral parenteral nutrition (PPN) – needs are met using only the peripheral veins; short term intravenous feeding (7-10 days); osmolarity must stay within 600- 900mOsm/L, phlebitis can occur. Total parenteral nutrition (TPN) – long term intravenous feeding, large volume of blood dilutes the parenteral solution allowing very nutrient dense solutions.

Concentrations of parenteral solutions Amino acids: 3.5 – 15%  4kcal/g Glucose: supplied as dextrose monohydrate; 2.5 – 70%  3.4kcal/g; may be given in a water or normal saline base. Lipids: Emulsion contain TAGs from safflower & soybean oil using PL as the emulsifier and glycerol to keep the solution isotonic; available as 10%, 20% & 30% solutions  1.1kcal, 2.0kcal & 3.0kcal per ml Fluids & electrolytes: 30-40ml/kg in young adults & 25-30ml/kg in older persons 1500-2500ml; Na, K, Cl, Ca, Mg, P; expressed as mEq

Estimation of the osmolarity of a 1-liter parenteral solution Multiply the grams of amino acids in the solution by 10. Multiply the grams of dextrose in the solution by 5. Multiply the milliequivalents of electrolytes in the solution by 2. Multiply the grams of lipids in the solution by 1.5. Add the values obtained to determine the approximate osmolarity.

Calculate osmolarity & energy content Amino acids: 30 g Sodium: 45 mEq Calcium: 2.8 mEq Dextrose: 150 g Potassium: 5 mEq Magnesium: 5 mEq Lipids: 30 g Chloride: 107 mEq Phosphate: 21 mEq