Question 4

Outline the dose (10% marks), composition (60% marks) and side effects (30% marks) of total parenteral nutrition (TPN).

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College Answer

The pharmacology of enteral and parenteral nutrition is a level 1 topic in the first part syllabus. The TPN dose in terms of daily calorie and other nutritional requirements were key expectations in first part of the question. A detailed list of all macro and micronutrients was required under TPN composition. Expected information about macronutrients were their forms in the TPN solution (e.g., carbohydrate in the form of glucose, protein in the form amino acids), their relative calorie contributions and their essential components (e.g., the names of the essential amino acids). Identification of potential variability in composition and dose based on specific patient factors scored extra marks. Side effects included metabolic derangements (refeeding syndrome, over or under-feeding, hyperglycaemia, hyperlipemia), biochemical disturbances (fluid and electrolyte imbalances), organ injury (liver, pancreas) and vascular access related complications. Limited breadth and depth of information as well as incorrect facts were prevalent in the answers that scored lower marks.