Chapter 8: Nutrition and fluid balance
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Related theory
The basic components of a parenteral nutrition regimen are provided by solutions including the following:
- Amino acids (nitrogen source): commercially available solutions provide both essential amino acids, usually in proportions to meet requirements, and non‐essential amino acids, such as alanine and glycine.
- Glucose (carbohydrate energy source): Glucose is the carbohydrate source of choice. It provides 3.75 kcal/g (15.5 kJ/g) and usually provides 50% of non‐nitrogen energy.
- Fat emulsion (fat energy source): fat generates 9 kcal/g (37 kJ/g) and its inclusion in parenteral nutrition is necessary to provide essential fatty acids. Fat usually provides 50% of non‐nitrogen energy.
- Nitrogen: non‐nitrogen energy is usually provided in the ratio of 1:150–200. An insufficient energy supply from carbohydrate and fat will encourage the use of nitrogen for energy.
- Electrolytes: for example sodium, potassium, calcium, magnesium and phosphate.
- Vitamins and minerals: both water‐soluble and fat‐soluble vitamins are required as part of a standard bag.
- Trace elements: for example zinc, copper, chromium and selenium (Singer et al. [171]).
