Assessment of Nutritional Status, Energy Requirements and Feeding

Micronutrients

These are compounds that can’t be made adequately in the body and are needed in minuscule quantities. They often act as cofactors for enzymes in metabolic reactions.

It can either be organic or inorganic:

• Organic - Vitamins:

  • Water soluble - B, C

  • Fat soluble - A, D, E, K

• Inorganic - Trace elements e.g. Iron, Zinc etc.

Energy Requirements

This should be equal to the body's Total Energy Expenditure (TEE).

Basal Metabolic Rate (BMR) is 60-70% of the TEE = Energy used in involuntary muscle contraction and cellular action

Thermic Effect of Food (TEF) is 10% of the TEE = Energy used during digestion, absorption, and metabolism of food

Nutritional Support

The reasons one would need enteral feeding (e.g. NG, NJ, PEG) are:

• Unsafe swallow i.e. risk of aspiration (e.g. recent CVA, parkinson’s, MND)

• Inability to meet oral requirements (e.g. anorexia)

• Oesophageal narrowing (e.g. strictures, malignancy)

The reasons one would need parenteral feeding (e.g. PICC, CVC, Port) are:

• Intestinal obstruction/perforation

• Short bowel syndrome

If a patient is suddenly fed after long periods of starvation/malnutrition, they can develop a condition known as Refeeding Syndrome:

• During the period of malnutrition, metabolism in cells slows down. When giving food quickly, the boost of Insulin pushes magnesium, potassium and phosphorus into cells, therefore leading to:

  • Hypomagnesaemia

  • Hypokalaemia

  • Hypophosphataemia

    • This is a dangerous as it can lead to Arrhythmias, HF and Fluid overload

N.B. These patients need very careful monitoring with an ECG when starting them on nutrition.