Nutritional SupportDepartment of Biochemistry

Faculty of PharmacySuez Canal University

Nutritional Support 

Oral, enteral or parenteral nutrition support, alone or in combination, should be considered for all people who are either malnourished or at risk of malnutrition.

Nutritional supportNutritional support should be considered in people

who are malnourished, as defined by any of the following:

1. A body mass index (BMI) of less than 18.5 kg/m2.

2. Unintentional weight loss greater than 10% within the last 3-6 months.

3. A BMI of less than 20 kg/m2 and unintentional weight loss greater than 5% within the last 3-6 months.

Nutritional supportNutritional support should be considered in people at

risk of malnutrition, defined as those who have:

1. Eaten little or nothing for more than 5 days and/or are likely to eat little or nothing for 5 days or longer.

2. A poor absorptive capacity.

3. High nutrient losses.

4. Increased nutritional needs from causes such as catabolism.

Nutritional requirements1) Water

For most patients, allow 1,500 ml for the first 20 kg of body weight plus 20 ml for every kg after this, and replace additional losses as they occur.

Nutritional requirements2) Energy

This can be estimated by multiplying body weight in kg by 30-35 kcal.

In obese patients, use ideal body weights.

Nutritional requirements3) Protein

Most patients need 0.8-1.2 g of protein/kg/day.In moderate-to-severe stress, up to 1.5 g/kg/day are

required.Use ideal weight for patients with significant obesity.

Nutritional requirements4) Electrolytes and minerals

There is a large number of essential electrolytes and daily requirements will need to be given to the patient.

There is also a need for adequate vitamins and trace minerals, usually supplied by premixed enteral solutions (lower quantities are needed in parenteral nutrition).

Nutritional requirements5) Essential fatty acids

2.4% of total calories should be given as linoleic acid.In parenteral nutrition, give at least 250 ml 20%

intravenous fat 2-3 times weekly.

Nutritional supportEnteral or parenteral nutrition may be required for

patients with prolonged unconsciousness, inability to swallow, intestinal failure, following major gastrointestinal (GI) surgery or in aggressive chemotherapy with severe inflammation of the mouth.

Where possible,  Enteral nutrition is preferred because it is less invasive, has a lower risk for infection, and is safer than the parenteral method.

Routes of Nutritional SupportThe nutritional needs of patients are met through a variety

of delivery routes and with an array of nutritional formulation components and administration equipment.

1) Enteral nutrition (EN)Long-term nutrition: (Gastrostomy, Jejunostomy)Short-term nutrition: (Nasogastric feeding,

Nasoduodenal feeding, Nasojejunal feeding)

2) Parenteral nutrition (PN)Peripheral Parenteral Nutrition (PPN)Total Parenteral Nutrition (TPN)

Parenteral nutrition

Specific indications for parenteral nutrition

1. Complete mechanical intestinal obstruction.

2. Ileus or intestinal hypomotility.

3. Severe uncontrollable diarrhoea.

4. Severe acute pancreatitis.

5. High-output fistulae.

6. Shock.

In patients who require immediate support but are expected to improve within 1-2 weeks, peripheral vein nutritional support can be given via standard intravenous (IV) lines.

Parenteral nutritional support systems

Basic solution comprises dextrose, amino acids and water.

Typical solution contains 25-35% dextrose and 2.75-6% amino acids, together with minerals, vitamins and trace elements and fat emulsion (20%).

Usually given at 30 ml/hour on day one and 60 ml/hour on day two.

Parenteral nutritional support systems

Provides adequate protein but usually inadequate energy that must be supplemented with intravenous lipids, as described earlier.

IV fat is increasingly used in patients with large energy requirements, to prevent excess administration of dextrose.

Complications of parenteral nutrition

Malposition of central venous catheter and possible pneumothorax.

Catheter blockage from reflux of blood into the catheter.

Infections.Hyperglycaemia, especially if the rate of infusion is

not properly regulated.

Enteral nutrition

Enteral feeding

Patients who are able to sit up in bed and can protect their airways, can be fed into the stomach.

Feeding tubes can be placed directly into the GI tract.

Enteral nutritional support systems

A wide range of commercially prepared solutions is available.

In most cases, isotonic solutions containing no lactose or fibre are preferred.

They generally contain 1,000 kcal and 37-45 g of protein/litre.

Enteral nutritional support systems

Preparations also available with elemental solutions containing hydrolysed proteins or crystalline amino acids without significant fat content for patients with malabsorption, especially pancreatic insufficiency. They are highly hypertonic and can cause severe diarrhoea.

Complications of enteral nutritionThe most common complications are nausea

or vomiting, abdominal bloating and cramps, diarrhoea and constipation.

Unconsciousness and impaired swallowing or vomiting may cause aspiration pneumonia, also caused by reflux.

Metabolic disturbances can occur, e.g. rebound hypoglycaemia after sudden withdrawal.

Blocked tubes.

Nutritional support

Hydration state and overall clinical status needs daily assessment, with nutrition adjusted accordingly.

There is also the need to measure electrolytes, serum glucose, phosphorus, magnesium, calcium and creatinine and urea daily until stabilised.

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