Nutritional Support in Hospital

A high level of malnutrition has been reported in hospital and is linked to poor clinical outcome.^1,2 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. Potential swallowing problems should be taken into account.³

• All hospital inpatients on admission and all outpatients at their first clinic appointment should be screened. Screening should be repeated weekly for inpatients and when there is clinical concern for outpatients.
• Nutrition support should be considered in people who are malnourished, as defined by any of the following:
  • A body mass index (BMI) of less than 18.5 kg/m².
  • Unintentional weight loss greater than 10% within the last 3-6 months.
  • A BMI of less than 20 kg/m² and unintentional weight loss greater than 5% within the last 3-6 months.
• Nutrition support should be considered in people at risk of malnutrition, defined as those who have:
  • Eaten little or nothing for more than 5 days and/or are likely to eat little or nothing for 5 days or longer.
  • A poor absorptive capacity.
  • High nutrient losses.
  • Increased nutritional needs from causes such as catabolism.

• Anti-emetics for nausea.
• Sloppy or liquid meals for patients with dysphagia from oesophageal stricture.
• Swallowing disorders from neurological causes benefit from more viscous liquids.
• Adequate pain relief may improve appetite.
• Dedicating time to feeding by nurses, healthcare assistants or relatives can help with the weak and elderly.
• When these measures are inadequate, oral supplements may be added.
• If these fail, enteral or parenteral nutrition may be required, e.g. for patients with prolonged unconsciousness, inability to swallow or intestinal failure. May also be needed following major GI surgery, in aggressive chemotherapy with severe inflammation of the mouth.
• Where possible, oral or enteral nutrition should be preferred to parenteral because it is cheaper, simpler and has other benefits, e.g. maintains integrity of gut barrier.

• Complete mechanical intestinal obstruction
• Ileus or intestinal hypomotility
• Severe uncontrollable diarrhoea
• Severe acute pancreatitis
• High output fistulae
• Shock

In patients who require immediate support but are expected to improve within 1-2 weeks, can use peripheral vein nutritional support via standard intravenous lines. Nutritional support needs to include lipid, dextrose with amino acids.

• Water:
  • For most patients allow 1,500 ml for the first 20 kg body weight plus 20 ml for every kg after this, and replace additional losses as they occur.
  • In average sized adult, approx. needs are 30-35 ml/kg or 1ml/kcal of energy.
• Energy:
  • Can be estimated by multiplying body weight in kg by 30-35 kcal (in obese patients use ideal body weights).
• Protein:
  • If adequate calories, most patients need 0.8-1.2g of protein/kg/day.
  • In moderate to severe stress up to 1.5 g/kg/day is required.
  • Use ideal weight for patients with significant obesity.
• Electrolytes and minerals:
  • Vary widely but most patients need 45-145 meq/day.
  • Also need adequate vitamins and trace minerals usually supplied by premixed enteral solutions (lower quantities are needed in parenteral nutrition).
• 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 x weekly.

• 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 1 and 60 ml/hour on day 2.
• 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.

• Malposition of central venous catheter and possible pneumothorax.
• Catheter blockage from reflux of blood into the catheter or coagulation of the feed - consider routine heparin solution. Remove clot with gentle suction or urokinase, hydrogen chloride or alcohol for lipid blockage.
• Infections: typically skin organisms. Needs to be inserted under aseptic conditions and not used for any other purpose.
• Fluid and electrolyte abnormalities:
  • Are common, e.g. hyperglycaemia, especially if rate of infusion not properly regulated.
  • Abnormal liver function tests, deficiencies of phosphate and essential fatty acids, hyperlipidaemia, hyperammonaemia, uraemia, mineral and vitamin deficiency, respiratory distress, intestinal atrophy, metabolic bone disease.

• Patients who are able to sit up in bed, and can protect their airways, can be fed into the stomach.
• Can place feeding tubes directly into gastrointestinal tract using tube enterostomies for long-term enteral nutritional support.
• Gastrostomies allow bolus feeding but jejunostomies need continuous infusion.

• Wide range of commercially prepared solutions are available.
• In most cases, isotonic solutions containing no lactose or fibre are preferred.
• They generally contain 1000 kcal and 37-45g of protein/litre.
• 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.

• Commonest 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. Can be prevented by giving feed directly into small intestine via a nasogastric tube placed directly into small intestine. Feed is controlled by infusion pump to prevent flooding.
• To prevent diarrhoea avoid contamination of feed with bacteria, control rate of infusion, give codeine phosphate or loperamide.
• Metabolic disturbances can occur, e.g. rebound hypoglycaemia after sudden withdrawal, hypokalaemia, hypophosphataemia during re-feeding.
• Blocked tubes: flush with water, warm solution of sodium bicarbonate, pancreatic enzymes. Consider using fizzy cola drinks.

• Hydration state and overall clinical status needs daily assessment, with nutrition adjusted accordingly.
• Also need to measure electrolytes, serum glucose, phosphorus, magnesium, calcium and creatinine and urea daily until stabilised.