Enteral tube feeding or enteral feeding refers to the delivery of a nutritionally complete feed (containing protein or amino acids, carbohydrate +/− fibre, fat, water, minerals and vitamins) directly into the gut via a tube. The tube is usually placed into the stomach, duodenum or jejunum via either the nose, mouth or the direct percutaneous route.
Enteral tube feeding can be used in combination with parenteral nutrition or alone.
Enteral tube feeding plays a major role in the management of patients who have poor intake, are critically ill or have gut dysfunction.
Indications for Enteral Tube Feeding
Enteral feeding in persons who are at at risk of malnutrition, all malnourished or who have a functional gastrointestinal tract but are unable to maintain an adequate or safe oral intake.
Common indications for enteral tube feeding are
- Critically ill patients
- Postoperative patients with limited oral intake.
- Elective gastrointestinal surgery
- Gastrointestinal cancer surgery
- Patients with severe pancreatitis, without pseudocyst or fistula complication
- Unconscious patient as in head injury
- Neuromuscular swallowing disorder
- Multiple sclerosis
- Motor neurone disease
- Parkinson’s disease
- Physiological anorexia
- Liver disease
- Upper GI obstruction
- Oro-pharyngeal or oesophageal stricture or tumour
- GI dysfunction or Malabsorption
- Inflammatory bowel disease
- Short bowel syndrome (parenteral nutrition may be needed)
- Increased nutritional requirements
- Cystic fibrosis
- Psychological problems
- Severe depression
- Anorexia nervosa
- Specific treatment
- Inflammatory bowel disease
- Short term enteral access during surgery i.e. head and neck cancer,
- Poor mental health
Routes of Access for Enteral Feeding
NG tubes are used mainly for short-term support in patients who do not have problems such as vomiting, gastroesophageal reflux, poor gastric emptying, ileus or intestinal obstruction.
Fine bore (5 – 8 FrG) NG tubes should be used for ETF unless there is a need for repeated large volume gastric.
There is a small risk that NG tubes can be misplaced on insertion or move out of position at a later stage.
Nasogastric tubes allow the use of hypertonic feeds, high feeding rates and bolus feeding .
Nasoduodenal and nasojejunal tubes
Nasoduodenal and nasojejunal tubes are those placed into the gastrointestinal tract with the distal tip lying beyond the stomach in the duodenum or jejunum respectively. These tubes can be placed at the bedside or with endoscopic/radiological assistance but the position needs to be confirmed by abdominal X-ray after .
These reduce the incidence of gastro-oesophageal reflux and are useful in the presence of delayed gastric emptying.
Tube enterostomy is the operative placement of a tube or catheter into the gastrointestinal tract. It is indicated when the passage of a fine-bore nasogastric tube is not possible or when more than 4 weeks of enteral feeding is anticipated.
It is contraindicates in complete or partial gastric or intestinal obstruction.
Jejunostomy is specifically considered for patient s where gastrostomy is contraindicated. This may include
- Gastric disease
- Impaired gastric emptying;
- Significant gastro-esophageal reflux
- Loss of the gag reflex.
Otherwise also jejunostomy is the procedure of choice for the ease of placement of the tube, the initiation of early postoperative feeding, and the avoidance of the risk of pulmonary aspiration.
Percutaneous endoscopic gastrostomy amd jejunostomy are preferred techniques to open surgery.
Types of Feed
Standard 1kcal/ml – with or without fibre
Suitable for the majority of patients.
Combination of soluble and insoluble fibre added for use in patients on long term feeding.
High energy 1.2–2.0 kcal/ml – with or without fibre
Used for patients on fluid restriction, or with increased nutritional requirements. Combination of soluble and insoluble fibre added for use in patients on long term feeding.
Low energy formulas
Contain 0.5 – 1 kcal/ml are complete for vitamins and minerals in a lower volume. Usually used for long term HETF patients with low energy requirements.
Provide nitrogen in the form of free amino acids or peptides and may be used in the presence of severe maldigestion or malabsorption
Milk free feed
Standard 1kcal/ml feed with a soya based protein source
Low Sodium feeds
Standard feeds with the sodium content reduced to around 10–15 mmol/litre
Contain reduced amounts of sodium, potassium and phosphate. The protein content is variable, providing similar or lower protein: calorie ratios compared to standard feeds.
Contain a higher percentage energy content from fat, which may reduce the amount of carbon dioxide produced from feed metabolism, and may be useful in patients with respiratory failure
Contain variable amounts of specific amino acids or fats, together with altered levels of specific micronutrients which have an immune benefit attributed to them
Jejunostomy/high output Ileostomy feeds
These need to have an osomolality of 300 mOsm/L and a sodium content of 100 mmol/L
Bolus feeding is as effective as continuous (16–24 hours) feeding.
If patients develop symptoms of abdominal distension vomiting, gastro oesophageal reflux , prokinetic agents like Metaclopromide and erythromycin appear to be effective in improving gastric motility.
Complications of enteral tube feeding
- Nasopharyngeal discomfort
- Nasal erosions
- Pharyngeal or oesophageal perforation [rare]
- Esophagitis, oesophageal ulceration and stricture [on prolonged used]
Fine-bore tubes should be used and replaced in the alternate nostril each month to pevent complications.
Percutaneous gastrostomy or jejunostomy tubes
- Compliction during procedure
- Bowel perforation
- Abdominal wall or intraperitoneal bleeding.
- Post-insertion complications
- Stoma site infections
- Peristomal leaks
- Dislodgement and gastrocolic fistula formation.
All feeding tubes should be flushed with water before and after use, as they block easily. Blockages can sometimes be removed by flushing with warm water or an enzyme solution but some tubes may need to be replaced.
Bacterial contamination of enteral feed can cause serious infectionFeed containers should be discarded every 24 hours to minimize the risk
Gastro-oesophageal reflux and aspiration
- Reflux occurs frequently in particularly in patients with impaired consciousness, poor gag reflex and when fed in the supine position. Patients should be propped up by at least 30° whilst feeding and should remain in that position for a further 30 minutes to minimise the risk of aspiration.
- If patient is required to be nursed flat post-pyloric tubes should be used.
- Use of repeated respiration and prokinetics added to reduce gastric pooling andreflux
- A abdominal bloating, cramps, nausea, diarrhoea and constipation are common.
- A of prokinetic drugs help
- Carbohydrates (eg, glucose) in the feed can cause a large increase in the circulating insulin level.
- This results in a rapid and dramatic fall in phosphate, potassium and magnesium –
- On refeeding, there is an increase in oxygen consumption, increased respiratory and cardiac workload
- Demand for nutrients and oxygen may outstrip supply.
- Both of the above can lead to multiple organ failure