Choice of Enteral Tube Feed
Enteral feed is a sterile, specifically designed nutritional liquid that is licensed to be administered via an enteral feeding tube. It is often nutritionally complete in specified volumes. There are a wide variety of different ‘feeds’ available from a range of manufacturers to meet patients individual requirements. They also come in different volumes and presentations (e.g. bottle or pack).
In order to determine which enteral feed is best suited to a patient; the dietitian will undertake a rigorous assessment of nutritional status and current clinical condition. The prescription of the feed is tailored to meet individual needs based on a persons’ specific nutritional requirements and the goals of the intervention. See Nutritional Assessment section for further information.
There are a wide variety of feeds available for use at the dietitians’ clinical discretion. Most commercial feeds available provide 1-2 kcal/ml, with or without fibre. Feeds can be broken down broadly into three categories:
- Polymeric (whole protein): these contain protein in the form in which it is normally within the diet i.e. as whole protein.
- Pre-digested (peptide/semi-elemental/elemental): these contain protein as smaller molecules i.e. short peptides, or free amino acids. Carbohydrate provides the majority of energy and the remaining proportion will be provided from fat as long or medium chain triglycerides where the ratio is variable based on preparation. The pre-digestion of components aims to improve nutrient absorption in the presence of malabsorption.
- Disease specific or immune enhancing feeds: these are special formulations for patients with organ failure, which often have nutrients that can modify the immune system.
Choice of Feed Modality
There are several methods of administering enteral feeds. The safest and most appropriate is selected following an individual assessment of the patient by a dietitian. Enteral feed can be administered either via an electronic feeding pump or using an enteral syringe.
Feeding via a syringe (bolus feeding)
Only enteral syringes, which are generally purple, have the word ‘Enteral’ on them and have either a female luer or catheter tip end, can be used to administer feed, water or medications via an enteral feeding tube. Both packs of enteral feed and oral nutritional supplements can be administered using this method. There are a number of companies that manufacture the syringes, giving sets and feeding pumps.
Bolus feeding via a syringe can be administered by two different methods:
- By gravity with the plunger removed. The plunger is removed from the barrel of the syringe, prior to attaching it to the feeding tube. The feed, water or medication is poured into the barrel, the clamp on the tube released and allowed to flow down the tube under gravity.
- Using the plunger. The plunger remains in the barrel of the syringe. The feed, water or medication is pulled up into the syringe and plunged down the tube at a slow rate.
Feeding via an enteral pump (pump feeding)
Pump feeding involves administering a pack of feed via a giving set that travels through a feeding pump and is attached to the end of the enteral feeding tube. Pump feeding allows for a set amount of feed to be delivered over a predetermined time. The feeding rate will depend on how well the feed is tolerated and the patients’ personal daily routine. The feed can run continuously for up to 24 hours or run intermittently over the day to suit the patients needs. Setting the pump to deliver boluses of feed at a faster rate, allows increased freedom from the pump.
|Continuous||Enteral pump||Slow hourly feed rate has may aid feed tolerance. Improved control of blood glucose levels due to consistent delivery of carbohydrate. Availability of mobile pumps and back-packs allows feeding to continue outside the home. Less labour-intensive. Allows overnight feeding.||Attached to pump for long periods of time which may restrict mobility/activity and quality of life. Requires some technical ability. Prolonged presence of a giving set may increase risk of tube displacement.|
|Bolus||Syringe or enteral pump||Mimics a normal pattern of eating. Allows for greater mobility/activity as the patient is not tied to the pump for long periods of time. Allows greater flexibility for the patient with regards when the feed is administered. Less equipment required.||The patient may not tolerate large bolus sizes. Patients with poor grip strength may struggle to push down plunger or hold syringe for time required to administer the feed. Syringes need to be cleaned and stored after use.|
Patients who either are unable to take any nutrition orally or who are unable to take sufficient nutrition orally, but in whom the gastrointestinal tract is functioning, may be fed enterally. This implies feeding into the gastrointestinal tract using a tube. Common underlying disease processes leading to enteral tube feeding include neurological disorders affecting swallowing, head and neck malignancy and oesophago-gastric diseases.
Thanks are due to many healthcare professionals who provided copy for this area of the BAPEN website. Among them are...
- Annelie Shaw
- Katrina Wood
- Caroline Goodger
- Kallum Rhule
- Sean White
- Dawn Jordan
With thanks also to the PENG committee of 2016 who reviewed content.