The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [269]
Enteral feeding equipment
The administration of enteral feeds may be as a bolus, intermittent or continuous infusion, via gravity drip or pump assisted (Table 8.7). There are many enteral feeding pumps available which vary in their flow rates from 1 to 300 mL per hour. The following systems may be used for feeding via a pump or gravity drip.
Table 8.7 Methods of administering enteral feeds
Feeding regimen Advantages Disadvantages
Continuous feeding via a pump
Easily controlled rate
Reduction of GI complications
Patient connected to the feed for majority of the day
May limit patient’s mobility
Intermittent feeding via gravity or a pump
Periods of time free of feeding
Flexible feeding routine
May be easier than managing a pump for some patients
May have an increased risk of GI symptoms, for example early satiety
Difficult if outside carers are involved with the feed
Bolus feeding
May reduce time connected to feed
Very easy
Minimum equipment required
May have an increased risk of GI symptoms
May be time consuming
Feed is decanted into plastic bottles or PVC bags. The administration set may be an integral part of the bag or may be supplied separately. The feed is sterile until opened and decanting feed into reservoirs will increase the risk of contamination of the feed from handling (Payne-James et al. 2001). Generally this method is only used for feeds that require reconstitution with water. Malnourished and immunocompromised patients are particularly at risk from contamination and infection so this method of administration should be avoided where possible.
The ‘ready-to-hang’ system has a glass bottle, plastic bottle or pack attached directly to the administration set. The bottles and packs are available in different types of feeds and sizes for flexibility. This is a closed sterile system which has been shown to be successful in preventing exogenous bacterial contamination (Payne-James et al. 2001).
Enteral feeds
Commercially prepared feeds should be used for nasogastric, gastrostomy or jejunostomy feeding. Available in liquid or powder form, they have the advantage of being of known composition and are sterile when packaged.
Whole protein/polymeric feeds
These contain protein, hydrolysed fat and carbohydrate and so require digestion. They may provide 1.0–1.5 kcal/mL (see manufacturer’s specifications). As the energy density of the feed increases, so does the osmolarity. Hyperosmolar feeds tend to draw water into the lumen of the gut from the bloodstream and can contribute to diarrhoea if given too rapidly. Fibre may be beneficial for maintaining gut ecology and function, rather than promoting bowel transit time (Thomas and Bishop 2007).
Feeds containing medium chain triglycerides (MCT)
In some whole-protein feeds a proportion of the fat or LCT may be replaced with MCT. The feed often has a lower osmolarity and is therefore less likely to draw fluid from the plasma into the gut lumen. MCT are transported via the portal vein rather than the lymphatic system. These feeds are suitable for patients with fat malabsorption and maybe steatorrhoea (Cummings 2000).
Chemically defined/elemental feeds
These contain free amino acids, short-chain peptides or a combination of both as the nitrogen source. They are often low in fat or may contain some fat as MCT. Glucose polymers provide the main energy source. These feeds require little or no digestion and are suitable for those patients with impaired GI function (Thomas and Bishop 2007). They are hyperosmolar and low in residue.
Special application feeds
These feeds have altered nutrients for particular clinical conditions. Low-protein and -mineral feeds may be used for patients with liver or renal failure. High-fat, low-carbohydrate feeds may be used for ventilated patients because less carbon dioxide is produced per calorie intake compared with a low-fat, high-carbohydrate feed. Very high-energy and protein feeds may be used where nutritional requirements