Nasogastric feeding is the most commonly used type of enteral tube feeding and is suitable for short‐term feeding – that is, 2–4 weeks (NCCAC [108]). Nasogastric and nasojejunal tubes (Figures 8.20 and 8.21) must be radio‐opaque throughout their length and have externally visible length markings. Fine‐bore feeding tubes should be used whenever possible as these are more comfortable for the patient than wide‐bore tubes. They are also less likely to cause complications such as rhinitis, oesophageal irritation and gastritis. Polyurethane or silicone tubes are preferable to polyvinylchloride (PVC) tubes as they withstand gastric acid and can stay in position longer than the 10‐ to 14‐day lifespan of the PVC tube (Payne‐James et al. [137]).

A gastrostomy may be more appropriate than a nasogastric tube when enteral tube feeding is anticipated to last longer than 4 weeks. It avoids delays in feeding and discomfort associated with tube displacement (NCCAC [108]).

A gastrostomy tube may be placed endoscopically (percutaneous endoscopically placed gastrostomy (PEG)) or radiologically (radiologically inserted gastrostomy (RIG)). PEG tubes may be placed while the patient is sedated, thereby avoiding the risks associated with general anaesthesia.

Certain groups of patients are not suitable for endoscopy; in these cases a RIG can be used. They are indicated for patients with oesophageal cancer with bulky tumours where it would be difficult to pass an endoscope and also for patients with a head and neck cancer whose airway would be obstructed by an endoscope. There is also a documented risk of the endoscope seeding the tumour to the gastrostomy site when it pulls the tube past a bulky tumour, although this is a rare complication (Cruz et al. [42]).

The tubes are made from polyurethane or silicone and are therefore suitable for short‐ and long‐term feeding. A flange, flexible dome, bumper, inflated balloon or pigtail sits within the stomach and holds the tube in position (Figure 8.22). Post insertion, T‐fasteners (Figure 8.23) are used to anchor the abdominal wall to the gastric wall until the gastrostomy tract is formed. For guidance on how to remove these, see Procedure guideline 8.14: Removal of T‐fasteners.

For longer‐term feeding, a low‐profile gastrostomy (Figure 8.24) or ‘button’ may be considered. This has the advantage of being less bulky and is therefore easier to conceal under clothing. A low‐profile device contains a valve to prevent reflux of gastric contents through the device. Access through the device is obtained by an extension set that opens the valve, allowing administration of fluids or feed via a syringe or giving set. If the button has a balloon retention device then this must be checked regularly in line with the manufacturer's recommendations to ensure that any leaked fluid is replaced and that the balloon has maintained its integrity.

A jejunostomy is preferable to a gastrostomy if a patient has undergone upper gastrointestinal surgery or has severe delayed gastric emptying; in some cases it can be used to feed a patient with pyloric obstruction (Gandy [58]). Fine‐bore feeding jejunostomy tubes may be inserted surgically or laparoscopically with the use of a jejunostomy kit, which consists of a needle‐fine catheter. The use of needles and an introducer wire allows a fine‐bore polyurethane catheter to be inserted into a loop of jejunum. Alternatively, some gastrostomy tubes allow the passage of a fine‐bore tube through the pylorus and into the jejunum. A double‐lumen tube allows aspiration of stomach contents while feed is administered into the small intestine. This is known as transgastric feeding (Toh Yoon et al. [182]).

ENFit is an international safety initiative (ISO 80369‐3) (Figure 8.25) applicable to all enteral feeding devices (e.g. feeding tubes, giving sets, enteral syringes and some Ryles tube drainage bags) that makes the connections of these devices incompatible with intravenous devices (EPSG [49]). A charitable organization (Global Enteral Device Supplier Association) has been set up to introduce the change and set international standards. This global change should reduce the risk of wrong route administration.

There is currently a period of transition where some patients who have long‐term indwelling feeding tubes still have a non‐ENFit connection. For these tubes an adapter is required to enable connection with feeding ancillaries such as giving sets and syringes. The adapters are a temporary step and will be withdrawn from the market at some stage. The dietitian responsible for the overall management of the patient must ensure that a suitable ENFit connection replaces any old connections still in use. This should be done before the manufacturers stop supplying adapters to the market.

These contain protein, lipids in the form of long‐chain triglycerides (LCTs) and carbohydrate and so require digestion. 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 (Lever et al. [84]).

In some whole‐protein feeds, a proportion of the fat or LCTs may be replaced with medium‐chain triglycerides (MCTs). These feeds often have a lower osmolarity and are therefore less likely to draw fluid from the plasma into the gut lumen. MCTs are transported via the portal vein rather than the lymphatic system. These feeds are suitable for patients with fat malabsorption and perhaps steatorrhoea (Hilal et al. [68]).

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 MCTs. Glucose polymers provide the main energy source. These feeds require little or no digestion and are suitable for patients with impaired gastrointestinal function, maldigestion or malabsorption (Gandy [58]). They are hyperosmolar and low in residue.

These feeds have altered nutrients for particular clinical conditions. Low‐protein and low‐mineral feeds may be used for patients with renal failure. High‐fat, low‐carbohydrate feeds may be used for ventilated patients because less carbon dioxide is produced per calorie of intake compared with a low‐fat, high‐carbohydrate feed. Very high‐energy and high‐protein feeds may be used where nutritional requirements are exceptionally high, for example in patients with burns or severe sepsis. These feeds contain approximately double the amount of energy and protein compared to standard whole‐protein feeds.

These are designed for children aged 1–12 years and/or 8–45 kg in weight. The protein, vitamin and mineral profile is suitable for children. Generally they are lower in osmolarity than adult feeds. The whole‐protein/polymeric feeds are based on cows’ milk but are lactose free. Some of these feeds contain dietary fibre. These feeds provide 1.0–1.5 kcal/mL for children who require additional energy and protein in a smaller volume. Hydrolysed protein feeds and elemental feeds are used in conditions such as food allergies and malabsorption. The osmolarity of these feeds is higher than whole‐protein feeds. They need to be introduced carefully (Gandy [58]).

There is evidence to show that the addition of glutamine, arginine or omega‐3 fatty acids, if given pre‐operatively, may benefit post‐surgical gastrointestinal patients by reducing the risk of post‐operative infections (Arends et al. [5]). These specialized liquids may be given pre‐ or post‐operatively. Up‐to‐date information on the exact composition of dietary supplements and enteral feeds can be obtained from the manufacturers.