Insertion of nasogastric and nasojejunal tubes overview

A nasogastric tube (NGT) is a long tube that is passed through the nasal passage, the oesophagus and into the stomach. It has two main uses; feeding and emptying of stomach contents.

NGTs come in a variety of sizes of diameters. Some tubes will also have a guidewire to help aid insertion. The size used will depend on the size of the child’s nostril and the measured landmarks for insertion.

NGTs are intended for short-term use. If the child requires a longer-term method of enteral feeding the child will be assessed for a gastrostomy.

It is vital that staff are trained and competent in passing NGTs and checking the correct positioning.

It is important to communicate the purpose of NGT with the child and carer and to obtain consent.

Equipment

Gloves and apron, NGT (of appropriate size), sterile water, tapes, 20 ml enteral syringe, pH testing paper, a dummy, bottle, or glass of water and a straw (dependent on age).

Insertion

Prior to insertion the tip of the NGT should be placed on the tip of the child’s nose and then measured to the tragus of the ear and down to the xiphisternum (where the ribs meet in the centre of the chest). A note should be taken of the number on the tube.

The child, depending on age, can be held by a parent/carer, ideally in an upright position but young babies may be swaddled and laid flat. The tip of the tube may have a light coating of sterile water applied to act as a lubricant to ease insertion through the nasal passage and should be passed through the larger of the nostrils along the floor of the nasal passage. The tube should be pushed slowly and not forced, past the back of the nostril. It may be useful at this point to try and encourage the child to suck a dummy or drink from a cup/bottle to help aid the NGT into the oesophagus and down into the stomach. This is then taped to the child’s face/cheek, once the required measurement on the NGT reaches the nostril.

To check for correct positioning, the 20 ml syringe should be connected to the end of the NGT and an aspirate obtained. This should be tested with pH paper. Correct positioning will give a reading of between pH 1–5.5 and is a reliable indicator in determining whether the tube is in or outside the stomach. However, X-ray remains the gold standard.

The tube should be checked at the following times:

• following the initial placement;
  
• before administering each feed or any medication;
  
• at least once a day if the patient is receiving a continuous feed;
  
• following an episode of vomiting/coughing;
  
• if there is any evidence that the tube has been displaced.

The correct procedure shows a sufficient aspirate of between 0.5–1 ml and this should be documented in the patient’s notes.

Orogastric tubes

Sometimes it is not appropriate to use the nostril for the insertion of an NGT, e.g. if a child is receiving CPAP, has a narrowing of a nasal passage (coanal atresia) or if there is any suspicion of a basal skill fracture. In this case the tube can be inserted via the child’s mouth in the same way as it would be nasally, with the exception that it is measured from the mouth to the tragus and xiphisternum.

Nasojejunal tubes (NJT)

Jejunal tube feeding is used to feed directly into the small bowel. It is indicated if a child has delayed gastric emptying, persistent vomiting, severe gastro-oesophageal reflux or in the presence or an absence of the gag reflex.

Similar to placing an NGT, it is important to inform the child family of the need for the NJT, how it will be placed and to gain consent.

Equipment

The equipment required is the same as that for an NGT but a nasojejunal tube is used.

Procedure

The NGT tube should be measured prior to insertion. This should be done by taking two measurements. The first measurement (distance A) is taken the same way that you would measure for an NGT. The second measurement (distance B) is measured according to age.

Insertion

The child should be laid on their right side with a head elevation of 15–30 degrees if possible. Pass the tube as if inserting an NGT to distance A and secure. An aspirate should be obtained of a reading of <5.5 pH. Once placement has been confirmed, a small flush of water (2 ml in child, 0.5 ml in a neonate) should be given to encourage peristalsis and then slowly the tube should be advanced by:

• 1 cm every 15–30 mins for neonates;
  
• 2–4 cm every 5–10 mins for an infant and small child;
  
• 4–6 cm every 5–10 mins for a bigger child

Flush with water prior to advancing each time until distance B is reached. Following insertion of the tube, it should be checked for placement via either a fluoroscopy or an extended chest X-ray. This should occur approximately one hour post insertion to allow time for peristalsis to move the tube through the pylorus.

A clinician experienced in the assessment of NJT placement should interpret the X-ray and confirm placement.

The procedure and measurements should be documented in the patient’s notes.

The NJT should not be checked by obtaining an aspirate as this can cause the tube to recoil. A visual check of the tube is necessary, checking the marked measurement at the nostril and ensuring there has been no displacement of the tube every time the tube is used and/or at least daily.

NJT cannot be used for bolus feeding due to the jejunum having no capacity and this may cause vomiting, diarrhoea and abdominal pain. Feeds should therefore be administered continuously via a feeding pump. Care should also be taken to ensure that feeds are prepared and given in a sterile manner as the NJT bypasses the natural microbiological defences of the stomach.