NG tube insertion Flashcards
Why do you use an NG tube
Delivery of enteral nutrition and medications. Due to:
• unconscious patient / reduced level of consciousness
• Swallowing disorders or unsafe swallow
• Increased nutritional requirements
• Specific NG medications and treatments
Drainage of gastric contents:
• gastrointestinal dysfunction e.g. ileus
• Gastrointestinal dysfunction
• Post GI surgery
• Decompression of the stomach e.g. following cardiac arrest and resuscitation
What are the contraindications to NG tube insertion
• Nasal and base of skull fractures • Nasal injuries or abnormalities • Recent head or neck surgery • Oropharyngeal, laryngeal, oesophageal or gastric abnormalities e.g. varices, tumours, strictures, pharyngeal pouch, severe hiatus hernia • Post op upper GI surgical patients • Trauma from poisoning e.g bleach • Clotting abnormalities
What are the risks of NG tube insertion
- Nasal trauma and epistaxis
- Sore throat and irritation by the NG tube
- Stimulus for nausea and vomiting, especially on insertion
- Coughing
- Low risk of passage into the trachea in a conscious patient with a normally protected airway. This risk is increased with a reduced GCS and loss of protective airway reflexes
- The insertion of the NG tube can be a vagal stimulus
- Failure of insertion
what cells in the stomach produce acid
- Hydrochloric acid is produced but he parietal cells in the stomach
what is the pH of cells in the stomach
1.5-3.5
How does control of gastric acid work
- Vagal nerve stimulation = Ach release = intracellular calcium and histamine from enterochromaffin cells
- Gastrin release = intracellular calcium and histamine from enterochromaffin cells
- Histamine = stimulates cyclic AMP
- All stimulate hydrogen ions secretion via H-K ATPase transporter
- H2O + CO2 = carbonic acid H2CO3 -> H + HCO3. HCO3 exchanged for Cl ion
What is the difference in NG tube structure for enteral nutrition and medications versus for drainage of gastric contents
Enteral nutrition and medications
- Fine bore nasogastric tubes are most often used for feeding patients with
Drainage of gastric contents
- wide bore nasogastric tubes are most often used for feeding patient with the following features
= gastrointestinal dysfunction
= gastrointestinal obstruction
= post GI surgery
= decompression of the stomach e.g. in cardiac arrest
How long can you feed a patient via an NG tube
- Feeding via NG tube is usually short term (<28 days) for a patient unable to meet nutritional requirements by mouth with a functional GI tract
What is a wide bore NGT know as
- Ryle’s tubes
What are the alternatives to an NGT
PEG: percutaneous endoscopic gastrostomy (endoscope assisted, guide wire inserted via skin and tube via guide wire form mouth)
RIG: radiologically inserted gastrostomy (fluoroscope assisted, tube inserted from skin via dilation, no guide wire)
TPN: total parenteral nutrition (nutrition via IV line, bypassing digestive process
What is the required equipment needed for an NG tube insertion
- Nasogastric tube - fit for purpose
- For feeding – fully radio-opaque, polyurethane, with 1cm markings along length of the tube and only accessible by oral/enteral syringes.
- For drainage – PVC, smallest Fr gauge suitable
- PPE
- Securing device
- pH testing strip (Johnson 0-6)
- Purple ENFit enteral syringes
- Cup of water and straw (if patient safe to swallow)
How do you measure the NG tube length required
NEX measurement (nose – ear lobe – xiphisternum):
- Best taken with the head to side
- If head is in the midline (facing forwards) add 5cm to the NEX to cover the ‘margin of error’
- Make sure you record this length before insertion
What tube do you need to lubricate
- Lubricate outside (tip) of fully radio-opaque nasogastric feeding tube with water but DO NOT flush tube.
- Fine bore NG tubes are self lubricating and so only need to be dipped in water.
- A Ryles tube (wide bore NGT) will need to be lubricated first before insertion as they are not self lubricating.
How do you insert the NG tube
Insert NGT into agreed nostril approximately 10 cm, aiming in the direction of the patient’s ear (rather that aiming the tube upwards in the nostril).
- If the patient coughs and gags at this stage, it is important to reassure them that this is normal.
- If there is an obstruction and you are unable to advance the NGT, try a slightly different angle, gently rotate the tube
Never apply force in order to advance the tube.
- Do not advance the tube any further than this until the patient has stopped coughing. This can prevent tracheal placement of the NGT
As the tube passes down into the nasopharynx ask the patient to start swallowing and sipping water through a straw unless nil-by-mouth
Note: swallowing closes the glottis thereby guiding the tube into the oesophagus.
Tilt the chin forward (unless contraindicated) and advance the tube to the length of the NEX measurement (see next slide) and then advance a few cm beyond this measurement.
If the patient shows signs of distress, e.g. gasping, coughing or cyanosis, remove the tube immediately.
If the tube is tolerated, collect 1ml of gastric aspirate with a purple enteral syringe and use the pH indicator method to check position. Secure the tape to the nostril with adherent dressing tape and also to the cheek. Attach a drainage bag if appropriate.
Note the depth of the tube by the centimetre markings at the nose. As a rough guide, the final NGT position is ideally at 50–60 cm from the incisor teeth.
Check the position of the NG tube as described with aspirate (pH 1 – 5). If this is not possible a CXR will be needed.
Remove gloves and wash hands. Ensure the patient is left comfortable
What gives evidence that the NGT is in the correct position
- Aspiration of gastric contents with a pH<5 gives evidence that the tip of the NG tube is sited correctly within the stomach
