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nasogastric tube insertion

NGT insertion

  • in the ED, a Ryles NGT is the tube most likely to be available:
    • it is a wide bore tube available in 10F, 12F, 14F and 16F sizes
    • it can be used for up to 2 weeks
    • have a permanent radio-opaque line down the tube
  • tube sizing:
    • adults: 16F
    • paed: (age in years + 16)/2
    • neonates >1.5kg: 6Fr or 8 oral feeding tube
    • neonates 1-1.5kg: 5-6Fr feeding tube
  • select nostril and optionally anaesthetise:
    • examine the patient's nostril for septal deviation
    • determine which nostril is more patent, ask the patient to occlude each nostril and breathe through the other
    • for adults and older children, instill 10 mL (max. 4mg/kg in children) of viscous lidocaine 2% (for oral use) down the more patent nostril with the head tilted backwards (see the images below), and ask the patient to sniff and swallow to anaesthetize the nasal and oropharyngeal mucosa
    • wait 5-10 minutes to ensure adequate anaesthetic effect
  • protect skin on face:
    • in neonates, tape Duoderm to skin of cheek abutting the nostril (for NGT) or on the chin below the lower lip (for OGT), prior to insertion of the tube
  • measure length from nose to stomach:
    • the distance from the patient’s nostril to the earlobe and then to the bottom of the xiphoid process, and note this length using the measured markings on the tube
      • for neonates, measure to half-way between xiphisternum and umbilicus with baby in supine position
  • position patient:
    • sitting up, or if unconscious, preferably with head end of bed up at 45deg
    • for neonates, wrap baby and consider sucrose analgesic
  • insertion:
    • Wash hands and apply gloves and lubricate tip of NGT to aid insertion (for neonates, use water or baby's saliva)
    • Insert the NGT into the nostril while pointing towards the ear, insert gently to pass it beyond the back of the nose.
      • If obstruction or resistance is evident do not use force, If unable to pass use alternate nostril.
    • Gently pass the NGT tube down the oesophagus whilst instructing the patient to dry swallow repetitively.
      • Do not ask the patient to swallow water during insertion unless certain the patient has an intact gag reflex, is alert, or is not on a modified diet.
    • Insert the tube further down the oesophagus until it reaches the measured length
    • If the patient becomes cyanosed or unduly distressed post insertion, immediately remove the NGT. Monitor oxygen saturations and apply oxygen if clinically indicated. Report the occurrence to the MO.
    • In some cases, NGT’s may need to be inserted under sedation/anaesthetic or via Fluroscopic Control in the Radiology Department
    • Open patient’s mouth using the tongue depressor and check with the torch that it has not coiled into the oral cavity
    • When the tubing has reached desired length, secure the NGT to the nose with nasofix tape
      • for neonates, tape the tube to the neonate’s face – either beside the nares for NGT or on the chin (below the lip margin) for OGT ensuring skin is protected with Duoderm prior to taping over the top of this area with Tegaderm.
  • the NGT must not be flushed with water or feed until position has been confirmed - see below

checking of correct placement of NGT

adults

  • confirm using a CXR
  • once the position of the NGT has been confirmed by chest xray as correct, place a tape marker on it at the tip of patient’s nose. This will allow rapid visual identification if the tube is dislodged during the shift;
  • auscultation of air insufflated through the feeding tube (whoosh test) is considered inaccurate and must not be used to test for the correct placement of NGTs.

neonates and paediatric patients where CXR is preferably avoided

  • CXR is the most accurate method but not recommended in neonates unless indicated as a diagnostic tool or requested by medical staff
  • checking aspirate pH:
    • aspirate stomach contents with the 5ml syringe and checking the pH, this should be 5.5 or lower.
    • if unable to aspirate stomach advance the tube 1cm further in or pull out by 1cm, alternatively pass 1ml of air into the tube as it may be lodged on the stomach wall preventing aspiration.
    • factors affecting the pH of gastric fluid may be the presence of amniotic fluid, milk when on continuous or frequent feeding and some medications
  • the following are NOT reliable and should NOT be used to indicate correct placement:
    • insert air into the tube and listen for a “whoosh” over the stomach
    • monitor bubbling at proximal end of a tube inserted in water
    • observing the appearance of aspirate

document insertion

  • Document in the patient’s medical history:
  • Date of insertion
  • Type of tube
  • External length of remaining NGT to the end of the cap
  • Date and time of post insertion CXR or confirmation tests
  • NGT length should be measured and documented in the patient’s medical history each shift.

NGT maintenance

  • NGT’s require flushing with 20-30mls water when pausing enteral feeds, after ceasing enteral feeding and before and after medication administration to prevent blockage.
  • Nasofix tapes (tape that secures NGT to nose) require changing every 3 days to allow for rotation of the tube and to avoid pressure areas; or more frequently if required to prevent NGT movement and dislodging.
  • enteral feeding gravity giving sets and pump giving sets must be changed every 24 hours.
  • daily confirmation of NGT placement must be obtained by pH testing or CXR to prevent serious complications prior to the administration of enteral feeds or medications.
  • daily pH testing for gastric positioning confirmation is preferred over CXR to reduce radiation exposure to the patient:
    • all feeds must be paused at 0700hrs, unless they are receiving insulin to avoid undesired hypoglycaemia, or are in ICU, as confirmation of placement is achieved through regular CXR.
    • therefore, at 0700hrs each day:
      • turn off the enteral feeds, disconnect the set and leave disconnected.
      • immediately post pausing enteral feeds at 0700hrs flush the NGT with 30mls water
      • flush again with a further 20mls air to ensure the pH result is not skewed by the remaining feed or water in the NGT
      • accurate pH results require enteral feeds to be paused for one hour
    • thus at 0800hrs:
      • aspirate the NGT with a 10 or 20ml syringe to obtain a minimum volume of 1ml of gastric fluid
      • Note: using a 50ml syringe may not generate enough pressure to aspirate gastric contents via a fine bore NGT
      • using the Acilit pH strips test the pH of the aspirated stomach contents, the aspirate only needs to be left on the strip until the colour indicator changes colour.
        • pH < 4 indicates gastric placement
      • If unable to obtain an aspirate:
        1. if possible, lay the patient on their left side and wait 5 minutes then attempt aspiration again.
        2. if step 1 unsuccessful insert the NGT a further 5cms and attempt aspiration again. Document the new NGT length on the NGT chart.
        3. if step 2 is unsuccessful notify the treating medical team and request a CXR for radiological confirmation of NGT position
      • NGT position confirmation by pH or CXR must be obtained prior to the re-commencement feeds, or administration of water and/or medications.
  • patients receiving insulin must not have their enteral feeds paused at 0700hrs for pH testing due to the increased risk of hypoglycaemia. These patients require greater vigilance with NGT placement monitoring as confirmation of placement can only be undertaken with TDS length measurement and monitoring for changes in respiratory status, i.e. increase in inflammatory markers, signs of respiratory infection or distress. CXR are to be taken if there is a suspicion of NGT dislodgement.
ngt.txt · Last modified: 2014/12/18 15:53 (external edit)