NGT insertion

Types of tube

• Terminology highly variable
• At Austin they seem to refer to two different types of tube, with slightly unclear differences between them
  • Ryles tube for NGT suction/drainage
  • Levin tube for feeding/medications

Contraindications

• Basal skull fracture
• Oesophageal stricture
• Oesophageal varices (relative)
• Bleeding diathesis

Technique

• Local anaesthetic spray (proven to reduce gagging and discomfort)
• Size to fit: nose to pinna to sternal angle to xiphisternum
  • If, for some reason, this was not or cannot be measured, the mean distance is 56cm
• Lubrication and insertion flat along nasal canal
• At 15cm (approaching trache-oesophageal junction):
  • Suck water through straw
  • Flex chin towards sternum
  • Turn head to either left or right
• Insert to appropriate depth (10cm below GOJ)
• For extreme safety, stop entry at 30cm and CXR to confirm oesophageal placement (if midline on CXR, continue)
• Secure
• CXR

Specific situations

• Tubes for decompression should be placed in the fundus
• Tubes for feeding should be placed in antrum, duodenum or jejunum
• Anaesthetised patients
  • If inserting blind, use a finger in mouth to direct posteriorly, combined with reverse Sellick's manoeuvre, and using a frozen tube (actually proven to help)
  • Laryngoscope if any difficulties
• Feeding tubes
  • Stylet placed and tube lubricated
  • Standard insertion
  • Remove stylet and image
  • If need to push further, have to fully withdraw then reinsert with stylet from the start again

Confirmatory tests:

• Soft (not reliable)
  • Easy placement to desired length
  • Absence of cough
  • Visual inspection of tube aspirate
  • Positive epigastric auscultation (only 80% sensitive)
• Medium
  • pH (mean 3.90 in stomach, 7.73 in lung, 7.35 in intestine) - but can be erroneously acidic in pulmonary infection
  • Bilirubin - high in intestine, medium in stomach, very low in lung
    • pH <5 and bili < 5 is 98% specific for stomach
    • pH >5 and bili <5 is 100% specific for respiratory
    • pH > 5 and bili > 5 88% specific for intestine
  • Capnography
• Hard
  • Radiography

Complications of placement

• Respiratory placement
  • Pneumothorax
  • Pleural effusion
  • Bronchoaspiration from enteral nutrition
• Oesophageal
• Pharyngeal injury
• Intracranial perforation
  • Majority basal skull fractures, mainly due to cribriform plate fracture

Complications after placement

• Oesophagitis/GORD (due to compromised lower oesophageal sphincter)
• Knotting - need gastroscopy to remove
• Gastritis/mucosal pressure necrosis
• Nasal alar ulceration or necrosis - frequent retaping, especially once discomfort occurs
• Tube obstruction
  • Mostly caused by concomitant administration of medication and enteral feeds
• Clogging

Management

• Don't fully spigot - always aspirate regularly to prevent overdistension of stomach