Nasogastric tube positioning

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Assessment of nasogastric (NG) tube positioning is a key competency of all doctors as unidentified malpositioning may have dire consequences, including death.

Evaluation of Nasogastric tube

Plain radiograph

A correctly placed nasogastric tube should :

  • descend in the midline, following the path of the esophagus and avoiding the contours of the bronchi
  • clearly bisect the carina or bronchi
  • cross the diaphragm in the midline
  • have its tip visible below the left hemidiaphragm

Ideally, the tip should be at least 10 cm beyond the gastro-esophageal junction .

Malpositioning may include tip position:

  • remaining in the esophagus
  • traversing either bronchus or more distally into the lung
  • coiled in the upper airway
  • intracranial insertion, possible in both patients with and without skull base trauma or surgery
  • spinal canal insertion is very rare, occurring after skull base surgery in one case report

In some circumstances fluoroscopic nasojejunal tube insertion is necessary.

Ultrasound

Point-of-care ultrasonography may be used to guide the nasogastric tube in real time with the probe placed sequentially in the following locations :

  • anterolateral neck
    • cervical esophagus typically visualized to the left, posterolateral to the trachea
    • an intraluminal curvilinear echogenic interface represents esophageal placement of the tube
  • epigastrium
    • with a longitudinal view of the gastroesophageal junction, the nasogastric tube may be advanced into the stomach under direct visualization
    • oblique and sagittal scan planes to view the tube coursing through the gastric fundus and terminating in the antrum, confirming correct placement

Complications

Overall, complications occur in 1-3% of cases, with complications leading to death occurring in approximately 0.3% of cases. Complications include :

  • upper airway
  • lower airway
  • enteral
    • viscus perforation and mediastinitis or peritonitis
      • may further complicate with intravascular placement
    • viscus obstruction
    • knotting/tangling of the tube
    • intramural esophageal dissection
  • intracranial and spinal canal