Nasogastric tube positioning

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

Radiographic features

Plain radiograph

A correctly placed nasogastric tube should ¹⁰:

• 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 ¹.

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 ²
• spinal canal insertion is very rare, occurring after skull base surgery in one case report ^8,9

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 ⁷:

• 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 fatal sequelae in ~0.3% of cases. Complications include ^1-6,8,9:

• upper airway
  • epistaxis from insertion trauma
• lower airway
  • aspiration pneumonia
  • pneumothorax
  • hemorrhage
  • empyema
• enteral
  • GI perforation and mediastinitis or peritonitis
    • may further complicate with intravascular placement
  • GI obstruction
  • knotting/tangling of the tube
  • intramural esophageal dissection
• intracranial and spinal canal
  • meningitis
  • focal neurological deficits