Learning Radiology xray montage

Endotracheal Tube (ETT) Positioning

General Considerations


  • The tip of the endotracheal tube should be about 5 cm from carina or roughly halfway between the clavicles and the carina
  • This is because the tip may travel up to 2 cm downward if the neck is flexed or 2 cm upward if the neck is extended


Imaging Findings – Correct Position


  • The carina is normally at the level of T5-T7
  • Tip of tube is usually diagonally shaped with a marker stripe in the side of the tube
  • 5 cm from carina
  • Width of tube should be ½ to 2/3 width of trachea
  • Cuff, if present, should not be inflated so as to distended the walls of the trachea


Imaging Findings – Malposition


  • Most often malpositioned in right mainstem bronchus because of shallower angle right main bronchus makes with trachea than does left mainstem bronchus
  • Right mainstem bronchus intubation will lead to atelectasis of entire left lung and hyperinflation right lung
  • Bronchus intermedius intubation may lead to atelectasis of entire left lung and the right upper lobe
  • ETT tip in the neck may lead to vocal cord injury
  • Also may lead to perforation of the pyriform sinus, larynx or trachea and pneumomediastinum, subcutaneous emphysema, pneumothorax
  • Esophageal intubation may be suspected if tube deviates from the tracheal air shadow and there is a dilated esophagus and stomach


Other Complications


  • Aspiration/pneumonia
    • Dependent portions of lungs
    • Lower lobes
  • Foreign body aspiration
    • Broken teeth
    • Dentures
    • Fillings
  • Pneumothorax, pulmonary interstitial emphysema, pneumomediastinum from barotrauma
    • Rupture of alveoli from high pressures with mechanical ventilation
  • Sinusitis from prolonged nasotracheal intubation


Long-term Sequelae


  • More common with tracheostomy tubes than endotracheal tubes
  • Laryngeal injury from scarring of posterior glottis, fusion posterior commissure, arytenoid injury, subglottic stenosis
  • Tracheal stenosis
  • Tracheomalacia
  • Fistulae to esophagus, adjacent blood vessels

Endotracheal Tube (ETT) too low

Endotracheal Tube (ETT) Too Low. The tip of the endotracheal tube (blue arrow)
is in the right mainstem bronchus so that only the right lung is aerated and the
left lung is completely atelectatic (black arrow).
The tip of the ETT
should normally be about 5 cm above the carina ((white arrow).

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