Can the stomach inflate after tracheal intubation with an Ambu (Artificial Manual Breathing Unit) bag?

Gastric Inflation After Tracheal Intubation with Ambu Bag

Yes, stomach inflation can occur after tracheal intubation if the endotracheal tube is incorrectly positioned in the esophagus or if there is an abnormal communication between the tube and the gastrointestinal tract. 1

Causes of Gastric Inflation After Tracheal Intubation

• Esophageal intubation is the most common cause of gastric inflation, where the tube is incorrectly placed in the esophagus instead of the trachea 2
• Defective endotracheal tube with an abnormal communication between the tube and the gastrointestinal tract 1
• Partial displacement of the tube from the trachea into a position where air can enter both the lungs and esophagus 2

Confirmation of Correct Tracheal Tube Placement

• Waveform capnography is the gold standard for confirming tracheal intubation and should be used in all settings 3
• If a flat capnographic trace is seen after intubation, the presumption must be that the tracheal tube is located in the esophagus until proven otherwise 2
• Secondary confirmation methods include:
  • Direct visualization of the tube passing through the vocal cords 2
  • Auscultation in the axillae and over the epigastrium (absence of gastric sounds) 2, 3
  • Esophageal detector device (for children >20 kg with a perfusing rhythm) 2
  • Fibreoptic inspection to visualize tracheal rings and carina 2
  • Ultrasound sliding lung sign has high sensitivity and specificity for confirming correct tube placement 4

Prevention of Gastric Inflation

• Ensure proper tube placement with waveform capnography before initiating mechanical ventilation 2
• Inflate the endotracheal tube cuff with air to a measured pressure of 20-30 cmH2O immediately after confirming tracheal intubation 2
• Start mechanical ventilation only after cuff inflation and ensure there is no leak 2
• Record the depth of tube insertion prominently to prevent displacement 2
• Consider passing a nasogastric tube after successful tracheal intubation to decompress the stomach 2

Management of Suspected Incorrect Tube Placement

• If gastric inflation is observed after intubation, immediately reassess tube position 2
• Consider the DOPE mnemonic if an intubated patient's condition deteriorates:
  • Displacement of the tube (most common) 3
  • Obstruction of the tube 3
  • Pneumothorax 3
  • Equipment failure 3
• If esophageal intubation is confirmed, remove the tube and re-attempt intubation, limiting to a maximum of three attempts 2
• If ventilation becomes difficult after multiple attempts, consider using a supraglottic airway device (SAD) 2

Important Caveats and Pitfalls

• Presence of condensation (vapor trail) on the inner surface of the endotracheal tube is not a reliable indicator of correct tube placement, as it can occur with esophageal intubation as well 5
• Capnography may be unreliable in cardiac arrest due to low pulmonary blood flow 3
• Repeated attempts at intubation increase the risk of trauma and progression to a "can't intubate, can't ventilate" situation 6
• If a "can't intubate, can't oxygenate" situation develops, follow emergency front-of-neck airway access protocols 2

Monitoring After Successful Intubation

• Continue monitoring with waveform capnography throughout mechanical ventilation 2
• Watch for equal bilateral chest wall expansion with ventilation 2
• Consider chest X-ray or lung ultrasound to confirm proper tube position if there is any doubt 2
• Maintain proper tube fixation to prevent displacement 3