Oesophageal Intubation

Oesophageal intubation is unrecognised or recognised placement of a tracheal tube in the oesophagus. Unrecognised placement leads to hypoxic brain injury and death.

Epidemiology. It occurs in about 1% to 5% of emergency intubations and up to 17% in some prehospital series. It is the commonest cause of death from airway management when capnography is not used.

Risk factors. Emergency settings, cardiac arrest, difficult laryngoscopy, obesity, trauma, inexperience, pulling the tube during repositioning and lack of waveform capnography.

Complications. Hypoxaemia, gastric distension, regurgitation and aspiration, oesophageal injury, cardiac arrest and death.

Pathophysiology.

Ventilation of the stomach does not exchange gas, so oxygen stores deplete and carbon dioxide accumulates. Gastric inflation raises intragastric pressure, and regurgitation follows.

Preoxygenation delays desaturation and may hide the error for minutes.

No chest rise, absent or distant breath sounds, epigastric gurgling or distension, no condensation in the tube, falling saturation (a late sign), bradycardia, cyanosis and absent end tidal carbon dioxide trace. A few breaths may show carbon dioxide from gastric gas that falls to zero.

Red flags.

• Flat capnography trace after 6 breaths.
• Desaturation under 90% with high airway pressures.
• Regurgitation.
• Bradycardia or arrest.

Continuous waveform capnography is the confirmation test. A trace sustained over 4 to 6 breaths means tracheal placement. In cardiac arrest, low flow states may give a weak trace, so confirm by direct vision with a video laryngoscope, bronchoscopy or ultrasound (a single trachea with movement of the lung pleura, and a double tracheal sign over the neck when the tube is in the oesophagus).

Differential diagnosis.

• Endobronchial intubation.
• Bronchospasm.
• Tube kink or blockage.
• Circuit disconnection.
• Cardiac arrest with low carbon dioxide output.
• Tension pneumothorax.

If there is any doubt, remove the tube. Ventilate by face mask or supraglottic airway with 100% oxygen. Then reintubate using a bougie or video laryngoscope, and confirm with capnography.

Gastric decompression. After the airway is secured, pass an orogastric tube to remove gas and contents.

Aspiration. Give oxygen, suction the airway, use bronchoscopy for particulate matter, and treat supportively. Start antibiotics only if infection develops (fever, new infiltrate, purulent secretions beyond 48 hours).

Prevention. Use waveform capnography in every intubation, confirm at least 4 to 6 breaths, and watch the tube pass through the cords.

Monitoring. Capnography, saturation, chest radiograph and blood gas after reintubation.

Referral and escalation. Critical care if hypoxic injury, aspiration or oesophageal injury (surgical emphysema, chest pain) is suspected. Report the incident.