How to confirm correct tracheal (endotracheal) intubation?

Confirming Correct Tracheal Intubation

The most reliable method to confirm correct tracheal intubation is using waveform capnography combined with direct visualization of the tube passing through the vocal cords, as this two-point check provides the highest certainty of proper tube placement. 1

Primary Confirmation Methods

• Waveform capnography is the gold standard for confirming tracheal intubation in patients with a perfusing rhythm, with 100% specificity for detecting correct tracheal placement 1
• Direct visualization of the endotracheal tube passing between the vocal cords during laryngoscopy is one of the only foolproof methods of confirming tracheal intubation 2
• For awake tracheal intubation, a two-point check is required: visualization of the tracheal lumen and capnography to exclude esophageal intubation 1
• In cardiac arrest patients, capnography may be less reliable due to low pulmonary blood flow; if exhaled CO2 is not detected, confirm tube position with direct laryngoscopy 1

Secondary Confirmation Methods

• Auscultation should be performed bilaterally in the axillae and over the epigastrium - gastric insufflation sounds should not be present if the tube is in the trachea 1, 3
• Check for oxyhemoglobin saturation with a pulse oximeter if there is a perfusing rhythm, but remember that following pre-oxygenation, saturation may not decline for up to 3 minutes even without effective ventilation 1
• An esophageal detector device (EDD) may be considered to confirm endotracheal tube placement in children weighing >20 kg with a perfusing rhythm 1
• In hospital settings, perform a chest x-ray to verify that the tube is not in a bronchus and to identify proper position in the midtrachea 1

Two-Person Verbal Check Protocol

• Implement a two-person verbal check where the intubator and assistant confirm:
  1. Visualization of the tube passing through the vocal cords (when using videolaryngoscopy)
  2. Presence of sustained exhaled carbon dioxide on capnography 4
• This two-person check improves communication, teamwork, and reduces the likelihood of unrecognized esophageal intubation 4

Clinical Confirmation of Double-Lumen Tube Placement

• After tracheal intubation with a left-sided double-lumen tube, confirm bilateral air entry with manual ventilation 1
• Inflate the bronchial cuff and check for isolated left-sided air entry when the tracheal lumen is clamped 1
• If clinical confirmation is inconclusive, bronchoscopy is essential to verify correct placement 1

Troubleshooting Deterioration in Intubated Patients

If an intubated patient's condition deteriorates, consider the DOPE mnemonic 1, 5:

• Displacement of the tube
• Obstruction of the tube
• Pneumothorax
• Equipment failure

Important Caveats and Pitfalls

• Capnography may be unreliable in cardiac arrest due to low pulmonary blood flow, giving false negatives despite correct tube placement 1
• Colorimetric CO2 detectors may show a consistent color rather than breath-to-breath change if contaminated with gastric contents or acidic drugs 1
• An IV bolus of epinephrine may transiently reduce pulmonary blood flow and exhaled CO2 below detection limits 1
• Severe airway obstruction (e.g., status asthmaticus) and pulmonary edema may impair CO2 elimination below detection limits 1
• A large glottic air leak may reduce exhaled tidal volume through the tube and dilute CO2 concentration 1
• Deaths from unrecognized esophageal intubation continue to occur despite national campaigns emphasizing the importance of capnography 4

Proper Tube Positioning and Securing

• After confirming tracheal placement, secure the tube to prevent displacement 1
• Maintain the patient's head in a neutral position, as neck flexion may push the tube further into the airway, and extension may pull it out 1
• The ideal position is with the distal tip of the tube in the middle of the trachea, approximately 4 cm above the carina 2