How do I confirm the placement of an endotracheal (ET) tube?

Confirming Endotracheal Tube Placement

Continuous waveform capnography combined with clinical assessment is the most reliable method for confirming and monitoring correct endotracheal tube placement, and should be used immediately after intubation and throughout patient care. 1

Primary Confirmation Method

Use continuous waveform capnography as your first-line confirmation device (Class I, LOE A). Studies demonstrate 100% sensitivity and 100% specificity for identifying correct ET tube placement in cardiac arrest victims. 1, 2 This method provides real-time monitoring and does not interrupt chest compressions during resuscitation. 2

Clinical Assessment (Always Perform Alongside Devices)

Providers must always combine device confirmation with clinical assessment. 1 Perform the following immediately after intubation:

• Visualize bilateral chest rise with ventilation 1
• Auscultate over both lung fields, especially the axillae, for equal breath sounds 1
• Listen over the epigastrium - gastric insufflation sounds should be absent if the tube is correctly placed 1
• Direct visualization - if uncertain, perform laryngoscopy to confirm the tube passes between the vocal cords 1

Alternative Confirmation Methods When Capnography Unavailable

If waveform capnography is not available, use these alternatives in order of preference:

Colorimetric CO2 Detectors

Use colorimetric or nonwaveform exhaled CO2 detectors as the initial confirmation method when waveform capnography is unavailable (Class IIa, LOE B). 1 However, their accuracy does not exceed auscultation and direct visualization in cardiac arrest patients. 1

Esophageal Detector Device (EDD)

The EDD can be used as an initial confirmation method in cardiac arrest when capnography is unavailable (Class IIa, LOE B). 1 The bulb or syringe technique works by creating suction - if the tube is esophageal, the esophagus collapses and the bulb won't re-expand or the syringe cannot aspirate. 1

Ultrasound

Upper airway ultrasonography by an experienced operator is a reasonable alternative (Class IIa, LOE C-LD). 3 Research shows ultrasound can confirm placement in as little as 3.8 seconds using tracheal views, faster than both auscultation and capnography. 4, 5

Critical Pitfalls and Limitations

False-Negative CO2 Detection (Tube Actually in Trachea)

CO2 may not be detected despite correct placement due to:

• Low pulmonary blood flow during cardiac arrest (most common cause) 1
• Pulmonary embolism reducing CO2 delivery to lungs 1
• Severe airway obstruction (status asthmaticus) 1
• Pulmonary edema 1
• Contamination with gastric contents or acidic drugs like epinephrine 1

If CO2 is not detected, use a second confirmation method such as direct laryngoscopy or esophageal detector device. 1

False-Positive CO2 Detection (Tube Actually in Esophagus)

Rare false-positives occur after ingestion of carbonated liquids, but the waveform will not continue during subsequent breaths. 1

EDD Limitations

The esophageal detector device may yield misleading results in:

• Morbid obesity 1
• Late pregnancy 1
• Status asthmaticus 1
• Copious endotracheal secretions 1

The trachea tends to collapse in these conditions, mimicking esophageal placement. 1

Ongoing Monitoring Requirements

Re-verify tube position:

• After securing the tube 1, 3
• During transport 1, 3
• Each time the patient is moved (gurney to bed) 1, 3
• Throughout the resuscitation 1

Obtain a chest x-ray when feasible to confirm the tube is positioned in the midtrachea and not in a mainstem bronchus. 1, 3

When Patient Condition Deteriorates

Use the DOPE mnemonic to systematically evaluate an intubated patient whose condition worsens: 1, 3

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

Special Considerations During Cardiac Arrest

During CPR, waveform capnography sensitivity may decrease to 64% in patients with prolonged resuscitation and transport times, though specificity remains 100%. 1 In cardiac arrest, if exhaled CO2 is not detected, confirm tube position with direct laryngoscopy because absence of CO2 may reflect very low pulmonary blood flow rather than misplacement. 1

Maintain head in neutral position after securing - neck flexion pushes the tube deeper, extension pulls it out. 1, 3