What is the best way to confirm endotracheal (ET) tube placement?

Best Method to Confirm Endotracheal Tube Placement

Continuous waveform capnography combined with clinical assessment is the most reliable method for confirming and monitoring correct endotracheal tube placement (Class I, LOE A). 1, 2

Primary Confirmation Methods

• Waveform capnography has demonstrated 100% sensitivity and 100% specificity for identifying correct endotracheal tube placement in cardiac arrest victims when used immediately after intubation 1, 3
• Clinical assessment should always be used in conjunction with devices to confirm tube placement immediately after insertion and throughout resuscitation 1
• For awake patients, a two-point check is required: direct visualization of the tube passing through the vocal cords and capnography to exclude esophageal intubation 2
• After initial confirmation, continuous monitoring with waveform capnography is essential to detect displacement 1, 4

Secondary Confirmation Methods

When waveform capnography is not available, alternative methods include:

• Colorimetric and non-waveform exhaled CO2 detectors can be used as initial confirmation methods (Class IIa, LOE B) 1
• Esophageal detector devices (EDD) can be used as an initial confirmation method (Class IIa, LOE B) 1
• Auscultation should be performed bilaterally in the axillae and over the epigastrium to detect the absence of gastric insufflation sounds 2, 5
• Chest X-ray should be performed in hospital settings to verify proper position in the midtrachea and rule out bronchial intubation 2

Important Limitations and Pitfalls

• False-negative capnography readings may occur during cardiac arrest due to:

  • Low pulmonary blood flow and CO2 delivery to the lungs 1, 3
  • Pulmonary embolism reducing pulmonary blood flow 1, 2
  • Severe airway obstruction or pulmonary edema reducing CO2 elimination 1
  • Contamination of colorimetric devices with gastric contents or acidic drugs 1

• Esophageal detector devices may yield misleading results in:

  • Morbid obesity 1
  • Late pregnancy 1
  • Status asthmaticus 1
  • Patients with copious endotracheal secretions 1

• Ultrasound techniques are emerging as promising methods for confirming tube placement, especially during dynamic assessment (during the intubation process) with reported 97% sensitivity and 100% specificity in cadaver models 6

Algorithm for ET Tube Confirmation

1. Primary confirmation during intubation:

   • Direct visualization of the tube passing through vocal cords 2
   • Continuous waveform capnography immediately after placement 1, 3

2. If waveform capnography is unavailable:

   • Use colorimetric CO2 detector AND esophageal detector device 1
   • Perform clinical assessment including bilateral chest auscultation 2, 5

3. If CO2 is not detected during cardiac arrest:

   • Use a second method (direct visualization or esophageal detector) 1
   • Consider that absence of CO2 may be due to low pulmonary blood flow rather than esophageal intubation 1, 5

4. After initial confirmation:

   • Secure the tube properly to prevent displacement 1, 4
   • Record and document the depth of the tube at the teeth or gums 4
   • Maintain continuous waveform capnography monitoring 3
   • Re-verify tube position after any patient movement or transport 4

5. If patient condition deteriorates after intubation:

   • Consider the DOPE mnemonic: Displacement of tube, Obstruction of tube, Pneumothorax, Equipment failure 2, 4

In emergency situations, particularly during cardiac arrest, multiple confirmation methods should be used as no single method is infallible in all circumstances 7, 5.