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The comparison of airway ultrasonography and continuous waveform capnography to confirm endotracheal tube placement in cardiac arrest patients: prospective observational study

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Ultrasound is a common examination tool in many emergency department and intensive care unit. Several studies have provided promising results of the use of ultrasound for the confirmation of endotracheal tube placement


This study aimed to assess the accuracy and timeliness of using tracheal ultrasound to examine endotracheal tube placement in cardiac arrest patients.

Patients and methods

This was a prospective, observational study, conducted at the emergency department of a university teaching hospital. Patients received emergency intubation due to cardiac arrest. Airway ultrasonography was performed during emergency intubation with the transducer placed transversely at the trachea over the suprasternal notch. Quantitative waveform capnography was used as the criterion standard for confirmation of tracheal intubation. The main outcome was the timeliness between the airway ultrasonography and the capnography.


A total of 16 patients and 19 intubations were included in the analysis. The endotracheal tube was placed in the trachea in 16 intubations and in the esophagus in 3 intubations. The overall sensitivity and specificity of ultrasound to confirm tracheal intubation was 100% respectively. Capnography application times after intubation were 17.5 (10.0~32.5) seconds. The Capnograpny confirmation times after application were 30 (10~120) seconds. Ultrasound confirmation times of endotracheal tube placement after application were 5 (4~5) seconds.


Ultrasound confirmation was very fast, accurate and not affected by pulmonary blood flow. Ultrasound confirmation of endotracheal tube placement is more useful in emergency department.


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    Neumar RW, Otto CW, Link MS, Kronick SL, Shuster M, Callaway CW, et al.: Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010, 112: S729–67.

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    Werner SL, Smith CE, Goldstein JR, Jones RA, Cydulka RK: Pilot Study to Evaluate the Accuracy of Ultrasonography in Confirming Endotracheal Tube Placement. Ann Emerg Med 2007, 49: 75–80. 10.1016/j.annemergmed.2006.07.004

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Author information

Correspondence to Young Soon Cho.

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About this article


  • Intensive Care Unit
  • Emergency Department
  • Cardiac Arrest
  • Endotracheal Tube
  • Tracheal Intubation