Comparison of Airway Ultrasonography and Continuous Waveform Capnography to Confirm Endotracheal Tube Placement in Cardiac Arrest Patients: Prospective Observational Study

Noh, Jong Kab; Cho, Young Soon; Kim, Ho Jung

Abstract

PURPOSE
The aim of this study was to assess the accuracy and timeliness of using tracheal ultrasound for examination of endotracheal tube placement in cardiac arrest patients.
METHODS
This was a prospective, observational study, conducted at the emergency department of a university teaching hospital. Patients underwent 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 airway ultrasonography and capnography.
RESULTS
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 three intubations. The overall sensitivity and specificity of ultrasound for confirmation of tracheal intubation was 100%, respectively. The capnography application time after intubation was 17.5(10.0~32.5) seconds. The capnograpny confirmation time after application was 30(10~120) seconds. The ultrasound confirmation time for endotracheal tube placement after application was 5(4~5) seconds.
CONCLUSION
When patients were in a low pulmonary blood flow state, such as cardiac arrest, capnography confirmation of endotracheal tube placement was not rapid and needed a lot of times. Ultrasound confirmation was very rapid and accurate, and was not affected by pulmonary blood flow. Ultrasound confirmation of endotracheal tube placement is more useful in the emergency department.