SGEM#249: Ace in the Hole – Confirming Endotracheal Tube Placement with POCUS

Date: March 12th, 2019

Reference: Gottlieb, Holladay and Peksa. Ultrasonography for the Confirmation of Endotracheal Tube Intubation: A Systematic Review and Meta-Analysis. Ann Emerg Med 2018.

Guest Skeptic: Chip Lange is an Emergency Medicine Physician Assistant (PA) working primarily in rural Missouri in community hospitals. He hosts a great #FOAMed blog and podcast called TOTAL EM. Chip is also the CEO of a new educational company called Practical POCUS.

Case: A 48-year-old male is in cardiac arrest and is not being successfully oxygenated by bag valve mask or with a supraglottic airway (SGEM#246).  While preparing to intubate the patient, you consider ways of quickly confirming endotracheal tube placement.  You have a colleague in the room who is proficient at ultrasound and asks if there is a role for bedside ultrasound in this situation.

Background: We have talked about ultrasound a number of times on the SGEM:

SGEM#245: Flash-errrs (POCUS for Retinal Detachments)
SGEM#177: POCUS – A New Sensation for Diagnosing Pediatric Fractures
SGEM#153: Simulation for Ultrasound Education
SGEM#124: Ultrasound for Skull Fractures – Little Bones
SGEM#119: B-Lines (Diagnosing Acute Heart Failure with Ultrasound)

The SGEM has also discussed endotracheal intubation a number of times:

SGEM#247: Supraglottic Airways Gonna Save you for an OHCA?
SGEM#197: Die Trying – Intubation of In-Hospital Cardiac Arrests
SGEM#186: Apneic and the O, O, O2 for Rapid Sequence Intubations
SGEM#75: Video Killed Direct Laryngoscopy?

Endotracheal intubation can be challenging and if incorrectly performed can lead to death.  Rapid confirmation of endotracheal tube placement is vital and ACEP has a policy statement on this issue. The various methods to confirm tube placement include:

Physical exam (auscultation of chest and epigastrium, chest wall movement, and condensation/fogging in the tube)
Direct visualization or videolaryngoscope of the tube going through the cords
Pulse oximetry
Chest x-ray
Esophageal detector devices
End-tidal carbon dioxide (CO2) detection (continuous wave form capnography, colorimetric and non-wave form capnography)

There is evidence indicating that commonly used endpoints for rapid confirmation can be inaccurate.  Quantitative waveform capnography, thought to be one of the best methods, correctly confirms tube placement only two-thirds of the time in cardiac arrest (Takeda et al, Tanigawa et al and Tanigawa et al).

A fast and reliable alternative would be great.  Point of care ultrasound (POCUS), has become more popular over time for its easy usability and accuracy in a variety of applications.  A number of small studies have been done using POCUS to confirm endotracheal tube placement. These studies have been relatively small with wide confidence intervals.

Clinical Question: What is the accuracy of ultrasonography for confirmation of endotracheal tube placement?

Reference: Gottlieb, Holladay and Peksa. Ultrasonography for the Confirmation of Endotracheal Tube Intubation: A Systematic Review and Meta-Analysis. Ann Emerg Med 2018.

Population: Patients over 18 years of age in a prospective or randomized controlled trial undergoing assessment of transtracheal ultrasonography for endotracheal tube placement confirmation.

Excluded: Case reports, case series, retrospective studies, cadaver studies, pediatric studies, and conference abstracts.

Intervention: Transtracheal ultrasonography to confirm endotracheal tube placement.
Comparison: Confirmatory testing of endotracheal tube placement such as end-tidal capnography, colorimetric capnography, or direct visualization.
Outcome:

Primary Outcome: Diagnostic accuracy of transtracheal ultrasound
Secondary Outcome: Time to confirmation and subgroup analyses.

Authors’ Conclusions: Transtracheal sonography is rapid to perform,