Date: April 10th, 2019

Guest Skeptic: Dr. Scott Weingart. He is an ED intensivist from New York City and runs the popular EMCrit blog and podcast. Scott is attempting to bring upstairs care, downstairs one podcast at a time.

This is an SGEM Xtra that came about due to SGEM#249. That episode was with Chip Lange from TOTAL EM and looked at using point of care ultrasound (POCUS) for endotracheal tube (ETT)  confirmation. It sparked a bit of a twitter conversation and lead to a key tweet by Scott.

Before we got into the the point of contention, Scott discussed a couple of key concepts (Blow to Know and No Trace-Wrong Place).

We also acknowledge a few parts of the SGEM podcast that we agreed upon:

* Waveform capnography should be used to confirm tube placement

* SGEM Bottom Line: “Transtracheal sonography represents a potential fast and accurate way to help confirm endotracheal tube placement in conjunction with other methods.”

* Case Resolution: “While you directly visualize the passage of the endotracheal tube through the vocal cords, she is able to see the appropriate findings consistent with successful placement. Waveform capnography is used in addition and further supports the appropriate placement.” 

* The Clinical Application:“[POCUS] represents another potential tool that can be used in combination with existing methods to verify correct tube placement. As these bedside devices become pocket size and more affordable, it will be interesting to see how clinicians continue to include POCUS in their practice.”

Scott then had five questions. Listen to the podcast to hear our discussion.

1) Who has the burden of proof? The person making the positive/new claim has the burden of proof. This is known as onus probandi in Latin. It can be a logical fallacy to shift the burden of proof onto the person who is not making the new claim.

When two individuals are discussing an issue the person who makes the new claim is responsible to justify or provide evidence to support their position. The evidence can then be reviewed and decided upon whether or not it is adequate.

* Carl Sagan Standard: “Extraordinary claims require extraordinary evidence”

* Hitchens’s Razor: “What can be asserted without evidence can be dismissed without evidence”

In the SGEM#249, we made a general claim in the background material. This was after providing the ACEP policy statement about physical exam, direct visualization, pulse oximetry, CXR, esophageal detector devices and EtCO2 detection.

There is evidence indicating that commonly used endpoints for rapid confirmation can be inaccurate. 

It was the specific claim about the accuracy of EtCO2 presented in our background material that really got Scott’s attention.

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 andTanigawa et al).

To support this claim we provided three citations. Scott and I discussed the multiple limitations to the three studies.