In
this episode, Tyler interviews Tom Bouthillet and Dr. Stephen Smith
on who exactly should get a right-sided ECG.
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Do
not delay transport to PCI to grab a right-sided ECG.
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If
you do decide to perform a right-sided ECG, it should not be for
the decision on whether or not to give nitro.
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If
time permits, it may be helpful and confirm your suspicions of RV
involvement.
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Isolates RV infarcts are extremely rare.
In EMT
school, I was taught how to
assist a patient taking their own nitroglycerin if they developed
chest pain. I had to make sure they weren't on any
phosphodiesterase inhibitors, grab a blood pressure, and make sure
they took the right dose. We would obtain a 12 lead, but I had no
clue what I was looking at, and my decision to give nitro was not
based on any specific ECG finding.
Fast-forward to paramedic school, and I am taught to ALWAYS perform a 12 lead
before giving nitroglycerin. Why? Wellll If they had an inferior
wall MI, nitroglycerin was a hard stop. Every time the student
would give nitro before obtaining a 12 lead in simulation, their
patients would code...Every. Time.
I
thought this was weird because patients were prescribed
nitroglycerin if they developed chest pain at home. They were
certainly not performing a 12 lead on themselves prior to doing
this. So what was the fear?
Because the RV is preload dependent, dropping preload
with nitroglycerin could cause hypotension. This is probably a good
place to say that the LV is preload dependent too, but the LV
preload is dependent on the RV preload. So if you wipe out the RV,
the LV follows.
I
believe the fear of nitro is probably healthy, but not for JUST
inferior wall MIs. The benefit of sublingual nitro has yet to be
proven (as Dr. Smith points out in the interview) and on top of
that, a study published in Prehospital Emergency Care
in 2015 found that
hypotension occurred
post-NTG in 38/466 inferior STEMIs and 30/339 non-inferior STEMIs,
8.2% vs. 8.9%, p
= 0.73. That means it makes
literally no difference where the MI is.