NTG and Morphine I’m Inferior AMIs

Tigger

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Huh, any specific reason? We're talking about ditching the paste since its rarely used and we have it in tab, spray, drip and push dose
Our medical director seems to think that they are as effective. I have no idea what he bases that on. He is also one of the flight program MDs and they have trying very hard to eliminate as many infusions impossible as possible due to space issues. So if flight gets it, we get it, but in this case we lost since I think they have IVP NTG and we do not.

Also, I've always tended to give nitro to hypertensive STEMIs because that just seemed like a good idea and that's what I was taught...but I can't find a whole ton to back that up?
 

rescue1

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We had a lecture from one of the interventional cardiologists at my hospital the other day and he was of the mind that nitro was appropriate in a right sided MI as long as it was given judiciously and you were aware of the potential for hypotension. I don't actually think its a terribly well studied phenomenon, but that's the case with most things we do in medicine.

He must have been reading this thread because he also went on a tangent about hating nitro paste. Specifically he disliked it for acute CHF patients who were peripherally vasoconstricted, since he felt that you would have initially very poor systemic absorption, followed by a sudden larger dose when the patient was stabilized and more normotensive and vasodilated, which could push them into hypotension. I'm not sure how much literature there is to back this up, though anecdotally I've never seen paste be very effective in severe CHFers.
 
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michael150

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Hey everyone, I know that it took me a long time to get back to all of you and I apologize. All of you had amazing responses and I appreciate your input. A lot of you brought up that administration of NTG should be taken out of the protocols for analgesia in an AMI whether with RVI or not. Most EMS units carry analgesics that can significantly reduce pain without the potential to knock out the patients pre-load.... If this is the case, why are paramedic courses still teaching the “MONA” protocol? I mean, when I worked in facility, we did the same thing. EVIDENCE-BASED MEDICINE.
 

CWATT

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[I believe] we’ve framed the issue of Nitro’s efficacy incorrectly. So far I’ve only read people measuring its efficacy based on mortality. We should instead consider quality of outcome as measured by heat muscle preservation. [I believe] Nitro’s therapeutic medhcnism of action is increasing venous capacitence which reduces pre-load, therefore a reducing Frank-Starling mechanisms (greater myocardial stretch = greater contractile force), thus reducing myocardial oxygen demand. This is interpreterd by the clinitian as a reduction in patient pain (as well as anxiolysis).

[I believe] those who think Nitro’s purpose is analgesia are only looking at its symptomatic effects whereas [I believe] Nitro’s physiological benefit is mitigating myocardial necrosis by reducing cardiac workload. In other words, if we approach this as a ‘but did you die’ binary situation we are overlooking the real clinical benefit. Unfortunately I can’t point to any study that supports my belief.
 

MSDeltaFlt

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Yes you can give nitroglycerine to inferior MI's. You can give it IV or SL. However, if you give it SL you must make sure that there is not RCA involvement. It cannot be a right side MI. Also, depending on a paramedic's scope of practice in your area, you will also need to get medical control authorization to give it. In what world would a medic give SL NTG to an Inf AMI? Simple. Standard ST elevation in II, III, and aVF plus NO RECIPROCAL ST depression in I, aVL, V5, or V6. Not to mention HR and BP must be high enough to allow NTG.

The trick is not just knowing where but also where it is not.
 

RocketMedic

Californian, Lost in Texas
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Yes you can give nitroglycerine to inferior MI's. You can give it IV or SL. However, if you give it SL you must make sure that there is not RCA involvement. It cannot be a right side MI. Also, depending on a paramedic's scope of practice in your area, you will also need to get medical control authorization to give it. In what world would a medic give SL NTG to an Inf AMI? Simple. Standard ST elevation in II, III, and aVF plus NO RECIPROCAL ST depression in I, aVL, V5, or V6. Not to mention HR and BP must be high enough to allow NTG.

The trick is not just knowing where but also where it is not.
I like how you manage to be a medium amount of wrong in everything you post. It’s an impressive talent.

It is generally safe to provide nitrates to patients with RCA occlusion, if their history, V/S and circumstances allow, and if you have good access. I wouldn’t worry too much about it if I’ve got great pressure, a reasonably healthy heart and adequate fluid volume. I wouldn’t be in a hurry to give it to the hypotensive dude on Viagra with CHF and a triple CABG.
 

VFlutter

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We tend to oversimplify things which leads to teaching "Inferior MI = RV Infarct" because it prevents the most potential harm. Most inferior MIs will do fine foregoing nitroglycerin whereas giving it to a true RV infarct can be disastrous. If you have the clinical knowledge to differentiate then by all means treat accordingly. Unfortunately there is some nuance to it.
 

StCEMT

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I see oversimplifications with cardiac treatments a lot though. Had a nurse tell me to put the non-STEMI chest pain pt with 98% room air sat on O2 to increase coronary perfusion or something. I know people who prefer to start off arrests with Epi/Bicarb/Narcan. Unfortunately, I don't think people actually understand why they are doing what they are doing half the time when it comes to cardiac issues.
 

Tigger

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Yes you can give nitroglycerine to inferior MI's. You can give it IV or SL. However, if you give it SL you must make sure that there is not RCA involvement. It cannot be a right side MI. Also, depending on a paramedic's scope of practice in your area, you will also need to get medical control authorization to give it. In what world would a medic give SL NTG to an Inf AMI? Simple. Standard ST elevation in II, III, and aVF plus NO RECIPROCAL ST depression in I, aVL, V5, or V6. Not to mention HR and BP must be high enough to allow NTG.

The trick is not just knowing where but also where it is not.
What?
 

Frank frankerson ESQ

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We carry it and do use it for Acute MI. 5mg IV every 5 minutes up to 15mg (in our guidelines)

It's not used very frequently, if the patient is hypertensive and HR is above 60 we discuss it with the Doc and will usually only give the first dose, we are usually at the hospital pretty quick with most of these folks.

As far as Nitro and Inferior we always do a right sided 12 lead on Inferior MI and would usually just give MS if the right side was positive but we have now finally made the switch to Fentanyl.
How many STEMIs you all get? Sounds like you get alot of them
 

Frank frankerson ESQ

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Alright guys, I know this has been covered before but I want to restart the conversation. With recent studies, (I will try to find them and link them) I want to kind of talk with the more experienced medics and leave an in-depth discussion for those in medic and learning.

During school, it was drilled into our heads to not give a SL nitro or morphine in patients that are presenting with inferior AMIs because of the potential of RVI and dropping their pressure through the floor. I have read studies proving this false and that with the supplement of NS boluses, we can effectively raise theBP back to therapeutic levels. I have also been told by attending ED docs that they don’t hesitate to give it or start a drip anymore. Just now, I cleared off of an IFT interior MI with 2 boxes of elevation in all 3 leads. He had heparin and NTG running. NTG at 5mcg/min on a pump. I got into an argument with the ED medic saying that it’s been proven that we can raise their BP. He says that we can’t do it quickly enough and he has seen patients crash with the administration of NTG.

What are your experiences with this? Anyone have protocols to still give NTG and supplement with a liter or 2? Thanks guys. I’m still within my first year of being a paramedic but I feel like withholding these two meds is an old wive’s tale.
Wow two boxes of elevation? Confirmed MI? Old wives tales? Someone said this or that? Find out these things for yourself. Great medic you will be.
 

Frank frankerson ESQ

Forum Crew Member
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We tend to oversimplify things which leads to teaching "Inferior MI = RV Infarct" because it prevents the most potential harm. Most inferior MIs will do fine foregoing nitroglycerin whereas giving it to a true RV infarct can be disastrous. If you have the clinical knowledge to differentiate then by all means treat accordingly. Unfortunately there is some nuance to it.
How do you differentiate b/w a true RV infarct and a mimic in an emergency setting? Yes there is some nuance to it.
 

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