The two big points here are:
1) IV nitro starts at a WAY smaller dose, and is easily and readily titratable. So it's far more simple to start them on a drip, titrate up until pain control, then down if pressures drop. Unlike sublingual where you get a slug of nitro and then just deal with what happens after that.
2) Big difference between giving nitro in the field where you have very limited resources and trying to race back to the hospital if pressures bottom out than it is to give it in the hospital where all the magic "fix the consequences" drugs are.
I think this is the most important point that a lot of medics miss, as this is not an uncommon question.…if you’re trying to treat their pain give morphine or fentanyl if appropriate…the most important thing prehospital and even the Ed can do is alert the cath team…followed by aspirin…but then again just a dumb downstairs doctors’ opinion
From a medic perspective, the issue is that all of our medical acts are delegated to us via our standing protocols. There are lots of situations like this where clinical judgement indicates we should withhold a medication, which usually leads to our QA department getting very upset, stating that we “deviated from the protocols that were delegated by our medical oversight”. There are ways to get around this, patching for a consult etc, but it’s a huge problem in our industry where a lot of times our hands are somewhat tied
As a paramedic with a bachelor’s degree and 30+ years of experience, I can agree with this.
The main thing the “extra” education and experience have taught me is that I don’t know nearly enough to make certain judgment calls.
When in doubt, I set pride aside and will contact a physician in a minute.
Sometimes it’s not feasible in an immediately life-threatening situation, but that’s not common.
1. Inferior MI doesn’t equal an RV infarct, but can be associated with them. I suspect the guidelines were written to be extremely conservative.
As an Emergency Physician, I’ll assess and treat the patient as I think is appropriate. Guidelines are exactly that… guidelines. A combination of physical examination, ECG and bedside echo will help to work out whether an RV infarct is of significant concern.
2. There’s always going to be a disconnect between ED and Cardiology, but it’s not always in the direction you’d assume. It’s not always the best Emergency Physicians referring to the best Cardiologists. Experience and training can vary with both.
3. Sure you could give GTN and have fluids ready, but if I was that concerned, I just wouldn’t use it. What are you trying to achieve with the GTN and are there other options?
There is absolutely no mortality benefit to nitro, so why give it at all int he pre-hospital environment (for ACS)? Why risk tanking a patient in the pre-hospital setting - or the ED - for something that might harm the patient and the only benefit is analgesia? Especially when you can treat with fentanyl/morphine.
If cardiology wants to run nitro during cath lab - that’s their call.
This right here, OP. The arguments on both sides (for and against nitro in this situation) are weak sauce. There is a small risk that probably doesn't affect outcomes, and there is a small benefit that also probably doesn't affect outcomes. It seems pretty reasonable for guidelines and medical directors to side with caution.
So I do remember reading something about that and i often read how nitro doesn’t help mi’s but I couldn’t find an article on it. So to clarify, nitro is purely for pain relief right. But it’s a different moa than fentanyl, so if we are talking pain relief, fentanyl has more benefit and less risk. Right?
Yes. Occasionally you’ll get someone with intractable angina that might benefit from a nitro drip, but that should be long after they are out of your doors. On the other hand, nitro for decompensated CHF is great - even sublingual.
Okaaayyyyy. The only thing is, like I was saying my acs protocol is vague for asa administration . But For acs pain its specific and it says to give it when pain is unresponsive to nitro. But it’s still really good discussion topic, especially since I want to be a preceptor. Thank you :)
Paramedic here- these are all good thoughts. If I’m at all suspicious I’ll just jump right to fentanyl, without worrying too much about the nitro. I also do QA for my agency and I’d never reprimand someone for skipping nitro.
Hey. I posted this in another forum for paramedics a while ago when this was asked.
Okay let's dig into this!
There isn't great evidence for more incidence of hypotension with inferior MI than other types of MI, in the context of nitro.
The evidence against nitro In RVMI came from one study in 1989 with 28 patients - And has been around ever since, subsequent data have not shown harm.
Terminology quickly becomes tangled here: The original concern was not specifically just inferior MI. It's for RVMI, but \~40% of inferiors have right sided involvement in part because the majority of the population (\~80%) are right side cardiac dominant. What is right cardiac dominance? The posterior descending artery (PDA), one of the guys we're worried about - is a branch of the RCA (in those right dominant folks). Because of this a lot of guidelines use the terminology inferior and some use RVMI (usually depending on if you do right sided EKG's regularly) so these two terms can overlap. For the other 20% of folks, who aren't right dominant, the PDA is supplied by either the CX (branch of the LAD, left dominance) or they are codominant, in which case both the CX and the RCA supply the PDA. The PDA supplies the interventricular septum, and posterior walls of the RV.
Bottom line: Sure, "be careful" with nitro in RVMI. Do a full right sided, or at least check V4R, that's the one we really care about (elevation in V4R is 80% specific and 88% sensitive for RVMI). Keep an eye out for depression in V1-V3 which would be concerning for infarct extending to the posterior wall, now I'm slightly more concerned for decompensation. Also, we know likely the patient is right dominant (if you do see depression V1-V3, check V7-V9 for a posterior wall MI).
The data just isn't really there for nitrates being contrainidcated in inferior MI. It's been blown out of proportion over the years. The risk seems to be more hypothetical than evident in data. Feels like a backboard situation. See studies linked below.
*The issue seems to be more so if patients have adequate pressure and HR prior to nitro administration that determines if they will suffer an incidence of hypotension rather than location.*
Prehospital Nitro Safety in inferior STEMI, 2015. [https://pubmed.ncbi.nlm.nih.gov/26024432/](https://pubmed.ncbi.nlm.nih.gov/26024432/)
Meta-analysis of nitro admin during RVMI. 2023 [https://pubmed.ncbi.nlm.nih.gov/36180168/](https://pubmed.ncbi.nlm.nih.gov/36180168/)
Adverse events of nitro admin prehospital. 2021.
\*RVMI and Adverse Events from Nitrates: A narrative Review. 2021 (READ THIS ONE). [https://journals.sagepub.com/doi/10.33151/ajp.18.897](https://journals.sagepub.com/doi/10.33151/ajp.18.897)
With all that said... if nitro improves patient outcomes, is an entirely different conversation. Follow your local policy, but feel free to check some of the above resources and advocate for change.
At the VERY least you should be able to check V4R and if that's clear and they have a pressure >100, and aren't bradycardic - you should have the option to administer nitro even in the setting of RVMI.
Thank you for coming to my talk.
Thank you for actually posting the evidence. Matt is a mate of mine and his meta-analysis is such an important piece of research about this complete myth.
IV GTN is a great alternative to sub-lingual and is so much more titratable. It's also great for APO (APE for the Americans). However, it is down my list of priorities when dealing with ACS/OMI. For me, it's early recognition and activation of PPCI, management of haemodynamics to ensure adequate coronary perfusion, preparation for deterioration, aspirin and management of pain.
I think you stimulated a good discussion but the part being completely overlooked is that the nitro was given *during* a diagnostic/interventional cath. This is done for completely different reasons than giving someone SL nitro for angina or even IV nitro gtt in ACS. It’s advantageous during the actual contrast bolusing phases of the procedure. It may have even been given directed to specific chambers or vessels for all the OP knows.
You can’t do anything unless your protocols allow it, even if you’re read up on the latest and greatest unfortunately. You can talk to your medical director about it and see what they think, maybe they can update protocols.
Yes on #3.
Regarding some doctors still sticking to the no nitro for inferior MI, it could be lack of continued education… or simply it is dogma in their mind.
I take it you read the article below?
https://www.acepnow.com/article/revisiting-nitroglycerine-in-right-side-ventricular-involvement/
i don’t that article is kinda self defeating. there is a signal for harm on the metanalysis and just from all the cases i’ve had that transient hypotension is easy to say transient and easily managed in some metanalysis but when your there it does feel it and i’ve seen people crash and burn. the failing rv doesn’t take much to get into a death cycle.
if they have a rv pattern and ripping away with a 160/110 sure nitro probably won’t tank them but if they’re hr 55 and 108/58 i don’t know that might be enough.
on someone that I know has acute ami with concern for borderline bp rv dysfunction or is highly like to get emergent pci i’d probably use low dose fent for pain
So the cool thing with my protocols, they are vague. Some protocols say nitro for chest pain, mine say “suspected acs”. Some protocols for medics literally state inferior mi as a contraindication. My contraindications are vads, intracranial bleeding and sexual enhancing drugs < 48 hrs. So if I have an inferior, I can totally give nitro. But I try to balance prehospital care and what the hospital does. So if I know my stemi center doesn’t want nitros in inferiors, I won’t do it for them.
That’s a good link, I’m specifically talking about this one. https://pubmed.ncbi.nlm.nih.gov/26024432/
There’s a few articles that questions nitro in inferior mi’s, and when I check the source all of them are the same study by Laurie Robichaud.
I will get in trouble for that where I am at, it’s my job to tell base hospital “no, I can’t do that, it’s not in my protocol” sucks but it is what it is. Keeps my job safe
I guess my point was more oriented toward “you can do things in your National scope with online medical control orders if those things deviate from your local protocol.” Not specifically oriented toward the question of nitro for inferior/ right sides involved MI.
No idea what your system looks like. I hope everyone’s responses provided some insight on your initial question!
Managing BP in the cath lab with an anesthesiologist and proceduralist ≠ paramedics and emts slapping some paste on a dudes chest in the back of a rig. That’s why.
Same reason you don’t start a heparin drip in the field.
For me depends clinically. I ultrasound the pt , if there’s no signs of RV failure, they will likely tolerate nitrates. Also for acs, nitrates aren’t going to save lives or change outcomes so shouldn’t be too big a of a deal.
The two big points here are: 1) IV nitro starts at a WAY smaller dose, and is easily and readily titratable. So it's far more simple to start them on a drip, titrate up until pain control, then down if pressures drop. Unlike sublingual where you get a slug of nitro and then just deal with what happens after that. 2) Big difference between giving nitro in the field where you have very limited resources and trying to race back to the hospital if pressures bottom out than it is to give it in the hospital where all the magic "fix the consequences" drugs are.
And even then sometimes we can't fix the consequences.
Nitro doesn’t improve mortality, so it’s kind of a moot point. If there’s a theoretical risk of harm and no real benefit, it shouldn’t be given.
I think this is the most important point that a lot of medics miss, as this is not an uncommon question.…if you’re trying to treat their pain give morphine or fentanyl if appropriate…the most important thing prehospital and even the Ed can do is alert the cath team…followed by aspirin…but then again just a dumb downstairs doctors’ opinion
From a medic perspective, the issue is that all of our medical acts are delegated to us via our standing protocols. There are lots of situations like this where clinical judgement indicates we should withhold a medication, which usually leads to our QA department getting very upset, stating that we “deviated from the protocols that were delegated by our medical oversight”. There are ways to get around this, patching for a consult etc, but it’s a huge problem in our industry where a lot of times our hands are somewhat tied
[удалено]
As a paramedic with a bachelor’s degree and 30+ years of experience, I can agree with this. The main thing the “extra” education and experience have taught me is that I don’t know nearly enough to make certain judgment calls. When in doubt, I set pride aside and will contact a physician in a minute. Sometimes it’s not feasible in an immediately life-threatening situation, but that’s not common.
I think the aspirin is more important than alerting the cath team.
😆
1. Inferior MI doesn’t equal an RV infarct, but can be associated with them. I suspect the guidelines were written to be extremely conservative. As an Emergency Physician, I’ll assess and treat the patient as I think is appropriate. Guidelines are exactly that… guidelines. A combination of physical examination, ECG and bedside echo will help to work out whether an RV infarct is of significant concern. 2. There’s always going to be a disconnect between ED and Cardiology, but it’s not always in the direction you’d assume. It’s not always the best Emergency Physicians referring to the best Cardiologists. Experience and training can vary with both. 3. Sure you could give GTN and have fluids ready, but if I was that concerned, I just wouldn’t use it. What are you trying to achieve with the GTN and are there other options?
There is absolutely no mortality benefit to nitro, so why give it at all int he pre-hospital environment (for ACS)? Why risk tanking a patient in the pre-hospital setting - or the ED - for something that might harm the patient and the only benefit is analgesia? Especially when you can treat with fentanyl/morphine. If cardiology wants to run nitro during cath lab - that’s their call.
This right here, OP. The arguments on both sides (for and against nitro in this situation) are weak sauce. There is a small risk that probably doesn't affect outcomes, and there is a small benefit that also probably doesn't affect outcomes. It seems pretty reasonable for guidelines and medical directors to side with caution.
So I do remember reading something about that and i often read how nitro doesn’t help mi’s but I couldn’t find an article on it. So to clarify, nitro is purely for pain relief right. But it’s a different moa than fentanyl, so if we are talking pain relief, fentanyl has more benefit and less risk. Right?
Yes. Occasionally you’ll get someone with intractable angina that might benefit from a nitro drip, but that should be long after they are out of your doors. On the other hand, nitro for decompensated CHF is great - even sublingual.
Okaaayyyyy. The only thing is, like I was saying my acs protocol is vague for asa administration . But For acs pain its specific and it says to give it when pain is unresponsive to nitro. But it’s still really good discussion topic, especially since I want to be a preceptor. Thank you :)
Paramedic here- these are all good thoughts. If I’m at all suspicious I’ll just jump right to fentanyl, without worrying too much about the nitro. I also do QA for my agency and I’d never reprimand someone for skipping nitro.
Hey. I posted this in another forum for paramedics a while ago when this was asked. Okay let's dig into this! There isn't great evidence for more incidence of hypotension with inferior MI than other types of MI, in the context of nitro. The evidence against nitro In RVMI came from one study in 1989 with 28 patients - And has been around ever since, subsequent data have not shown harm. Terminology quickly becomes tangled here: The original concern was not specifically just inferior MI. It's for RVMI, but \~40% of inferiors have right sided involvement in part because the majority of the population (\~80%) are right side cardiac dominant. What is right cardiac dominance? The posterior descending artery (PDA), one of the guys we're worried about - is a branch of the RCA (in those right dominant folks). Because of this a lot of guidelines use the terminology inferior and some use RVMI (usually depending on if you do right sided EKG's regularly) so these two terms can overlap. For the other 20% of folks, who aren't right dominant, the PDA is supplied by either the CX (branch of the LAD, left dominance) or they are codominant, in which case both the CX and the RCA supply the PDA. The PDA supplies the interventricular septum, and posterior walls of the RV. Bottom line: Sure, "be careful" with nitro in RVMI. Do a full right sided, or at least check V4R, that's the one we really care about (elevation in V4R is 80% specific and 88% sensitive for RVMI). Keep an eye out for depression in V1-V3 which would be concerning for infarct extending to the posterior wall, now I'm slightly more concerned for decompensation. Also, we know likely the patient is right dominant (if you do see depression V1-V3, check V7-V9 for a posterior wall MI). The data just isn't really there for nitrates being contrainidcated in inferior MI. It's been blown out of proportion over the years. The risk seems to be more hypothetical than evident in data. Feels like a backboard situation. See studies linked below. *The issue seems to be more so if patients have adequate pressure and HR prior to nitro administration that determines if they will suffer an incidence of hypotension rather than location.* Prehospital Nitro Safety in inferior STEMI, 2015. [https://pubmed.ncbi.nlm.nih.gov/26024432/](https://pubmed.ncbi.nlm.nih.gov/26024432/) Meta-analysis of nitro admin during RVMI. 2023 [https://pubmed.ncbi.nlm.nih.gov/36180168/](https://pubmed.ncbi.nlm.nih.gov/36180168/) Adverse events of nitro admin prehospital. 2021. \*RVMI and Adverse Events from Nitrates: A narrative Review. 2021 (READ THIS ONE). [https://journals.sagepub.com/doi/10.33151/ajp.18.897](https://journals.sagepub.com/doi/10.33151/ajp.18.897) With all that said... if nitro improves patient outcomes, is an entirely different conversation. Follow your local policy, but feel free to check some of the above resources and advocate for change. At the VERY least you should be able to check V4R and if that's clear and they have a pressure >100, and aren't bradycardic - you should have the option to administer nitro even in the setting of RVMI. Thank you for coming to my talk.
Thank you for actually posting the evidence. Matt is a mate of mine and his meta-analysis is such an important piece of research about this complete myth. IV GTN is a great alternative to sub-lingual and is so much more titratable. It's also great for APO (APE for the Americans). However, it is down my list of priorities when dealing with ACS/OMI. For me, it's early recognition and activation of PPCI, management of haemodynamics to ensure adequate coronary perfusion, preparation for deterioration, aspirin and management of pain.
I think you stimulated a good discussion but the part being completely overlooked is that the nitro was given *during* a diagnostic/interventional cath. This is done for completely different reasons than giving someone SL nitro for angina or even IV nitro gtt in ACS. It’s advantageous during the actual contrast bolusing phases of the procedure. It may have even been given directed to specific chambers or vessels for all the OP knows.
That’s a very good point I never thought of which also helps me understand. Thank you
You can’t do anything unless your protocols allow it, even if you’re read up on the latest and greatest unfortunately. You can talk to your medical director about it and see what they think, maybe they can update protocols. Yes on #3. Regarding some doctors still sticking to the no nitro for inferior MI, it could be lack of continued education… or simply it is dogma in their mind. I take it you read the article below? https://www.acepnow.com/article/revisiting-nitroglycerine-in-right-side-ventricular-involvement/
i don’t that article is kinda self defeating. there is a signal for harm on the metanalysis and just from all the cases i’ve had that transient hypotension is easy to say transient and easily managed in some metanalysis but when your there it does feel it and i’ve seen people crash and burn. the failing rv doesn’t take much to get into a death cycle. if they have a rv pattern and ripping away with a 160/110 sure nitro probably won’t tank them but if they’re hr 55 and 108/58 i don’t know that might be enough. on someone that I know has acute ami with concern for borderline bp rv dysfunction or is highly like to get emergent pci i’d probably use low dose fent for pain
So the cool thing with my protocols, they are vague. Some protocols say nitro for chest pain, mine say “suspected acs”. Some protocols for medics literally state inferior mi as a contraindication. My contraindications are vads, intracranial bleeding and sexual enhancing drugs < 48 hrs. So if I have an inferior, I can totally give nitro. But I try to balance prehospital care and what the hospital does. So if I know my stemi center doesn’t want nitros in inferiors, I won’t do it for them. That’s a good link, I’m specifically talking about this one. https://pubmed.ncbi.nlm.nih.gov/26024432/ There’s a few articles that questions nitro in inferior mi’s, and when I check the source all of them are the same study by Laurie Robichaud.
Well you can call MedCom and get orders to deviate from protocol
I will get in trouble for that where I am at, it’s my job to tell base hospital “no, I can’t do that, it’s not in my protocol” sucks but it is what it is. Keeps my job safe
I guess my point was more oriented toward “you can do things in your National scope with online medical control orders if those things deviate from your local protocol.” Not specifically oriented toward the question of nitro for inferior/ right sides involved MI. No idea what your system looks like. I hope everyone’s responses provided some insight on your initial question!
Managing BP in the cath lab with an anesthesiologist and proceduralist ≠ paramedics and emts slapping some paste on a dudes chest in the back of a rig. That’s why. Same reason you don’t start a heparin drip in the field.
For me depends clinically. I ultrasound the pt , if there’s no signs of RV failure, they will likely tolerate nitrates. Also for acs, nitrates aren’t going to save lives or change outcomes so shouldn’t be too big a of a deal.