# Acute coronary syndrome /MI/STEMI and Oxygen administration



## beaucait (Jan 20, 2018)

I heard recently that research suggests not to give O'z to a patient who is having acute coronary syndrome/MI/STEMI because it constricts blood vessels and can lead to further infarction of the myocardium. What do you guys think? Should we be giving oxygen anyway? Do you think that the damage caused by the oxygen is less than the benefits? I understand oxygen is important and all, but if it is harming our patient is it really doing so good. 

I come from a non transporting BLS service. It can be 5-10 minutes after we arrive on scene before ALS gets there. We are volunteer, so we usually show up in our POV with no monitor, and we can't read rhythms anyway.

Our Maine EMS protocol states the following:
1. Administer O2 only to patients with dyspnea, hypoxia (less than 94%) or signs of heart failure at a rate to keep O2 sats greater than or equal to 94% and less than 99% (avoid hyperoxia) 
2. Treat for shock if indicated 
3. Request ALS 
4. If patient has not taken an aspirin: administer chewable aspirin 324 mg PO, if not contraindicated by allergy. 
5. Contact OLMC for the OPTION of assisting w ith the administration of patient's own nitroglycerin


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## medichopeful (Jan 20, 2018)

O2 is important like you said, but only in the right amount. An SpO2 of 93/94% in almost all patients (cardiac, respiratory, etc) is generally acceptable. 

An SpO2 of 100% might sound great, but the problem is the PaO2 might be higher. 

Go with the research on this one. Hope that helps!


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## VFlutter (Jan 20, 2018)

Hyperoxia is probably more harmful than we first thought. We probably harmed a lot of people with the 15L NRB for everyone.  Here is the AVOID trial that looks at suppliental O2 in STEMI. There are a few other studies as well, at best they show no benefit to patients with normal oxygen stats at worst they show possible harm. 
http://circ.ahajournals.org/content/early/2015/05/22/CIRCULATIONAHA.114.014494

Treat hypoxia, <94%, with the minimal amount of supplemental oxygen necessary to increase saturations. Start with a cannula and go from there. If the patient is 100% do not give them oxygen. If you have to, a NC at 2L probably will not increase your pa02 significantly but it really is not necessary.


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## DesertMedic66 (Jan 20, 2018)

MONA has turned into FAN in our system haha


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## VFlutter (Jan 20, 2018)

DesertMedic66 said:


> MONA has turned into FAN in our system haha



Don't even get me started on Morphine. Just picked up a guy yesterday with a massive Anterolateral MI that they were pumping full of morphine because..."MONA". Isn't it common knowledge that morphine is horrible?


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## DesertMedic66 (Jan 20, 2018)

VFlutter said:


> Don't even get me started on Morphine. Just picked up a guy yesterday with a massive Anterolateral MI that they were pumping full of morphine because..."MONA". Isn't it common knowledge that morphine is horrible?


In some systems yes but in other systems morphine is still considered to be god.


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## hometownmedic5 (Jan 20, 2018)

We don't even carry morphine at my primary service anymore; we still have it at my second job. 

As for the op, I'm quite happy with an SpO2 of <94%. The days of strapping a NRB and flooding them with oxygen are over. I just wish I could get this message to the firefighters in my town who throw everybody on a mask and then get all butthurt when I walk in and take it off.


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## StCEMT (Jan 20, 2018)

Morphine isn't even an option for me, Fentanyl all day.


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## hometownmedic5 (Jan 20, 2018)

hometownmedic5 said:


> We don't even carry morphine at my primary service anymore; we still have it at my second job.
> 
> As for the op, I'm quite happy with an SpO2 of <94%. The days of strapping a NRB and flooding them with oxygen are over. I just wish I could get this message to the firefighters in my town who throw everybody on a mask and then get all butthurt when I walk in and take it off.



Damnit it. I got the > and the < backwards again. Now I look like an idiot and the other kids in my class won't want to play with me....


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## beaucait (Jan 20, 2018)

hometownmedic5 said:


> Damnit it. I got the > and the < backwards again. Now I look like an idiot and the other kids in my class won't want to play with me....


Remember, the alligator eats the larger number *chomp*


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## taxidriver (Jan 21, 2018)

When I was getting my basic an old schol Fire medic told us to put all patients with chest pain on a nrb 15lpm to get more oxygen to the oxygen deprived tissue. Yep, good thing I looked through my protocols. The protocol in my area is to keep the sa02 greater than or equal to 94%. If pulse oximetry is not available then every patient with chest pain gets a nc at 4lpm.


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## Colt45 (Jan 21, 2018)

I'm pretty sure that ACS according to AHA doesn't call for oxygen administration for anything more than a 90% spo2.


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## VentMonkey (Jan 21, 2018)

We’re starting to split hairs here.

I’m well aware of the detrimental effects of hyperoxia, however, hi-flow O2 for the short time that we have our patients will not make that big of a difference. Also, it is still indicated for certain patient populations (e.g., septic patients, CO poisoning patients, and critically injured trauma patients), and quite pertinent.

I don’t dry every patient I encounter out with hi-flow O2, and I almost always find myself having to remove even an NC on many of the CVA patients we pick up from many of our outlying crews.

I do think something worth mentioning is how we go one huge foot in only to take that foot back out with the next set of guidelines in 5 or so years. Hyperoxia- bad, oxygen deprivation in acutely ill patient in need of a temporary dose of oxygen- very bad.


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## DrParasite (Jan 21, 2018)

hometownmedic5 said:


> I just wish I could get this message to the firefighters in my town who throw everybody on a mask and then get all butthurt when I walk in and take it off.


While I do understand your feelings, i think there is more to this.  Do their protocols (from their medical director) still say to put a NRB on everyone?

Many years ago I had a paramedic who "tried to impart knowledge" on a bls crew, but telling them that the chest pains patient did not need a NRB at 15LPM.  He explained how the pulse ox was 99%, the patient was in no serious distress, and he got all butthurt when the BLS crew promptly ignored him.  Why was he ignored?  Because their protocols still called for a NRB on cardiac issues, which were written by their clinical coordinators, and approved by their medical director.  The medic was correct, but their bosses still wanted them to do it a certain way, and hadn't updated their protocols.  

Maybe it's the same way if your firefighters in town?



VentMonkey said:


> critically injured trauma patients


So the trauma patients should still get a NRB?


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## Colt45 (Jan 21, 2018)

VentMonkey said:


> Also, it is still indicated for certain patient populations (e.g., septic patients, CO poisoning patients, and critically injured trauma patients), and quite pertinent.



I agree Vent. I should have been more specific. The general ACS patient with no other pertinent comorbidities should not recieve oxygen unless their oxygen saturation is showing 90% or less, or showing signs of dyspnea or distress per 2015 AHA update. 

AHA isn't everyone's protocol, and a medical director can set forth whatever he wants but just an observation.


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## VentMonkey (Jan 21, 2018)

DrParasite said:


> So the trauma patients should still get a NRB?


Mine certainly do. Again, the critically-ill trauma patient. Particularly those I suspect of having a closed head injury, and/ or internal bleeding. Obviously we can’t fix what we can’t see, but we also know the two primary causes for high 
mortality in the TBI patient. 

I appreciate and agree with the data showing the detriment oxygen can bring to the ischemic heart, particularly coronary blood flow, but again, I think before this becomes “a hi-flow oxygen should not be given” sort of mindset we need to be able to think through when in fact it _is_ still indicated.

The brain-injured patient who is electively intubated is started on an FiO2 of 1.0 (hi-flow), and carefully trended down based on parameters and numbers. Their care becomes a waiting game approach depending on the severity, and extent of their injuries obviously, but hypoxia and hypotension are not to be taken lightly with this folks.

I guess what I’m trying to say is that we’d all be better off if we did our collective homework a bit more and realized how sometimes current literature doesn’t apply to all patients across the board. I’d hate to impress upon the inexperienced masses a one-size fits all approach to patient care. 

I think in general the tenured forum members here understand this, but some of the newer and up-and-coming providers can stand to learn a bit more from their peers on this forum that are willing to impart their own experiences, and/ or provide data. Kind of like @VFlutter did.


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## NPO (Jan 23, 2018)

I'm not really sure why trauma patients we're intoduced into the conversation. The OP specifically cited ACS patients.

Fact is (and seems to be echoed by the OPs protocols) that hyperoxia for ACS is potentially bad. Oxygen is used to treat hypoxia, not chest pain.

As far as trauma, since it was introduced into conversation, I have no problem with a NRB at 15lpm as long as it's needed. A single episode of hypoxia in head injury patients is associated with significant increases in mortality.

But, I disagree with the idea that "for the amount of time we have a patient it won't make a difference." Sorry @VentMedic. And you're probably not wrong, and I know that's a common mentality for a lot of things, it's just not mine. I don't like the idea of having a different (potential lower) set of standards than in hospital, just because it probably doesn't matter. Continuity of care and evidence based practice for me.


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## VentMonkey (Jan 24, 2018)

@NPO I clearly stated my points re: hi-flow oxygen, and its pertinent correlations. I even went so far as to keep the point about oxygens detriment with the suspected ACS patient relevant so as to keep it on topic.

I have no clue where you’re coming from with your “continuity of care, and EBM” remark because _that is_ continuity of relevant EBM-driven care on an array of patients that are outside of the ACS category for higher concentrations of oxygen even “if only” for the time being. 

Aren’t we here to help each other out, and prevent a closed-minded train of thought for even the newer/ newest of providers? How doesn’t hyperoxia have relevance in this thread with regard to when it is required?


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## NPO (Jan 24, 2018)

VentMonkey said:


> We’re starting to split hairs here.
> 
> I’m well aware of the detrimental effects of hyperoxia, however, hi-flow O2 for the short time that we have our patients will not make that big of a difference.



This is what I was referring to in regards to my continuity of care comment. I have no doubts that you provide good (better than many) care. I was just adding that I don't like the idea of doing things because "it won't matter for as long as I'm with them." And this isn't specific to this topic, it's a general philosophy, like not giving analgesia for a short ride to the ED, or not giving fluids to a septic patient because "they'll just get 100ml by the time I get there." Obviously we can't always do everything, but it's just a general idea I try to follow that if I can provide care that is appropriate, and would likely be continued or started in the ED then I should do that thing.

I think I just built a personal vendetta against that type of verbage after hearing it so long from medics that I'd consider inferior, with whom I definitely don't group you with.


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## VentMonkey (Jan 24, 2018)

NPO said:


> This is what I was referring to in regards to my continuity of care comment. I have no doubts that you provide good (better than many) care. I was just adding that I don't like the idea of doing things because "it won't matter for as long as I'm with them." And this isn't specific to this topic, it's a general philosophy, like not giving analgesia for a short ride to the ED, or not giving fluids to a septic patient because "they'll just get 100ml by the time I get there." Obviously we can't always do everything, but it's just a general idea I try to follow that if I can provide care that is appropriate, and would likely be continued or started in the ED then I should do that thing.
> 
> I think I just built a personal vendetta against that type of verbage after hearing it so long from medics that I'd consider inferior, with whom I definitely don't group you with.


I think we both know enough to know better and when, or when not to apply hi-flow vs. no-flow, or low-flow O2.

The reason I felt compelled to add other pathologies into the mix was so that, again, we don’t adopt a blanket-mindset-to-medicine approach. It wasn’t meant specifically to mean I advocate, or apply high concentrations of a drug that carries every bit the potential dangers as the others in the box.

Afterall, you and I both come from the same region known to give “hi-flow” to abdominal pain, and N/V patients for absolutely no reason. And even 10 plus years ago that was the first thing I would _not_ do once those ambulance doors shut, and that patient was mine to care for.

I don’t think my remark is quite the same as a pain management comparison, and perhaps it was simply completely misconstrued on your behalf after it struck a nerve; fair enough, no harm, no foul.

I was simply suggesting we—specifically the less experienced folks on here—keep from putting blinders on when it comes to high flow O2 with some of the other kinds of sick patients that we will see.

How many EMT’s do you know who are up on things such as ApOx and nitrogen washout, let alone their clinical relevance? Why shouldn’t they be?...seems perfectly pertinent when they want know if SPO2, or CO2 monitoring would help them do their job better.


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## NPO (Jan 24, 2018)

VentMonkey said:


> I don’t think my remark is quite the same as a pain management comparison, and perhaps it was simply completely misconstrued on your behalf after it struck a nerve; fair enough, no harm, no foul.



Quite possible. In practice, I'm sure we're both advocating the same thing.


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## EMTlash (Mar 15, 2018)

If it helps the dyspnea, based on experience, I'd say its fine, but the book does say that O2 is not beneficial for a PT you just talked about, however, does it provide comfort at times? Yes. So again if in resp. Distress, depending on its severity, I'd say it is fine if not and the pt has no sign of SOB or resp. Distress then low dosage or nothing would probably make little to no difference.


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## MSDeltaFlt (Mar 16, 2018)

The thing about hyperoxemia is that it produces a lot free radicals which actually do a lot of harm by overdosing on oxygen and cells won't regenerate properly.  That being said, generally speaking cells do regenerate faster in a hyperoxic environment like certain traumas like pneumo's.  The cells at the breach that prompt the pneumo in the first place with regenerate in a hyperoxic environment.  Which is why some physicians will keep them on NRM for several days regardless of SpO2.  But it is a benefit versus risk thing left up to those with MD behind their names.  So maintaining SpO2's 94% and higher on minimal supplemental oxygen will do just fine.

So everyone says >/= 94%.  How can you tell if you're actually maintaining that?  Officially you can't.  But you can have a good idea if your machine is telling you the truth or lying to you.  The best way is if your pulse oximeter has a plethysmograph.  If you do have one of these then your machine is being as honest with you as it possibly can.  If you don't then it is lying to you regardless of what your sat reads.  Don'e believe it.  That's when you will have to treat clinically.

Now as far as "high flow O2" goes.  I am an old school respiratory therapist.  And I fundamentally and adamantly disagree with National Registry as to what "high flow oxygen" is.

So treat your patient.  If you treat mechanically know when your machine is lying to you.  If you treat clinically then treat clinically.


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## Carlos Danger (Mar 17, 2018)

MSDeltaFlt said:


> The best way is if your pulse oximeter has a plethysmograph.  If you do have one of these then your machine is being as honest with you as it possibly can.  If you don't then it is lying to you regardless of what your sat reads.  Don'e believe it.  That's when you will have to treat clinically.



So if you have a pleth, the sat is accurate, but if you don’t have a pleth, the same exact technology is innacurate?

Modern pulse oximeters are actually very precise.


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## Tigger (Mar 18, 2018)

MSDeltaFlt said:


> The thing about hyperoxemia is that it produces a lot free radicals which actually do a lot of harm by overdosing on oxygen and cells won't regenerate properly.  That being said, generally speaking cells do regenerate faster in a hyperoxic environment like certain traumas like pneumo's.  The cells at the breach that prompt the pneumo in the first place with regenerate in a hyperoxic environment.  Which is why some physicians will keep them on NRM for several days regardless of SpO2.  But it is a benefit versus risk thing left up to those with MD behind their names.  So maintaining SpO2's 94% and higher on minimal supplemental oxygen will do just fine.
> 
> So everyone says >/= 94%.  How can you tell if you're actually maintaining that?  Officially you can't.  But you can have a good idea if your machine is telling you the truth or lying to you.  The best way is if your pulse oximeter has a plethysmograph.  If you do have one of these then your machine is being as honest with you as it possibly can.  If you don't then it is lying to you regardless of what your sat reads.  Don'e believe it.  That's when you will have to treat clinically.
> 
> ...


Treat clinically. As in correlating the diagnostic readings you get to your patient's condition? Sometimes (*gasp*) we use a lil finger tip pulse oximeter. It is much lighter than the lifepak when walking in the woods. Or sometimes there or are multiple patients. I could go on. But really, why exactly would I assume the pulse ox is "lying" with it reads 94% with a patient who is not dyspneic or tachycardic and has skin that is well-perfused, warm, and dry along with being eupneic, non-anxious, and with clear lung sounds?

You can't spout things about "treating clinically" and then not have it the other way.


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## MSDeltaFlt (Mar 18, 2018)

Remi said:


> So if you have a pleth, the sat is accurate, but if you don’t have a pleth, the same exact technology is innacurate?
> 
> Modern pulse oximeters are actually very precise.


 
Yes.  In the absence of a saw tooth waveform with a dicrotic notch, that number (whatever that number is) is wrong.  Period.


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## MSDeltaFlt (Mar 18, 2018)

Tigger said:


> Treat clinically. As in correlating the diagnostic readings you get to your patient's condition? Sometimes (*gasp*) we use a lil finger tip pulse oximeter. It is much lighter than the lifepak when walking in the woods. Or sometimes there or are multiple patients. I could go on. But really, why exactly would I assume the pulse ox is "lying" with it reads 94% with a patient who is not dyspneic or tachycardic and has skin that is well-perfused, warm, and dry along with being eupneic, non-anxious, and with clear lung sounds?
> 
> You can't spout things about "treating clinically" and then not have it the other way.



You always treat clinically.  You take the data you are given with a grain of salt.  As a clinician you physically assess your patient.  You put your hands on them and feel their skin.  You look at their mucosa.  You listen to their lungs.  You ask them questions.  You look around you.  You gather all kinds of data including the data your machine(s) give you and you, as a clinician, interpret said data.  Is your machine's data coinciding with your patient's complaint and physical findings?  Is it not coinciding?

This isn't rocket science.  IF you use a machine then you HAVE to interpret the data as accurate or inaccurate.  Otherwise you run the risk of becoming a V.O.M.I.T. medic.  Something I believe the OP is trying NOT to be.


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## Carlos Danger (Mar 18, 2018)

MSDeltaFlt said:


> Yes.  In the absence of a saw tooth waveform with a dicrotic notch, that number (whatever that number is) is wrong.  Period.


Uh....Ok.


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## Tigger (Mar 19, 2018)

MSDeltaFlt said:


> You always treat clinically.  You take the data you are given with a grain of salt.  As a clinician you physically assess your patient.  You put your hands on them and feel their skin.  You look at their mucosa.  You listen to their lungs.  You ask them questions.  You look around you.  You gather all kinds of data including the data your machine(s) give you and you, as a clinician, interpret said data.  Is your machine's data coinciding with your patient's complaint and physical findings?  Is it not coinciding?
> 
> This isn't rocket science.  IF you use a machine then you HAVE to interpret the data as accurate or inaccurate.  Otherwise you run the risk of becoming a V.O.M.I.T. medic.  Something I believe the OP is trying NOT to be.


So if the data coincides with the patient's presentation but there is no pleth wave available, the data is still wrong?


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## ThadeusJ (Mar 20, 2018)

MSDeltaFlt said:


> es. In the absence of a saw tooth waveform with a dicrotic notch, that number (whatever that number is) is wrong. Period.



To state without further evidence that its categorically wrong (IMHO) is a bit incorrect.  I would suggest "suspect" as a more appropriate term, as it includes possible errors from the device as well as the user.


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## Jubal (Jul 6, 2018)

I literally just passed my practicals and I was scared to death I'd failed it because I did NOT admin 02 on a non hypoxic pt with acute MI and said why I wasn't doing it....  My proctor told me after that he was impressed that I didn't and knew why even though this wasn't a critical fail.   ON MY WHOPPING 100 hours an ambulance with multiple Mi' s not a one has been put on 02.  If it ain't broke, don't fix it, comes to mind


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