# ASA in Chest Pain



## Arovetli (Mar 30, 2012)

Not sure which forum is most appropriate.

My service/hospital administers 325mg ASA to chest pain patients. I'm interested to know, how many of you administer this dose? AHA recommends the 160mg dose over the 325mg. The literature indicates we are overdosing people on ASA and doing nothing except increasing the risk for an adverse event. Off the top of my head ISIS-2, GUSTO-1, GUSTO-3 and CURE are trials which advocate the 160mg dose. 

Also thoughts on administering ASA to chest pain patients who take long term low dose (81mg) ASA? My previous service did not administer additional ASA under the belief that the cyclooxegenase was fully inhibited while at my current service the attendings administer, and want us to administer 243mg of ASA so they can go down on paper saying the patient got 325mg of ASA today. How does you service do it and what are your thoughts?

***

In the spirit of education ASA, or acetylsalicylic acid, reacts its acetyl group with serine in the cyclooxegenase (COX-1/COX-2) receptor. The binding of the acetyl group irreversibly blocks the cyclooxegenase. The affected platelet is inactive until it dies (life span 10 days). In normal function the cyclooxegenase catalyzes prostiglandin production (prostiglandin H2) and thromboxane A2 production. Thromboxane A2 acts as a local messenger mediating glycoprotein 2b/3a sites (fibrinogen binding sites) and activating and attracting platelets. It hangs out for about 30 seconds before disintegrating into inactive thromboxane b2.


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## Medic Tim (Mar 30, 2012)

Where I work we give 160mg even if the pt has already taken ASA.


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## EpiEMS (Mar 30, 2012)

Medic Tim said:


> Where I work we give 160mg even if the pt has already taken ASA.



Quick question:
I asked an instructor about this a while ago, and he indicated that if a patient has taken ASA in the morning, then it's not necessary to give them (and is contraindicated, even) ASA when they present with chest pain, because the ASA has already reached whatever level in the blood necessary to act as an anti-clotting agent. Does that strike you as reasonable?
I'm assuming that another 160 mg certainly wouldn't harm the patient, but curious whether it would help.


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## Handsome Robb (Mar 30, 2012)

EpiEMS said:


> Quick question:
> I asked an instructor about this a while ago, and he indicated that if a patient has taken ASA in the morning, then it's not necessary to give them (and is contraindicated, even) ASA when they present with chest pain, because the ASA has already reached whatever level in the blood necessary to act as an anti-clotting agent. Does that strike you as reasonable?
> I'm assuming that another 160 mg certainly wouldn't harm the patient, but curious whether it would help.



Umm you just reiterated the original question. You just used simpler wording.... It's not contraindicated unless they have taken the max dose already. 


We give 324 mg. If they have already taken ASA today and we can determine how much they took and it is less than 324 mg we are supposed to give them enough to reach the 324 mg dose.


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## awesomemedic (Mar 30, 2012)

Give this, don't give that. Too much of this, not enough of that. I find that there are enough studies to effectively put an end to pre-hospital care. My favorite is the study about pre-hospital NS in trauma patients is causing an increase in mortality rates. But what the study failed to mention was that patients requiring pre-hospital fluid infusion are typically on their way to death anyway. I'm not bashing the OP and am interested to hear more about this new study about the one proven med we carry to help an ACS patient is suddenly causing adverse effects. I just want to know when the study on studies is published.


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## Bullets (Mar 30, 2012)

I am allowed to give up to 325mg of ASA or if the patient has relief. So if i give the patient 81mg and they have total relief i dont have to give them more.


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## EMSrush (Mar 30, 2012)

We administer 324mg ASA for CP.


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## Arovetli (Mar 30, 2012)

awesomemedic said:


> I'm not bashing the OP and am interested to hear more about this new study about the one proven med we carry to help an ACS patient is suddenly causing adverse effects. I just want to know when the study on studies is published.



Not new studies and plenty of research showing increased risks with ASA administration. It's not suddenly causing anything, its been well established that asa increases bleeding risks. There's alot of data out there other than the 4 studies I quoted. Just wondered how practices varied and who followed what regimen.

We should constantly be questioning ourselves and our established practices to ensure optimal care. Note I said constant questioning not constant change. Change should only follow well established science. I do find it interesting how resistant to change physicians and clinicians can become at times, even though we tout evidence based approaches.


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## EpiEMS (Mar 30, 2012)

NVRob said:


> We give 324 mg. If they have already taken ASA today and we can determine how much they took and it is less than 324 mg we are supposed to give them enough to reach the 324 mg dose.



Sorry, guess I misread the original question. That makes sense.


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## Anjel (Mar 30, 2012)

We give the 324mg.  4 81mg tabs. Unless they took.it prior to us getting there. Then we dont.


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## Medic Tim (Mar 30, 2012)

Bullets said:


> I am allowed to give up to 325mg of ASA or if the patient has relief. So if i give the patient 81mg and they have total relief i dont have to give them more.



so your protocols use ASA as pain relief for ACS? How long do you wait before giving more?
do you have your pt's chew the ASA or swallow?


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## mycrofft (Mar 30, 2012)

*If ASA is such a perilously dosed anticoagulant...*

With so many people presumably taking ASA for pain as it was originally intended, why aren't they dropping like flies from exsanguination caused by traumas large and small? I think armchair scientists try to see the most minimal dose to reach a 50% (median) of sample positive response to avoid giving one extra atom, and to achieve scientific elegance.

A lifelong chronic dental patient, I have seen that other NSAIDS like Ibuprophen and naproxyn sodium really increase bleeding too, and are taken in large doses (500 mg for Naprosyn, 800 for Motrin).

PS: An NSAID given for chest pain due to complaint and not assessment may be addressing chest wall pain. No harm unless the pain is referred from a gastric or esophageal ulcer...going back to why the smaller dose of enteric coated drug is given. Even in those cases, it could decrease pain for a little while before it came back.


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## Devilz311 (Mar 30, 2012)

Bullets said:


> I am allowed to give up to 325mg of ASA or if the patient has relief. So if i give the patient 81mg and they have total relief i dont have to give them more.



Unless it's psychologic, I highly doubt the Pt is going to report a relief in CP from ASA in the field... AND it's given all at once.  What protocols are you referencing? NJ EMT-B's can't directly give a Pt ASA anyway...


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## Devilz311 (Mar 30, 2012)

Medic Tim said:


> so your protocols use ASA as pain relief for ACS? How long do you wait before giving more?
> do you have your pt's chew the ASA or swallow?



It's not. NJ ALS standing orders are a max dose of 324mg ASA and SL NTG q5 for a SBP >100mmHg.

I just checked the NJ EMT-B regs, ASA isn't even mentioned. They can ASSIST with SL NTG, but can not physically give aspirin.


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## EpiEMS (Mar 30, 2012)

Devilz311 said:


> I just checked the NJ EMT-B regs, ASA isn't even mentioned. They can ASSIST with SL NTG, but can not physically give aspirin.



"Oops, I must have dropped these 4 81 mg chewable tablets of aspirin, which can possibly help in the situation you're in, sir. If I were having an MI, I'd take four 81 mg chewable aspirin like these..."


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## tylerp1 (Mar 30, 2012)

Our protocol states we give 325 mg ASA whether they've had ASA already or not.


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## Cup of Joe (Mar 31, 2012)

tylerp1 said:


> Our protocol states we give 325 mg ASA whether they've had ASA already or not.



Almost the same for us.  We give max 325mg (4x 81mg chewable tablets) unless the patient takes chewable ASA, in which case we subtract their dose from the max allowable.


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## Tigger (Mar 31, 2012)

Straight from the MA protocols:



> administer aspirin (dose 162-325mg, chewable preferred) if not contraindicated and not already administered.



If they've already taken ASA, I've been told to just give the 162mg dose, if not give all.


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## the_negro_puppy (Mar 31, 2012)

We carry 300mg aspirin tabs, and aim for a dose between 300-450mg.

Many cardiacd pts are on daily 100mg tabs so we usually give another 300mg on top.

What are the protocols in other services for patient on warfarin/plavix?

I tend not to give ASA to pts on warfarin unless they are strongly suspected to be suffering from ACS.


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## jjesusfreak01 (Mar 31, 2012)

I don't want to be the bad guy here, but whenever someone just lists their protocol in one of these conversations, it sounds like this,

"here's what my protocol says. I don't know why it says that, or whether i'm doing what's best for my patient, but a doctor wrote the protocol so it must be right"

Interspersed between these posts are the occasional instructional posts about the mechanism of the drug or new studies that have demonstrated new risks to certain dosages of administration. That's what we like to see here.

As EMS struggles to gain recognition as a true profession, it should be everyone's focus to educate themselves to the point of being experts on what we do, why we do it, and how it affects the human body. Even if at times this means that our medical knowledge supersedes or even differs from protocol, so be it. That's a good problem to have.


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## jjesusfreak01 (Mar 31, 2012)

the_negro_puppy said:


> We carry 300mg aspirin tabs, and aim for a dose between 300-450mg.
> 
> Many cardiacd pts are on daily 100mg tabs so we usually give another 300mg on top.
> 
> ...



Well, here's a good question. Warfarin works by blocking production of clotting factors, but depending on the patients specific needs and the target INR, we can't know to what degree these clotting factors are in effect. Aspirin inactivates the protein that causes platelets to stick together, preventing further clots or worsening ischemia in the case of ACS.

On one hand you could argue that since your patient is already taking anticoagulants, then they probably don't need aspirin.

On the other hand, you can argue that because your patient is already taking anticoagulants, a little bit of aspirin probably isn't going to hurt them more than the coumadin they are already on, and that if somehow they are still clotting up their coronary arteries even with all that coumadin running through their system, then they need all the help they can get.


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## Hellsbells (Mar 31, 2012)

Heres an interesting fact about my service (forgive me for quoting protocols). Dispatch now directs pts to take 325mg of ASA online, prior to our arrival. A practice I find reprehenisible, as our dispatch struggles with determining a proper C/C on the average call, let alone directing pts to take meds over the phone. 

There is no hard and fast rule where I work about the dose of ASA, so long as its between 160-325mg range. I typically administer 160mg, even if the pt has taken their normal Rx dose, as I don't know for sure if they have actually taken their ASA that day, I'd hate to see an MI pt not receive any ASA due to a drug error on the pts part.


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## tylerp1 (Mar 31, 2012)

jjesusfreak01 said:


> I don't want to be the bad guy here, but whenever someone just lists their protocol in one of these conversations, it sounds like this,
> 
> "here's what my protocol says. I don't know why it says that, or whether i'm doing what's best for my patient, but a doctor wrote the protocol so it must be right"



With all due respect, I, along with others, was simply answering OP's question; I shared what my protocols are, though I haven't come to a conclusion whether I should or shouldn't give ASA in certain circumstances after having discussed this matter to doctors with whom I work. 

It also seems as if OP also explained some biochemistry of ASA. I figured why beat a dead horse?

In case you forgot:



Arovetli said:


> Not sure which forum is most appropriate.
> 
> My service/hospital administers 325mg ASA to chest pain patients. I'm interested to know, how many of you administer this dose? AHA recommends the 160mg dose over the 325mg. The literature indicates we are overdosing people on ASA and doing nothing except increasing the risk for an adverse event. Off the top of my head ISIS-2, GUSTO-1, GUSTO-3 and CURE are trials which advocate the 160mg dose.
> 
> ...


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## mycrofft (Mar 31, 2012)

The standardized procedure I referenced was for RN's in our correctional setting. If vitals were stable and pt was otherwise unremarkable as far as signs (no diaphoresis, skin color good, resp unlabored at rest, chest clear, no distal leg edema) and symptoms (no c/o n/v, no weakness), we could actually give a swallow of liquid antacid while monitoring. We caught quite a few esophagitis, upper gastritis and spastic esophagi this way, but we also had a hair trigger about calling the doc if things just didn't look right. Also while doing the rest, we would palpate the rib cage including sternal depression while lying down or supporting the mid-thoracic spine with the other hand and ask if that reproduced the pain. 
It's a professional decision thing, within the SP's.


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## jjesusfreak01 (Mar 31, 2012)

tylerp1 said:


> With all due respect, I, along with others, was simply answering OP's question; I shared what my protocols are, though I haven't come to a conclusion whether I should or shouldn't give ASA in certain circumstances after having discussed this matter to doctors with whom I work.
> 
> It also seems as if OP also explained some biochemistry of ASA. I figured why beat a dead horse?
> 
> In case you forgot:



You make a good point, the OP did ask for protocols. That said, I don't believe its generally helpful to list protocols without the evidence behind them. It is extremely common for many people to pipe up on threads here simply listing their protocols when the objective of the OP was to have a genuine medical discussion about the evidence and efficacy of drugs and treatments.


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## Melclin (Apr 1, 2012)

We give 300 in one tablet. Regardless of previous administration.

Aspirin being the most important drug we give and reasonably harmless, even on top of a previous dose. Add that to people being rubbish historians especially when they old/scared. I almost always just give them one of ours.  

I'd be interested to see the outcome of this thread.


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## Arovetli (Apr 2, 2012)

Thanks everyone for the replies. Its interesting how different things can be from one place to the next.


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## johnrsemt (Apr 2, 2012)

Kind of scary how many areas out there that the EMT-B's can't give ASA to cardiac symptom patients or assist with patients NTG:  here they have to call and get permission from Medical control; and half of our response area is out of radio and cell range for upto 1-2hrs.
   So they are taking away what little Basics can do to help people.


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## johnrsemt (Apr 2, 2012)

Back where I used to work Basics could give 162mg baby ASA chewable, and assist with up to 3 doses of patients NTG (BP dependent), and O2,  all without needing to call in for orders.

  and that was with an average of 10 minute transport time with medics crawling out of the woodwork.


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## Bullets (Apr 3, 2012)

Medic Tim said:


> so your protocols use ASA as pain relief for ACS? How long do you wait before giving more?
> do you have your pt's chew the ASA or swallow?



ASA can be administered in any incident of non-traumatic chest pain. It is to be delivered in a cumulative dose not to exceed 325mg but does not give a specific time period. All aspirin must be chewed

And this is literally a brand new change from the NJ DOH/OEMS, some agencies aren't even aware of it


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## Cawolf86 (Apr 4, 2012)

Our service carries 325mg tablets. I will give a patient 325mg ASA and have them chew - regardless of daily dosing of ASA or other anticoagulants. Our county dispatch uses EMD protocols which often directs chest pain patients to take their own 324/325mg prior to our arrival. In that case we will not administer more. All this taking allergies/ulcers into consideration.

Edit: When I was in a past county we gave 81mg regardless of them taking it prior to our arrival.


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## 18G (Apr 4, 2012)

I've always given 324mg in the three states I've practiced. If a patient has already taken 81mg of ASA I would still give them 324mg most times as it's not going to hurt them and then I know for sure they got ASA onboard. 

And unless a patient has a true allergy to ASA (ie hives, swelling, dyspnea, etc)... give the ASA! Many times you have to ask the patient about why they claim to be allergic to it. Many will say it makes their stomach upset, etc. If that's the case they need to be getting ASA. It's a risk/benefit thing. What would you rather have, a minimal chance of some bleeding or irritation that can be managed or a 23% decreased chance of dying? I will choose a 23% reduction in mortality. 

ASA is vital and is the only drug we give that has been shown to decrease mortality in MI. I went to the JEMS Conference and Dr. Cory Slovis spoke about this very thing. 

One of the dispatch centers around here also instructs patients to take ASA when they call 911.


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## 18G (Apr 4, 2012)

jjesusfreak01 said:


> On one hand you could argue that since your patient is already taking anticoagulants, then they probably don't need aspirin.
> 
> On the other hand, you can argue that because your patient is already taking anticoagulants, a little bit of aspirin probably isn't going to hurt them more than the coumadin they are already on, and that if somehow they are still clotting up their coronary arteries even with all that coumadin running through their system, then they need all the help they can get.



Coumadin isn't a contraindication for ASA. It is important to know that ASA and Coumadin compete for the same binding site on the cell. When ASA is given, it causes more Coumadin to become unbound and exert it's effect. 

There is more than one pathway to inhibit clotting and preventing platelet aggregation. This is why patient's on heparin may also be started on Aggrestat or Integrilin. And again, in some patient's who are poor historians they may not be the best to know if they took their Coumadin or not.


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