Axis deviation and the 12 lead

[rhan101277]

We are getting into the more complicated 12 lead details. Beyond the easy, tell where the MI is and what artery could be occluded.

Anyhow, many medics I talk to say they don't look at this. It is extremely important though as lidocaine is contraindication in hemiblocks and LBBB or RBBB. I am going to use all my knowledge to do the best I can in the field, regardless if others get grumpy because I don't do things the easy way.

Same goes with chest pain, when i asked one about right versus left side MI, he said I just give nitro like the protocols say. But right MI needs fluids, if you give nitro you can make them worse off and be at their funeral. Same goes with giving lidocaine in bradycardia or the blocks above which I previously listed or any 2nd degree or complete HB.

Seems like many medics I talk to, just blow this stuff off, like it won't happen to them.

Just wanted to blow off some steam about it. Some medics seem to not take patient care seriously and I think it is a problem in EMS.

 

[Shishkabob]

Just as an FYI, you can determine RBBB and LBBB without looking at axis deviation.

 

[reaper]

If you get a chance, go to a Bob Page seminar. You will be very enlightened.

 

[rmellish]

Right sided MIs typically respond well to fluid boluses, so they're exactly right, give nitro per protocol. Just be conservative with dosing, and be prepared to bolus. nitro can still be beneficial. This is also why it pays to have your IV access prior to dosing someone with nitro.

 

[medic417]

If you get a chance, go to a Bob Page seminar. You will be very enlightened.

That ain't no lie. You will find out most of what you have been taught is not very reliable. He shows you how to raise the odds of catching items that could cost patients their lives if you miss them. Well worth the money.

 

[rhan101277]

Right sided MIs typically respond well to fluid boluses, so they're exactly right, give nitro per protocol. Just be conservative with dosing, and be prepared to bolus. nitro can still be beneficial. This is also why it pays to have your IV access prior to dosing someone with nitro.

Thanks for your input. I am being taught to just use it judiciously, but can't really use it judiciously when its .4mg SL per dose. Maybe IV nitro is better since it is less powerful than SL. I will do whatever is best for the patient though. If I don't give nitro and I am wrong then I am screwed. I will just be ready for a bolus.

 

[ah2388]

in right sided MI's you can also give low dose dopamine to up the patients pressure in addition to fluid boluses so that you can give NTG

 

[reaper]

If you identify a RVI, I will bolus first, then nitro. Once you bottom the pressures, they can be very hard to bring back. It's like chasing your tail!

 

[Shishkabob]

in right sided MI's you can also give low dose dopamine to up the patients pressure in addition to fluid boluses so that you can give NTG

Low dose dopamine dialates renal vessels and has little/no effect on systemic circulation. Mid-dose has B1 and B2 effects, but that's not a good thing when it comes to MI... you dont want to increase myocardial workload in a situation where it already isn't getting enough oxygen. High-dose dopamine is where the vasoconstriction lies, but again, you're causing excess work on an injured heart.

Dopamine / Nitro ping-pong is not a good thing.



It depends on your protocols, but usually around here, give ASA, then bolus NS up to 1l to get a decent BP before giving a vasodialator, and confer with med control.

 

[reaper]

Bingo! We have a winner! Tell him what he wins, Wink.

 

[EMTinNEPA]

Thanks for your input. I am being taught to just use it judiciously, but can't really use it judiciously when its .4mg SL per dose. Maybe IV nitro is better since it is less powerful than SL. I will do whatever is best for the patient though. If I don't give nitro and I am wrong then I am screwed. I will just be ready for a bolus.

I'm not sure how far along you are in school, so if I seem preachy and I'm telling you something you already know, forgive me.

It's not that the IV nitro is less powerful, it's just a much smaller dose. MUCH smaller dose as in MICROgrams. Nitro drips are good for maintenance, but in the setting of pre-hospital treatment for Acute Coronary Syndromes, you might as well have brought a toothpick to a gunfight.

What happens with giving nitro to right-sided MIs is nitro causes vasodilation, which decreases peripheral vascular resistance and in turn cardiac workload... however, it also decreases blood pressure and venous return, which in turn decreases preload, which decreases cardiac output. This is why you always want to have a patent IV line before you administer nitro to an inferior wall MI, because if their pressure craps out, you might not be able to get an IV. This is also why you always check a blood pressure before repeat doses.

 

[zmedic]

Also keep in in mind that there isn't good evidence that nitro decreases mortality. Aspirin and Beta blockers are the only two pre hospital meds that have been shown to do that. So the real question is why are you playing with fire, trying to give nitro to a right sided MI? I think that for CYA that is a good time to call online medical control and say "we have big elevations in II, III, AvF, did a V4R and think it's a right sided MI. Pressure is 110/70, should I give nitro because I'm worried about bottoming out the patient's pressure."

 

[usalsfyre]

I can't find the citation right now, but I believe the American College of Cardiology is reccomending against using ANY NTG in the setting of RVI.

IV NTG is not bringing a toothpick to a gun fight, it's just usually underdosed in the prehospital setting. 400 mcgs SL every 5 minutes with a 75% absporption rate (the usual figure for SL) is roughly 60mcgs/min. How many folks are scared to take their IV NTG doses that high?

 

[TomB]

usalsfyre -

If you can find the citation, I'd love to see it. I think of RVI as a relative contraindication rather than an absolute.

If anyone is interested there is a comprehensive tutorial on axis determination that you can find HERE.

Tom

 

[usalsfyre]

It's here in the "ACC/AHA Guidelines for the Management of Patients With
ST-Elevation Myocardial Infarction" located at http://www.acc.org/qualityandscience/clinical/guidelines/stemi/STEMI Full Text.pdf

Check page E35, it places NTG as a class III(Conditions for which there is evidence and/or general agreement that a procedure/treatment is not useful/effective and in some cases may be harmful)for suspected right ventricular infarction.

 

[reaper]

Funny, I was at a cardiac seminar and all 5 cardiologists there said "Do not withhold NTG", But also stated that Fluid boluses are a must. We are not talking 500-1000cc's, they are talking 2-3 liters.

They talked about RVI Pt's going to Cath lab. Some are getting up to 15-20 liters, prior to procedure!

 

[AnthonyM83]

Low dose dopamine dialates renal vessels and has little/no effect on systemic circulation. Mid-dose has B1 and B2 effects, but that's not a good thing when it comes to MI... you dont want to increase myocardial workload in a situation where it already isn't getting enough oxygen. High-dose dopamine is where the vasoconstriction lies, but again, you're causing excess work on an injured heart.

Dopamine / Nitro ping-pong is not a good thing.



It depends on your protocols, but usually around here, give ASA, then bolus NS up to 1l to get a decent BP before giving a vasodialator, and confer with med control.

Would you say the same for CHF'ers? With pulmonary edema, you're having left-side failure, but one would assume right-side would go along with it (especially if Pedal edema and JVD). Being limited in amount of fluids you'd give in this case (and not a STEMI) would you give the dopamine even with its effects effects on the failing heart?

Just looking for opinions on this. Heard some differing ones....

 

[usalsfyre]

Funny, I was at a cardiac seminar and all 5 cardiologists there said "Do not withhold NTG", But also stated that Fluid boluses are a must. We are not talking 500-1000cc's, they are talking 2-3 liters.

They talked about RVI Pt's going to Cath lab. Some are getting up to 15-20 liters, prior to procedure!

The only thing I would say is, why are we fluid loading (i.e. increasing preload) patients to give an agent that is primarily used to reduce preload?

I'm not saying don't go withwhat your local standard is, just that the largest group of cardiologist in the country has come to a consensus that it probably won't help and may hurt.

 

[usalsfyre]

Would you say the same for CHF'ers? With pulmonary edema, you're having left-side failure, but one would assume right-side would go along with it (especially if Pedal edema and JVD). Being limited in amount of fluids you'd give in this case (and not a STEMI) would you give the dopamine even with its effects effects on the failing heart?

Just looking for opinions on this. Heard some differing ones....

Cardiogenic shock is often not caused by fluid overload but rather not being able to move fluid. I wouls still try a VERY CONSERVATIVE fluid bolus before jumping to vasoactives.

Dopamine in the setting of CHF/cardiogenic shock is one of those treatments that might help short term but may kill the patient down the road. Sometimes we've got to do what we can to keep people kicking to the ED and hope any damage we did can be undone.

 

[reaper]

It's here in the "ACC/AHA Guidelines for the Management of Patients With
ST-Elevation Myocardial Infarction" located at http://www.acc.org/qualityandscience/clinical/guidelines/stemi/STEMI Full Text.pdf

Check page E35, it places NTG as a class III(Conditions for which there is evidence and/or general agreement that a procedure/treatment is not useful/effective and in some cases may be harmful)for suspected right ventricular infarction.

I have not had time to read the entire study, but did read E35 and E100. In neither place did it mention that NTG was harmful or not effective in RVI.

It stated the same as any other literature. That NTG may cause hypotension, which is treatable by fluid bolus of NS.

It also states that agressive fluids may be needed and that NTG does help dilate the RCA. That is the main reason why you are giving it in the first place.