Electrolyte shifts and fluid overload in AMI patients?

[Aliakey]

I am looking for some sage advice and maybe some finger pointin' to where I need to find further information.

I am currently an EMS paramedic who is working on her degree in nursing. However, I cannot find much information in my textbooks (for nursing) about fluid overload and electrolyte imbalances.

In short, one of my EMS calls involved a 60ish year old male patient who presented with an anterior AMI --- symptoms of sudden-onset anterior chest heaviness (10/10 pain) radiating to the left arm that occurred while sitting. (+) nausea, (-) vomiting, (-) SOB, (-) trauma. 15 minute duration. Initial BP of 106/70, HR of 66 (weak/regular radial pulses), R: 24, SpO2 of 97%. GCS of 15. Skin: pale, warm, dry. No difficulty breathing was again confirmed. Lungs clear to all fields. No peripheral edema. No hx of this pain.

Hx: CAD, GERD. recent prostate surgery 2 weeks ago.

Supplemental oxygen was administered on scene, and patient already took a 325 mg aspirin prior to EMS arrival. Initial 12-lead ECG showed hyperacute T waves in the anterior leads, which progressed to ST elevation during rapid transport. 12-lead was transmitted to the ED early enroute. Inferior leads began showing small reciprocal changes on arrival to the ED.

Two 18g IV lines (one with NS and the other a saline lock) were established with a blood draw for the hospital, and one nitroglycerin administered (0.4 mg SL; protocol allows us to administer NTG until the systolic BP falls below 90 mmHg or patient is pain-free).

Patient's BP five minutes after the NTG was 92 mmHg (palpated). I chose to withhold additional NTG due to the borderline BP in conjunction with the patient's reported new-onset of dizziness and generalized weakness. Pain did decrease to a "7". About 300 mL of NS was already infused --- lungs again were clear, no difficulty breathing reported, no edema. I chose to continue the fluids to improve his pressure before considering more NTG --- we were 2 minutes from the hospital at this time.

On ED arrival, the physician ordered another 1000 mL of NS and to withhold the nitro drip until the pressure increased (was just a hair over 100 mmHg systolic when obtained at the ED, if I remember right). The patient received 600 mL of NS by the time I finished verbal report and handed care over to the RN (I TKO'd the infusion once we entered the ED doors). Again, lungs were clear and no reports of difficulty breathing by the patient.

So here's my question: Did I "fluid overload" my AMI patient? What was the risk of shifting his electrolytes significantly with this amount of NS?

I was reprimanded based on several things, but contributing was the fact was that I did not administer a second NTG during transport and that I infused too much fluid to cause concern for fluid overload and electrolyte shifts. My Service Director (EMS "boss") who brought forth these concerns was previously an ICU RN (I apologize for not knowing the specialty) before returning to EMS as our Director.

I still feel confident in how I treated this patient knowing that the ED physician continued the same train of thought in his orders, and that the patient did have a significant occlusion as found by the cath lab. What has bugged me is that I recently learned that now my Service Director has used me as the Village Idiot example outside of our service. While he has not used my name or referenced to my station/shift, it was learned that I was used as an "example" to why some of our future medics required further education, and based it on this particular case. I am not an outspoken person at all, but this really rips at me.

Honestly, if I "did wrong", please let me know. I know the last thing a patient needs with an AMI is more work for the heart. The last thing I would ever want to do is cause more harm to my patients or make the receiving RNs' lives more difficult. If anyone has a literary reference to a textbook or other source that could offer a better understanding of fluid and electrolyte shifts, I would greatly appreciate it! I would like to speak to my Medical Director (physician) about the call as well, but armed with far more knowledge on fluid and electrolyte balance than what I currently have.

Thank you so much!

[Biffbradford]

It seems to me that the NS bolus was ordered to improve his already low blood pressure of 92/xx. I'm not an EMT, MD, nor ER nurse, but I don't see how this would screw up the pt's lytes. If it did, such as K+, then that could be quickly corrected if it became a life threatening issue. Fluid overload? Perhaps down the road, but you need to have a blood pressure in order to have a patient to work with, so I would see that as #1 priority. My .02 FWIW.

[Pinkster]

I am a new RN (undr one yr) but I have worked ER as a tech and now on a cardiac foor as an RN and I fail to see where this major issue is on your part. The patient made it to the hospital and to cath lab and was treated.. you followed protocol. Used good judgement. Another nitro dose might have been appropriate based on the drop of 14mmhg in systolic pressure and your pollicy states 'until under 90' as u stated but based on this patients reaction he would have dropped to 78 systoli. And with the administration of fluids might not have been that low. But that's your judgement and I know I don't feel comfortable taking care of someone when there bp is that low. Anyway. Back to the fluid overload part, he continued to get fluids infused in the er under direction of the er doc (600ml) to combat the low bp, which would have been even lower if u would have given the second dose of nitro. So I think that you did the right thing in this instance based on the scenario u presented. And I love how u send an ekg to er while enroute and draw blood on the way. that would save so much time if our area did that!

Sry for the typos. I'm on a mobile phone :)

[MunoRN, RN]

You followed your orders appropriately and I see your predicament, but yes as a general rule you shouldn't fluid challenge a patient having an anterior MI as it's usually considered an absolute contraindication with an MI affecting the LV unless it's your last option in a code or pre-code situation. For some reason ED docs love to give IVF for everything, it's the cure all, I've gotten patients admitted for CHF where the ED doc writes for both lasix and IVF, I've even had an ED doc write orders for IVF on anuric 5x/week dialysis patient.

An anterior wall MI affects mainly the wall motion of the left ventricle. Additional fluid volume increases afterload, makning the LV work harder. It also increases pre-load, which is of little benefit to the LV, although if the MI affects mainly the R ventricle, then increasing fluid volume can be beneficial by increasing pre-load.

One way to think of it is that when a patient decompensates with an anterior MI, you'll often see flash pulmonary edema- the LV can no longer push forward sufficiently, the RV continues to push into the lungs, so fluid builds up suddenly and the primary goal is to diurese, so increasing fluid volume just moves you closer to decompensation in a left sided MI. One of the benefits of both NTG and Morphine is that they not only dilate the coronary arteries, but their general vasodilation allows for a relative drop in fluid volume, decreasing afterload.

You do also run the risk of diluting their potassium and mag levels, which isn't beneficial in an MI, although my main issue would be with the fluid volume.

[GilaRRT]

Oh no, it's the big bad scarecrow of giving an anterior wall MI fluids, causing overload and failure. Your biggest mistake was treating the patient clinically instead of treating squiggly lines on a monitor that may or may not mean anything. For shame.

[MunoRN, RN]

A helpful article comparing treatment of R sided MI's vs. Left:

http://www.consultantlive.com/cardiovascular-diseases/content/article/10162/1659292

In particular: "Unlike the low-output hypotension pattern of LV infarction with associated pulmonary venous congestion, which requires judicious use of small volumes of fluid, he hypotension in RV infarction resulting from inadequate LV preload may require large volumes of fluids for support."

[wtbcrna, MSN, DNP, CRNA]

You gave 600ml of NS over several minutes while transporting a patient to the ER, and you are worried about fluid overload with electrolyte shifts.....?

VS were stable (BP maybe a little low but who knows what the patient's baseline is anyways, if he already has known CAD his BP if well controlled should be in the low normal range anyways) and lungs were clear. 600ml of NS is nothing, and how such a little amount of NS in this patient is going to cause any noticeable electrolyte shift is beyond me.

It doesn't matter if the patient is a renal failure patient or having an AMI if they need a small fluid bolus give it to them. Most elderly patients are chronically dehydrated anyways. Also, with his recent surgery he is probably still recovering/mildly dehydrated depending on the type of procedure that was done for the prostatectomy.

I would have probably given the other nitro tab(s) unless I knew this patient was chronically hypertensive, and therefore had a compensatory rightward shift.

You treated the patient clinically, and if someone wants to questions everything you do they need to either be there everytime you treat a patient or shutup. It is always easier for someone to be an armchair quarterback.

[nurse2033, MSN, RN]

I'm both a paramedic and an ICU/ER RN. I agree that your treatment sounds right on. The answer to your question is evident in that your patient was not fluid overloaded. Perhaps the potential existed but the fact is that lungs remained clear, and more important, the patient had a perfusing blood pressure. Perhaps your director is insecure and trying to show how much they know. In fact you would have been remiss had you not given the fluid as their low BP would extend the MI. In the field we have few choices to raise BP- fluid, epi, or dopamine. Gee what's the safest choice? Your boss, even regardless of whether they're right or not, is showing what a poor manager they are by flogging you for no good reason. Good luck on the RN.

[cwhitebn]

A posterior wall MI could be a possibility if you saw reciprocal changes on the EKG (which I don't know what the EKG was). Giving NTG S/L would decreased their blood pressure due to decreased preload in the RV and therefore decreased CO. Therefore you would need to bolus your patient lots of fluids to maintain an adequate blood pressure.

A 12 EKG with a v4R lead indicating a posterior MI could make all the difference in the world.

[GilaRRT]

Actually, a V4R looks at the right ventricular. You would be correct in that a RVI (Right Ventricular Infarction) is often associated with hypotension due to loss of left ventricular preload. RVI is not typically associated with an anterior wall MI (LCA and LAD). A RVI is associated with inferior wall MI (RCA and PDA). However, strange things can happen and I would definitely recommend you do a V4R on any suspected MI patient with hypotension. If anything, it's hard to argue for giving nitro to a borderline patient when you have a positive ECG finding for RVI.

[CCL RN, RN]

I would have given the second nitro. The BP was high enough, even just barely, and the pt was still having significant CP at 7/10.

In the cath lab, we give several hundred mcgs of ntg and all kinds of fluid boluses. Especially for a STEMI. And you'd be suprised how low we let their BP get. Of course, we are right there intervening, so it's easier to let a BP get low because we are actively treating it.

We give our ntg IC, and we can see immediate results. We can see an almost completely occluded coronary artery open up enough to allow some flow. Remember, we are trying to get O2 to the heart tissues.

I wouldn't be worried about the fluid issue at all. This person needed the ntg, O2, and cardiac cath.

[highlandlass1592, BSN, RN]

As I see it, you have two very distinct issues here: did you follow the best treatment plan possible for your patient BASED UPON THE INFORMATION YOU HAD AT HAND and the unprofessional behavior of your director.

There is the old rule that you don't give an AMI fluids unless you know you've infarcted the RV (due to the need for improved pre-load) as others have discussed more succinctly than I can at this time. But looking at it from the view in the field, you had limited time and information, and continued to reassess your patient as you administered treatment. All things to give you kudos for. Would I have done anything differently? Only thing I would have done is given another dose of nitro but I am comfortable with lower BP's due to my practice. My reasoning would be you are already administering IVF which will support the BP giving you a bit more room to allow for a lower BP. The NTG may have improved patient comfort. Do I think you did anything wrong? Nope, not really. As you stated, your patient didn't go into flash edema, got him to the cath lab asap and he got a PTCA (I'm assuming based upon your comment re: cath lab).

As for the issue regarding fluid and electrolytes, I honestly don't think it relevant to the issue at hand. And if this is the issue your boss has, they need to rethink priority of care. If your patient is crashing, you're going to start fluids regardless till you can get them to the treatment area (in this instance, the cath lab). You're not going to worry about what the K+ level is..your patient isn't in Vtach for heavens sake. While I may have this patient in the unit, in the same scenario, I'm going to worry about stablilizing the patient. Lyte replacement isn't at the top of the list.

What is of concern is how you are describing your boss as handling the situation. If you followed the protocols you are working under, (I have no way of knowing this) then you your boss has no right to "rip" you. Baloney, plain and simple. Using your situation as an example when it's easy to identify you as the care provider is just plain mean. As I said, if you did follow protocol, I'd take it to your medical director and explain your concerns. This smacks of unprofessionalism and needs to be addressed.

One other point: I don't disagree with the idea that you all may need further education. But that's not a bad thing...we all need continuing education. However, it sounds like your boss is trying to use that idea as a way to make you or your peers look bad. That isn't appropriate. I've been a nurse for a long time, I'm constantly seeking out new education situations as I realize I still have much to learn. But if you smack down your employees and belittle them, they aren't going to want to continue learning because you are placing them in a defensive position. They aren't going to be open to further learning. I commend you for being able to keep the desire to learn more active. I'd also bring that point up to your director. IMHO, your boss needs to take some management training classes.