[Nurse1966]

I'm in a "critical care consortium" and today's lecture covered MI's. The speaker said Nitro and Diuretics are contraindicated for treating Right sided MI's, due to the need to keep fluid moving, so there is volume to keep cardiac output up. Does this sound correct? In my mind, I keep wrapping around fluid overload, pulmonary edema, vasodilation, etc...I've been looking in a Critical Care text, but can't find anything specific. Can you all help make sense of this? Thanks-

[heartrn4duke]

If you think about a right sided Mi can incule the Rv. Which affects preload and forward flow. So the tank needs to be filled to push the blood flow forward. The right side is damaged due to the MI so the ventricle cannot push the blood flow forward. I have given 11 liters of fluid in one 12 hour shift to an right sided MI. Pulm edema can happen in heart failure patients but in a CCU we can intubate to keep the cardiac output going with fluids. Sometimes vasopressors are used in severe heart failure patients to prevent such complications.

[Nurse1966]

Thanks for your reply, I think I was merging a Right sided MI with Right sided failure. I get it now, but...where did the 11 liters of fluid go that you gave? I understand the need for it, but would the patient become fluid overloaded, or did their kidneys keep up? I just made the giant leap from telemetry to ICU and am trying to understand a little deeper the pathophysiology of all this stuff. Again, thanks for your explanation, it makes it clearer.

[heartrn4duke]

Well these types of patients ballon up then in a few days when the RV begins to pump a little better they begin to auto diurese. Lots of times we monitor CVP to help monitor fluid status.

[ghmccart]

RV MI folks need the two p's preload and pacing. then we dont wanna give drugs to decrese either of those

[luvtheOBX]

So, what are the best drugs for right sided MI's to increase preload? Or do you just give fluids?

[Sweetooth EMT-P, RN]

If you have a patient with an inferior MI whether they are hypotensive or not always suspect acute ischemic right ventricular disfunction, and you do this by placing v4-v6 on the right side which will result in elevation of the ST segment. Do this before given them meds, especially if there BP is on the cusp of being low, as giving medications like nitrates and morphine can result in irriversible shock. Also asses LUNG SOUNDS as the patient may be hypotensive from LV failure resulting in CHF and withholding of fluid. Just keep in mind that BACKWARDS failure results in CHF which is why RV infarct does not cause pulmonary edema, but it does cause JVD.

The reason these patients drop their pressure is becuase the left ventricle is very dependent on the preload it receives from the right ventricle (alough it does not receive this blood directly). In acute ischemic RV disfunction the right ventricle walls become almost immobile and are not able to efficiently pump the blood through the pulmonary curcuit and eventually into the left ventricle. This results in a significant drop in preload in the left ventricle which results in a significant drop in cardiac output leading to hypotension.

These patients usually need about 2 liters of fluid in order to recover there blood pressure and the purpose of that fluid is to increase afterload as the right ventricle is very dependent on afterload which results in an increase preload in the left ventricle which in turn increases cardiac output. This is why you do not give medications that are going to decrease afterload such as morphine and nitrates. If the patient is really anxious you may want to try a low dose of fentanyl which does not drop pressures like other narcotics 25-50 mcg IVP.

Just need to be cautious as to much fluid can put pressure on the septum and result in LV failure so the BP needs to be monitored closely. I usually slow the fluids down the second their systolic pressure is in the 100's.


To answer your last two questions fluids will generally do the trick in getting their pressure up until they can be reprofused either with fibrinolytics or angioplasty. They may require medications for pressure support although that should be a last resort since those can worsen MIs.

hope this helps.

Swtooth