Leaving Phenylephrine on with an Epi Drip?

aCRNAhopeful · Jul 24, 2013

When i worked in CVICU it was not uncommon to have both going at once but not for the rationale you're stating. First of all even if epi and neo are structurally similar they are night and day different as far as pressors go. Epi is a powerful Beta1, beta 2, and alpha1 agonist while phenylephrine is a pure alpha 1 agonist. The reason why you would put someone on neo is for hypotension with low SVR and adequate cardiac output. Neo can DECREASE HR and CO secondary to reflex baroreceptor stimulation and increased afterload respectively. Epi obviously doesnt do either of those things as it is a powerful inotrope, chronotrope, and vasopressor. Maybe you already know this stuff but your post made it seem like you did not so i just wanted to clarify this. Now we would often receive pts from CVOR on epi and neo but it was guided by CCO from a swan and such. The scenario when you would not want neo and epi is if you were starting epi for cardiogenic shock, neo in that situation would mostly serve to increase afterload and SVR and fight against your goal of increasing CO. Other times it may be reasonable to continue both depending on the particular hemodynamic status of the patient.

ICUPrincessNurse · Jul 25, 2013

At my facility we only use those two when the poo has gone down so chances are if we're on both, we're staying on both because we're waiting on family or miracles. Usually both.

Dodongo, APRN, NP · Jul 25, 2013

Crnahopeful, you're going off on tangents. I'm sure everyone reading this knows what receptors they both act upon and how they influence CO, SVR, etc. The point I'm making is that having neo with epi is theoretically superfluous as epi has a much stronger affinity for alpha receptors than does neo. So the neo is effectively doing nothing when the epi is infusing with it. The fact they are structurally similar is important here. The -OH group attached to the neo makes it, essentially, less potent than epi. So, with this being the case, why have both going, especially when it's possible for patients to become refractory to neo.

aCRNAhopeful · Jul 27, 2013

I wouldnt be so sure that everyone knows what receptors they work on... Yes there are situations where it is useful to have both drugs on. Unless the doses of epi were so high that they have saturated all the alpha 1 receptors then neo is still going to have an effect. For example, a post CABG pt is on neo and an epi gtt. Currently the CI is 2.8, MAP is 55, and SVR is 680. You can titrate up on the neo and achieve the desired effect of increasing vascular tone and SVR and it will certainly work. If your goal at the time is increasing SVR but you dont need inotropic or chronotropic effects of epi then use neo.

blucrna · Jul 28, 2013

I agree, having both gtts seems redundant. Any effects the neo is giving can easily be attained by simply going up on the epi.

Currently the CI is 2.8 MAP is 55, and SVR is 680. You can titrate up on the neo and achieve the desired effect of increasing vascular tone and SVR and it will certainly work. If your goal at the time is increasing SVR but you dont need inotropic or chronotropic effects of epi then use neo.[/quote']
In this case the heart is working fine as indicated by the index. If your worried about heart rate and low MAP then give volume. 250-500 mls of albumin would give you adequate preload to raise your MAP.

aCRNAhopeful · Jul 29, 2013

I agree, having both gtts seems redundant. Any effects the neo is giving can easily be attained by simply going up on the epi.
In this case the heart is working fine as indicated by the index. If your worried about heart rate and low MAP then give volume. 250-500 mls of albumin would give you adequate preload to raise your MAP.

I agree but the point is you can still use neo with epi. It does work even if epi may have a stronger affinity for alpha1 receptors. So in my opinion it is reasonable in circumstances where you want more vascular tone without the increased myocardial o2 demand of epi. Of course preload should be optimized in preference to vasopressors though i agree with you there

bmacks · Jul 29, 2013

Currently the CI is 2.8, MAP is 55, and SVR is 680. You can titrate up on the neo and achieve the desired effect of increasing vascular tone and SVR and it will certainly work. If your goal at the time is increasing SVR but you dont need inotropic or chronotropic effects of epi then use neo.

I agree with aCRNAhopeful, Epi is more useful in increasing CO and HR and only at higher doses are its alpha effects noted. I'd also just go up on the Neo because of the low SVR. At my CTICU we use Norepinephrine/Epinephrine on our immediate post op cardiac cases because Levo has great beta1 and alpha properties. Once we de-line them and they still remain hypotensive is when we use Phenylephrine. Because at that point we've achieved good CO/CI and they just need some press to increase their SVR.

Dodongo, APRN, NP · Jul 30, 2013

Ok, so I talked to the pharmd at work and here's what he had to say about it. He said, I general, at high doses of epi, it's redundant to have neo, because the epi is exhibiting alpha stimulation. However, if the epi is at a low dose it is stimulating B1 and B2, so you would have some peripheral vasodilation from B2 and an increased systolic pressure and decreased diastolic pressure creating a widened pulse pressure. It's in this scenario that neo would be beneficial with epi. To counteract it's B2 effects. So once you're titrating the epi to low dose it might be beneficial to start neo to bridge the epi off if you can.