Dobutrex

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This is one weird drug to me sometimes. You never know from patient to patient how it's going to work. We were discussing it at work the other night. I had a patient a while back who was at our sister facility where they don't do hearts, pt had a big MI,VFIB, coded, got CPR all the way over to us, went for emergent bypass. Needless to say, pt came out from OR with IABP, Dobutrex at 5 mcg. We had orders to wean the IABP and Dob per the surgeons parameters. It was interesting b/c this is a surgeon we don't see much, he was covering for the weekend, but routinely we leave the Dob at 5 until the IABP comes out, then start weaning it off. Anyway, when I come on shift, my pressures-aline,iabp,cuff are all correlating well and a sagging a little compared to what days had, hanging mostly in the 80's. I call the surgeon, b/c pt didn't need the volume, svr was up so I didn't want neo, got orders to increase the Dob and can start some low dose dopamine in a little while if upping the dob didn't help. My CI was great, so we only needed a little something to help with the bp.

Anyways, continue on through my shift, I wean the Dob back down to 5 mcgs, keeping bp about the same, went on the dopa with only about a 5-10 point change in my bp, but the uop is good, pt is alert, other numbers all look great. Next nurse comes in, surgeons RN is making rounds and 7a nurse asks if it's okay to half the dob. I kind of cringed to myself, b/c I could see a big change in my pressure during the night when I came off it slowly, so I'm thinking pts not going to tolerate halfing it cold turkey, plus, they were going to pull the IABP and it didn't make much sense to me to take away 2 cardiac augments so rapidly. But, I figured, I'm going home, its the daytime, surgeon will available to the day nurse all day long without having to get a call and woken up in the middle of the night like I'd have to do if pt starts heading south.

Long story short, when I leave an hour later, bp is in the 120's range with the dob at 2.5, I was amazed and asked the day nurse what happened. The reasoning was the dob was dilating the patient out, hence the low bp. I can't remember the exact numbers now on the svr, but I know it never got below 750-800 range, which I don't consider too dilated out. I did see some decrease in svr after I increased the dob, but the svr was variable, and the exact same svr the nurse had at 0800 I had several times during my shift with no where near that good of a bp. It's just interesting to me how titrating drugs sometimes what you're expecting with a med is not what you get. I don't know if it was just a timing thing, at this point, we're about 24 hours out from the initial cardiac insult, and the body just took a while to adjust maybe. The patient wasn't sedated or sleeping on my shift all night, pt would be wide awake with same bp regardless of being awake/sleeping. Absolutely nothing else had changed to explain having that good of a bp within an hour.

In the end, pt got the iabp out, dob was off and transferred out within 48 hours of surgery. Has anyone else ever had similar experiences with Dobutrex?

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Specializes in ICUs, Tele, etc..

Tenn,

This sounds quite interesting, and I'm just kind of thinking about it. I kinda skimmed thru your post, I'm not sure if my brain is working right, but here goes. Since you don't have the numbers, I'm just assuming here, it'd be nicer if you had the swan numbers, so I won't make a fool out of myself. Assuming you didn't touch the ratio on the balloon all night, cuz I'm not sure if you did or not, and let's just say that the balloon ratio was constant all night, and we're just talking about the dobutrex. You said your CI was okay, and your SVR was kinda high in the beginning? Was this when you started dopa? I think probably starting the dopamine was what started helping you at night and leading them cut the dobutrex dose in half in the morning, by increasing you CI more, but since you don't have the pre and post CI with dopa then I'm just winging it here. So that in the morning when they decreased the dobutrex to half, then you still had dopa on board. I'm also assuming you didn't touch the dopamine and you kept it a constant rate. That's one of my theories. Second one is a little far fetched, meaning, what was your HR at 5mcg of dobutrex, I doubt you were tachy, cuz if you were you would have mentioned it. Just in case though that you were tachycardic, maybe that's why your pressure wasn't that good, but of course you'd have to be mighty tachycardic before it can make much difference, so maybe when they decreased the dobutrex to 2.5mcg, your HR slowed down a little, giving you more time for filling, and thus increasing your CO, maximizing your curve, and stabilizing your BP?

Again maybe I didn't read the details about your post, so forgive me if I'm way way way off. I'd be interested in what other thinks as well.

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Tenn,

This sounds quite interesting, and I'm just kind of thinking about it. I kinda skimmed thru your post, I'm not sure if my brain is working right, but here goes. Since you don't have the numbers, I'm just assuming here, it'd be nicer if you had the swan numbers, so I won't make a fool out of myself. Assuming you didn't touch the ratio on the balloon all night, cuz I'm not sure if you did or not, and let's just say that the balloon ratio was constant all night, and we're just talking about the dobutrex. You said your CI was okay, and your SVR was kinda high in the beginning? Was this when you started dopa? I think probably starting the dopamine was what started helping you at night and leading them cut the dobutrex dose in half in the morning, by increasing you CI more, but since you don't have the pre and post CI with dopa then I'm just winging it here. So that in the morning when they decreased the dobutrex to half, then you still had dopa on board. I'm also assuming you didn't touch the dopamine and you kept it a constant rate. That's one of my theories. Second one is a little far fetched, meaning, what was your HR at 5mcg of dobutrex, I doubt you were tachy, cuz if you were you would have mentioned it. Just in case though that you were tachycardic, maybe that's why your pressure wasn't that good, but of course you'd have to be mighty tachycardic before it can make much difference, so maybe when they decreased the dobutrex to 2.5mcg, your HR slowed down a little, giving you more time for filling, and thus increasing your CO, maximizing your curve, and stabilizing your BP?

Again maybe I didn't read the details about your post, so forgive me if I'm way way way off. I'd be interested in what other thinks as well.

No, even when I had the dopamine going, it was early enough in my shift if it was going to make a difference, I should have been able to see a result. It didn't change anything significantly that I remember, CI/bp/SVR all remained relatively constant during the night. The Dob did cause a small reduction in SVR when I increased it from 5-8, but that was it. I didn't touch the balloon's ratio, pts HR was NSR I think in the 70's or at most 80's. The consistency of the SVR was why I didn't buy that running at 5 mcgs was dilating the pt out contributing to the low bp-b/c the oncoming nurse had almost identical SVR to what I had when swan numbers were shot on 5 mcgs- only with a much better bp, so that couldn't be it. I think scenarios like this are what make hears the most fun to take care of, but also the most challenging. There are so many explanations for what you see, so many ways of augmenting them post operatively, it's a combination sometimes of what you're doing that works.

I'm just one of those people it drives me nuts if I can't figure something out. We've seen Dob work kinda quirky in a few patients though, so I think it's just patient drug dependant.

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Specializes in CIC, CVICU, MSICU, NeuroICU.

Dobutamine can also vasodilate thus may lower some BP.

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Specializes in Critical Care, Cardiothoracics, VADs.

Well, dobutamine IS a dilator so that wouldn't be surprising. I think, given the different response at different times in one patient though (esp first inght after surgery) I would think the bypass-related histamine released and vasodilation had been somewhat ameliorated by the next day, and enabled them to wean the dobutamine.

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Any sedation? Might be the patient started to wake up a little more in the AM.

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Specializes in ICU, Education.

I think the OP knows that dobutamine can dilate, but he did state the SVR was relatively constant and borderline normal despite his titrations. It would be interesting to see what the SVR was for the day nurse when she weaned and stopped the dobutamine in relaition to your numbers.

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I think the OP knows that dobutamine can dilate, but he did state the SVR was relatively constant and borderline normal despite his titrations. It would be interesting to see what the SVR was for the day nurse when she weaned and stopped the dobutamine in relaition to your numbers.

That was what got me. The day nurse tells me as I'm leaving "oh my bp is better b/c I've halfed the Dob and pt isn't so dilated out now". Just out of curiosity I looked at the flowsheet and I had the exact same SVR (700-800) range most of the night, so that's why I know that isn't it. Now, if the 7a nurse halfed the dob, then the SVR went up to 1100-1200, I might buy that explanation.

I've seen similar situations with patients on dopamine. Some of them we'll put on if they're still pacer dependent for a good CI in the am (usually if intrinsic HR is SB in 40-50's), some of the docs like it if patients need diuresing, or a little inotrope and they don't think pt needs dob. We had one patient an hour after being put on 3 mcgs (our standard dose in the hearts), he's SR 70's CI up to 3.0 from 2.4 (he never came out on any dob). Then there's patients who go on it and you don't really see much of anything, same with the UOP. Some patients diurese like crazy and some don't do anything with it, regardless of fluid status, assuming these are pts with healthy kidneys and no CRI. Alot of our patients have borderline kidney function to begin with and the kidneys take a big hit post op they go into ARF.

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Well, dobutamine IS a dilator so that wouldn't be surprising. I think, given the different response at different times in one patient though (esp first inght after surgery) I would think the bypass-related histamine released and vasodilation had been somewhat ameliorated by the next day, and enabled them to wean the dobutamine.

This is a good explanation. But, our docs still use Trasylol (in spite of the new england journal's article), which really cuts down on the inflammation process/response post op.

The IABP also causes afterload reduction, and depending on when you shoot your numbers you can be more dilated. But, like I said before nothing really changed over the night except going on dopamine and then increasing the dob and weaning it back down by 7 am.

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Specializes in Critical Care, Cardiothoracics, VADs.

Trasylol does not prevent bypass-related histamine release and dilatation. IABPs do not cause vascular dilation, but mechanical manipulation of the Windkessel effect (aortic stretch).

I am not basing my response necessarily on data, but just saying in my opinion and experience, the patient is less dilated one day post surgery than immediately post surgery, which allows inodilators to be weaned. SVR is not necessarily the holy grail number, as it is only a derived index; that is it is relevant to the overall picture but not as a standalone figure.

eg. a massive number of VAD patients need vasopressors (norepi or vasopressin) postoperatively for 12 hours, then it can be weaned as the systemic inflammatory response reduces.

Edit: please note that I said I was basing this reponse on MY experience.

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Specializes in Critical Care, Psych, Transport.

Augigi,

Please review your information before you post. Trasylol does in fact help to prevent the bypass-related hiastamine release. Being a protease inhibitor, it inhibits multiple mediators including cytokine and kinin-kallikrein system.

The only two things an IABP does is improve coronary artery blood flow and decreases the afterload on the heart by mechanical means and not the Windkessel effect. As the ballon deflates onces the aortic valve opens, it creates a vaccum therfore reducing resistance.

To the original poster, Maybe this will explain the results you were seeing. Systemic vascular Resistance is determined by the pressure(MAP-RAP) divided by the flow(cardiac output) Since this is just a calculated number, a small decrease in your Cardiac Output by decreasing your Dobutamine would lead to an increase in your systemic resistance usually evidenced by an increase in your SBP and MAP.(Your RAP would likely go up also.) It will not take large numbers to skew the physiological changes you noticed. I may be off course as it is late and i just spent the last three hours learning about the sterochemistry and volume of distribution of pharmacological agents.

Hope this helps,

Troy

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Thanks Troy, your post is very informative.

I just realized part of what I forgot to mention in the initial post. The reason I say dob is a funny drug is because what we will often see in post op hearts on dob is that on low dose, say 2-3 mcgs, when we start weaning off, we usually see pts bp go down. I know the explanation for this is because the dob is augmenting your CO, which will in turn give more pump, if you are not supporting the pump as much, your bp can decrease. That was what I found so interesting about the pt in my first post was the I would never have thought his bp would go up so quickly when the dob was cold turkey cut in half like that, usually just the opposite would happen.

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