Fentanyl Infusion and Hypotension

[Iso4ane]

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I’m been doing some cases recently that require TIVA, and been using fentanyl infusions as part of the multi-modal therapy. We learn that fentanyl is supposed to be reasonably stable for classical cardiac inductions, but I’ve notice quite a bit of hypotension in the OR. Anyone else experience this? I think it’s weird because I know ICUs use it for their sedation but they are not battling hypotension on the floor around the clock.

 

[shepardsun]

What is your goal for using a fentanyl infusion, and why would you use an agent with a super unfavorable context sensitive half time?

 

[shepardsun]

This is like the first graph we were told to memorize as a CA1

 

[vector2]

I’m been doing some cases recently that require TIVA, and been using fentanyl infusions as part of the multi-modal therapy. We learn that fentanyl is supposed to be reasonably stable for classical cardiac inductions, but I’ve notice quite a bit of hypotension in the OR. Anyone else experience this? I think it’s weird because I know ICUs use it for their sedation but they are not battling hypotension on the floor around the clock.

Pts in the ICU aren't typically under general anesthesia. Most of the time the body can take a mild hit vis a vis one low-dose agent that knocks out the sympathetics and/or is vasodilatory. Add 0.5-1 MAC of volatile or propofol running at 100-150 u/kg/min + 1 mcg/kg/hr of fentanyl and you're going to get hypotension.

I don't consider high-dose opioid inductions to be all that cardiac stable either. They are a relic from a time when the only reliable induction agents were severe cardiac depressants, i.e. thiopental or high dose halothane, so in relation to those 1000 mcgs of fentanyl (plus a bit of diazepam) seemed like a good deal. With CABGs, I find hypotension to be pretty persistent when using a higher dose fentanyl technique and many times requires bit of background norepi gtt to treat since stimulation is relatively low during vein harvest, so I usually stick to ~100-150 mcg around induction and will use esmolol or a wisp of mask vapor if I need further sympathetic blunting for laryngoscopy.

 

[woopedazz]

TIVA ... fentanyl infusions ... multi-modal therapy

If you want to use fentanyl with TIVA, just bolus it.

 

[Iso4ane]

In response to a few comments, I just want to mention that this is a strong attending preference, not my preference. Hell, I don’t like bolus fentanyl all that much either in some of these cases. But, anecdotally, incidence of hypotension appears to be higher.

 

[deleted171991]

What is your goal for using a fentanyl infusion, and why would you use an agent with a super unfavorable context sensitive half time?

That's the whole idea. One gets both the advantages of an infusion and of a long context-sensitive half-time (i.e. as if giving dilaudid, but without the bolus effects). So, tram-track during the case and no need for separate long-acting opiates for the end.

Btw, padawans, say thank you to attendings who show you that there is more than one way to skin the cat, instead of complaining about them. Even if it's the "wrong" way to skin the cat.

 

[drmwvr]

I’m been doing some cases recently that require TIVA, and been using fentanyl infusions as part of the multi-modal therapy. We learn that fentanyl is supposed to be reasonably stable for classical cardiac inductions, but I’ve notice quite a bit of hypotension in the OR. Anyone else experience this? I think it’s weird because I know ICUs use it for their sedation but they are not battling hypotension on the floor around the clock.

Why are you attributing the hypotension to the fentanyl?

 

[itwasalladream]

We used fentanyl infusions where I trained, on most of the craniotomies. Sure it was not entirely necessary, but I had many cases of stable vitals for the whole day, with a drowsy but responsive, comfortable patient on wakeup. Works well in certain situations.

I think of fentanyl's hemodynamic profile as a sympatholytic, not a pure vasodilator. So if someone has high sympathetic tone (i.e. pain or extremis), fentanyl seems to cause more drop in pressure. If they already have normal sympathetic tone, I don't find it has much effect, particularly if it's not being bolused. Another reason sympathetic tone can be increased is compensation for hypovolemia. So I find that dry patients tend to drop their pressure with fentanyl more than euvolemic patients. In your case if you have to use it, I'd consider lower infusion rates (perhaps back off once the infusion's been on awhile) and/or gentle fluids. Of course, if you're doing TIVA there are other agents in your mix that can also cause hypotension...

 

[Iso4ane]

Why are you attributing the hypotension to the fentanyl?

I know correlation does not equal causation, but when the fentanyl is there, the patients are more hypotensive compared to the patients who don’t get it. Outside of the fentanyl infusion, there is nothing else apparently obvious that this particular attending does compared to others that would be notable for hypotension. This attending always seems to have his patient on inotropes/pressors a few clicks higher than other attendings. We are taught to be observant, this is just what I have observed. So it’s either the fentanyl infusion, of this attending is exuding something that is causing hypotension.

 

[deleted171991]

I know correlation does not equal causation, but when the fentanyl is there, the patients are more hypotensive compared to the patients who don’t get it. Outside of the fentanyl infusion, there is nothing else apparently obvious that this particular attending does compared to others that would be notable for hypotension. This attending always seems to have his patient on inotropes/pressors a few clicks higher than other attendings. We are taught to be observant, this is just what I have observed. So it’s either the fentanyl infusion, of this attending is exuding something that is causing hypotension.

Your patients are hypotensive also because you are growing up in a culture that is obsessed about IV fluids, and runs everybody on pressor infusions.

First thing we used to do, back in residency, was to give the patient up to 2 liters of IV crystalloid (for having been NPO). The number of cases that needed a pressor infusion was minuscule, when compared to nowadays. I am an intensivist, and still I will give those first 2 liters without blinking, if my non-septic patient needs a lot of pressors in the OR.

On the other hand, if my patient is hypotensive on a fentanyl infusion, I will probably drop the main agent. The main reason that patient is hypotensive is not just vasodilation, or loss of sympathetic response, it's the imbalance between the surgical stimulus and anesthesia. So the problem is probably not your attending; the problem is you not adjusting your anesthesia to having a good amount of fentanyl on board.

Btw, that fentanyl infusion is probably not much different than when an attending pushes 2 mg of dilaudid at the beginning of the case. 😉

 

[MirrorTodd]

I know correlation does not equal causation, but when the fentanyl is there, the patients are more hypotensive compared to the patients who don’t get it. Outside of the fentanyl infusion, there is nothing else apparently obvious that this particular attending does compared to others that would be notable for hypotension. This attending always seems to have his patient on inotropes/pressors a few clicks higher than other attendings. We are taught to be observant, this is just what I have observed. So it’s either the fentanyl infusion, of this attending is exuding something that is causing hypotension.

What's the standard tiva mix for this guy vs the other docs?

 

[Iso4ane]

Your patients are hypotensive also because you are growing up in a culture that is obsessed about IV fluids, and runs everybody on pressor infusions.

First thing we used to do, back in residency, was to give the patient up to 2 liters of IV crystalloid (for having been NPO). The number of cases that needed a pressor infusion was minuscule, when compared to nowadays. I am an intensivist, and still I will give those first 2 liters without blinking, if my non-septic patient needs a lot of pressors in the OR.

On the other hand, if my patient is hypotensive on a fentanyl infusion, I will probably drop the main agent. The main reason that patient is hypotensive is not just vasodilation, or loss of sympathetic response, it's the imbalance between the surgical stimulus and anesthesia. So the problem is probably not your attending; the problem is you not adjusting your anesthesia to having a good amount of fentanyl on board.

Btw, that fentanyl infusion is probably not much different than when an attending pushes 2 mg of dilaudid at the beginning of the case. 😉

Do you know those attendings that don’t like you to think, and won’t allow you to do anything, or doesn’t like independent thought, even as so much that I can’t choose to use 20gtt/ml or 15gtt/ml tubing, that’s what I have been working with.

What's the standard tiva mix for this guy vs the other docs?

So usually propofol+dexmedetomidine infusion +/- ketamine infusions on one hand; prop+dex+fentanyl Infusions (+fentanyl blouses) on the other.

 

[2Fast2Des]

Add some ketamine in there, you can back off on the fent requirements

 

[MirrorTodd]

Do you know those attendings that don’t like you to think, and won’t allow you to do anything, or doesn’t like independent thought, even as so much that I can’t choose to use 20gtt/ml or 15gtt/ml tubing, that’s what I have been working with.


So usually propofol+dexmedetomidine infusion +/- ketamine infusions on one hand; prop+dex+fentanyl Infusions (+fentanyl blouses) on the other.

How about rates? Does this attending run things higher than other attendings? I'm asking cause I'm curious really. It really shouldn't be the fentanyl causing hypotension, but you never know. As far as the difference between icu and the OR, the fentanyl infusions in icu are generally lower rates and the sedation infusions in the icu are as well, generally titrated to a specific rass score whereas us providing general anesthesia is a MUCH deeper plane requiring higher doses. Can guarantee, if the icon's ran anesthetics at our rates they'd have very significant hypotension.

 

[MoMoGesiologist]

Do you know those attendings that don’t like you to think, and won’t allow you to do anything, or doesn’t like independent thought, even as so much that I can’t choose to use 20gtt/ml or 15gtt/ml tubing, that’s what I have been working with.


So usually propofol+dexmedetomidine infusion +/- ketamine infusions on one hand; prop+dex+fentanyl Infusions (+fentanyl blouses) on the other.

Ahhh got it. That used to frustrate me as a resident. Remember, this is not your case. This is your attendings case. His/her name is on the chart. You are just a body there to do as they say, and learn as much as you can without ruffling feathers. There will be other attendings, people you will like much better, with which you can practice being a physician. This is not that attending. Goal of residency is to keep your head down and get through it while learning as much as you can. Good luck.

 

[2Fast2Des]

Ahhh got it. That used to frustrate me as a resident. Remember, this is not your case. This is your attendings case. His/her name is on the chart. You are just a body there to do as they say, and learn as much as you can without ruffling feathers. There will be other attendings, people you will like much better, with which you can practice being a physician. This is not that attending. Goal of residency is to keep your head down and get through it while learning as much as you can. Good luck.

This, so much. As I got more comfortable and competent in residency, it drove me through a wall working with attendings who would not allow any leeway or give any semblance of independence. For those types I developed learned helplessness and just succumbed. It was very frustrating and non-conductive to active learning. While those types maybe should work in a job where they do their own cases or work with CRNAs only, I understand it is their license on the line and their apprehensiveness to allow a resident to potentially jeopardize that. That being said, the days you work with the "cool" attendings, are the best to days to really learn the most and practice new things, or hey, even extubate as a CA3 without attending in the room

 

[abolt18]

Yeah, I feel like those are days you just do whatever they want and manipulate things within the confines of their preferences.

As far as extubating without an attending in the room? This happens often. I text them to tell them they're closing with an ETA, followed by a text that drapes are coming down and the gas is off. After that I proceed with my planned extubation when the patient is ready. I have given my attending fair warning to make themselves available.

On the other hand, I have plenty of attendings that will just say "proceed. Call if you need help"

This, so much. As I got more comfortable and competent in residency, it drove me through a wall working with attendings who would not allow any leeway or give any semblance of independence. For those types I developed learned helplessness and just succumbed. It was very frustrating and non-conductive to active learning. While those types maybe should work in a job where they do their own cases or work with CRNAs only, I understand it is their license on the line and their apprehensiveness to allow a resident to potentially jeopardize that. That being said, the days you work with the "cool" attendings, are the best to days to really learn the most and practice new things, or hey, even extubate as a CA3 without attending in the room

 

[deleted171991]

Yeah, I feel like those are days you just do whatever they want and manipulate things within the confines of their preferences.

As far as extubating without an attending in the room? This happens often. I text them to tell them they're closing with an ETA, followed by a text that drapes are coming down and the gas is off. After that I proceed with my planned extubation when the patient is ready. I have given my attending fair warning to make themselves available.

On the other hand, I have plenty of attendings that will just say "proceed. Call if you need help"

DO NOT EXTUBATE ALONE, unless explicitly permitted. If the patient gets into trouble, and you can't fix it, or your attending walks in on that, you will be in trouble. I rarely if ever write up residents, but, if you extubated in my absence and something happened, I would make a fuss. Cockiness in the OR is dangerous (and also the main reason we have oral boards).

My answer to the emphasized part is "who the heck do you think you are?". If anything happens, your attending is legally and financially responsible. Wait for their answer. They may have missed your message, or may be busy with their other room.

 

[deleted171991]

Do you know those attendings that don’t like you to think, and won’t allow you to do anything, or doesn’t like independent thought, even as so much that I can’t choose to use 20gtt/ml or 15gtt/ml tubing, that’s what I have been working with.


So usually propofol+dexmedetomidine infusion +/- ketamine infusions on one hand; prop+dex+fentanyl Infusions (+fentanyl blouses) on the other.

I feel your pain and frustration. You had me at propofol + precedex.

The reason they need fentanyl and/or ketamine, plus a ton of pressors, is that precedex is just a dumbing/sympatholythic agent. I would never use it for maintenance of general anesthesia. It's utterly unpredictable (and just minimally analgesic); I have had people wide awake on 1.5 mcg/kg/h, or after 1 mcg/kg initial bolus.

Best advice I ever got about anesthesia (or medicine in general): KISS.

 

[abolt18]

DO NOT EXTUBATE ALONE, unless explicitly permitted. If the patient gets into trouble, and you can't fix it, or your attending walks in on that, you will be in trouble. I rarely if ever write up residents, but, if you extubated in my absence and something happened, I would make a fuss. Cockiness in the OR is dangerous (and also the main reason we have oral boards).

My answer to the emphasized part is "who the heck do you think you are?". If anything happens, your attending is legally and financially responsible. Wait for their answer. They may have missed your message, or may be busy with their other room.

Perhaps the environment is just very different at my institution. I have never been greeted with anything but "oh cool, you already extubated. They look good. Nice job." If anything, when I have waited a long time and the patient was clearly ready, I've been told things like "what are you waiting for? take that tube out"

Early in my training (end of CA-1), attengings gave me space and said things like "go ahead an proceed with the case, call if you need me" for both induction and extubation. They are often still peeking in through the window (you notice every now and then) but they're trying to promote a little independent thinking and proactivity.

I'm obviously not doing this for any and every case. Patients in whom I have significant concerns about the airway or hemodynamics, I'll either have a clearly established plan-of-action for extubation or wait for my attending.

 

[dhb]

I feel much more involved as a provider when i can chase the BP after inducing with 200 of propofol 150 of fenta and cranking the sevo to 2.2 on 6L FGF while starting a precedex lidocaine and ketamine infusion.

 

[deleted87051]

Your patients are hypotensive also because you are growing up in a culture that is obsessed about IV fluids, and runs everybody on pressor infusions.

First thing we used to do, back in residency, was to give the patient up to 2 liters of IV crystalloid (for having been NPO). The number of cases that needed a pressor infusion was minuscule, when compared to nowadays. I am an intensivist, and still I will give those first 2 liters without blinking, if my non-septic patient needs a lot of pressors in the OR.

On the other hand, if my patient is hypotensive on a fentanyl infusion, I will probably drop the main agent. The main reason that patient is hypotensive is not just vasodilation, or loss of sympathetic response, it's the imbalance between the surgical stimulus and anesthesia. So the problem is probably not your attending; the problem is you not adjusting your anesthesia to having a good amount of fentanyl on board.

Btw, that fentanyl infusion is probably not much different than when an attending pushes 2 mg of dilaudid at the beginning of the case. 😉

AKA anesthetic overdose. It’s the cause of at least 80% of hypotension. I don’t think hypovolemic is the cause of hypotension as often as we think it is. If a patient doesn’t need pressors in preop or pacu and they got minimal fluids intraop, the cause of intraop hypotension is probably not hypovolemia.

 

[Hoya11]

AKA anesthetic overdose. It’s the cause of at least 80% of hypotension. I don’t think hypovolemic is the cause of hypotension as often as we think it is. If a patient doesn’t need pressors in preop or pacu and they got minimal fluids intraop, the cause of intraop hypotension is probably not hypovolemia.

Hypovolemia could certainly exist in the situation you are describing, but the patient is able to compensate when not under GA with sympathetics blunted. If these dehydrated but compensating patients were better hydrated maybe they wouldn't need pressors intraop at all

 

[deleted87051]

Hypovolemia could certainly exist in the situation you are describing, but the patient is able to compensate when not under GA with sympathetics blunted. If these dehydrated but compensating patients were better hydrated maybe they wouldn't need pressors intraop at all

Agree it’s relative. Hypovolemia under deep general anesthesia is not the same as hypovolemia in the rest of life.

 

[fakin' the funk]

I’m been doing some cases recently that require TIVA, and been using fentanyl infusions as part of the multi-modal therapy. We learn that fentanyl is supposed to be reasonably stable for classical cardiac inductions, but I’ve notice quite a bit of hypotension in the OR. Anyone else experience this? I think it’s weird because I know ICUs use it for their sedation but they are not battling hypotension on the floor around the clock.

Um, have you been in an ICU?

 

[deleted9493]

Propofol and volatile anesthetics decrease SVR significantly. Fentanyl inhibits the primary compensatory mechanism for vasodilation in that of increased HR by inhibiting sinoatrial/AV nodal conduction and sinus node automaticity...probably from both direct and indirect (vagal) mechanisms. This effect holds for the other synthetic opioids, as well.

 

[deleted875186]

opioids and volatile are very synergistic. Try doing a GA case without opioids, significantly less hypotension, even when there’s not much pain fron the surgery.

 

[Hork Bajir]

I’m all about esmolol for induction. Or, if you must use some opioid in order to supplement induction, alfenta is a great way to do it without having to deal with the effects for more than a couple of minutes

 

[anbuitachi]

DO NOT EXTUBATE ALONE, unless explicitly permitted. If the patient gets into trouble, and you can't fix it, or your attending walks in on that, you will be in trouble. I rarely if ever write up residents, but, if you extubated in my absence and something happened, I would make a fuss. Cockiness in the OR is dangerous (and also the main reason we have oral boards).

My answer to the emphasized part is "who the heck do you think you are?". If anything happens, your attending is legally and financially responsible. Wait for their answer. They may have missed your message, or may be busy with their other room.

depends on the culture. in residency, even as CA1s we routinely extubate alone. there's an understanding that for most attendings shoot them a text/page, and unless they say otherwise, it's okay to extubate alone. obviously if something goes wrong, teh resident will get the blame. that's an understanding.

 

[anbuitachi]

I’m been doing some cases recently that require TIVA, and been using fentanyl infusions as part of the multi-modal therapy. We learn that fentanyl is supposed to be reasonably stable for classical cardiac inductions, but I’ve notice quite a bit of hypotension in the OR. Anyone else experience this? I think it’s weird because I know ICUs use it for their sedation but they are not battling hypotension on the floor around the clock.

fentanyl decrease HR, decrease sympathetic response from stimulation, and reduces MAC. either add a phenylephrine infusion if needed or reduce propofol.

i routinely use fentanyl for TIVA cases. Remi is way too expensive. And i'm not a huge fan of sufentanil or alfentanyl. I usually do not have to use much pressors at all. I do sometimes run a background phenylephrine infusion in older patients for spine cases

 

[Norepi]

I’m all about esmolol for induction. Or, if you must use some opioid in order to supplement induction, alfenta is a great way to do it without having to deal with the effects for more than a couple of minutes

What do you give for surgical stimulation then, and for immediate postop pain?

 

[2Fast2Des]

What do you give for surgical stimulation then, and for immediate postop pain?

Roc for the movement, glyco for the tears, esmolol for the sympathetic 😛

 

[Drwine]

I feel much more involved as a provider when i can chase the BP after inducing with 200 of propofol 150 of fenta and cranking the sevo to 2.2 on 6L FGF while starting a precedex lidocaine and ketamine infusion.

I compare that kind of "art of anesthesia" to the so called art of Jackson Pollock. Going back to the original thread Fentanyl is a poor choice for TIVA due to its context sensitive half life. Remifentanil and sufentanil are much better choices.

 

[chocomorsel]

I feel much more involved as a provider when i can chase the BP after inducing with 200 of propofol 150 of fenta and cranking the sevo to 2.2 on 6L FGF while starting a precedex lidocaine and ketamine infusion.

Are you Europeans also using the word "provider" now? Oh boy.

 

[chocomorsel]

I am with FFP. Why are you using Propofol plus Dex, plus Fentanyl plus Ketamine. I mean are you throwing the kitchen sink at these people for a reason?
No wonder your patients are hypotensive. It's not the Fentanyl. It's all the other **** on top of it.

 

[deleted87051]

I am with FFP. Why are you using Propofol plus Dex, plus Fentanyl plus Ketamine. I mean are you throwing the kitchen sink at these people for a reason?
No wonder your patients are hypotensive. It's not the Fentanyl. It's all the other **** on top of it.

It’s Eurohumor

 

[chocomorsel]

It’s Eurohumor

I totally don't know jack about Eurohumor. I see though that OP doesn't do both Ketamine and Fentanyl.
I am not sure why he is blaming the Fentanyl though instead of the other other two drugs.

 

[Iso4ane]

I totally don't know jack about Eurohumor. I see though that OP doesn't do both Ketamine and Fentanyl.
I am not sure why he is blaming the Fentanyl though instead of the other other two drugs.

To address a few questions, the reason these cases are done under TIVA is that we are utilizing an ICU ventilator for these cases either for their specialized vent settings or nebulization of epoprostenol (for some reason we don’t have the equipment to administer epoprostenol with the OR ventilator.)

Anecdotally, the TIVA is some combo of The four medications, and even when it’s just propofol and fentanyl, on average those patients then to be more hypotensive than the patients on who are on prop+dex+ketamine+no fentanyl (although the ketamine is really low dose usually no more than 50mg over 5hours). Also, the fentanyl drip is only used by particular attending, and they definitely seem to have a harder time with hypotension than the other attendings, it could be something else they do, but the fentanyl is the one that sticks out.