Spinals for C-sections

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

Urzuz

Full Member
10+ Year Member
Joined
Aug 24, 2011
Messages
837
Reaction score
2,045
Just a quick question to get a sense for what others are doing -- do you add fentanyl into your spinals for C-sections? Why or why not? And how much do you add?

Members don't see this ad.
 
Yes. Helps with the visceral discomfort, and lets you use less bupivacaine, which keeps recovery times down.

15 mcg fentanyl, 0.2 mg morphine, and 1.2 - 2.0 mL .75% bupiv depending on who's operating. With a fast surgeon 1.2 - 1.4 is enough. Some people here will put in a CSE just in case the section goes a couple+ hours ... for those you probably don't get anything useful out of the fentanyl.
 
Members don't see this ad :)
Anybody using isobaric bupic? How much?

Not for C/S. Only for Joints and usually about 12.5mg. I would be worried that you wouldn't get high enough of a level for a C/S, but I'd love to hear other's experiences.

We typically do 100mcg epi, 10mcg fentanyl & 150mcg duramorph at my training program

While the epi might be necessary in training where you have long C/S times, it's completely unnecessary out in practice where a C/S is a 30-45min case. It does seem to cause nausea for some reason. Not sure what it is about the Bupi+Epi+Fent+Morph combo but it tends to make people yak compared to just Bupi+Fent+Morph.
 
15 mcg of fentanyl added to the 1.4-1.5 ml of heavy bupivicaine. If I'm with the academic team the residents will slow the process down a bit so I might add an epi wash if I suspect the case might go long (lots of scar tissue, BTL, etc).
 
we usually do, as i said above, 15mcg fentanyl with 150mcg duramorph with 0.75% hyperbaric bupiv (typically 1.6mL unless you're with a faculty that doses by height, in that case its 1.0mL for 5 feet then basically .1mL up to 1.6mL for each inch above 5 foot) Many studies show that 1.6mL for everyone is fine, its just the speed of injection that makes the difference.
 
ive never used epi in an a SAB, how much longer does that prolong the block? 30 minutes? we usually get 1.5 hours without, maybe we should add epi in early July on the previous x1-2 for BTL. Whenever its previous x3 and BTL its automatic CSE.
 
When I trained from 2007-10, the standard spinal was 1.6 ml 0.75% marcaine, fentanyl 20 mcgs, and duramorph 0.2 mg. I would venture to guess on average, I would use 2-3 sticks of neo throughout the case (this happened to all of us).

When I came to PP, I noticed no one was adding fentanyl to the spinals. Now I typically do 1.6 ml 0.75% marcaine and duramorph 0.15 mg (just recently decreased from 0.2 mg). I have done quite a few C/S without ANY neo and I can't remember the last time I needed more than half the stick. Now I cannot possibly explain how just the fentanyl made that much difference but I have zero plans to add fentanyl back to the spinal. I have not noticed any increased discomfort from that "visceral" pain.

As an FYI, we do have some surgeons who are skin to skin in less than 20 mins but I'd say our average surgeon takes 45-60 minutes, definitely not the speedy surgeons I was expecting.
 
1.6 mL hyperbaric 0.75% bupi, 20 mcg fentanyl and 200 mcg duramorph.

I'm a CA3 and if OB-Gyn residents are involved I will do a CSE for repeats. Usually the OB residents seem to want to torture the med students by watching them close muscle and sub-q and refuse to help especially if the poor guy/gal has done surgery already bc "you should know how to do this". Even primary sections can take a long time bc that is apparently an OB intern case. The other day an uncomplicated c/s clocked in at 3hrs 15mins.

I've noticed that scheduled sections seem to require less phenyl the later in the day it gets. My theory is those at the end of the day have had 1-2 L of LR infusion while waiting for med students to close skin. Not scientific I know but it's something I've noticed.

My understanding of local anesthetics is that epinephrine will minimally increase your block with long acting agents like bupi but dramatically enhances length of block with intermediate agents like lidocaine. I never use it since I don't see the benefit.

For post partum BTLs I stick to bupi only.
 
  • Like
Reactions: 1 user
epi probably adds about 30 minutes of block duration. Extends my median from about 1:45-2:00 to 2:15 to 2:30.
 
  • Like
Reactions: 1 user
Members don't see this ad :)
No fentanyl - I honestly don't think it adds anything. 1.6ml bupi + 100mcg morphine. Anything over 100 has not been shown to give no improvement in analgesia but increased incidence of side effects. A few studies actually say 50mcg is adequate but, I prefer 100mcg b/c it's easier to measure out.
 
To reiterate what everyone has already been saying we use 1.6cc of .75% bupi with 200mcg of duramorph (+/- 20mcg of fentanyl depending on the attending). Several attendings I have worked with say the fentanyl does nothing but add pruritis.

at 20 mcg they'd probably be correct. Then again with 200 mcg of duramorph you are also signing them up for some itching. 15 mcg seems to be the sweet spot for benefit with minimal side effects on the fentanyl.
 
I don't think it's right to have to do an unnecessary cse because the junior residents take forever to close skin or let the med students close. I don't mind them doing it because I was once a student and dreamed of getting to do something after standing around for hours. But I always remind the OB team when the spinal began and if it's been over 1.5 hours I tell the senior or attg that the patients spinal will wear off soon. Definitely do cse with really large people or 3x c-section or other abdominal surgeries tho.
 
Typically, I don't add fentanyl. Haven't needed it and they start to itch during the c/s when it's added. No itching with just morphine until later. Fentanyl may add some visceral component but I don't think it is reproducable enough to consider using it.
But if a pt comes for c/s that had an epidural running and maybe hit the PCEA button a coup,e of times or got a bolus then I will cut the Bupiv from 1.6cc to 1.2 and add 20mcg of Fent.
 
Typically, I don't add fentanyl. Haven't needed it and they start to itch during the c/s when it's added. No itching with just morphine until later. Fentanyl may add some visceral component but I don't think it is reproducable enough to consider using it.
But if a pt comes for c/s that had an epidural running and maybe hit the PCEA button a coup,e of times or got a bolus then I will cut the Bupiv from 1.6cc to 1.2 and add 20mcg of Fent.
If you don't trust the epidural to load for the section and pull it in favor of single shot spinal?

I think I'm going to start leaning this way more if there is any chance that epidural isn't golden. It's pretty easy to pull it and bang in a spinal vs loading a questionable epidural where you have now burned some bridges potentially.
 
If you don't trust the epidural to load for the section and pull it in favor of single shot spinal?

I think I'm going to start leaning this way more if there is any chance that epidural isn't golden. It's pretty easy to pull it and bang in a spinal vs loading a questionable epidural where you have now burned some bridges potentially.
Oh yeah, I should have my mentioned that I don't use the epidurals. I always pull them.
 
We typically do 100mcg epi, 10mcg fentanyl & 150mcg duramorph at my training program
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?
 
Oh yeah, I should have my mentioned that I don't use the epidurals. I always pull them.

You pull out the epidural and give a normal dose of spinal for a C/S? A good working epidural is more than adequate for a C/S. If you do that every time, have you ever had a high spinal? If you did that and patient ended up with a high spinal, intubated in the ICU, you'd be buried by any attorney and a long line of "expert" witnesses who would say that is bad practice (no offense).

In terms of the epi, I agree with Plankton. That's a big, whopping dose when there is no real added benefit of epi to marcaine.
 
  • Like
Reactions: 1 user
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?

It's been awhile and I never use epi now, but I believe 100mcg is the dose used at northwestern.
 
You pull out the epidural and give a normal dose of spinal for a C/S? A good working epidural is more than adequate for a C/S. If you do that every time, have you ever had a high spinal? If you did that and patient ended up with a high spinal, intubated in the ICU, you'd be buried by any attorney and a long line of "expert" witnesses who would say that is bad practice (no offense).

Really? Unless an epidural is working GREAT, I pull it and do a spinal. Anything other than a perfect epidural and you end up telling the patient that it's pressure, not pain that you are feeling for the entire case. Epidurals SUCK for c-sections in many instances. Spinals don't. If the epidural is iffy, I pull it and do a spinal with a 0.8-1.0 ml dose of hyperbaric bupivicaine. Personal incidence of high spinal from it is zero, though I have a low threshold for putting the patient in reverse T-berg if the level is coming up fast.

I'd bet that if you tend to use most epidurals for c-sections, you have a higher incidence of having to convert to GA than the incidence of high spinals from doing a low dose spinal in a patient with a previously running epidural.
 
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?

We used more epi than this in residency all the time without problem.
 
  • Like
Reactions: 1 user
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?

People in my program used 100 mcg. Some did something called an "epi wash" which was the odd unscientific method of drawing up the whole ampule of 1:1000 epi into the spinal syringe, swishing it around, and then squirting it all out, leaving some amount in the syringe needle hub. Probably about 0.1 mL or 100 mcg, probably. I didn't like that approach. Never heard of any injuries or problems though.

I don't put epinephrine in my spinals. If I want a longer acting spinal, I use more bupivacaine.
 
Really? Unless an epidural is working GREAT, I pull it and do a spinal.

As a fresh attending this is something I still struggle with (deciding to pull the epidural or bolus it up for section). I'm having a hard time determining what constitutes a great block vs an ok block. If it's been in 6 hours and you have had no calls and the pt appears comfortable? Demonstrable dermatomal block (not always consistent or easily identifitable with a weak infusate running)? Good initial analgesic effect when you placed it?

Lots of gray areas I feel like. Seems like if time allows just pulling it and doing a spinal is less risky often.
 
As a fresh attending this is something I still struggle with (deciding to pull the epidural or bolus it up for section). I'm having a hard time determining what constitutes a great block vs an ok block. If it's been in 6 hours and you have had no calls and the pt appears comfortable? Demonstrable dermatomal block (not always consistent or easily identifitable with a weak infusate running)? Good initial analgesic effect when you placed it?

Lots of gray areas I feel like. Seems like if time allows just pulling it and doing a spinal is less risky often.

I ask the patient.

1) Do you hurt anywhere with contractions?
2) Can you even tell you are having them?

Then I check levels with an ice cube.

If they have zero pain and don't really know they are contracting and have good levels...I use the epidural. Any question...I pull it and place a spinal.
 
Really? Unless an epidural is working GREAT, I pull it and do a spinal. Anything other than a perfect epidural and you end up telling the patient that it's pressure, not pain that you are feeling for the entire case. Epidurals SUCK for c-sections in many instances. Spinals don't. If the epidural is iffy, I pull it and do a spinal with a 0.8-1.0 ml dose of hyperbaric bupivicaine. Personal incidence of high spinal from it is zero, though I have a low threshold for putting the patient in reverse T-berg if the level is coming up fast.

I'd bet that if you tend to use most epidurals for c-sections, you have a higher incidence of having to convert to GA than the incidence of high spinals from doing a low dose spinal in a patient with a previously running epidural.

We have quite a few "FTP" and urgent C/S on laboring patients with epidurals. It is not very often any of us have had to convert to GETA with an epidural. A few times I've replaced an epidural for a patient who needs a C/S that can wait for a new one and it's worked well for me. We do about 3000 deliveries a year so I am not at some po dunk community hospital that sees 20 a month.

Sorry if I struck a bad nerve. My Attending always trained us not to do a spinal after an epidural. If you have perfect success with it, more power to you. I also don't like the idea of pulling out an adequate epidural and doing an extra, unnecessary (IMO, not yours obviously) procedure on the patient. I've never tried to do a spinal after epidural so maybe I'm the ignorant one, just how I was trained I suppose.
 
We have quite a few "FTP" and urgent C/S on laboring patients with epidurals. It is not very often any of us have had to convert to GETA with an epidural. A few times I've replaced an epidural for a patient who needs a C/S that can wait for a new one and it's worked well for me. We do about 3000 deliveries a year so I am not at some po dunk community hospital that sees 20 a month.

Sorry if I struck a bad nerve. My Attending always trained us not to do a spinal after an epidural. If you have perfect success with it, more power to you. I also don't like the idea of pulling out an adequate epidural and doing an extra, unnecessary (IMO, not yours obviously) procedure on the patient. I've never tried to do a spinal after epidural so maybe I'm the ignorant one, just how I was trained I suppose.


I know it "isn't very often" you have to convert to GA. You can usually get by with Midazolam and Fentanyl and Nitrous and Ketamine and any other number of things people use on half working epidurals half way through a c-section.

That's why I said I've never had to intubate a patient I put a spinal in after an epidural. Zero. Out of hundreds or perhaps thousands of times I've done it. I don't put in a full normal dose as that'd just be stupid. Only takes a little to get their current block denser.

The only thing that strikes a nerve with me is trying to get by with an epidural that isn't perfect. The patient suffers and we try to tell them "it's OK, it's just pressure" while they are writhing in pain. I'd much rather take the 30 seconds to put the spinal in and then they have a perfect experience with no IV sedation needed. I'm sorry you never learned how to do that. It's quite safe and like I said I think fewer patients get intubated after a spinal than not doing the spinal and trying to get by with the epidural.
 
I know it "isn't very often" you have to convert to GA. You can usually get by with Midazolam and Fentanyl and Nitrous and Ketamine and any other number of things people use on half working epidurals half way through a c-section.

That's why I said I've never had to intubate a patient I put a spinal in after an epidural. Zero. Out of hundreds or perhaps thousands of times I've done it. I don't put in a full normal dose as that'd just be stupid. Only takes a little to get their current block denser.

The only thing that strikes a nerve with me is trying to get by with an epidural that isn't perfect. The patient suffers and we try to tell them "it's OK, it's just pressure" while they are writhing in pain. I'd much rather take the 30 seconds to put the spinal in and then they have a perfect experience with no IV sedation needed. I'm sorry you never learned how to do that. It's quite safe and like I said I think fewer patients get intubated after a spinal than not doing the spinal and trying to get by with the epidural.

Ok, the holiness and God of anesthesia has spoken. I have no defense for that. Man, I really suck for using our half working epidurals. I always thought them screaming in pain was just being a whiny, pregnant patient. You've enlightened me in so many ways, THANK YOU!
 
You pull out the epidural and give a normal dose of spinal for a C/S? A good working epidural is more than adequate for a C/S. If you do that every time, have you ever had a high spinal? If you did that and patient ended up with a high spinal, intubated in the ICU, you'd be buried by any attorney and a long line of "expert" witnesses who would say that is bad practice (no offense).

In terms of the epi, I agree with Plankton. That's a big, whopping dose when there is no real added benefit of epi to marcaine.
Easy big fella.
I am more than a crna. I don't need you lecturing me on the risks of my practice.
This is now the normal practice in my group as all of my partners have seen the superior results. And the OBs now prefer it as well.
 
Ok, the holiness and God of anesthesia has spoken. I have no defense for that. Man, I really suck for using our half working epidurals. I always thought them screaming in pain was just being a whiny, pregnant patient. You've enlightened me in so many ways, THANK YOU!
You started this debate.
Your attending was less knowledgeable than I would expect a diplomat of the ABA to be.
As Mman stated, you must cut down your Bupiv dose in order to prevent the high spinal. That's why I add some fentanyl to this spinal, which was the original question on this thread.
Bar none, IMO the spinal is a far superior block for a c/s.
And nobody should be afraid to pull even a working epidural to place a spinal. If you are an average anesthesiologist then a spinal should not be much of a challenge.
 
Ok, the holiness and God of anesthesia has spoken. I have no defense for that. Man, I really suck for using our half working epidurals. I always thought them screaming in pain was just being a whiny, pregnant patient. You've enlightened me in so many ways, THANK YOU!

WTF buddy? You are the one that is apparently unaware it is safe to place a spinal in a patient that has a running epidural. I'm not breaking new ground here or practicing outside the standard of care. And I've never met an anesthesiologist that would prefer to have an epidural compared to a spinal for a c-section. We've all been there and it can be not fun. If I have a patient going for a non-stat c-section with an epidural that I have any degree of concern over, epidural out, spinal in and proceed with the case. If it's a stat c-section, however, I'm just dosing the epidural and will deal with the consequences if it doesn't work.
 
Mman,
I agree with your approach to using epidural for CS in general. Though it seems like you have a low threshold to pull one if it's iffy, i.e., you don't want to deal with or don't feel it's appropriate to do the "pain vs pressure" dance. Which is really just, awful.
What do you do about dosing intrathecal morphine? You didn't mention it in your spinal dose.
 
Let's say you think you have a good epidural and go ahead and dose it up for C/S but fail to get an adequate level or it ends up patchy, or whatever. Would you still go ahead with a spinal after a fresh epidural bolus or do you consider the risk of a high block too great at that point? I ask bc this happened to a partner of mine recently who went ahead with an SAB after a failed epidural bolus. He ended up with an unconscious pt for about 10 min.

Since I've been out of training I've really contemplated switching to Noy's approach, but just haven't had any epidurals fail to be plenty adequate for a C/S yet so I haven't been able to justify the extra step in my head. I definitely agree though that an SAB is a superior block for a C/S.
 
  • Like
Reactions: 1 user
Let's say you think you have a good epidural and go ahead and dose it up for C/S but fail to get an adequate level or it ends up patchy, or whatever. Would you still go ahead with a spinal after a fresh epidural bolus or do you consider the risk of a high block too great at that point? I ask bc this happened to a partner of mine recently who went ahead with an SAB after a failed epidural bolus. He ended up with an unconscious pt for about 10 min.

Since I've been out of training I've really contemplated switching to Noy's approach, but just haven't had any epidurals fail to be plenty adequate for a C/S yet so I haven't been able to justify the extra step in my head. I definitely agree though that an SAB is a superior block for a C/S.

If dosing up the epidural doesn't work, they get a GA, hence my reluctance to even try unless I'm convinced ahead of time it's going to work.
 
Mman,
I agree with your approach to using epidural for CS in general. Though it seems like you have a low threshold to pull one if it's iffy, i.e., you don't want to deal with or don't feel it's appropriate to do the "pain vs pressure" dance. Which is really just, awful.
What do you do about dosing intrathecal morphine? You didn't mention it in your spinal dose.

We don't use IT morphine.
 
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?
Yep, all the OB faculty use it at my program. We've never had problems with it
 
To answer the question regarding failed epidural and proceeding with spinal. First it would depend on the status of baby and m0m. If the section was urgent IE fetal bradycardia, fetal distress. I would proceed with general anesthesia after failed bolus of epiduiral. If the section was due to failure to progress I would wait 4-6 hrs and pull the epidural catheter and redose with a spinal. How about the other way what if you had a failed spinal(bad bupi) would you place an epidural and proceed? Or straight to general anesthesia?
 
To answer the question regarding failed epidural and proceeding with spinal. First it would depend on the status of baby and m0m. If the section was urgent IE fetal bradycardia, fetal distress. I would proceed with general anesthesia after failed bolus of epiduiral. If the section was due to failure to progress I would wait 4-6 hrs and pull the epidural catheter and redose with a spinal. How about the other way what if you had a failed spinal(bad bupi) would you place an epidural and proceed? Or straight to general anesthesia?
You would take a FTP pt and make her wait 4-6 hrs to have a spinal? That is insanity in my opinion and I'm sure in the pts and OBs opinions as well. Please explain this line of reasoning?

Failed spinals get GETA!
 
If the section was due to failure to progress I would wait 4-6 hrs and pull the epidural catheter and redose with a spinal.

As I'm studying for my oral boards, this seems like a very diplomatic, boards-y kind of answer. From a practical standpoint, as mom is lying on the OR table exhausted from a prolonged labor, the OB and scrub tech have scrubbed with instruments in hand staring at me, I can't imagine announcing to everyone, "Alright peeps, let's hold on the section for now and take five.....hours."
 
My line of reasoning is I do not like general anesthesia for c-sections. In my practice I have become more tolerant of general anesthesia for for c-sections. The decision tree pivots at the airway if the patient has a reassuring airway then proceed to geta. If not wait. The number 4-6 comes more from bumping the patient on the schedule IE usually we have 3-4 c-sections a day as long as the patient is stable I would bump her to the last case and place the spinal. If that failed then general anesthesia it is. I have had one case where the spinal failed with high suspicion of bad bupivicaine and I placed an epidural slowly bolused it up and proceeded to c-sections. C-section was uneventful. Spinal after epidural is tricky. You have to be cognizant of the EVE effect IE epidural volume expansion and reduce the dose of bupi to 1.2ml of .75% bupivicaine.
 
Last edited:
Spinal after epidural is tricky. You have to be cognizant of the EVE effect IE epidural volume expansion and reduce the dose of bupi to 1.2ml of .75% bupivicaine.

Why is it tricky? Reduce the dose and you are fine. I personally go with between 0.8 ml to 1.0 ml depending on how relatively numb they are from epidural. It's no more dangerous than placing a spinal in a person that doesn't have an epidural.
 
Not tricky from a tactical standpoint more so that you have to be aware the EVE effect. How compressed is the intrathecal sac from the full bolus of lidocaine? How much CSF has been spread cephalad? I have seen a handful of these cases in training, these patients often required greater vasopressor support. Placing a spinal in a patient without an expanded epidural space is different then placing a spinal with and expanded epidural space.
 
Not tricky from a tactical standpoint more so that you have to be aware the EVE effect. How compressed is the intrathecal sac from the full bolus of lidocaine? How much CSF has been spread cephalad? I have seen a handful of these cases in training, these patients often required greater vasopressor support. Placing a spinal in a patient without an expanded epidural space is different then placing a spinal with and expanded epidural space.

Placing a lower dose spinal in a patient with an "expanded epidural space" is equivalent in risk to placing a larger dose spinal in a patient without an "expanded epidural space".

I'm not advocating bolusing the epidural and then doing a spinal 10 minutes later. We are talking about a patient with an infusion running that then needs a c-section. It's perfectly safe and reasonable to just place a spinal in them albeit at a smaller dose than what you'd normally use.
 
Makes you wonder if the enhanced anesthesia is not actually caused by spinal cord ischemia!

I'm not aware of any case reports of spinal cord ischemic damage following epi in the spinal injection. In fact I remember one of my attendings telling me years ago that they injected upto 1 mg per kilo of epi intrathecally in monkeys and found no cord damage. The wash does nothing to prolong blockade. You have to add at least 100 micrograms. I don't use epi any more because I don't use lido for my spinals, just heavy or isobaric bupivacaine.
 
100mcg of epi is a huge dose and it might produce longer anesthesia by causing cord ischemia!
Think about it: your typical premixed Bupivacaine with epi commercial solution is usually 1/200,000 epinephrine which translates into 100mg/200,000 ml ---> 5mcg/ml
You are basically giving an epinephrine solution that is 20 times more concentrated!
Did some one actually teach you to use that concentration or is it a typo?

Very different applied pharmacology. 100 mcg is a completely appropriate intrathecal dose and is well within published guidelines. Bridenbaugh recommends 200 mcg in his Neural Blockade text.

When you administer Lido + Epi 1:100,000 (10mcg/mL) or Bupi+ Epi 1:200,000 (5mcg/mL), you are either testing for IV placement, in which case a small dose of dilute epi is optimal, or you are applying it to an enclosed, nerve containing space with only the local anesthetic volume as the diluent. Your typical 30cc bupivacaine block would contain 150 mcg of epinephrine bathing the nerves in a very confined area. (Ok, there is also infiltration, but I think we can ignore that for this discussion)

Epinephrine administered intrathecally, spreads rapidly throughout the spinal portion of the csf, much like the lipophillic opiods. Typical adult total CSF volumes range from 120-150mL with 25-35mL of that volume being in the spinal portion of the CSF. Pregnant and obese individuals occupy the lower end of the spectrum. So, your 100mcg of epinephrine is being diluted in 25 mL of CSF for a final concentration of 4mcg/mL. This is comparable to the 5-10 mcg/mL concentration used in peripheral nerve block.

In addition to prolonging the block due to reduced clearance (vasoconstriction or decreased metabolism?), epinephrine has intrinsic anesthetic action through alpha-2 agonism, and may carry some of the local anesthetic with it as it spreads higher in the spinal column. The alpha-2 agonism and higher spread may explain the nausea someone mentioned in this thread.

Although spinal cord ischemia has long been brought up as a concern, to date there is little evidence to support the concern. Animal studies show blood flow reduction from intrathecal epinephrine is primarily and preferentially in the dura, as opposed to the cord itself. There are reductions in spinal cord blood flow when bupivacaine and epi are administered, but this is likely explained by decreased metabolic activity resulting in decreased demand for blood flow. Epinephrine added to a low-dose bupi spinal reduces the spinal cord blood flow to a greater magnitude than epinephrine added to a higher-dose bupi spinal. This supports the supposition that the reduction in blood flow results from decreased metabolic activity instead of direct vasoconstriction.

- pod
 
  • Like
Reactions: 3 users
Very different applied pharmacology. 100 mcg is a completely appropriate intrathecal dose and is well within published guidelines. Bridenbaugh recommends 200 mcg in his Neural Blockade text.

When you administer Lido + Epi 1:100,000 (10mcg/mL) or Bupi+ Epi 1:200,000 (5mcg/mL), you are either testing for IV placement, in which case a small dose of dilute epi is optimal, or you are applying it to an enclosed, nerve containing space with only the local anesthetic volume as the diluent. Your typical 30cc bupivacaine block would contain 150 mcg of epinephrine bathing the nerves in a very confined area. (Ok, there is also infiltration, but I think we can ignore that for this discussion)

Epinephrine administered intrathecally, spreads rapidly throughout the spinal portion of the csf, much like the lipophillic opiods. Typical adult total CSF volumes range from 120-150mL with 25-35mL of that volume being in the spinal portion of the CSF. Pregnant and obese individuals occupy the lower end of the spectrum. So, your 100mcg of epinephrine is being diluted in 25 mL of CSF for a final concentration of 4mcg/mL. This is comparable to the 5-10 mcg/mL concentration used in peripheral nerve block.

In addition to prolonging the block due to reduced clearance (vasoconstriction or decreased metabolism?), epinephrine has intrinsic anesthetic action through alpha-2 agonism, and may carry some of the local anesthetic with it as it spreads higher in the spinal column. The alpha-2 agonism and higher spread may explain the nausea someone mentioned in this thread.

Although spinal cord ischemia has long been brought up as a concern, to date there is little evidence to support the concern. Animal studies show blood flow reduction from intrathecal epinephrine is primarily and preferentially in the dura, as opposed to the cord itself. There are reductions in spinal cord blood flow when bupivacaine and epi are administered, but this is likely explained by decreased metabolic activity resulting in decreased demand for blood flow. Epinephrine added to a low-dose bupi spinal reduces the spinal cord blood flow to a greater magnitude than epinephrine added to a higher-dose bupi spinal. This supports the supposition that the reduction in blood flow results from decreased metabolic activity instead of direct vasoconstriction.

- pod
All this is fantastic and sounds great but unfortunately we still don't really know what exactly happens when you add epinephrine to local anesthetics intrathecally, and we don't know how it spreads or where it acts.
We do know though that epinephrine causes nerve ischemia that is sometimes clinically significant when added to local anesthetics in nerve blocks and that's why many people avoid using it in nerve blocks.
So if we are concerned about iscehemia when we inject a 1/200,000 solution around a big nerve like the sciatic nerve shouldn't we be concerned about injecting it around the cord and the nerve roots?
And for those who say it has not been reported that there was cord ischemia with intrathecal epi you need to remember that people only report things that they diagnose and if something is undiagnosed or attributed to another cause it will not be reported.
 
Top