TKA: LIA + AC block. Worried about local toxicity?

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excalibur

excalibur

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Reading the articles on my newly acquired RAPM journals.

Regarding TKA the literature and reading previous posts here on SDN, it seems that LIA and AC block is the way to go. Articles in RAPM show that AC block + LIA is superior to continuous femoral catheter, and AC block + LIA is superior to just LIA alone.

My concern was the amount of local that was being used for LIA and AC block. One study I read stated that the orthopedic surgeon would inject 300 mg of ropivacaine into the joint, and at the end of the surgery the anesthesiologist would then perform AC block with anywhere from 15-20 mL of Ropi 0.5%. So aonther 100 mg of Ropi for a total of 400? Anyone else concerned with the amount? I know Blade uses Exparel and has detailed the amount. Anyone else doing this techniqe have numbers of total amount of local used?

One study did address the amount of ropiivacaine they used stating I believe it was 325 mg. They stated that the injections were well over an hour apart and felt it was fine I guess.

Thoughts on the amount of local used for this technique? Personal amounts of local that you guys are using with your orthopods?
 
dhb said:
I do AC cath pre-op, GA and if pain in the pacu a pop-sciatic
Click to expand...

OK, but I am more curious about the total amount of local anesthetic used for the TKA if there is an AC block, local infiltration by the surgeon, and I guess in your case a rescue pop-sciatic block.

What's the total dose given to your TKA's combining the surgeon's local infiltration?
 
Not to hijack, but I don't want a catheter or a big pool of local sitting under a 300mmHg tourniquet. I do my acb (single shot with decadron) after the procedure before the dressing goes on.
 
excalibur said:
OK, but I am more curious about the total amount of local anesthetic used for the TKA if there is an AC block, local infiltration by the surgeon, and I guess in your case a rescue pop-sciatic block.

What's the total dose given to your TKA's combining the surgeon's local infiltration?
Click to expand...

I limit my surgeons' cocktail to 200 mg of Ropivacaine if they want any kind of block.
This means they get 40 mls of 0.5% Rop mixed with Toradol, Epi, etc diluted with NS (usually another 40 mls) for injection into the knee. 80 mls is still plenty of volume and I have a buffer to do nerve blocks as well.
 
Anyone care to comment on the total dose of local that is used in your cases. That is what I want to know as te articles report what I consider to be beyond toxic doses, so I want to know how much you guys use
 
The joint was infiltrated by the attending surgeon intraoperatively under direct visualization with 300 mg of ropivacaine (150 mL of 0.2% ropivacaine), 30 mg of ketorolac, and 0.6 mg of epinephrine. The posterior capsule was infiltrated before placement of the prosthesis, and the peri-articular and superficial soft tissues were infiltrated after the prosthesis was in place and before wound closure.


http://www.ncbi.nlm.nih.gov/pubmed/23759708
 
BLADEMDA said:
I limit my surgeons' cocktail to 200 mg of Ropivacaine if they want any kind of block.
This means they get 40 mls of 0.5% Rop mixed with Toradol, Epi, etc diluted with NS (usually another 40 mls) for injection into the knee. 80 mls is still plenty of volume and I have a buffer to do nerve blocks as well.
Click to expand...

Then you use how much for the AC block? 20 mls of Ropi 0.5% for a grand total of 300 mg of Ropi?
 
BLADEMDA said:
The joint was infiltrated by the attending surgeon intraoperatively under direct visualization with 300 mg of ropivacaine (150 mL of 0.2% ropivacaine), 30 mg of ketorolac, and 0.6 mg of epinephrine. The posterior capsule was infiltrated before placement of the prosthesis, and the peri-articular and superficial soft tissues were infiltrated after the prosthesis was in place and before wound closure.


http://www.ncbi.nlm.nih.gov/pubmed/23759708
Click to expand...

In addition, certain patients received the cocktail above plus an ACB with 20 mls of 0.5% Ropivacaine.

So, I feel quite comfortable limiting my surgeons to 200 mg of Ropivacaine for LIA as this leaves me room to do nerve blocks. If 80 mls (0.25% Rop) isn't enough volume then dilute the Ropivacaine to 0.2% which will give you 100 mls of volume to inject into the knee.
 
Last edited:
Furthermore,
injections of ropivacaine were given both during the
surgery (400 mg) and on the first postoperative day (150 mg),
and the anesthetic doses were much higher than those used in
other studies, in which the patients received single injections
ranging from 50 to 200 mg of bupivacaine28,30-32. The large dose
of local anesthetic that we used appears to be safe, as no side
effects were observed in our study group.


http://hmrortho.ca/files/arthroplastie/Analgesie-du-genou.pdf
 
One article reported 312.5 mg of Ropivacaine with LIA + AC block and the other used 400 mg of Ropivacaine (300 mg LIA + 100 mg AC block). These studies were in issues of this year's RAPM
 
BLADEMDA said:
The large dose
of local anesthetic that we used appears to be safe, as no side
effects were observed in our study group.
Click to expand...

Just playing devil's advocate because I don't necessarily believe this is unsafe, but isn't that statement kinda like if I said if I drove home drunk a bunch of times and never crashed, that meant the practice of driving drunk appears to be safe?
 
Hawaiian Bruin said:
Just playing devil's advocate because I don't necessarily believe this is unsafe, but isn't that statement kinda like if I said if I drove home drunk a bunch of times and never crashed, that meant the practice appears to be safe?
Click to expand...

I'm only providing the peer reviewed evidence that is out there. What you do with it is your business. I've already posted how I handle it at my hospital and the evidence strongly suggests my technique is safe.

200 mg (or less) for LIA which leaves you 100 mg to do nerve blocks. If the surgeon wants two nerve blocks then give him 150 mg of Rop (diluted up) to inject.

I'm not comfortable exceeding 300 mg of Ropivacaine unless the patient is massive and I need to do a rescue block on top of the ACB.
 
At my residency program we routinely put AC in catheters for both uni's and TKA's. Never had any issues with the catheter being under the Tourniquet. And that was with our speedy academic surgeons and their 2hr tourniquet times 🙄.
 
1. Use bupivacaine for less cost and better duration for AC and LIA
2. Clinically you can go past the toxicity guidelines without a hitch, especially with US.
3. I think the classic LIA cocktail was 75cc for three compartments of the knee, and 25cc for the skin. I have the ortho skip the skin.
4. 15cc is enough for ACB.
5. Watch your ortho do LIA. A lot of it leaks out immediately, so they don't get the full amount.
6. I don't see how a TQT over a catheter could do any addl harm.
7. Most of our Orthos have TQT on the whole time, but we have one ortho who only uses it during implantation (10min) -- he efficiently achieves hemostasis somehow. Not really any increase in EBL. It's great. The techs say it's definitely more red on the field, but plenty clean enough to do the surgery.
&. We routinely add a low dose sciatic with ropiv
 
They just talked about tourniquet and ACB at the ASA. It is not a problem. Lot's of people doing this.

Putting in the AC catheter at the end of the case and blousing before waking up is perfectly acceptable.

BTW, as I've stated before, femoral nerve blocks are a thing of the past for TKA's.

I haven't done a femoral nerve block for TKA in well over a year. If you are still doing them, you are behind the curve.
 
sevoflurane said:
I haven't done a femoral nerve block for TKA in well over a year. If you are still doing them, you are behind the curve.
Click to expand...

I hear you Sevo. Problem is two-fold at my current gig:

1) I think I'm the only one that knows how to do them (or even know what an ACB is for that matter)

2) I've broached the topic with most of our orthopods who are all uninterested for the most part, I guess old habits die hard (maybe I'll try harder, but again it's a challenge given #1)
 
sevoflurane said:
They just talked about tourniquet and ACB at the ASA. It is not a problem. Lot's of people doing this.

BTW, as I've stated before, femoral nerve blocks are a thing of the past for TKA's.

I haven't done a femoral nerve block for TKA in well over a year. If you are still doing them, you are behind the curve.
Click to expand...

You went to different talks at ASA than I did.
 
I'll be glad if evidence bears out that a catheter under the tourniquet is safe. But since we have no similar practice anywhere else in anesthesiology, I will continue to err on the side of caution with this. I still think a catheter is overkill for this operation and needlessly complicates management, but hey, do what you feel like doing. I'm a "set it and forget it" kinda guy.

I still like doing my single shot at the end, since 1) the tourniquet could in theory spread the local proximal and knock out some motor fibers, and 2) I get a couple extra hours of analgesia doing it later.

I was at the ASA and while the ACB got a cursory mention here and there, it's not like there was a "OMGOMG ACB is da bomb for TKA" lecture, unless I missed it. I definitely heard nothing about ACB and tourniquets. What talk was that?
 
So while I wasn’t there, I’ve had several conversations over the last couple of days with a handful of colleagues who spoke to several of the lecturers about ACB in particular. Here is what the take home points were:

  • If you don’t want a motor block AND do not plan on placing a catheter, AC has proven to be an effective modality in combination with LIA. It is easy to perform, a lot more effective than originally thought, and very safe with regards to placement and motor weakness. Early and late ambulation scores are higher with ACB. Several large studies are ongoing. Some comparing LIA, LIA + AC and CFNB.
  • Femoral nerve blocks are excellent form of analgesia. As single shots, you will 100% of the time have quad weakness. Therefore, if early ambulation (POD 0) is part of your orthopedic post-op care, then quad weakness is something that will get in the way. The way around this is CFNB. CFNB can be dialed in with extremely low concentrations of LA that still provide effective analgesia and motor function. However, not all patients respond in the same way to a CFNB so not only are you committed to a catheter, but you likely will be in need of a pain service that can round on these patients and tweak their catheters as necessary. This depends on individual practices wether an AP service is feasible or not.
  • As reimbursement tightens and the possibility of bundled payments coming to your practice location, early ambulation and discharge will be goals of the hospital as insurance companies may or may not pay for longer hospital stays. This emphasis on early ambulation and discharge within a specific time frame might become more important over the coming years.
  • Although Exparel has gained a lot of attention, it’s duration of action doesn’t seem to be quite as long as some may think. After about 36 hours it can start to loose much of it’s analgesic properties in some patients. 3 days of analgesia is probably not the norm.
  • Regarding tourniquet and ACC, it was asked about at the end of one of the lectures. I think it was one that dealt with regional and neuropathy. Not sure. There are many orthopedic hospitals that have been doing this for the last couple of years. Persoanly, I don't find the need to do them pre-op.

So here is the way I see it:

IF you wave a dedicated regional team, CFNB might be best. However, there are some studies out there that actually conclude that ACC provide equal amount of analgesia with better ambulation. I'm not sure of this, but this doesn't apply to my practice.

IF you are like most groups and don’t have a dedicated regional team, a single shot ACB + LIA is a strong performer that is easy to place and has an excellent safety profile that is devoid of motor block (although some report that you can get the vastus- I have not seen this clinically). It also is not labor intensive in the sense that it does not require an AP service to round on them and maintain them.
 
There is no motor block after preop ACB in the holding area. I've performed almost a hundred ACBs preoperatively and not a single patient had a motor block in PACU despite the use of the tourniquest in the O.R.

Second, ACBs are not worth dog poop without good LIA; Pain scores are very high in the PACU after an ACB if no LIA Was utilized intraop. Hence, I'm still doing Femoral Blocks for about 1/2 the TKAs.
 
BLADEMDA said:
There is no motor block after preop ACB in the holding area. I've performed almost a hundred ACBs preoperatively and not a single patient had a motor block in PACU despite the use of the tourniquest in the O.R.

Second, ACBs are not worth dog poop without good LIA; Pain scores are very high in the PACU after an ACB if no LIA Was utilized intraop. Hence, I'm still doing Femoral Blocks for about 1/2 the TKAs.
Click to expand...

Do u mean u are still doing femoral blocks for 1/2 the TKA's because no LIA is done?

Or are you saying that the LIA is so poor in 1/2 the TKA's that the patients require femoral block?
 
excalibur said:
Do u mean u are still doing femoral blocks for 1/2 the TKA's because no LIA is done?

Or are you saying that the LIA is so poor in 1/2 the TKA's that the patients require femoral block?
Click to expand...

I'm saying that 1/2 the surgeons (older guys) don't use any local whatsoever so a Femoral block is required for postop pain control.
 
Standard O' Care Man ought to come talk to our orthopods. NONE of our TKAs get blocks. The ortho department here forbids it. They don't even like neuraxial opioids. They want zero motor block, and prefer to to do all their pain management themselves. I fought that culture for a couple years but now I just accept it.


I went to ''Regional Anesthesia and Patients With Neuropathy: Understanding the Risks to Enhance Safety" on the first day and don't recall a lot said about tourniquets, except just acknowledging that they're a risk factor and most nerve injuries are the surgeon's fault. I think two of the panelists talked about adductor canal blocks. What I remember most from that session was one of them arguing, pretty strenuously, that 4 mg of dexamethasone in a PNB was too much. He favored 25 of clonidine, 300 buprenorphine, 1 dexamethasone. Also a strong emphasis on reducing the LA dose in patients with diabetic neuropathy.

I think I'll stick with 4 mg dex and not play nausea games with bup. Anecdotally have never been real impressed with clonidine in a PNB.


I bet the risk is low but I wouldn't put a catheter under a tourniquet. I don't worry about a pool of local under a tourniquet, except that maybe with an ACB some of the local might get forced more proximal and get more motor fibers I was trying to avoid. In practice though my preop ACBs in patients who get tourniquets have good quad strength postop so I doubt that issue too.
 
Is there a risk for mechanical injury to the nerve from the catheter plus TQT? I'm still unclear why a catheter under a TQT would be risky
 
Hadzic is a leader in the field. I was fortunate to have met him for the first time when he came to our residency program as a guest speaker. That was probably 7-8 years ago. We exchange emails a couple times a year. His practice is different than say, my practice. He has a lot more man power than we do and he has a fully developed acute pain service. Honestly, to call CFNBs "standard of care" is not even close to being true. That would assume that the rest of the practices that don't place CFNBs are practicing substandard anesthesia especially with ACBs and LIA on the playing field.

What is true however, is that single shot femoral nerve blocks have a lot of negatives when you compare it to adductor canal blocks + LIA. Who here has taken a patient back to the OR because they fell after a femoral nerve block? I saw it in residency, and I've seen it here at our current practice. ACBs will not let you down in that way.

I'm really pumped for the research that will be coming out the next couple of years. I truly believe that CFNBs will not be as common as ACBs with LIA once the dust settles. The lack of quad weakness is such a positive when comparing FNBs to ACBs:

Replacing Continuous Femoral Nerve Blocks with Continuous Adductor Canal Blocks Within a Clinical Pathway for Total Knee Arthroplasty: A Case-Control Study of Postoperative Ambulation:

http://www.asra.com/display_spring_2013.php?id=59


p_579_00205.jpg



More to come. 😀
 
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