Supraclavicular Block Questions

[kmurp]

I wonder if you all could chime in on a couple/three questions I have on SCB?
1. Do you all inject into the epineurium of the brachial plexus or just surround it? The block seems to set up better injecting into it but I worry about nerve damage.

2. If you see an areterial structure (transverse cervical artery?) in your field, down low, do you abandon this approach and go infraclavicular?

3. Lastly, I sometimes have trouble with the needle angle in getting the tip above the main brachial plexus bundle (superficial to it). My needle angle seems to want to direct me directly at it. Is there something different that I should be doing?

Thanks

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[dhb]

1. into the sheath
2. not necessarily i'll go a little higher or lower
3. don't know

 

[BLADEMDA]

I wonder if you all could chime in on a couple/three questions I have on SCB?
1. Do you all inject into the epineurium of the brachial plexus or just surround it? The block seems to set up better injecting into it but I worry about nerve damage.

2. If you see an areterial structure (transverse cervical artery?) in your field, down low, do you abandon this approach and go infraclavicular?

3. Lastly, I sometimes have trouble with the needle angle in getting the tip above the main brachial plexus bundle (superficial to it). My needle angle seems to want to direct me directly at it. Is there something different that I should be doing?

Thanks

1. Never! I never inject into the epinerium if at all possible. It may take 20-30 minutes for the block to setup but injection into the Epineurium is a bad idea and unnecessary for a successful block.

2. No. I will work around any blood vessels as needed. I've never abandoned the block.

3. Practice. Sometimes by moving the probe so it is off angle to the clavicle the injection is easier to do.

 

[BLADEMDA]

Anesth Analg. 2014 May;118(5):1120-5. doi: 10.1213/ANE.0000000000000155.
Ultrasound-guided supraclavicular brachial plexus block: single versus triple injection technique for upper limb arteriovenous access surgery.
Arab SA1, Alharbi MK, Nada EM, Alrefai DA, Mowafi HA.
Author information

Abstract
BACKGROUND:
Although ultrasound-guided supraclavicular block has a good success rate, it remains unclear whether multiple injections are superior to single injection (SI). We compared the sensory block success rate of SI versus triple injection (TI).

METHODS:
In this randomized double-blind study, 96 end-stage renal disease patients undergoing arteriovenous fistula creation or superficialization were randomly allocated to receive either SI or TI. The primary outcome was the combined score of sensory blockade of the 5 nerves (median, ulnar, radial, medial cutaneous nerve of the forearm, and musculocutaneous) measured at 5, 10, 15, and 20 minutes after injection. Secondary outcome variables were the time to onset of the blockade, performance time (time to do the block), separate success rate for each of the above nerves, success rate of surgical anesthesia, and the complication rate.

RESULTS:
The combined success of the sensory block was 20% to 31% higher in the TI group than in the SI group at 10, 15, and 20 minutes after injection (all P < 0.035). The block of the musculocutaneous nerve in the TI group was faster and more successful than in the SI group, at all time points (all P < 0.026). The average time needed to perform the block was significantly longer in the TI than the SI group (6.5 ± 2.1 vs 4.7 ± 2.1 minutes, P = 0.001). The overall success of surgical anesthesia measured at 30 minutes did not differ significantly between the 2 groups (96% in TI vs 87% in SI, P = 0.253).

CONCLUSIONS:
Although the performance time of the SI technique was shorter, TI had a faster onset and resulted in a more successful block of all nerves in the first 20 minutes.

 

[BLADEMDA]

 

[BLADEMDA]

I usually align the probe off angle from the clavicle for my triple injection technique.

 

[BLADEMDA]

 

[BLADEMDA]

 

[BLADEMDA]

I don't usually turn the probe this much off axis from the clavicle. But, the point here is try changing the probe axis a bit like my previous picture(post7) and see if this helps you. I've found that by performing blocks with various techniques, probe rotations etc, you develop a good idea what works well in your hands.

 

[DreamLover]

I wonder if you all could chime in on a couple/three questions I have on SCB?

1. Do you all inject into the epineurium of the brachial plexus or just surround it? The block seems to set up better injecting into it but I worry about nerve damage.

I never inject into the epineurium. Why risk it? Wait the extra 10 mins it might take to set up and be safe. Maybe I'm conservative but it's extremely successful when you don't do that so to me, the reward does not outweigh the risk.

 

[kmurp]

Thank you for your replies. I was at an umltrasound course a few years ago and complained to the attending teaching the SCB station that at imps, my block seemed “weak” and took forever to set up. She told me to injuct into the epineurium, but, like you guys, I’m a bit concerned about nerve damage.

 

[okayplayer]

Thank you for your replies. I was at an umltrasound course a few years ago and complained to the attending teaching the SCB station that at imps, my block seemed “weak” and took forever to set up. She told me to injuct into the epineurium, but, like you guys, I’m a bit concerned about nerve damage.

How would you know you were in epineurium? Hard to inject? It's a little tough for me to tell the difference between my needle tip being very near the plexus and epineurial.

 

[dhb]

There is a difference between the plexus's sheath and the individual nerve's epineurium...

 

[kmurp]

There is a difference between the plexus's sheath and the individual nerve's epineurium...

I feel dumb… I guess that I’ve been injecting into the sheath.

 

[BLADEMDA]

I feel dumb… I guess that I’ve been injecting into the sheath.

I'd rather inject 0.5-1.0 mls of local accidentally into the Epineurium than seek it out and inject 5,10 or even 15 mls.

Remember, the SCB has a lot of nerves in a small area so incremental movements with the needle combined with careful, low volume injection under low pressure will help reduce the chance of an intraneural injection.

The Main reason I use a nerve stimulator at all these days is to make sure I am not injecting local with a twitch response less than 0.5. I prefer 0.6 or even 1.0 as this reduces the incidence of intraneural injection when combined with u/s visualization of the needle tip and low pressure injection technique.

 

[okayplayer]

I have a question for you guys in private practice. I presume you have an assistant (RN I presume?) injecting for you if you have one hand on the needle and one hand on the probe...how can you tell how much resistance there truly is to injection? Do you just have to hope your assistant can recognize too much resistance and tell you to slightly reposition your needle?

I have on a few occasions put a 20cc syringe directly on the block needle but I find it a bit cumbersome to maintain needle position where I want while aspirating/injecting myself with the same hand.

Something I've been wondering since I am just finishing residency and most of my blocks have been with the attending pushing the local for me. (this will change in about a week and I need to develop a good system)

 

[BLADEMDA]

I have a question for you guys in private practice. I presume you have an assistant (RN I presume?) injecting for you if you have one hand on the needle and one hand on the probe...how can you tell how much resistance there truly is to injection? Do you just have to hope your assistant can recognize too much resistance and tell you to slightly reposition your needle?

I have on a few occasions put a 20cc syringe directly on the block needle but I find it a bit cumbersome to maintain needle position where I want while aspirating/injecting myself with the same hand.

Something I've been wondering since I am just finishing residency and most of my blocks have been with the attending pushing the local for me. (this will change in about a week and I need to develop a good system)

You need an RN who does blocks regularly so he/she develops a "feel" for the correct pressure. If the RN needs to push harder than usual consider moving your needle tip.

I trained several RNs to get a feel for the correct pressure by having them inject into a non neural area with D5W or saline. This trains them to get the correct feel. Once you get near a nerve you can inquire about any increased resistance compared to the other non neural areas. Over time the Nurse gets very good at judging the pressure.

 

[B-Bone]

left hand on US. right hand on needle. place needle appropriately. Let go of needle with right hand. Inject with right hand under live US guidance. The needle isn't going anywhere.

 

[okayplayer]

left hand on US. right hand on needle. place needle appropriately. Let go of needle with right hand. Inject with right hand under live US guidance. The needle isn't going anywhere.

Even for superficial blocks like ISBs (even a femoral NB)? I mean, sure for a popliteal approach sciatic where the needle is embedded in a bunch of muscle. For really superficial blocks I'm not so sure. I guess using the 50mm needle helps too.

 

[RxBoy]

left hand on US. right hand on needle. place needle appropriately. Let go of needle with right hand. Inject with right hand under live US guidance. The needle isn't going anywhere.

Do the same. I advance catheters in the IS same approach. Let go touhy, advance catheter half a cm see it exit on the US, let go catheter and hold touhy, put ultrasound down and carefully remove tuohy. Bolus through catheter and watch with US. I try to do everything independently.

 

[dhb]

I never have someone inject for me.

 

[cowbydoc]

Don't risk causing problems to someone's nerve, don't inject into the epineurium, nerve sheath or whatever. I have permanent nerve damage from a block and it sucks and I will never risk someone else's well being to save a couple of minutes.

 

[dhb]

Don't risk causing problems to someone's nerve, don't inject into the epineurium, nerve sheath or whatever. I have permanent nerve damage from a block and it sucks and I will never risk someone else's well being to save a couple of minutes.

If you're not injecting into the supra-clav sheath you're going to be waiting a lot more than a couple of minutes. I'll even bet that outside of it you must stimulate a more than 1.5mA to get a twitch

 

[pjl]

Either inject yourself or get a block nurse, who will obtain meds, equipment, chart vitals, prep site +/-ultrasound, sedate patient and inject for you. New nurses suck and if I can't inject myself or with one of the regulars I will accept and aim for a further distance from nerve. They aren't that hard to train right unless you partners are telling them something different. I always make it my goal to be the "nice" one that the new nurses are started with, so they learn the (my) right way.

 

[BuzzPhreed]

Hard to inject and/or injection pain is a sure sign. Also if you stim and are getting a robust twitch below 0.3 mA you are way too close. Just pull back slightly, re-aspirate, and inject there. It will get where it needs to be. There's no block that needs to set-up in 30 seconds or less.

While not a supraclavicular I just did an axillary block a few days ago on a patient who was having a bone lesion removed from her distal radius. I easily pegged the median and radial nerves with the ultrasound, as well as ulnar and musculocutaneous though not as robustly on the stim, and by the time I finished the block until she was in the room and had her incision there was plenty of time for the block to set up. The CRNA called me to the room as they were draping and asked, "Are you sure she doesn't need an LMA?" Patience, grasshopper. Well she laid there wide awake enduring the tourniquet on her forearm and everything. She went straight from the OR to Stage II recovery and home. Nothing like a satisfied customer.