"The French Connection"
Following a thread on an Internet Discussion Group, I contacted one of the individuals on the list, Dr. Xavier Ledoux, who sent me some based interesting information on a number of regional anesthesia techniques.
The single shot ISB with mutiple days of analgesia
Paravertebral blcoks
The single shot ISB with mutiple days of analgesia
"Typically I would use a mix of a fast-taking / short acting agent, and a slow taking / long lasting agent, as the main LA mix :
1) in each of two 20 ml syringes, I put 10 ml of each drug, so the total amount is 40 ml of the mix. I add to each 20 ml vial
1 ml of the adjuvant drug, eg 1 ml = 300 mcg buprenorphine and 1 ml = 150 mcg clonidine. + sometimes epinephrine,
200 mcg mixed with the 40 ml (which makes a "4 thirds cocktail", 43 ml
instead of 40.) according to the patient's weight,
BMI, morphology... and to the surgery I'll inject 25-40 ml.
2) I always try and keep some spare LA mix, in order to improve
the block if it's not taking fast and well enough. The LA mixes can be (whatever you like, in fact, this is what I've been
using currently - always 2 times 10 + 10 ml) :
a) 2% Lido + 0.5% bupi ;
b) 2% lido + 0.75% ropi ;
c) 1.5% lido ;
d) 2% mepi + 0.5% ropi ;
e) 2% mepi + 0.75% ropi
with such concentrations you get a phrenic motor blockade, very often, not to say always. (in prehospital situations such as mountain rescue, and to replace shoulder dislocations, I only use 1% lido or mepi, 10-12 ml, which do respect the phrenic motor function.)
<snip>
I don't use a nerve locator, but I do palpate the region very
cautiously, in order to perfectly localize the scalene muscles and
the plexus. after injecting the first 4-5 ml I leave the needle in place
but stop injecting, and wait for the patient to have an objective
loss of thermal sensitivity in C5 (external aspect of the shoulder). If
it's quickly achieved I keep on injecting. If it is not frank after
5 minutes something's wrong (improper injction site) and the needle must be replaced
In most of my painful shoulder operations, this 4 or 5-drug scalenic
block is enough, together with a minor pain-killer such as
oral acetaminophen, to allow early mobilization and rehabilitation with mepi + ropivacaine + clonidine + buprenorphine, with or without epinephrine, you can expect, after 5 to 30 minutes, a
surgical anesthesia which lasts 10 to 16 hours, and the residual
analgesia does cover several days. That's why I gave up on
placing catheters in most peripheral blocks. except in fascia iliaca
blocks, maybe the dilution space is too wide to allow a very
long action of the LA mix ? and in "special" indications, such as cancer pain.
Dr. Leboux sent me the following pictures on the fascia iliaca. This method, using a Tuohy needle that allows you can feel the pops better, and aiming it up with a 45 degree angle makes it far easier, as it increases the distance between the fibrous planes. This loss of resistance technique was described by good friend Dr. Yves Jullien). "The secret is, naturally, to be in the proper anatomic plane..."
I has some futher technical questions including advancing the needle following the second "pop". His response was:
"I don't, at all. the trick is to inject 20 ml of *fluid* prior to place
the cath, this fluid will open the proper space. There's a byzantine
debate :either you inject your LA first. My most frequent choice, as I do have some experience with this block, and am seeking a fast-actinganalgesia if it's a trauma patient (as opposed to elective knee surgery); there's a (theoretical) risk of misplacing your cath (practically this is not actually relevant, as your cath is not forced up, so it can only go into the previously water-dissected space. Or you are an anxious guy,expecting several days of LA infusion, in a previously painless patient. Inject 20 ml *isotonic* saline in order to force your space open. Then, only after the cath has been pushed up, you'll inject your LA : if you get a proper analgesia, this proves that your cath is properly placed,period. (NEVER hypotonic solutions, especially plain water, in peripheral anesthesia, for dilutions, testing, washing a catheter, etc... severe sepsis has been reported, due to extended tissular necrosis)"
