Category: Regional Anesthesia

Journal Watch: Local Anesthestic Toxicity and Lipid Rescue

The toxicity of local anesthetics makes many a sphincter clench, especially for those of us who routinely practice regional anesthesia.  The advent of lipid rescue by Dr Weinberg and colleagues, has been a tremendous advance in the safety of regional anesthesia.  Dr Weinberg has established the excellent registry of cases over at Lipid Rescue.org

The advances keep a-happenin as they say.  It is a relatively new area of study one not amenable to randomized controlled trials in humans…hard to tell the IRB that the control group gets sugar water after a mega-dose of bupivicaine.   Therefore, most new data comes from our friends at the bench.  This months Anesthesiology further adds to our knowledge base on this topic.  Researchers in the U.K. analyzed the difference between mixed (medium- and long-chain) and long-chain lipid emulsions, for their ability to extract local anesthetic from serum.  They concluded that the type of emulsion may make the reversal more effective:

Lipofundin®, a lipid emulsion containing 50% each of medium-and long-chain triglycerides, sequestered all three drugs to a significantly greater extent than Intralipid® (long-chain triglycerides only) from human serum, which is in contrast with previous studies describing extraction from a buffer solution. These findings call into question the current advanced cardiac life support guidelines specifying use of a long-chain triglyceride emulsion for lipid rescue,23 although further in vivo studies that confirm a significant improvement in resuscitation from local anesthetic toxicity with Lipofundin® are obviously required before drawing any confident conclusions.

In case you ended up here at this post in an emergency, or just want a refresher the protocol is as follows (from lipidrescue.org):

20% Intralipid:

  1. Administer 1.5 mL/kg as an initial bolus; the bolus can be repeated 1- 2 times for persistent asystole.
  2. Start an infusion at 0.25 mL/kg/min for 30-60 minutes; increase infusion rate up to 0.50 mL/kg/min for refractory hypotension.

or you can print it out here.  ASRA pdf version of protocol here.

Update 1/31/12.

Thanks to Dr Patel for bringing the “Lipid ALS” app to my attention.  We may get around to a full review but from the screenshots its seems worth the price:


Image: digitalart / FreeDigitalPhotos.net

 

 

Jan 29, 2012 | 0 comments View Post

NYSORA 10th Annual Winter Symposium – The Recap

NYOSRA’s 10th annual winter symposium recently wrapped up in New York City.  In what apparently was record attendance, the conference was an important update in the world of regional anesthesia and was attended by yours truly. 

For those who don’t know, the NYSORA conference is held every winter in NYC and focuses on regional anesthesia and pain medicine.  The majority of attendees register to learn the latest and greatest in regional anesthesia.  I attended the hands-on workshops in the past and they are a great introduction to regional anesthesia for those with little or no experience in regional anesthesia.  There were also two sets of lectures.  One set focused on the basic science of the blocks and the other side on the latest research.

The sessions regarding the latest from academia were hit or miss as many of theses conferences tend to be.  My take home points are as follows:

  • The euphoria behind continuous catheters may be on the wane as their is little hard evidence at the moment of improved outcomes
  • Ultrasound is a nice tool and might help lower amount of local used but nerve stim just as good.
  • Exparel might very well be the game changer I half-jokingly said it’d be
  • Epidurals for unilateral TKR aren’t worth the complications if you are blocking the femoral nerve anyway
  • Multimodal good, esp Acetaminophen.
  • Don’t skewer the nerve with your block needle (duh).
  • Times Square around the holidays is a NIGHTMARE

There you have it, a six bullet point summary of the NYSORA conference…sorry no CME offered.  Anyone attend and want to chime in?  Comments are open.

Dec 19, 2011 | 0 comments View Post

The end of catheter-based continuous nerve blocks?

Continuous nerve block techniques have become part of the mainstream of regional anesthesia practice.  The placement of a perineural catheter infusing the dilute local anesthetic cocktail du-jour, undoubtedly leads to a reduction in postoperative pain scores, opiod-sparing effects and increased patient satisfaction…amongst other things.  A nice review appeared this past October in Anesthesia & Analgesia here (subscription required for full-text).

So why would we want to change this oh-so-wonderful technique?  For one, catheter-based techniques require skill.  Not everyone who can do single-shot  nerve blocks can place catheters successfully, and many aren’t willing or able to learn.  Secondly, catheters require close follow-up and not every practice has the resources to devote to the endeavor.

What if we could do a single-shot technique and have the local anesthetic last longer or as long as a catheter technique?  Enter EXPAREL.  Exparel is a 1.3% solution of bupivicaine in a liposomal suspension designed to extend the duration of action of bupivicaine to around 72 hours.

From Medscape:

Eugene R. Viscusi, MD, director of acute pain management at Thomas Jefferson University in Philadelphia, Pennsylvania, told Medscape Medical News that this product is “definitely novel, and there is a tremendous need for more nonopioid analgesics as we attempt to limit or reduce opioids because of their side effects and risks. Long-acting agents are particularly desirable because they provide less-complicated, prolonged pain relief for an extended period.”

Current local anesthetics, Dr. Viscusi explained, have a duration of action less than the pain duration of most procedures, leading to pain later or to the need for cumbersome indwelling catheter and pump delivery systems for these drugs.

As it stands now the medication was approved for subcutaneous infiltration only and seems to have been only studied in butts and toes so the leap to continuous catheters is admittedly a big one.  I see this going the way of Depodur, the morphine formulation using the same technology…nice idea but not worth the cost or the lack of control a catheter gives you.  Looking forward to the research.

Image: dream designs / FreeDigitalPhotos.net

Dec 04, 2011 | 0 comments View Post

Epidurals, fun to do and good for you too!


As any 38-weeker 7 cm dilated with contractions q4min can tell you….epidurals rock. What hasn’t been as obvious in clinical practice and in the literature, is their effects in the general surgical population. The blunting of the sympathetic response, opiod-sparing effect and earlier return of bowel function have been well documented. This month an article in Anesthesiology provides an interesting observation about the slinky plastic catheter:


From Anesthesiology:


Anesthetic Technique for Radical Prostatectomy Surgery Affects Cancer Recurrence: A Retrospective Analysis

We evaluated cancer recurrence in men undergoing radical prostatectomy. After adjustment for confounding factors, patients who received general anesthesia combined with epidural analgesia had a 57% (95% CI, 17-78%) lower risk of cancer recurrence than patients who had general anesthesia and postoperative opioids. A propensity-matched analysis on a subset of the data gave a similar result: Epidural analgesia had a 52% (95% CI, 0-77%) lower risk of cancer recurrence.

While this study had some notable limitations, the potential benefit in outcomes is darn compelling.

Aug 28, 2008 | 0 comments View Post