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:
- Administer 1.5 mL/kg as an initial bolus; the bolus can be repeated 1- 2 times for persistent asystole.
- 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
