02 Oct 12

Lipid emulsion infusion: resuscitation for local anesthetic and other drug overdose

Posted in Regional anaesthesia, Resuscitation at 1:07 by Laci

By G L Weinberg

Anesthesiology 2012;117:180–187

IT seems implausible that an injection of a simple, off-the-shelf, intravenous nutritional solution could be acutely life-saving for a patient with severe drug overdose. But dozens of published case reports support this observation, first made more than a decade ago in a rodent model of bupivacaine toxicity. It is even more surprising that such a simple formulation can rapidly reverse severe clinical toxicity from a variety of vastly disparate medications with distinct pharmacodynamics and mechanisms of action. This review will focus on the clinical application of lipid emulsion therapy in resuscitation from drug-related toxicity and will provide an introduction to the development of the method, guidelines for its use, and insights into potential controversies and future applications.

Background
Weinberg et al. first showed in 1998 that an infusion of a soybean oil emulsion normally used as a total parenteral nutrition solution could prevent (by pretreatment) or improve resuscitation from cardiovascular collapse caused by severe bupivacaine overdose in the intact, anesthetized rat. Subsequent studies from the same laboratory confirmed these findings in isolated rat heart and anesthetized dog. Under the latter experimental model, return of spontaneous circulation after a bupivacaine challenge occurred in all animals receiving lipid, but in none of the saline controls. This study was accompanied by an editorial asking whether lipid might be the long-sought “silver bullet” for local anesthetic systemic toxicity (LAST). Since then, the effectiveness of lipid emulsion infusion in reversing LAST has been confirmed in other laboratories and by systematic analysis4 in the clinical setting, as well.

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