Current evidence is not in support of lipid rescue therapy in local anaesthetic systemic toxicity.

It is now 10 years since the first case reports of the use of intravenous lipid emulsion (ILE) as treatment for local anaesthetic systemic toxicity (LAST). In spite of very scarce data on efficacy, safety and mechanism of action, this novel therapy was enthusiastically adopted by anaesthesiologists, clinical toxicologists and emergency medicine physicians worldwide. However, recent thoroughly performed systematic reviews, preceded by the description of the applied methodology, suggest that reliable evidence in support of the usefulness of ILE in LAST or non-local anaesthetic poisonings is still not available. While there seem to be some anecdotal indications which might suggest potential benefits of ILE in LAST, the evidence is quite heterogenous (very low quality), and so far the usefulness of ILE in LAST is unproven. The human data on ILE in LAST consist only of some 70 positive case reports, plus one small human volunteer case series, and no randomized and controlled studies in patients. The number of case reports with no effect of ILE represents only about 5% of all case reports of the use of ILE in LAST suggesting a strong publication bias. Animal studies are also nonsupportive regarding the usefulness and success of ILE therapy since effective doses of ILE in experimental animals need to be much higher than the guideline recommended doses for patients, i.e., an initial bolus of 20% Intralipid (Fresenius Kabi AB, Uppsala, Sweden) 1.5 ml/kg followed by an infusion of 0.25 ml/kg/min for 30 min, with additional boluses up to a total amount of 10 ml/kg (American Society of Regional Anesthesia and Pain Medicine) or 12 ml/kg (Association of Anaesthetists of Great Britain and Ireland). In fact, the high doses (volumes) of 20% or 30% Intralipid in animal studies would be impossible to administer rapidly enough to a human patient, and would violate profoundly the pharmacopoeial recommendation of intravenous nutritional lipid emulsion administration, both regarding dose and rate of administration; the risk of adverse effects of ILE would rise. The adverse effects of ILE (Intralipid ) in treatment of poisonings have been largely ignored. In healthy human volunteers, who have received ILE according to current guideline recommendations, adverse reaction have been very rare and mild. In patients occasionally very severe complications have been observed, such as pancreatitis and ARDS. Rapid intravenous lipid emulsion infusion may also result in a complex fat overload syndrome. Acute hypersensitivity reactions (soy allergy), known from reports of