Lipid emulsion layering in extracorporeal membrane oxygenation circuit

Excerpt

Intravenous lipid emulsion is indicated in the treatment of local anesthetic systemic toxicity or management of lipophilic drug intoxications, including tricyclic antidepressants and calcium channel blockers when patients develop malignant arrhythmias. If lipid administration is unsuccessful, guidelines recommend extracorporeal membrane oxygenation (ECMO) until clearance of the responsible toxic agent is achieved. Layering is a phenomenon that results when the separation of intact fat emulsion from blood occurs in vitro within the ECMO circuit. Administering lipid emulsion is not without risk and may result in a circuit obstruction by fat emulsion agglutination, malfunction of the membrane oxygenator, and increased risk of blood clot formation. Layering is demonstrated in a patient placed under ECMO after administration of 20 mL/kg of lipid emulsion over a 60-min period for treatment of toxicity from ingestion of 10 g of Aconitum napellus, a toxic mid-altitude wild plant (Fig. 1). Administration of lipid emulsion is not without risk and the total dose should probably not exceed 10 mL/kg as layering in the ECMO or other complications may occur and jeopardize resuscitation.

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