Inadvertent intravascular injection of local anesthetics (LA) during regional anesthesia causes Local Anesthetic Systemic Toxicity (LAST). Theories of lipid rescue in the case of LAST proved that the administration of lipids in LAST has beneficial effects. One possible mechanism of action is based on the lipophilic properties of LA which allow plasma-free LA to be bound by the molecules of Lipid Emulsion (LE). The association LA-LE is shuttled towards organs such as liver and the kidneys, and the half-life of LA is shortened. The main objective of this experimental study was to assess the possible cardio-prophylactic effect of LE administration before the induction of LAST by intravenous administration of Ropivacaine. This was an experimental, interventional, prospective, and non-randomized study. The subjects were divided into groups and received, under general anesthesia, LE 20% first 0.3-0.4 mL, followed by 0.1 mL Ropivacaine 2 mg/mL, or Ropivacaine alone. At the end of the experiment, the subjects were sacrificed, and tissue samples of kidney, heart and liver were harvested for histopathological examination. LE, when administered as prophylaxis in Ropivacaine-induced LAST, had protective cardiac effects in rats. The LE known side effects were not produced if the substance was administered in the low doses used for LAST prophylaxis.
Keywords: lipid emulsion; local anesthetic systemic toxicity; morphopathology; protective effect; ropivacaine.