Intravenous lipid emulsion for local anaesthetic systemic toxicity in pregnant women: a scoping review

Background Local anaesthetic systemic toxicity (LAST) is a rare but life-threatening complication that can occur after local anaesthetic administration. Various clinical guidelines recommend an intravenous lipid emulsion as a treatment for local anaesthetic–induced cardiac arrest. However, its therapeutic application in pregnant patients has not yet been established. This scoping review aims to systematically identify and map the evidence on the efficacy and safety of intravenous lipid emulsion for treating LAST during pregnancy. Method We searched electronic databases (Medline, Embase and Cochrane Central Register Controlled Trials) and a clinical registry (lipidrescue.org) from inception to Sep 30, 2022. No restriction was placed on the year of publication or the language. We included any study design containing primary data on obstetric patients with signs and symptoms of LAST. Results After eliminating duplicates, we screened 8,370 titles and abstracts, retrieving 41 full-text articles. We identified 22 women who developed LAST during pregnancy and childbirth, all presented as case reports or series. The most frequent causes of LAST were drug overdose and intravascular migration of the epidural catheter followed by wrong-route drug errors (i.e. intravenous anaesthetic administration). Of the 15 women who received lipid emulsions, all survived and none sustained lasting neurological or cardiovascular damage related to LAST. No adverse events or side effects following intravenous lipid emulsion administration were reported in mothers or neonates. Five of the seven women who did not receive lipid emulsions survived; however, the other two died. Conclusion Studies on the efficacy and safety of lipids in pregnancy are scarce. Further studies with appropriate comparison groups are needed to provide more robust evidence. It will also be necessary to accumulate data—including adverse events—to enable clinicians to conduct risk–benefit analyses of lipids and to facilitate evidence-based decision-making for clinical practice.