Peripheral nerve blocks are regional anaesthesia which are injected near a specific nerve or bundle of nerves to block sensations of pain from one particular area of the body, which usually last longer than local anaesthesia. The clinical significance of local anaesthetic systemic toxicity (LAST) has been well explained in this study, which provided useful results.

Peripheral nerve blocks are increasingly used. However, despite low complication rates, concerns regarding local anesthetic systemic toxicity remain. Although recent studies suggest that this severe complication has decreased considerably, there is a paucity of data about it on a national level. We sought to elucidate the incidence of local anesthetic systemic toxicity on a national level and therefore provide guidance toward the need for preparedness in daily anesthetic practice.

We searched a large administrative database for patients who received peripheral nerve blocks for total joint arthroplasties from 2006 to 2014. Their discharge and billing data were analyzed for International Classification of Diseases, Ninth Revision, Clinical Modification codes coding for local anesthetic systemic toxicity or surrogate outcomes including cardiac arrest, seizures, and use of lipid emulsion on the day of surgery. Rates for these outcomes were determined cumulatively and over time.

We identified 238,473 patients who received a peripheral nerve block within the study period. The cumulative rate of outcomes among these patients in the study period was 0.18%. There was a significant decrease of overall outcome rates between 2006 and 2014. Use of lipid emulsion on the day of surgery increased significantly in total knee replacement from 0.02% 2006 to 0.26% in 2014.

The incidence of local anesthetic systemic toxicity is low but should be considered clinically significant. Since it may cause substantial harm to the patient, appropriate resources and awareness to identify and treat local anesthetic systemic toxicity should be available wherever regional anesthesia is performed.