Incidence of Local Anesthetic Systemic Toxicity in orthopedic patients receiving peripheral nerve blocks
Eva E. Mörwald MD*†, Nicole Zubizarreta M.P.H‡, Crispiana Cozowicz MD*†, Jashvant Poeran MD PhD‡, Stavros G. Memtsoudis MD PhD FCCP*
Introduction: Peripheral nerve blocks are increasingly used. However, despite low complication rates1, concerns regarding local anesthetic systemic toxicity remain. Although recent studies suggest that this severe complication decreased considerably2, 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.
Material and Methods: After approval by the Institutional Review Board of Mount Sinai Medical Center and the Hospital for Special Surgery 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 was analyzed for ICD-9 CM 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.
Results: We identified N = 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
Discussion: The incidence of local anesthetic systemic toxicity is low but should be considered clinically significant. Since it may cause substantial harm to the patient3, appropriate resources and awareness to identify and treat local anesthetic systemic toxicity should be available wherever regional anesthesia is performed.
1. Sites BD, Taenzer AH, Herrick MD et al. Incidence of local anesthetic systemic toxicity and postoperative neurologic symptoms associated with 12,668 ultrasound-guided nerve blocks: An analysis from a prospective clinical registry. Regional anesthesia and pain medicine 2012;37:478-482.
2. Liu SS, Ortolan S, Sandoval MV et al. Cardiac arrest and seizures caused by local anesthetic systemic toxicity after peripheral nerve blocks: Should we still fear the reaper? Regional anesthesia and pain medicine 2016;41:5-21.
3. Vasques F, Behr AU, Weinberg G, Ori C, Di Gregorio G. A review of local anesthetic systemic toxicity cases since publication of the american society of regional anesthesia recommendations: To whom it may concern. Regional anesthesia and pain medicine 2015;40:698-705.