Cardiac arrest after small doses ropivacaine: Local Anesthetic Systemic Toxicity in the course of continuous femoral nerve blockade

Background: The paper presents a case report of an episode of local anesthetic systemic toxicity (LAST) with cardiac arrest after continuous femoral nerve blockade in a 74-year-old female patient after elective total knee replacement surgery. Case presentation: A 74-year-old patient burdened with hypertension, osteoarthritis, underwent elective total knee replacement surgery (TKR). After surgery, a continuous femoral nerve blockade was performed and an infusion of a local anesthetics (LA) was started using an elastomeric pump. Five hours after surgery, the patient had an episode of generalized seizures followed by cardiac arrest. After resuscitation, spontaneous circulation was restored and the patient was transferred to the Intensive Care Unit. 20% lipid emulsion was used in the treatment. On day 2 of the ICU stay, the patient was fully cardiovascularly and respiratorily stable without neurological deficits and was discharged to the orthopedic department to continue treatment. Conclusion: Systemic toxicity of LA is a serious and potentially fatal complication of the use of LA in clinical practice. The incidence of LAST is underestimated, although in recent years there has been a significant decrease in the incidence of this serious complication. It should be noted that in nearly 40% of patients, LAST deviates from the classic and typical course and may have an atypical manifestation, and the first symptoms may appear with a long delay, especially when continuous blockades are used. Therefore, proper supervision of the patient and the developed procedure in the event of LAST is undoubtedly important here. If the first serious symptoms of LAST appear, current guidelines recommend early application of 20% lipid emulsion.