Apparent local anesthetic systemic toxicity following activation of an epidural catheter for cesarean delivery: diagnosis and management of an uncommon obstetric anesthesia complication.

We present a 25-year-old, gravida 2, para 1 woman who developed apparent local anesthetic systemic toxicity (LAST) following activation of an epidural catheter for an urgent cesarean delivery. The patient had a height of 150 cm, weight of 92 kg, body mass index of 41 kg/m², and calculated ideal body weight of 40 kg. A combined spinal epidural anesthetic was placed and the spinal component did not provide anesthesia to clamping of the abdomen. Subsequently, 300 mg of lidocaine was administered through the epidural catheter in three 5 mL doses over 8 minutes and surgery commenced. Approximately 30 minutes following the final 5 mL dose of epidural lidocaine, the patient had progressive loss of consciousness and was difficult to arouse. A presumptive diagnosis of LAST was made, and 60 mL of 20% intravenous lipid emulsion was administered. The patient's mental status improved to baseline within 5 minutes of lipid emulsion administration, and she made a complete recovery. Anesthesiologists should consider using ideal body weight when calculating the maximum dosage of local anesthetics, and LAST should be part of the differential diagnosis when patients have altered mental status in the setting of local anesthetic administration that exceeds recommended dosages.