Cardiac arrest during a sub-tenon block: a sign of acute lidocaine and bupivacaine toxicity

The neurologic and cardiac toxicities of local anesthetics lidocaine and bupivacaine have long been documented and can be potentiated by inadvertent systemic administration, pre-existing cardiac disease, shock states, and renal failure. We report a peculiar case of acute lidocaine and bupivacaine toxicity during orbital surgery in a woman with stable chronic systolic heart failure due to unexpected, rapid systemic absorption through a carotid-cavernous fistula. This case was marked by persistent bi-hemispheric coma, cardiac arrest, and ultimately death from repeated bradycardic pulseless electrical activity despite the presence of a functional cardiac pacemaker. Lidocaine and Bupivacaine toxicities are discussed as well as complications of orbital surgery which may mimic them. Correspondence to: Luke Masha, Internal Medicine, Boston University, 72 East Concord Street, Evans 124, Boston, MA 02118, USA, Tel: 617-638-6500; Fax: 617-638-6501; E-mail: [email protected]