Methemoglobinemia after axillary block with bupivacaine and additional injection of lidocaine in the operative field.

Methemoglobinemia may occur after the administration of various drugs, including some local anesthetics. We report a patient with chronic renal failure and ischemic heart disease who developed clinically significant methemoglobinemia after an axillary block with bupivacaine and additional injection of lidocaine in the operative field. Although the two local anesthetics usually do not cause methemoglobinemia, we suspect that the displacement of lidocaine from protein binding by bupivacaine, in combination with metabolic acidosis and treatment with other oxidants, was the reason for the development of methemoglobinemia.