Acquired methemoglobinemia: a rare but serious complication.

Topical and local anesthetics are employed during minor invasive procedures to increase patient tolerance and to reduce the need for intravenous sedation. A potentially fatal complication of these anesthetics is methemoglobinemia (Met-Hgb). Met-Hgb should be suspected in patients with cyanosis that does not respond to administration of oxygen and who have a discrepancy in oxygen saturation measured by pulse oximetry compared with the arterial partial pressure of oxygen (PaO2) determined by blood gas analysis. We present a patient who developed life-threatening Met-Hgb from the local anesthesia required during percutaneous endoscopic gastrostomy tube placement.