Drug Induced Methemoglobinemia

The normal presentation of a patient with a drug induced methemoglobinemia is a low pulse oximetry (SpO2) reading, usually in the mid 80% range, while having a very high PaO2 on an arterial blood gas (ABG)1. We present a case where the initial ABG showed a very high PaO2 and a metabolic alkalosis while the SpO2 fluctuated (85%- 99%). Those findings combined with hemodynamic instability complicated the diagnosis and delayed optimal care.