Methemoglobinemia should be suspected when oxygen saturation apparently decreases after prilocaine infiltration during intravenous sedation

Abstract

During intravenous sedation, a decrease in SpO2 is usually the result of respiratory failure. However, we experienced a case with SpO2 decrease that was caused by methemoglobinemia in prilocaine infiltration anesthesia during sedation. This indicates that methemoglobinemia should be considered if low SpO2 is sustained unrelated to sedation level.