Patient with Persistent Low Oxygen Saturation for Emergency Cesarean Section.

A 24-year-old woman with previous undiagnosed congenital methemoglobinemia presented for the emergency cesarean section in view of fetal distress. The patient had a persistent low oxygen saturation on pulse oximetry with normal heart rate and blood pressure. Arterial blood gas values were normal. The patient was asymptomatic and respiratory and cardiovascular system examination was normal. The patient underwent cesarean section under general anesthesia and was shifted to the Intensive Care Unit postoperatively. The oxygen saturation was low throughout the intraoperative and postoperative period. A complete evaluation was done postoperatively. Mass spectrophotometry was done, which confirmed methemoglobinemia in the patient.