Prilocaine‐Induced Methemoglobinemia During Surgically Assisted Rapid Palatal Expansion (SARPE) Under General Anesthesia: A Case Report

Methemoglobinemia is a condition in which methemoglobin levels in the blood increase. Methemoglobin lacks oxygen-binding ability, resulting in oxygen deprivation in tissues. This high level of methemoglobin in the blood presents as a severely worsening condition. Herein, we report a case of methemoglobinemia caused by the administration of 3% prilocaine hydrochloride containing 0.03 IU/mL feripressin as a local anesthetic during orthognathic surgery. Following drug administration, the patient's atrial oxygen saturation (SpO₂) decreased. We diagnosed methemoglobinemia based on arterial blood gas analysis, which revealed an increased level of methemoglobin. To maintain the SpO₂ level, oxygen was administered. The patient's condition improved over time. Careful monitoring and maintenance of SpO₂ levels are essential to ensure proper diagnosis and effective management.