title: Methemoglobinemia with the use of benzocaine spray for awake fiberoptic intubation.
abstract: We report a case in which the use of benzocaine spray to facilitate awake fiber optic intubation (FOI) in a patient with a difficult airway caused methemoglobinemia intraoperatively. Local benzocaine was sprayed to numb the patient's airway for a total time of one second, fifteen minutes later SpO2 decreased to 85% on the pulse oximeter. Arterial blood gas (ABG) showed a MetHb of 24.6% of total Hemoglobin. The patient was successfully treated with methylene blue intravenously and recovered uneventfully. Small amounts of local benzocaine sprayed to numb the airway can cause significant methemoglobinemia that requires immediate recognition and appropriate management.
authors.forename: Samer
authors.initials: S
authors.lastname: Abdel-Aziz
authors.forename: Nazish
authors.initials: N
authors.lastname: Hashmi
authors.forename: Sabina
authors.initials: S
authors.lastname: Khan
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ismaeil
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects*; D001566:Benzocaine / Q000008:administration & dosage / Q000009:adverse effects*; D001784:Blood Gas Analysis; D005260:Female; D005336:Fiber Optic Technology; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D008708:Methemoglobinemia / Q000139:chemically induced*; D014851:Wakefulness
chemical_list: D000779:Anesthetics, Local; D001566:Benzocaine