title: Pulse oximetry signals local anesthetic-induced methemoglobinemia.
abstract: An otherwise healthy patient with a fractured mandible was scheduled to undergo an open reduction under general anesthesia. Just before transport to the operating room, bimaxillary arch bars were placed under local anesthesia with 4% prilocaine and 1:200,000 epinephrine. Although induction of anesthesia and nasoendotracheal intubation were uneventful, pulse oximetry values fell to 89% despite adequate ventilation and an inspired oxygen concentration of 50%. Inquiry by the anesthesiologist and arterial blood gas measurements revealed that methemoglobinemia had developed in response to the large amount 576 mg) of prilocaine administered. A total of 150 mg of methylene blue administered in two doses corrected the problem. The oral surgeon, having recently switched to prilocaine because of a manufacturer's recall of lidocaine, was unaware of the potential of prilocaine to cause this disorder.
authors.affiliation: Department of Anesthesiology, Cook County Hospital, Chicago, Illinois 60612, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000766:Anesthesia, Dental / Q000009:adverse effects* / Q000379:methods; D000768:Anesthesia, General; D000772:Anesthesia, Local / Q000009:adverse effects* / Q000379:methods; D000779:Anesthetics, Local / Q000009:adverse effects*; D006801:Humans; D007431:Intraoperative Complications / Q000188:drug therapy; D008297:Male; D008337:Mandibular Fractures / Q000601:surgery; D008708:Methemoglobinemia / Q000139:chemically induced* / Q000188:drug therapy; D008751:Methylene Blue / Q000627:therapeutic use; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D010347:Patient Care Planning; D010348:Patient Care Team; D011318:Prilocaine / Q000009:adverse effects*
chemical_list: D000779:Anesthetics, Local; D011318:Prilocaine; D010100:Oxygen; D008751:Methylene Blue