- 期刊
使用Benzocaine局部麻醉導致變性血紅素血症－病例報告
Methemoglobinemia Induced by Topical Benzocaine-Case Report
摘要
局部麻醉藥所導致之變性血紅素血症(methemoglobinemia)是一種不常見但容易致命的併發症，診斷有賴於臨床線索及高度的警覺心。本病例報告爲30歲女性患者，因車禍造成下顎骨骨折而接受開放式復位手術治療。全身麻醉採用插管前給予20%胺基苯甲酸乙酯(Benzocaine)局部噴劑於口腔與鼻孔黏膜。完成插管後約15分鐘，病人出現嘴唇與四肢末端發紺的情形，此時脈搏血氧飽和度(SpO2)降至約74%，但動脈血氧分析卻發現其脈搏血氧分壓(PaO2)爲406毫米汞柱(mmHg)，動脈血氧飽和度(SaO2)爲100%。在懷疑是表面麻醉藥所引發之變性血紅素血症，以一氧化碳測氧器(CO-oximetry)檢驗變性血紅素濃度(Methemogiobin concentration)高達25.9%。在一小時後，其持續升高至39.6%。於是經靜脈給予甲基藍(methylene blue)50毫克。期間病人之血行動力學並與顯著變化，在八小時後，變性血紅素濃度降至0.3%，趨於正常。要診斷因使用局部噴劑式麻醉劑引起變性血紅素血症併發症的重要因素，包括檢驗變性血紅素濃度，分數氧氣飽和度降低與氧化劑接觸史等最具診斷價值。靜脈給予甲基藍是治療此併發症的首選藥物。
並列摘要
Methemoglobinemia, although uncommon, is a potential life-threatening complication of local anesthetics. It could be diagnosed by paying careful attention on clinical signs. We identified the case of a 30-year-old female who received open reduction with intermaxillary fixation for mandible fracture caused by a traffic accident. Before the use of general anesthesia, 20% Benxocaine was locally sprayed in patient's oral and nasal cavity. Fifteen minutes later, cyanosis on lips and extremities occurred and SpO2 fell to around 74%. But high PaO2 (406 mmHg) and SaO2 (100%) were read by arterial blood gas analysis. Therefore, acute methemoglobinemia caused by local anesthetics was highly suspected. The diagnosis was confirmed by CO-oximetry, which methemoglobin concentration was examined as high as 25.9%. One hour later, 50 mg of methylene bule was used because methemoglobin concentration was up to 39.6%. During the treatment, we did not observe significant change in patient's hemodynamics. Eight hours later, methemoglobinemia was resolved gradually to 0.3%, back to normal status. In conclusion, for the complication of methomoglobinemia caused by local anesthetics, the most valuable factors for diagnosis are examing methemoglobin concentration, lowering fractional oxygen saturation, and identifying oxidant history. Meanwhile, intravenous administration of methylene blue is the choice for treatment.