BheemReddy Swarnalatha, Messineo Frank, Roychoudhury Debasish
Department of Internal Medicine, New York Hospital Queens, Flushing, New York, New York 11355, USA.
Echocardiography. 2006 Apr;23(4):319-21. doi: 10.1111/j.1540-8175.2006.00159.x.
Benzocaine (ethyl aminobenzoate) is a topical anesthetic widely used for oropharyngeal anesthesia prior to transesophageal echocardiography (TEE). Topical anesthetics have been reported to cause methemoglobinemia, but this adverse event is extremely rare and has not been listed as one of the possible complications of TEE. However, recently the number of published case reports of TEE-associated methemoglobinemia has increased. Since its first description in 1950, 65 cases of methemoglobinemia have been reported including a recent report of five cases from a single center. Physicians who are not familiar with the association of TEE with benzocaine-induced methemoglobinemia may not recognize the idiosyncratic and often nonspecific characteristic of this condition. Recognition is critical, however, since left untreated methemoglobinemia can lead to cardiopulmonary compromise, neurological sequelae, and even death. The current report documents an additional case of TEE-associated methemoglobinemia from a high-volume (8000 cases /year including 400-450 TEE/year) echo lab. A review of the literature suggests that this complication may be more prevalent, than generally appreciated. This case report emphasizes the importance of appropriate dose, recognition, and the treatment of this entity to cardiologists performing TEE.
苯佐卡因（氨基苯甲酸乙酯）是一种局部麻醉剂，广泛用于经食管超声心动图（TEE）检查前的口咽麻醉。据报道，局部麻醉剂可导致高铁血红蛋白血症，但这种不良事件极为罕见，尚未被列为TEE可能的并发症之一。然而，最近发表的与TEE相关的高铁血红蛋白血症病例报告数量有所增加。自1950年首次描述以来，已报告了65例高铁血红蛋白血症病例，包括最近一个单中心报告的5例病例。不熟悉TEE与苯佐卡因诱导的高铁血红蛋白血症之间关联的医生可能无法识别这种情况的特殊且往往不具特异性的特征。然而，识别至关重要，因为未经治疗的高铁血红蛋白血症可导致心肺功能不全、神经后遗症，甚至死亡。本报告记录了一家高工作量（每年8000例，包括每年400 - 450例TEE）超声心动图实验室发生的另一例与TEE相关的高铁血红蛋白血症病例。文献综述表明，这种并发症可能比普遍认为的更为普遍。本病例报告强调了适当剂量、识别以及对进行TEE的心脏病专家治疗这种病症的重要性。
