A rare side effect of transesophageal echocardiography: Methemoglobinemia from topical benzocaine anesthesia☆

Abstract

Physicians using topical anesthesia in endoscopic suites should be aware of this rare, potentially life-threatening treatable condition. High clinical suspicion and availability of methylene blue in endoscopy suites will facilitate prompt diagnosis and treatment.

Liposomal encapsulation improves the duration of soft tissue anesthesia but does not induce pulpal anesthesia

“…This circumstance is reported when benzocaine is used in overdoses, usually greater then 500 mg, for procedures such as bronchoscopy, laryngoscopy, transesophageal echocardiography, fiberoptic nasal intubation, or upper gastrointestinal endoscopy [7,8,28,[30][31][32][33][34]. Even though methemoglobinemia after the use of 20% benzocaine in dentistry has not been reported, lowering the concentration of the anesthetic salt could reduce its toxicity in procedures that require large doses.…”

“…Benzocaine is one of the most used anesthetic agents, especially in pediatric dentistry [4], due to its characteristics of rapid onset of action (30 sec), acceptable taste, lack of systemic absorption, and effectiveness [5,6]. Despite these advantages, adverse reactions such as methemoglobinemia have been documented after topical benzocaine use [7,8].…”

Benzocaine-induced methaemoglobinaemia: a life-threatening complication after a transoesophageal echocardiogram (TEE)

“…As in our case, the use of benzocaine can rarely lead to a potentially fatal complication such as methaemoglobinaemia. Benzocaine induced methaemoglobinaemia during TEE, although rare, has been reported before 2 3 5 6 8–10…”

Unusual cause of severe toxic methemoglobinemia in an infant: a case report

“…Methemoglobinemia is a rare blood disorder, characterized by abnormal levels of oxidized hemoglobin that cannot bind to and transport oxygen [1, 2]. The clinical picture is characterized by acute cyanosis and low oxygen saturations on pulse oximetry but normal oxygen saturation on arterial blood gas analysis [1].…”

“…The clinical picture is characterized by acute cyanosis and low oxygen saturations on pulse oximetry but normal oxygen saturation on arterial blood gas analysis [1]. When untreated, methemoglobinemia can lead to major cardiopulmonary compromise, neurologic sequela, and even death [2].…”