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

Aryal, Madan Raj; Gupta, Shobhit; Giri, Subarna; Fraga, Julian Diaz

doi:10.1136/bcr-2013-009398

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…Known risk factors for the development of benzocaine-induced methemoglobinemia include anemia, elderly age, malnutrition, history of smoking, and inflammation from an NG tube. 2,3 The case patient exhibited most of these risk factors. She received the maximum recommended daily dose of benzocaine 20% spray but also got additional benzocaine in the form of 2 lozenges.…”

Section: Discussionmentioning

confidence: 92%

A Case Report of Benzocaine-Induced Methemoglobinemia

Sewell

Rivey

2017

Journal of Pharmacy Practice

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Methemoglobinemia is a serious medical condition characterized by the disrupted binding of oxygen to iron on hemoglobin, with a consequent impaired oxygen delivery to body tissues. Various drugs including the local anesthetics such as benzocaine can cause acquired methemoglobinemia. The reported case describes methemoglobinemia that occurred in association with the use of topical benzocaine spray and lozenges in a previously healthy 51-year-old female who had undergone colon surgery to remove a bleeding polyp. Pulse oximetry revealed the patient was hypoxic and a measured methemoglobin (MetHB) serum concentration was 32.4%, well above the normal of less than 2%. Treatment with intravenous methylene blue resulted in a rapid improvement in the patient's respiratory status. The case emphasizes the need for practitioners to appreciate that topical benzocaine products can cause potentially fatal methemoglobinemia.

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Section: Discussionmentioning

confidence: 92%

A Case Report of Benzocaine-Induced Methemoglobinemia

Sewell

Rivey

2017

Journal of Pharmacy Practice

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“…The lack of improvement in oxygen saturation with high-flow oxygen without any apparent causes and the gap in oxygen saturation >5% between ABG and pulse oximetry (saturation gap) are considered to be the diagnostic clues. The diagnosis is confirmed by the level of methemoglobin in blood ( 1 , 6 ).…”

Section: Discussionmentioning

confidence: 93%

“…Clinical manifestations of methemoglobinemia may not always correlate with blood MetHb level. Patients usually develop cyanosis without any symptoms in levels of 10–20%, with confusion starting above these levels and progressively worsening symptoms as the level increases resulting in coma, cardiovascular collapse, and death in levels above 70% ( 1 , 6 ). The most common oxidizing agents are dapsone, topical anesthetic agents (benzocaine, lidocaine, and prilocaine), nitrites, and aniline dyes ( 7 ).…”

Section: Discussionmentioning

confidence: 99%

Do all patients with acquired methemoglobinemia need treatment? A lesson learnt

Khanal

Karmacharya

Pathak

et al. 2015

Journal of Community Hospital Internal Medicine Perspectives

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Acquired methemoglobinemia is a medical emergency, and its prompt recognition and treatment can avoid catastrophic complications including death. However, in mild asymptomatic cases without any comorbid conditions, it would be reasonable to simply observe and treat symptomatically to avoid severe treatment-related complications, especially in patients with suspected glucose-6-phosphate dehydrogenase (G6PD) deficiency. We present a case of mild methemoglobinemia in occult G6PD deficiency in which the patient developed hemolysis after treatment with intravenous methylene blue, requiring transfusion.

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“…In a review presenting 242 cases of local anesthesia–related methemoglobinemia 159 (65.7 %) patients were anesthetized with agents containing benzocaine, among which 105 (43.4 %) patients were treated with benzocaine alone. 12 incidents of methemoglobinemia were initially connected with lidocaine application, however only three patients episode could not be attributed with any other cause than topical lidocaine administration [ 12 , 15 – 17 ].…”

Section: Discussionmentioning

confidence: 99%

The influence of lidocaine topical anesthesia during transesophageal echocardiography on blood methemoglobin level and risk of methemoglobinemia

Filipiak-Strzecka

Kasprzak

Wiszniewska

et al. 2015

Int J Cardiovasc Imaging

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Methemoglobinemia is a relatively rare, but potentially life-threating medical condition, which may be induced by application of topical anaesthetic agents commonly used during endoscopic procedure. The aim of our study was to assess the influence of lidocaine used prior to transesophageal echocardiography (TEE) on the blood level of methemoglobin in vivo. Additionally we attempted to establish the occurrence rate of clinically evident lidocaine-induced methemoglobinemia on the basis of data collected in our institution. We retrospectively analyzed patient records from 3,354 TEEs performed in our echocardiographic laboratory over the course of 13 years in search for clinically evident methemoglobinemia cases. Additionally, 18 consecutive patients referred for TEE were included in the prospective part of our analysis. Blood samples were tested before and 60 min after pre-TEE lidocaine anesthesia application. Information concerning concomitant conditions and pharmacotherapy were also obtained. In 3,354 patients who underwent TEE in our institution no cases of clinically evident methemoglobinemia occurred. In the prospective part of the study, none of 18 patients [16 (89 %) men, mean age 63 ± 13] was diagnosed with either clinical symptoms of methemoglobinemia or exceeded normal blood concentration of methemoglobin. Initial mean methemoglobin level was 0.5 ± 0.1 % with mild, statistically (but not clinically) significant rise to 0.6 ± 0.1 % after 60 min (p = 0.02). Among the analyzed factors only the relation between the proton pump inhibitors intake and methemoglobin blood level rise was identified as statistically relevant (p = 0.03). In adults, pre-TEE lidocaine anesthesia with recommended dosage results in significant increase in methemoglobin blood level, which however does not exceed normal values and does not result in clinically evident methemoglobinemia.

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

Cited by 7 publications

References 9 publications

A Case Report of Benzocaine-Induced Methemoglobinemia

A Case Report of Benzocaine-Induced Methemoglobinemia

Do all patients with acquired methemoglobinemia need treatment? A lesson learnt

The influence of lidocaine topical anesthesia during transesophageal echocardiography on blood methemoglobin level and risk of methemoglobinemia

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