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

Zehra Jaffery, Karthik Ananthasubramaniam

Research output: Contribution to journalArticle

8 Scopus citations


Background: Benzocaine induced methemoglobinemia is an uncommon, potentially fatal condition. Case report: A 44-year-old woman with a history of hepatitis C and intravenous drug use was referred for transesophageal echocardiography for bacteremia evaluation. During induction of topical anesthesia with benzocaine spray she became cyanotic. Pulse oximetry revealed marked desaturation (75%) but was discordant from arterial blood O2 saturation (99%). Due to clinical suspicion, methemoglobin level was measured and noted to be 69%. The patient was treated with 2 mg/kg of methylene blue intravenously with resolution of her symptoms. Conclusion: 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.

Original languageEnglish (US)
Pages (from-to)289-290
Number of pages2
JournalEuropean Journal of Echocardiography
Issue number2
StatePublished - Mar 2008
Externally publishedYes



  • Methemoglobinemia
  • Methylene blue
  • Topical anesthetics
  • Transesophageal echocardiography

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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