title: Infection and the risk of topical anesthetic induced clinically significant methemoglobinemia after transesophageal echocardiography.
abstract: BACKGROUND
  Methemoglobinemia is a recognized complication of topical anesthesia with benzocaine during transesophageal echocardiography (TEE). Though several risk factors have been described, the importance of individual factors is not known. We performed a retrospective study to identify determinants of the risk of methemoglobinemia.
  
  
  METHODS
  All patients who underwent TEE with benzocaine topical anesthesia between June 2005 and June 2007 were included in this retrospective study.
  
  
  RESULTS
  Of the 886 patients who were included in the study, 140 had active infection (15.8%). The incidence of methemoglobinemia in this group was 2.9% (vs. 0%, P < 0.001). Compared to those without infection, patients in the active infection group were more likely to have a lower hemoglobin (P < 0.001), serum albumin level (P < 0.001), glomerular filtration rate less than 60 ml/min per 1.73 m(2) (P < 0.001), higher rates of dialysis (P < 0.001), a higher incidence of malignancy (P = 0.01), and increased use of acetaminophen and sulfa drugs (P < 0.001). However, multivariate logistic regression analysis did not identify any statistically significant covariates.
  
  
  CONCLUSIONS
  In conclusion, patients with an active systemic infection who undergo TEE are at a higher risk of methemoglobinemia. However, none of the risk factors for methemoglobinemia including active infection reached statistical significance in the regression analysis which has to be interpreted with caution in view of the low event rate.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, Southern Illinois University School of Medicine, Springfield, Illinois 62794, USA. svallurupalli@siumed.edu
authors.forename: Srikanth
authors.initials: S
authors.lastname: Vallurupalli
authors.forename: Smita
authors.initials: S
authors.lastname: Das
authors.forename: Shalini
authors.initials: S
authors.lastname: Manchanda
mesh_terms: D000368:Aged; D000779:Anesthetics, Local / Q000009:adverse effects*; D001566:Benzocaine / Q000009:adverse effects*; D017548:Echocardiography, Transesophageal / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007239:Infections / Q000139:chemically induced / Q000209:etiology; D008297:Male; D008708:Methemoglobinemia / Q000139:chemically induced* / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000779:Anesthetics, Local; D001566:Benzocaine