title: Hypoxaemia during transoesophageal echocardiography.
abstract: OBJECTIVE
  To establish the incidence and severity of arterial oxygen desaturation during transoesophageal echocardiography performed under light intravenous sedation; to determine which patients are at greatest risk; and to assess the effects of supplementary oxygen treatment.
  
  
  METHODS
  Prospective study of 150 patients referred for transoesophageal echocardiography.
  
  
  METHODS
  Echocardiography laboratory in a tertiary cardiothoracic referral centre.
  
  
  METHODS
  Transcutaneous arterial oxygen saturation.
  
  
  RESULTS
  During transoesophageal echocardiography mean (SD) arterial oxygen saturation (SaO2) fell in 144 of 150 patients (96%) from 95.4%(2.6%) to 90.7%(6.3%) (p < 0.001). Significant hypoxaemia, defined as SaO2 < 90%, was found in 27 of 150 patients (18%); in this group SaO2 fell from 92.9%(3.5%) to 81.8%(9.6%) (p < 0.001), but rose rapidly on oxygen to 95.5%(2.4%) (p < 0.001). Two patients became profoundly hypoxaemic with SaO2 values of 35% and 74%. The principal risk factors for hypoxaemia during transoesophageal echocardiography were mitral valve disease, severe mitral regurgitation, and New York Heart Association symptomatic class III or IV.
  
  
  CONCLUSIONS
  Transcutaneous oximetry and supplementary oxygen should be available routinely during transoesophageal echocardiography.
authors.affiliation: Department of Medical Cardiology, Royal Infirmary, Glasgow.
authors.forename: A J
authors.initials: AJ
authors.lastname: Scriven
authors.forename: S M
authors.initials: SM
authors.lastname: Cobbe
mesh_terms: D000328:Adult; D000368:Aged; D001785:Blood Gas Monitoring, Transcutaneous; D017548:Echocardiography, Transesophageal / Q000009:adverse effects*; D005260:Female; D006331:Heart Diseases / Q000097:blood / Q000000981:diagnostic imaging*; D006801:Humans; D000860:Hypoxia / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012307:Risk Factors