title: Dynamic anatomic relationship of the esophagus and trachea on sonography: implications for endotracheal tube confirmation in children.
abstract: OBJECTIVE
  Sonographic visualization of an empty esophagus to confirm endotracheal tube placement during intubation may be more reliable than identifying an endotracheal tube within the trachea. Our objective was to determine the frequency in which the normal empty esophagus can be identified at or below the level of the cricoid ring in children.
  
  
  METHODS
  A prospective cohort of children and young adults presenting to the emergency department were examined by sonography to determine the dynamic anatomic relationship of the trachea and esophagus at or below the level of the cricoid ring. For children with the esophagus behind or partially behind the trachea, cricoid pressure was applied using a linear array transducer to visualize the presence of lateral sliding of the esophagus from behind the trachea.
  
  
  RESULTS
  A total of 55 patients 21 years or younger were examined; 51% (28) were male. Sixty-two percent (34) had esophagi positioned partially to the left of the cricoid ring, 20% (11) completely to the left of the cricoid ring, 16% (9) behind the cricoid ring, and 2% (1) partially to the right of the cricoid ring. When cricoid pressure was applied using the ultrasound transducer, the esophagus was visualized lateral to the trachea in all patients (54 to the left and 1 to the right; n = 55 of 55; 95% confidence interval, 94%-100%).
  
  
  CONCLUSIONS
  With cricoid pressure applied using a linear transducer, the esophagus was visualized lateral to the trachea in all children and young adults. Visualizing an empty esophagus by point-of-care sonography may be feasible to confirm endotracheal tube placement by a process of elimination.
authors.affiliation: Department of Emergency Medicine, Mount Sinai School of Medicine, 1 Gustave Levy Pl, Guggenheim Pavilion Box 1149, New York, NY 10029, USA. jtsung@gmail.com
authors.forename: James W
authors.initials: JW
authors.lastname: Tsung
authors.forename: Daniel
authors.initials: D
authors.lastname: Fenster
authors.forename: David O
authors.initials: DO
authors.lastname: Kessler
authors.forename: Joseph
authors.initials: J
authors.lastname: Novik
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004947:Esophagus / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007442:Intubation, Intratracheal; D008297:Male; D011446:Prospective Studies; D014132:Trachea / Q000000981:diagnostic imaging*; D014159:Transducers; D014463:Ultrasonography; D055815:Young Adult