title: Alignment of cricoid cartilage and esophagus and its potential influence on the effectiveness of Sellick maneuver in children.
abstract: OBJECTIVE
  The effectiveness of cricoid pressure in preventing aspiration of gastric contents during rapid sequence intubation may be limited if the esophagus is laterally displaced from the trachea at the level of the cricoid cartilage. Esophageal lateral displacement has been reported to occur in 50% to 90% of adults. Children 8 years and older assume the anatomic airway characteristics of adults, and therefore, we hypothesized that esophageal displacement would be significantly more common in older versus younger children. The purposes of this study were to determine the alignment of the trachea to the esophagus at the level of the cricoid cartilage on cervical spine or neck computed tomographic (CT) scans and to compare the frequency and quantity of esophageal displacement between children younger than 8 years and children 8 years and older.
  
  
  METHODS
  This is a retrospective cross-sectional study of children (aged 0-17 years) who had cervical spine/neck CT scans performed at a 110-bed urban children's hospital. Two pediatric radiologists blinded to the patients' clinical symptoms and signs and final diagnosis independently determined the alignment of the airway at the level of the cricoid cartilage with the esophagus from cervical spine/neck CT scans. Lateral displacement of the esophagus from the airway was determined by measuring the distance from the ipsilateral outer wall edges of the esophagus and trachea.
  
  
  RESULTS
  There were 172 cervical spine/neck CT scans reviewed. Of 87 children younger than 8 years, 27 were excluded, and of 85 children 8 to 17 years, 25 were excluded. The remaining 120 patients were eligible for the study, 60 patients were younger than 8 years and 60 patients were aged 8 to 17 years. For children younger than 8 years, their mean age was 3.58 years. There were 34 (57%) males. The most common indication for CT scan of the cervical spine/neck was motor vehicle crash 26 (46%). For children aged 8 to 17 years, their mean age was 13.3 years. There were 30 (50%) males. The most common indication for CT scan of the cervical spine/neck was motor vehicle crash 34 (57%). Alignment of the airway with the esophagus showed esophageal displacement in 36 (30%) of the patients with displacement in 27 (45%) of the younger children compared with 9 (15%) of the older children. The rate of displacement was significantly greater in the younger children (difference in rates was 30% and 95% confidence interval was 14%-46%). All displacements were to the left. The mean distance of esophageal displacement was significantly greater in the older children (2.42 vs 1.81 mm). The difference in the means was 0.61 mm, and the 95% confidence interval was 1.2 to 0.02 mm.
  
  
  CONCLUSIONS
  This is the first pediatric study on the rate and degree of esophageal displacement from the airway at the level of the cricoid cartilage. Lateral displacement of the esophagus occurred at a significantly greater rate in the younger (45%) compared with the older (15%) children, which was directly opposite of our hypothesis. Of the 36 children (30%) with esophageal displacement, all had displacement to the left of the cricoid cartilage.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Kurtis
authors.initials: K
authors.lastname: Dotson
authors.forename: James
authors.initials: J
authors.lastname: Kiger
authors.forename: Cody
authors.initials: C
authors.lastname: Carpenter
authors.forename: Madelene
authors.initials: M
authors.lastname: Lewis
authors.forename: Jeanne
authors.initials: J
authors.lastname: Hill
authors.forename: Laurence
authors.initials: L
authors.lastname: Raney
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Losek
mesh_terms: D000063:Accidents, Traffic; D000293:Adolescent; D000367:Age Factors; D000402:Airway Obstruction / Q000000981:diagnostic imaging / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003413:Cricoid Cartilage / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology*; D003430:Cross-Sectional Studies; D004947:Esophagus / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D007442:Intubation, Intratracheal / Q000379:methods*; D008297:Male; D019838:Neck Injuries / Q000000981:diagnostic imaging; D011312:Pressure; D053120:Respiratory Aspiration / Q000517:prevention & control; D012189:Retrospective Studies; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology