title: Pneumomediastinum following blunt trauma: Worth an exhaustive workup?
abstract: BACKGROUND
  Incidental pneumomediastinum is a common radiologic finding following blunt thoracic injury; however, the clinical significance of pneumomediastinum on screening imaging is poorly defined (Curr Probl Surg. 2004;41(3):211-380; Injury. 2010;41(1):40-43). The purpose of this study was to define the incidence of aerodigestive injuries in patients with pneumomediastinum after blunt thoracic and neck injury.
  
  
  METHODS
  After institutional review board approval was obtained, a retrospective review was performed of all patients admitted to Los Angeles County + University of Southern California Medical Center with blunt neck and/or thoracic injuries between January 2007 and December 2012. All patients with pneumomediastinum on radiologic investigation were included. Data accrued included demographics, admission clinical data, injury severity patterns, incidence of aerodigestive injuries, operative findings, morbidity, mortality, as well as intensive care unit and hospital lengths of stay.
  
  
  RESULTS
  A total of 9,946 patients were included in the study. The predominant mechanism was motor vehicle collision (49%), disproportionately male (76%). Overall, 258 patients (2.6%) had a pneumomediastinum: 65 (25%) and 193 (75%) were diagnosed on a chest x-ray or on a computed tomography (CT) scan, respectively. A total of 21 patients (8.1%) had an aerodigestive workup with bronchoscopy, esophagram, and/or esophagoscopy. Overall, four aerodigestive lesions (1.6%) were diagnosed. Three tracheobronchial injuries were identified on CT scan, and one esophageal injury was diagnosed on an esophagram. Two tracheobronchial injuries required surgery, while the remaining cases were managed nonoperatively. The overall mortality in this cohort was 10.9%.
  
  
  CONCLUSIONS
  Isolated findings of pneumomediastinum on screening chest x-ray or CT following blunt trauma is a poor predictor of an aerodigestive injury. Highly selective workup in this clinical setting is warranted.
  
  
  METHODS
  Prognostic/epidemiologic study, level III; therapeutic study, level IV.
authors.affiliation: From the Los Angeles County + University of Southern California Medical Center, Los Angeles, California.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Chouliaras
authors.forename: Elias
authors.initials: E
authors.lastname: Bench
authors.forename: Peep
authors.initials: P
authors.lastname: Talving
authors.forename: Aaron
authors.initials: A
authors.lastname: Strumwasser
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Benjamin
authors.forename: Lydia
authors.initials: L
authors.lastname: Lam
authors.forename: Kenji
authors.initials: K
authors.lastname: Inaba
authors.forename: Demetrios
authors.initials: D
authors.lastname: Demetriades
mesh_terms: D000328:Adult; D004064:Digestive System / Q000293:injuries*; D005260:Female; D006801:Humans; D008297:Male; D008478:Mediastinal Emphysema / Q000000981:diagnostic imaging / Q000209:etiology*; D008875:Middle Aged; D019838:Neck Injuries / Q000150:complications / Q000175:diagnosis*; D013902:Radiography, Thoracic; D012137:Respiratory System / Q000293:injuries*; D012189:Retrospective Studies; D013898:Thoracic Injuries / Q000150:complications / Q000175:diagnosis*; D014057:Tomography, X-Ray Computed; D014949:Wounds, Nonpenetrating / Q000150:complications*; D055815:Young Adult