title: Delayed pneumothorax after stab wound to thorax and upper abdomen: Truth or myth?
abstract: BACKGROUND
  Stab wounds to the thorax and upper abdomen have the potential to cause pneumothorax (PTX). When a CXR (CXR) obtained during initial resuscitation is negative, a second CXR (CXR-2) is commonly performed with the goal of identifying delayed PTX.
  
  
  OBJECTIVE
  To assess the diagnostic yield of the CXR-2 in identifying delayed PTX.
  
  
  METHODS
  Prospective observational study of patients (age >or=13 years) with stab wounds to the thorax (chest/back) and upper abdomen with suspected PTX, in a level 1 trauma centre. Patients were included if they had a negative initial CXR followed by a repeat CXR 3-6h after the initial one.
  
  
  METHODS
  patients who died, were transferred out of the ED, or received chest tubes before the second CXR. The outcome of interest was delayed PTX. All CXR were read by an attending radiologist. To test the inter-observer agreement, another blinded radiologist reviewed 20% of CXR. Continuous data is presented as mean+/-standard deviation and categorical data as percentages with 95% confidence interval (CI). Kappa statistics were used to measure the inter-observer agreement between radiologists.
  
  
  RESULTS
  Between January 2003 and December 2006 a total of 185 patients qualified for the enrollment (mean age: 28+/-10 years, age range: 13-65, 94% male). Only 2 patients (1.1%, 95% CI, 0.4- 4.1%) had PTX on the CXR-2. Both patients received chest tubes. The inter-observer agreement for radiology reports was high (kappa: 0.79).
  
  
  CONCLUSIONS
  Occurrence of delayed PTX in patients with stab wounds to the thorax and upper abdomen and negative triage CXR is rare.
authors.affiliation: Department of Emergency Medicine, State University of New York, Downstate Medical Center/Kings County Hospital Center, United States. szehtabchi@yahoo.com
authors.forename: Shahriar
authors.initials: S
authors.lastname: Zehtabchi
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Morley
authors.forename: Dana
authors.initials: D
authors.lastname: Sajed
authors.forename: Oded
authors.initials: O
authors.lastname: Greenberg
authors.forename: Richard
authors.initials: R
authors.lastname: Sinert
mesh_terms: D000007:Abdominal Injuries / Q000150:complications* / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D011030:Pneumothorax / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D011336:Probability; D011446:Prospective Studies; D011859:Radiography; D013898:Thoracic Injuries / Q000150:complications* / Q000000981:diagnostic imaging; D013997:Time Factors; D014218:Triage / Q000379:methods; D014951:Wounds, Stab / Q000150:complications* / Q000000981:diagnostic imaging; D055815:Young Adult