title: Clinical Presentation of Patients With Tension Pneumothorax: A Systematic Review.
abstract: OBJECTIVE
  To determine whether the reported clinical presentation of tension pneumothorax differs between patients who are breathing unassisted versus receiving assisted ventilation.
  
  
  BACKGROUND
  Animal studies suggest that the pathophysiology and physical signs of tension pneumothorax differ by subject ventilatory status.
  
  
  METHODS
  We searched electronic databases through to October 15, 2013 for observational studies and case reports/series reporting clinical manifestations of tension pneumothorax. Two physicians independently extracted clinical manifestations reported at diagnosis.
  
  
  RESULTS
  We identified 5 cohort studies (n = 310 patients) and 156 case series/reports of 183 cases of tension pneumothorax (n = 86 breathing unassisted, n = 97 receiving assisted ventilation). Hypoxia was reported among 43 (50.0%) cases of tension pneumothorax who were breathing unassisted versus 89 (91.8%) receiving assisted ventilation (P < 0.001). Pulmonary dysfunction progressed to respiratory arrest in 9.3% of cases breathing unassisted. As compared to cases who were breathing unassisted, the adjusted odds of hypotension and cardiac arrest were 12.6 (95% confidence interval, 5.8-27.5) and 17.7 (95% confidence interval, 4.0-78.4) times higher among cases receiving assisted ventilation. One cohort study reported that none of the patients with tension pneumothorax who were breathing unassisted versus 39.6% of those receiving assisted ventilation presented without an arterial pulse. In contrast to cases breathing unassisted, the majority (70.4%) of those receiving assisted ventilation who experienced hypotension or cardiac arrest developed these signs within minutes of clinical presentation.
  
  
  CONCLUSIONS
  The reported clinical presentation of tension pneumothorax depends on the ventilatory status of the patient. This may have implications for improving the diagnosis and treatment of this life-threatening disorder.
authors.affiliation: *Department of Surgery, University of Calgary, Calgary, Alberta, Canada †Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada ‡Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada §Regional Trauma Program, University of Calgary and the Foothills Medical Centre, Calgary, Alberta, Canada ¶United Kingdom Defence Medical Services and Emergency Department, Royal Infirmary of Edinburgh, Scotland, United Kingdom ‖Alberta Health Sciences Research-Research Analytics, University of Calgary and the Foothills Medical Centre, Calgary, Alberta, Canada **Department of Oncology, University of Calgary, Calgary, Alberta, Canada ††Health Sciences Library, University of Calgary, Calgary, Alberta, Canada; and ‡‡Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Roberts
authors.forename: Simon
authors.initials: S
authors.lastname: Leigh-Smith
authors.forename: Peter D
authors.initials: PD
authors.lastname: Faris
authors.forename: Christopher
authors.initials: C
authors.lastname: Blackmore
authors.forename: Chad G
authors.initials: CG
authors.lastname: Ball
authors.forename: Helen Lee
authors.initials: HL
authors.lastname: Robertson
authors.forename: Elijah
authors.initials: E
authors.lastname: Dixon
authors.forename: Matthew T
authors.initials: MT
authors.lastname: James
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Kirkpatrick
authors.forename: John B
authors.initials: JB
authors.lastname: Kortbeek
authors.forename: Henry T
authors.initials: HT
authors.lastname: Stelfox
mesh_terms: D006801:Humans; D011030:Pneumothorax / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D012121:Respiration, Artificial / Q000009:adverse effects