title: Cleared for takeoff: The effects of hypobaric conditions on traumatic pneumothoraces.
abstract: BACKGROUND
  Current guidelines suggest that traumatic pneumothorax (tPTX) is a contraindication to commercial airline travel, and patients should wait at least 2 weeks after radiographic resolution of tPTX to fly. This recommendation is not based on prospective, physiologic study. We hypothesized that despite having a radiographic increase in pneumothorax size while at simulated altitude, patients with a recently treated tPTX would not exhibit any adverse physiologic changes and would not report any symptoms of cardiorespiratory compromise.
  
  
  METHODS
  This is a prospective, observational study of 20 patients (10 in Phase 1, 10 in Phase 2) with tPTX that has been treated by chest tube (CT) or high flow oxygen therapy. CT must have been removed within 48 hours of entering the study. Subjects were exposed to 2 hours of hypobaria (554 mm Hg in Phase 1, 471 mm Hg in Phase 2) in a chamber in Salt Lake City, Utah. Vital signs and subjective symptoms were recorded during the "flight." After 2 hours, while still at simulated altitude, a portable chest radiograph (CXR) was obtained. tPTX sizes on preflight, inflight, and postflight CXR were compared.
  
  
  RESULTS
  Sixteen subjects (80%) were male. Mean (SD) age and ISS were 49 (5) years and 10.5 (4.6), respectively. Fourteen (70%) had a CT to treat tPTX, which had been removed 19 hours (range, 4-43 hours) before the study. No subject complained of any cardiorespiratory symptoms while at altitude. Radiographic increase in tPTX size at altitude was 5.6 (0.61) mm from preflight CXR. No subject developed a tension tPTX. No subject required procedural intervention during the flight. Four hours after the study, all tPTX had returned to baseline size.
  
  
  CONCLUSIONS
  Patients with recently treated tPTX have a small increase in the size of tPTX when subjected to simulated altitude. This is clinically well tolerated. Current prohibitions regarding air travel following traumatic tPTX should be reconsidered and further studied.
  
  
  METHODS
  Therapeutic study, level IV.
authors.affiliation: From the Division of Trauma Services and Critical Care Medicine (S.M., T.W.W., D.H.V.B., S.G.), Department of Emergency Medicine (J.B.), Department of Radiology (K.C.), Department of Pulmonary and Critical Care Medicine (E.W.),and Division of Hyperbaric and Critical Care Medicine (L.K.W.), Intermountain Medical Center; and Mountain Medical Physician Specialists (K.C.), Murray, Utah.
authors.forename: Sarah
authors.initials: S
authors.lastname: Majercik
authors.forename: Thomas W
authors.initials: TW
authors.lastname: White
authors.forename: Don H
authors.initials: DH
authors.lastname: Van Boerum
authors.forename: Steven
authors.initials: S
authors.lastname: Granger
authors.forename: Joseph
authors.initials: J
authors.lastname: Bledsoe
authors.forename: Karen
authors.initials: K
authors.lastname: Conner
authors.forename: Emily
authors.initials: E
authors.lastname: Wilson
authors.forename: Lindell K
authors.initials: LK
authors.lastname: Weaver