title: An analysis of and new risk factors for reexpansion pulmonary edema following spontaneous pneumothorax.
abstract: BACKGROUND
  The major risk factor for reexpansion pulmonary edema (RPE) following the treatment of spontaneous pneumothorax is thought to be chronic lung collapse. However, a long-term collapsed lung does not always cause RPE. The purpose of this study was to define other risk factors for RPE among patients undergoing drainage for the treatment of spontaneous pneumothorax.
  
  
  METHODS
  We retrospectively reviewed all the patients with spontaneous pneumothorax who had been treated at our hospital during a 5-year period. The duration of symptoms, location and size of the pneumothorax, size of the chest tube, and pleural effusion, which can occur coincidentally with pneumothorax, were compared in patients who did and did not experience RPE.
  
  
  RESULTS
  Forty patients were underwent drainage for the treatment of a spontaneous pneumothorax between January 2007 and December 2012. RPE developed in 13 of the 40 (32.5%) patients. In the multivariate analysis, the presence of pleural effusion coincident with pneumothorax contributed to the risk for RPE [odds ratios (OR), 1.557; 95% confidence intervals (CI), 1.290-1.880]. The duration of symptoms, location and size of the pneumothorax and size of the chest tube were similar between the groups. Symptomatic RPE was associated with a larger pneumothorax size.
  
  
  CONCLUSIONS
  The rate of RPE following spontaneous pneumothorax is higher than was previously reported. Our findings suggest the presence of pleural effusion coincidentally with pneumothorax may therefore be a new risk factor for RPE.
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Taira
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kawabata
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Ichi
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Yohena
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Kawasaki
authors.affiliation: Department of General Surgery, National Hospital Organization, Okinawa National Hospital, Ginowan, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ishikawa
keywords: Lung; pneumothorax