title: Occult pneumothoraces in critical care: a prospective multicenter randomized controlled trial of pleural drainage for mechanically ventilated trauma patients with occult pneumothoraces.
abstract: BACKGROUND
  Patients with an occult pneumothoraces (OPTXs) may be at risk of tension pneumothoraces (TPTXs) without drainage or pleural drainage complications if treated.
  
  
  METHODS
  Adults with traumatic OPTXs and requiring positive-pressure ventilation (PPV) were randomized to pleural drainage or observation (one side only enrolled if bilateral). All subsequent care and method of pleural drainage was per attending physician discretion. The primary outcome was a composite of respiratory distress (RD) (need for urgent pleural drainage, acute/sustained increases in O2 requirements, ventilator dysynchrony, and/or charted respiratory events).
  
  
  RESULTS
  Ninety severely injured patients (mean [SD], Injury Severity Score [ISS], 33 [11]) were studied at four centers: Calgary (55), Toronto (27), Quebec (6), and Sherbrooke (3). Forty were randomized to tube thoracostomy, and 50 were randomized to observation. The risk of RD was similar between the observation and tube thoracostomy groups (relative risk, 0.71; 95% confidence interval, 0.40-1.27). There was no difference in mortality or intensive care unit (ICU), ventilator, or hospital days between groups. In those observed, 20% required subsequent pleural drainage (40% PTX progression, 60% pleural fluid, and 20% other). One observed patient (2%) undergoing PPV at enrollment had a TPTX, which was treated with urgent tube thoracostomy without sequelae. Drainage complications occurred in 15% of those randomized to drainage, while suboptimal tube thoracostomy position occurred in an additional 15%. There were three times (24% vs. 8%) more failures and more RDs (p = 0.01) among those observed with OPTXs requiring sustained PPV versus just for an operation, which increases threefold after a week in the ICU (p = 0.07).
  
  
  CONCLUSIONS
  Our results suggest that OPTXs may be safely observed in hemodynamically stable patients undergoing PPV just for an operation, although one third of those requiring a week or more of ICU care received drainage, and TPTXs still occur. Complications of pleural drainage remain unacceptably high, and future work should attempt to delineate specific factors among those observed that warrant prophylactic drainage.
  
  
  METHODS
  Therapeutic study, level III.
authors: Regional Trauma Services, Departments of Surgery, University of Calgary and the Foothills Medical Centre, Calgary, Alberta. Andrew.Kirkpatrick@albertahealthservices.ca
authors: Andrew W
authors: AW
authors: Kirkpatrick
authors: Sandro
authors: S
authors: Rizoli
authors: Jean-Francois
authors: JF
authors: Ouellet
authors: Derek J
authors: DJ
authors: Roberts
authors: Marco
authors: M
authors: Sirois
authors: Chad G
authors: CG
authors: Ball
authors: Zhengwen Jimmy
authors: ZJ
authors: Xiao
authors: Corina
authors: C
authors: Tiruta
authors: Maureen
authors: M
authors: Meade
authors: Vincent
authors: V
authors: Trottier
authors: George
authors: G
authors: Zhu
authors: Francois
authors: F
authors: Chagnon
authors: Homer
authors: H
authors: Tien
mesh_terms: D000328:Adult; D015505:Chest Tubes; D003422:Critical Care; D004322:Drainage / Q000379:methods*; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D011030:Pneumothorax / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D013907:Thoracostomy / Q000379:methods*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014949:Wounds, Nonpenetrating / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D055815:Young Adult