title: Pleural Gas Analysis for Detection of Alveolopleural Fistulae.
abstract: OBJECTIVE
  Visual inspection (VI) of bubbles in the chest drainage unit does not differentiate a true leak of alveolopleural fistula (APF) from a false leak. We hypothesized that detection of elevated levels of carbon dioxide, increase in oxygen content, or both, in pleural gas upon the administration of supplemental oxygen would accurately identify APF.
  
  
  METHODS
  Prospective study comparing pleural gas analysis (GA) with VI to detect APF after surgical lobectomy (n = 50).
  
  
  RESULTS
  APF was found in 22 (44%) patients at the time of analysis. VI revealed air bubbles in 31 (62%) patients, indicating the presence of APF, of whom 12 (38.7%) were false leaks. VI failed to identify APF in 3 (6%) patients that resulted in post-tube removal pneumothorax. By contrast, GA accurately demonstrated APF in 21 patients, with only one false negative and no false positives. GA demonstrated better sensitivity (95.5% vs 86.4%), specificity (100% vs 57.1%), positive predictive value (100% vs 61.3%), and negative predictive value (96.6% vs 84.2%) compared to VI.
  
  
  CONCLUSIONS
  Pleural gas analysis is an effective technique to detect APF and can facilitate timely and safe chest tube removal.
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Northwestern University, Chicago, Illinois. Electronic address: abharat@nm.org.
authors.forename: Ankit
authors.initials: A
authors.lastname: Bharat
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Northwestern University, Chicago, Illinois.
authors.forename: Nicole
authors.initials: N
authors.lastname: Graf
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Northwestern University, Chicago, Illinois.
authors.forename: Emily
authors.initials: E
authors.lastname: Cassidy
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Sean
authors.initials: S
authors.lastname: Smith
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Colin
authors.initials: C
authors.lastname: Gillespie
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Northwestern University, Chicago, Illinois.
authors.forename: Shari
authors.initials: S
authors.lastname: Meyerson
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University, Chicago, Illinois; Jesse Brown Veterans Medical Center, Chicago, Illinois.
authors.forename: Peter H S
authors.initials: PH
authors.lastname: Sporn
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University, Chicago, Illinois.
authors.forename: Jacob I
authors.initials: JI
authors.lastname: Sznajder
authors.affiliation: Division of Thoracic Surgery, Department of Surgery, Northwestern University, Chicago, Illinois.
authors.forename: Malcolm M
authors.initials: MM
authors.lastname: DeCamp
mesh_terms: D000388:Air / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D035422:Pleural Cavity / Q000737:chemistry*; D010995:Pleural Diseases / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D011013:Pneumonectomy / Q000009:adverse effects*; D011446:Prospective Studies; D011650:Pulmonary Alveoli; D015203:Reproducibility of Results; D016156:Respiratory Tract Fistula / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery