title: Utility and safety of draining pleural effusions in mechanically ventilated patients: a systematic review and meta-analysis.
abstract: BACKGROUND
  Pleural effusions are frequently drained in mechanically ventilated patients but the benefits and risks of this procedure are not well established.
  
  
  METHODS
  We performed a literature search of multiple databases (MEDLINE, EMBASE, HEALTHSTAR, CINAHL) up to April 2010 to identify studies reporting clinical or physiological outcomes of mechanically ventilated critically ill patients who underwent drainage of pleural effusions. Studies were adjudicated for inclusion independently and in duplicate. Data on duration of ventilation and other clinical outcomes, oxygenation and lung mechanics, and adverse events were abstracted in duplicate independently.
  
  
  RESULTS
  Nineteen observational studies (N = 1,124) met selection criteria. The mean PaO2:FiO2 ratio improved by 18% (95% confidence interval (CI) 5% to 33%, I2 = 53.7%, five studies including 118 patients) after effusion drainage. Reported complication rates were low for pneumothorax (20 events in 14 studies including 965 patients; pooled mean 3.4%, 95% CI 1.7 to 6.5%, I2 = 52.5%) and hemothorax (4 events in 10 studies including 721 patients; pooled mean 1.6%, 95% CI 0.8 to 3.3%, I2 = 0%). The use of ultrasound guidance (either real-time or for site marking) was not associated with a statistically significant reduction in the risk of pneumothorax (OR = 0.32; 95% CI 0.08 to 1.19). Studies did not report duration of ventilation, length of stay in the intensive care unit or hospital, or mortality.
  
  
  CONCLUSIONS
  Drainage of pleural effusions in mechanically ventilated patients appears to improve oxygenation and is safe. We found no data to either support or refute claims of beneficial effects on clinically important outcomes such as duration of ventilation or length of stay.
authors.affiliation: Interdepartmental Division of Critical Care, Mount Sinai Hospital and the University Health Network, University of Toronto, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.
authors.forename: Ewan C
authors.initials: EC
authors.lastname: Goligher
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Leis
authors.forename: Robert A
authors.initials: RA
authors.lastname: Fowler
authors.forename: Ruxandra
authors.initials: R
authors.lastname: Pinto
authors.forename: Neill K J
authors.initials: NK
authors.lastname: Adhikari
authors.forename: Niall D
authors.initials: ND
authors.lastname: Ferguson
mesh_terms: D018849:Controlled Clinical Trials as Topic; D016638:Critical Illness; D004322:Drainage / Q000009:adverse effects; D006801:Humans; D010996:Pleural Effusion / Q000628:therapy*; D012121:Respiration, Artificial; D016896:Treatment Outcome