title: Usefulness of ultrasonography in predicting pleural effusions > 500 mL in patients receiving mechanical ventilation.
abstract: OBJECTIVE
  To assess the accuracy of chest ultrasonography in predicting pleural effusions > 500 mL in patients receiving mechanical ventilation.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Surgical and medical ICU in a teaching hospital.
  
  
  METHODS
  Forty-four patients receiving mechanical ventilation with indications of chest drainage of a nonloculated pleural effusion.
  
  
  METHODS
  Diagnosis of pleural effusion was based on clinical examination and chest radiography. Chest drainage was indicated when considered as potentially useful for the patient (hypoxemia and/or weaning failure). Sonograms were performed before drainage at the bedside, in the supine position, and measurements were performed at the end of expiration. Effusions were classified as > 500 mL or < or = 500 mL according to the drained volume.
  
  
  RESULTS
  The drained volume ranged from 100 to 1,800 mL (mean, 730 +/- 440 mL [+/- SD]). The distance between the lung and posterior chest wall at the lung base (PLDbase) and the distance between the lung and posterior chest wall at the fifth intercostal space (PLD5) were significantly correlated with the drained volume (PLDbase, r = 0.68, p < 0.001; PLD5, r = 0.56, p < 0.001). A PLDbase > 5 cm predicted a drained volume > 500 mL with a sensitivity of 83%, specificity of 90%, positive predictive value of 91%, and negative predictive value of 82%. Interobserver and intraobserver percentages of error were, respectively, 7 +/- 6% and 9 +/- 6% for PLDbase, and 6 +/- 5% and 8 +/- 5% for PLD5. The PaO2/fraction of inspired oxygen ratio significantly increased after chest drainage in patients with collected volumes > 500 mL (p < 0.01).
  
  
  CONCLUSIONS
  Bedside pleural ultrasonography accurately predicted a nonloculated pleural effusion > 500 mL in patients receiving mechanical ventilation using simple and reproducible measurements.
authors.affiliation: Service de Réanimation Polyvalente, Hôpitaux Sud, Marseille, France. Antoine.Roch@mail.ap-hm.fr
authors.forename: Antoine
authors.initials: A
authors.lastname: Roch
authors.forename: Mirela
authors.initials: M
authors.lastname: Bojan
authors.forename: Pierre
authors.initials: P
authors.lastname: Michelet
authors.forename: Fanny
authors.initials: F
authors.lastname: Romain
authors.forename: Fabienne
authors.initials: F
authors.lastname: Bregeon
authors.forename: Laurent
authors.initials: L
authors.lastname: Papazian
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Auffray
mesh_terms: D000368:Aged; D004322:Drainage; D006801:Humans; D008875:Middle Aged; D010996:Pleural Effusion / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D014463:Ultrasonography