title: Response to recruitment maneuver influences net alveolar fluid clearance in acute respiratory distress syndrome.
abstract: BACKGROUND
  Alveolar fluid clearance is impaired in the majority of patients with acute respiratory distress syndrome (ARDS). Experimental studies have shown that a reduction of tidal volume increases alveolar fluid clearance. This study was aimed at assessing the impact of the response to a recruitment maneuver (RM) on net alveolar fluid clearance.
  
  
  METHODS
  In 15 patients with ARDS, pulmonary edema fluid and plasma protein concentrations were measured before and after an RM, consisting of a positive end-expiratory pressure maintained 10 cm H2O above the lower inflection point of the pressure-volume curve during 15 min. Cardiorespiratory parameters were measured at baseline (before RM) and 1 and 4 h later. RM-induced lung recruitment was measured using the pressure-volume curve method. Net alveolar fluid clearance was measured by measuring changes in bronchoalveolar protein concentrations before and after RM.
  
  
  RESULTS
  In responders, defined as patients showing an RM-induced increase in arterial oxygen tension of 20% of baseline value or greater, net alveolar fluid clearance (19 +/- 13%/h) and significant alveolar recruitment (113 +/- 101 ml) were observed. In nonresponders, neither net alveolar fluid clearance (-24 +/- 11%/h) nor alveolar recruitment was measured. Responders and nonresponders differed only in terms of lung morphology: Responders had a diffuse loss of aeration, whereas nonresponders had a focal loss of aeration, predominating in the lower lobes.
  
  
  CONCLUSIONS
  In the absence of alveolar recruitment and improvement in arterial oxygenation, RM decreases the rate of alveolar fluid clearance, suggesting that lung overinflation may be associated with epithelial dysfunction.
authors: Surgical Intensive Care Unit, Department of Anesthesiology, Hôtel-Dieu Hospital, University Hospital of Clermont-Ferrand, INSERM U384, Clermont-Ferrand, France. jmconstantin@chu-clermontferrand.fr
authors: Jean-Michel
authors: JM
authors: Constantin
authors: Sophie
authors: S
authors: Cayot-Constantin
authors: Laurence
authors: L
authors: Roszyk
authors: Emmanuel
authors: E
authors: Futier
authors: Vincent
authors: V
authors: Sapin
authors: Bernard
authors: B
authors: Dastugue
authors: Jean-Etienne
authors: JE
authors: Bazin
authors: Jean-Jacques
authors: JJ
authors: Rouby
mesh_terms: D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration; D011650:Pulmonary Alveoli / Q000378:metabolism*; D011654:Pulmonary Edema / Q000378:metabolism*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D013990:Tidal Volume / Q000502:physiology*
chemical_list: D001798:Blood Proteins; D010100:Oxygen