title: Prone position augments recruitment and prevents alveolar overinflation in acute lung injury.
abstract: BACKGROUND
  Mechanical ventilation in the prone position may be an effective means of recruiting nonaerated alveolar units and minimizing ventilation-induced lung injury.
  
  
  OBJECTIVE
  To evaluate and quantify regional lung volume alterations when patients with lobar or diffuse acute lung injury (ALI) were turned prone after a recruitment maneuver.
  
  
  METHODS
  In 21 patients with ALI, a recruitment maneuver was applied in the supine position followed by a multislice spiral computed tomography (CT) scan; then, patients were turned prone and a second CT scan was performed.
  
  
  RESULTS
  Both the recruitment maneuver and prone position resulted in improved oxygenation in patients with lobar ALI. Prone position also resulted in increased respiratory system compliance and decreased Pa(CO(2)) in lobar ALI. In lobar ALI, the proportion of overinflated and nonaerated areas declined, whereas the proportion of well-aerated areas increased in the prone position. The decrease in overinflated areas was observed mainly in the ventral areas. The dorsal regions showed a decrease in nonaerated areas and an increase in well-aerated areas. Recruitment maneuver and prone position improved oxygenation but had no effect either on Pa(CO(2)) or on the respiratory system compliance of patients with diffuse ALI. These patients responded to prone position with a decrease in nonaerated areas.
  
  
  CONCLUSIONS
  Prone position recruited the edematous lung further than recruitment maneuvers and reversed overinflation, resulting in a more homogeneous distribution of aeration. The effects of the prone position were more pronounced in patients with lobar ALI.
authors.affiliation: Intensive Care Unit, University Hospital of Ioannina, University Street, 45500 Ioannina, Greece.
authors.forename: Eftichia
authors.initials: E
authors.lastname: Galiatsou
authors.forename: Eleonora
authors.initials: E
authors.lastname: Kostanti
authors.forename: Eugenia
authors.initials: E
authors.lastname: Svarna
authors.forename: Athanasios
authors.initials: A
authors.lastname: Kitsakos
authors.forename: Vasilios
authors.initials: V
authors.lastname: Koulouras
authors.forename: Stauros C
authors.initials: SC
authors.lastname: Efremidis
authors.forename: Georgios
authors.initials: G
authors.lastname: Nakos
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D001239:Inhalation; D008168:Lung / Q000000981:diagnostic imaging; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D016684:Prone Position / Q000502:physiology*; D011650:Pulmonary Alveoli / Q000503:physiopathology*; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000517:prevention & control*; D015656:Respiratory Mechanics; D016683:Supine Position; D014057:Tomography, X-Ray Computed