title: Net alveolar fluid clearance is associated with lung morphology phenotypes in acute respiratory distress syndrome.
abstract: BACKGROUND
  The acute respiratory distress syndrome (ARDS) is a heterogeneous syndrome that encompasses multiple phenotypes, e.g. with regards to lung morphology as assessed by computed tomography (CT). Focal or non-focal lung morphology may influence the response to positive end-expiratory pressure (PEEP), recruitment manoeuvres and prone position. Lung morphology has been hypothesized to be associated with alveolar fluid clearance (AFC), thus explaining various responses to such therapeutic interventions; however, this hypothesis has not been specifically studied in humans.
  
  
  METHODS
  We measured net AFC rates in 30 patients with ARDS as a secondary data analysis of a prospective single-centre study. Net AFC rates were compared between patients with focal ARDS and those with non-focal ARDS, as assessed by lung CT-scans.
  
  
  RESULTS
  Net AFC rates were significantly lower in patients with non-focal ARDS (n=23; median [interquartile range], 1.5 [0-5.5] %/h) as compared to those with focal ARDS (n=7; 10.3 [4.5-15] %/h) (P=0.01). The area under the receiver-operating characteristic curve when net AFC rates were used to differentiate the presence from absence of non-focal ARDS was 0.93 (95% confidence interval, 0.81-1). Tidal volumes and PEEP levels differed between focal and non-focal ARDS patients, but there was no difference in arterial oxygenation or in alveolar-capillary permeability.
  
  
  CONCLUSIONS
  Non-focal lung morphology may be characterized by a functional endotype consistent with marked AFC impairment. Despite study limitations and the need for validating studies in larger cohorts, such novel findings may reinforce our understanding of the association between ARDS phenotypes and therapeutic responses.
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France. Electronic address: mjabaudon@chu-clermontferrand.fr.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Jabaudon
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Raiko
authors.initials: R
authors.lastname: Blondonnet
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Lutz
authors.affiliation: EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France; Department of Medical Biochemistry and Molecular Biology, CHU de Clermont-Ferrand, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Roszyk
authors.affiliation: EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France; Department of Medical Biochemistry and Molecular Biology, CHU de Clermont-Ferrand, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Bouvier
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France.
authors.forename: Renaud
authors.initials: R
authors.lastname: Guérin
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Perbet
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Cayot
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Godet
authors.affiliation: EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Blanchon
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Jean-Etienne
authors.initials: JE
authors.lastname: Bazin
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Futier
authors.affiliation: EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France; Department of Medical Biochemistry and Molecular Biology, CHU de Clermont-Ferrand, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Sapin
authors.affiliation: Department of Perioperative Medicine, CHU de Clermont-Ferrand, Intensive Care Unit, University Hospital of Clermont-Ferrand, 63003 Clermont-Ferrand, France; EA 7281, R2D2, Clermont Université, Université d'Auvergne, 63003 Clermont-Ferrand, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Constantin
mesh_terms: D000368:Aged; D002199:Capillary Permeability; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010366:Peak Expiratory Flow Rate; D010539:Permeability; D010641:Phenotype; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000503:physiopathology*; D012128:Respiratory Distress Syndrome / Q000473:pathology* / Q000503:physiopathology*; D013990:Tidal Volume; D014057:Tomography, X-Ray Computed
chemical_list: D010100:Oxygen
keywords: Alveolar epithelium; Alveolar fluid clearance; Endotype; Lung morphology; Phenotype; Pulmonary oedema