title: Recruitment maneuvers modulate epithelial and endothelial cell response according to acute lung injury etiology.
abstract: OBJECTIVE
  To investigate the effects of the rate of increase in airway pressure and duration of lung recruitment maneuvers in experimental pulmonary and extrapulmonary acute lung injury.
  
  
  METHODS
  Prospective, randomized, controlled experimental study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Fifty adult male Wistar rats.
  
  
  METHODS
  Acute lung injury was induced by Escherichia coli lipopolysaccharide either intratracheally (pulmonary acute lung injury) or intraperitoneally (extrapulmonary acute lung injury). After 24 hours, animals were assigned to one of three different recruitment maneuvers, targeted to maximal airway pressure of 30 cm H2O: 1) continuous positive airway pressure for 30 seconds (CPAP-30); 2) stepwise airway pressure increase (5 cm H2O/step, 8.5 s at each step) over 51 seconds (STEP-51) to achieve a pressure-time product similar to that of CPAP-30; and 3) stepwise airway pressure increase (5 cm H2O/step, 5 s at each step) over 30 seconds with maximum pressure sustained for a further 30 seconds (STEP-30/30).
  
  
  RESULTS
  All recruitment maneuvers reduced static lung elastance independent of acute lung injury etiology. In pulmonary acute lung injury, CPAP-30 yielded lower surfactant protein-B and higher type III procollagen expressions compared with STEP-30/30. In extrapulmonary acute lung injury, CPAP-30 and STEP-30/30 increased vascular cell adhesion molecule-1 expression, but the type of recruitment maneuver did not influence messenger ribonucleic acid expression of receptor for advanced glycation end products, surfactant protein-B, type III procollagen, and pro-caspase 3.
  
  
  CONCLUSIONS
  CPAP-30 worsened markers of potential epithelial cell damage in pulmonary acute lung injury, whereas both CPAP-30 and STEP-30/30 yielded endothelial injury in extrapulmonary acute lung injury. In both acute lung injury groups, recruitment maneuvers improved respiratory mechanics, but stepwise recruitment maneuver without sustained airway pressure appeared to associate with less biological impact on lungs.
authors.affiliation: 1Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. 2Laboratory of Experimental Surgery, Faculty of Medicine, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. 3Laboratory of Cellular and Molecular Physiology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. 4Department of Pathology, School of Medicine, University of São Paulo, São Paulo, Brazil. 5Rio de Janeiro Federal Institute of Education, Science and Technology, Rio de Janeiro, Brazil. 6Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Therapy, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden, Germany. 7IRCCS AOU San Martino-IST, Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy. 8University of Minnesota, Minnesota Regions Hospital, Pulmonary and Critical Care Medicine, Minneapolis-St Paul, MN.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Silva
authors.forename: Lillian
authors.initials: L
authors.lastname: Moraes
authors.forename: Raquel S
authors.initials: RS
authors.lastname: Santos
authors.forename: Cynthia
authors.initials: C
authors.lastname: Samary
authors.forename: Maíra B A
authors.initials: MB
authors.lastname: Ramos
authors.forename: Cintia L
authors.initials: CL
authors.lastname: Santos
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Morales
authors.forename: Vera L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: Cristiane S N B
authors.initials: CS
authors.lastname: Garcia
authors.forename: Marcelo Gama
authors.initials: MG
authors.lastname: de Abreu
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: John J
authors.initials: JJ
authors.lastname: Marini
authors.forename: Patricia R M
authors.initials: PR
authors.lastname: Rocco
mesh_terms: D055371:Acute Lung Injury / Q000382:microbiology / Q000503:physiopathology*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D042783:Endothelial Cells / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D008170:Lung Compliance / Q000502:physiology*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D015415:Biomarkers