title: Effects of different tidal volumes in pulmonary and extrapulmonary lung injury with or without intraabdominal hypertension.
abstract: OBJECTIVE
  We hypothesized that: (1) intraabdominal hypertension increases pulmonary inflammatory and fibrogenic responses in acute lung injury (ALI); (2) in the presence of intraabdominal hypertension, higher tidal volume reduces lung damage in extrapulmonary ALI, but not in pulmonary ALI.
  
  
  METHODS
  Wistar rats were randomly allocated to receive Escherichia coli lipopolysaccharide intratracheally (pulmonary ALI) or intraperitoneally (extrapulmonary ALI). After 24 h, animals were randomized into subgroups without or with intraabdominal hypertension (15 mmHg) and ventilated with positive end expiratory pressure = 5 cmH(2)O and tidal volume of 6 or 10 ml/kg during 1 h. Lung and chest wall mechanics, arterial blood gases, lung and distal organ histology, and interleukin (IL)-1β, IL-6, caspase-3 and type III procollagen (PCIII) mRNA expressions in lung tissue were analyzed.
  
  
  RESULTS
  With intraabdominal hypertension, (1) chest-wall static elastance increased, and PCIII, IL-1β, IL-6, and caspase-3 expressions were more pronounced than in animals with normal intraabdominal pressure in both ALI groups; (2) in extrapulmonary ALI, higher tidal volume was associated with decreased atelectasis, and lower IL-6 and caspase-3 expressions; (3) in pulmonary ALI, higher tidal volume led to higher IL-6 expression; and (4) in pulmonary ALI, liver, kidney, and villi cell apoptosis was increased, but not affected by tidal volume.
  
  
  CONCLUSIONS
  Intraabdominal hypertension increased inflammation and fibrogenesis in the lung independent of ALI etiology. In extrapulmonary ALI associated with intraabdominal hypertension, higher tidal volume improved lung morphometry with lower inflammation in lung tissue. Conversely, in pulmonary ALI associated with intraabdominal hypertension, higher tidal volume increased IL-6 expression.
authors.affiliation: Laboratório de Investigação Pulmonar, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Ilha do Fundão, Rio de Janeiro 21941-902, Brazil.
authors.forename: Cíntia L
authors.initials: CL
authors.lastname: Santos
authors.forename: Lillian
authors.initials: L
authors.lastname: Moraes
authors.forename: Raquel S
authors.initials: RS
authors.lastname: Santos
authors.forename: Mariana G
authors.initials: MG
authors.lastname: Oliveira
authors.forename: Johnatas D
authors.initials: JD
authors.lastname: Silva
authors.forename: Tatiana
authors.initials: T
authors.lastname: Maron-Gutierrez
authors.forename: Débora S
authors.initials: DS
authors.lastname: Ornellas
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Morales
authors.forename: Vera L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: Nelson
authors.initials: N
authors.lastname: Jamel
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Patricia R M
authors.initials: PR
authors.lastname: Rocco
authors.forename: Cristiane S N B
authors.initials: CS
authors.lastname: Garcia
mesh_terms: D055371:Acute Lung Injury / Q000276:immunology* / Q000473:pathology; D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D024061:Collagen Type III; D016207:Cytokines / Q000276:immunology; D004926:Escherichia coli; D007263:Infusions, Parenteral; D059325:Intra-Abdominal Hypertension / Q000150:complications / Q000276:immunology*; D007442:Intubation, Intratracheal; D008070:Lipopolysaccharides / Q000008:administration & dosage; D011175:Positive-Pressure Respiration / Q000379:methods; D011658:Pulmonary Fibrosis / Q000209:etiology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013990:Tidal Volume / Q000502:physiology*
chemical_list: D024061:Collagen Type III; D016207:Cytokines; D008070:Lipopolysaccharides