title: Factors associated with variation in intracranial pressure in a model of intra-abdominal hypertension with acute lung injury.
abstract: OBJECTIVE
  To evaluate the effects of hemodynamic, respiratory and metabolic changes on intracranial pressure in a model of acute lung injury and abdominal compartment syndrome.
  
  
  METHODS
  Eight Agroceres pigs were submitted to five different clinical scenarios after instrumentation: 1) a baseline condition with low intra-abdominal pressure and healthy lungs; 2) pneumoperitoneum with 20 mmHg intra-abdominal pressure; 3) acute lung injury induced by pulmonary lavage with surfactant deactivation; 4) pneumoperitoneum with 20 mmHg intra-abdominal pressure with lung pulmonary injury and low positive end-expiratory pressure; and 5) 27 cmH2O positive end-expiratory pressure with pneumoperitoneum and acute lung injury. Respiratory and hemodynamic variables were collected. A multivariate analysis was conducted to search for variables associated with increased intracranial pressure in the five scenarios.
  
  
  RESULTS
  Only plateau airway pressure showed a positive correlation with intracranial pressure in the multivariate analysis. In the models with acute lung injury, plateau airway pressure, CO2 arterial pressure, end tidal CO2 and central venous pressure were positively correlated with increased intracranial pressure.
  
  
  CONCLUSIONS
  In a model of multiple organ dysfunction with associated clinical conditions causing increased intra-thoracic and abdominal pressure, increased intracranial pressure triggered by elevated intra-abdominal pressure is apparently caused by worsened respiratory system compliance and a reduced brain venous drainage gradient due to increased central venous pressure.
authors.affiliation: Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Fernando Godinho
authors.initials: FG
authors.lastname: Zampieri
authors.affiliation: Hospital Sírio-Libanês, São Paulo, SP, Brasil.
authors.forename: Juliana Roberta
authors.initials: JR
authors.lastname: Almeida
authors.affiliation: Hospital Sírio-Libanês, São Paulo, SP, Brasil.
authors.forename: Guilherme Pinto de Paula
authors.initials: GP
authors.lastname: Schettino
authors.affiliation: Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Park
authors.affiliation: Hospital Sírio-Libanês, São Paulo, SP, Brasil.
authors.forename: Fabio Santana
authors.initials: FS
authors.lastname: Machado
authors.affiliation: Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Luciano Cesar Pontes
authors.initials: LC
authors.lastname: Azevedo