title: Prone positioning improves oxygenation without adverse hemodynamic effects during partial liquid ventilation in a canine model of acute lung injury.
abstract: BACKGROUND
  Partial liquid ventilation (PLV) and prone positioning can improve the arterial oxygenation (PaO2) in acute lung injury (ALI). We evaluated the effect of prolonged prone positioning during partial liquid ventilation (PLV) in a canine model of acute lung injury.
  
  
  METHODS
  Six mongrel dogs (weighing 17.4 +/- 0.7 kg each) were anesthetized, intubated and mechanically ventilated. After 1 hour of baseline stabilization, the dogs' lungs were instilled with 40 mL/kg perfluorocarbon (PFC). PLV was first performed in the supine position for 1 hour (S1), then in the prone position for 3 hours with hourly measurements (P1, P2, P3), and finally, PLV was performed with the animal turned back to the supine position for 1 hour (S2).
  
  
  RESULTS
  After instillation of the PFC, the PaO2 significantly increased from 992 +/- 32.6 mmHg at baseline to 198.1 +/- 59.2 mmHg at S1 (p = 0.001). When the dogs were turned to the prone position, the PaO2 further increased to 288.3 +/- 80.9 mmHg at P1 (p = 0.008 vs. S1): this increase was maintained for 3 hours, but the PaO2 decreased to 129.4 +/- 62.5 mmHg at S2 (p < 0.001 vs. P3). Similar changes were seen in the shunt fraction. There were no significant differences for the systemic hemodynamic parameters between the prone and supine positions.
  
  
  CONCLUSIONS
  Prolonged prone positioning during PLV in an animal model of ALI appears to improve oxygenation without any hemodynamic compromise.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jung Hye
authors.initials: JH
authors.lastname: Hwang
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Kwon
authors.forename: Eun Hae
authors.initials: EH
authors.lastname: Kang
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Koh
authors.forename: Kyeong Woo
authors.initials: KW
authors.lastname: Kang
authors.forename: Ho Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Man Pyo
authors.initials: MP
authors.lastname: Chung
authors.forename: Hojoong
authors.initials: H
authors.lastname: Kim
authors.forename: O Jung
authors.initials: OJ
authors.lastname: Kwon
authors.forename: Gee Young
authors.initials: GY
authors.lastname: Suh
mesh_terms: D000818:Animals; D004285:Dogs; D021061:Liquid Ventilation / Q000379:methods*; D023421:Models, Animal; D016684:Prone Position / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*