Causes of failure in acute respiratory distress syndrome modeling and treatment in animal research and new approaches

Table 1 Animal models of acute respiratory distress syndrome

Direct lung injury	Intratracheal or intranasal delivery of bacteria or bacterial product such as lipopolysaccaride
	Hydrochloric acid or gastric particles to create acid aspiration
	High inspired fraction of oxygen
	Surfactant depletion (0.9% NaCl lavage)
	Lung ischemia/reperfusion
	Mechanical ventilation at high tidal volumes
Indirect lung injury	Cecal ligation and puncture
	Intravenous bacteria or LPS administration
	Mesenteric ischemia/reperfusion
	Oleic acid model
Combination models	Cecal ligation and puncture followed by hemorrhage
	Saline lavage after mechanical ventilation
	Intraperitoneal LPS injection after intravenous oleic acid

LPS: Lipopolysaccharide.