Does animal model on ventilator-associated pneumonia reflect physiopathology of sepsis mechanisms in humans?

Ventilator-associated pneumonia (VAP) is the leading cause of death in critically ill patients in intensive care units. In the last 20 years, different animal models have been a valuable tool for the study of pathophysiology and phenotypic characteristics of different lung infections observed in humans, becoming an essential link between ‘‘in vitro’’ testing and clinical studies. Different animal models have been used to study the mechanism of a deregulated inflammatory response and host tissue damage of sepsis in VAP, as well as different infection parameters such as clinical, physiological, microbiological and pathological facts in several large and small mammals. In addition, the dosage of inflammatory modulators and their consequences in local and systemic inflammation, or even the administration of antibiotics, have been evaluated with very interesting results. Although some bronchial inoculation ways do not resemble the common pathophysiologic mechanisms, the experimental model of VAP induced by the inoculation of high concentrations of pathogens in mechanically ventilated animals is useful for studying the local and systemic responses of sepsis in VAP and it reproduces biological mechanisms such as acute lung injury, distress response, cardiac events and immune modulation comparable with clinical studies