ABSTRACT
The acute respiratory distress syndrome (ARDS), the most severe form of
acute lung injury (ALI), is a devastating clinical syndrome affecting approximately 1,000,000 people worldwide per year. Despite recent advances, the
mortality rate is at least 30% (1). Predisposing factors for ARDS are diverse (2,3) and include sepsis, pneumonia, aspiration, trauma, and severe acute
respiratory syndrome. No drug has been proven to improve the clinical
outcome of ARDS, and therapy is largely supportive with mechanical venti-
lation (MV). However, MV can cause and/or worsen preexisting lung injury,
the so-called ventilator-induced lung injury (VILI). Although the most
obvious clinical and laboratory abnormalities of ARDS are related to the lung, death is usually due to the dysfunction of other organs, termed ‘‘multi-
ple organ dysfunction syndrome’’ (MODS) (1). One hypothesis that has
recently been advanced to explain this observation is that MV per se may
not only be responsible for worsening of the preexisting lung injury but also,
by a number of mechanisms including the development of systemic inflam-
matory response, contribute to the development of MODS (Fig. 1) (4).
