Ventilator-associated pneumonia (VAP) is a major concern in the intensive
care unit. It is estimated that the risk of developing VAP may be as high as
1% per ventilated day, and the attributable mortality approaches 50% in some
series. A growing body of evidence implicates the role of microaspiration of
contaminated oropharyngeal and perhaps gastroesophageal secretions into the
airways as an integral step in the pathogenesis of VAP. In patients who have
been intubated and mechanically ventilated for >72 hours, the majority of
VAP is caused by enteric gram-negative organisms, presumably of
gastrointestinal origin. As a result, strategies designed to minimize the risk
of these contaminated secretions into the normally sterile airways are of
paramount importance in terms of VAP prevention. This review highlights the
important etiological role of the gut in the development of VAP and also
discusses the evidence behind interventions that may modulate the risk of both
aspiration and subsequent VAP.
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