Aspiration and the Risk of Ventilator‐Associated Pneumonia

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.