Future considerations in aspiration pneumonia in the critically ill patient: what is not known, areas for future research, and experimental methods.

The medical literature supports the use of enteral feeding to provide nutrition and improve patient outcomes. A major complication of enteral feeding is aspiration and associated morbidity and mortality. Many knowledge gaps exist that inhibit our ability to define and diagnose aspiration, identify patients at risk, and develop prevention techniques. Several areas of inquiry should be explored to help us define and prevent the disorder--for instance, standardized criteria should be developed for diagnosing aspiration pneumonia and for differentiating it from other types of pneumonia, and accurate tests should be devised for detecting it. Research also is needed to evaluate the influence of (1) various enteral feeding sites on aspiration risk, (2) the effects of risk reduction techniques such as selective decontamination and use of promotility agents, and (3) potential benefits of immunonutrition. Current parameters used in decisions about when to initiate enteral feeding in critically ill patients are defined.