New approaches to prevention and treatment of nosocomial pneumonia.

The critical care environment contributes to the development of respiratory infections. The mortality rate of nosocomial pneumonia is as high as 50% to 70%, and approximately half of the deaths are directly attributable to the presence of lung infection. Altered host defenses, emergence of bacterial resistance, and technological advances that result in various therapeutic interventions contribute to pneumonia and its associated mortality in the critically ill population. Nasogastric intubation, elevated gastric pH, large gastric volumes, and endotracheal intubation may all promote exposure of the lungs to large numbers of bacteria. An understanding of the pathogenesis of this serious illness could allow us to devise methods for curbing the incidence and severity of the disease. The clinical setting in which pneumonia develops can be a guide to the organisms responsible, and an understanding of this relationship is helpful in developing a treatment plan. The diagnosis of nosocomial pneumonia is not always accurate, and empiric therapy with appropriately selected antibiotics can be potentially life-saving.