The Influence of pH Elevation on the Incidence of Nosocomial Pneumonia.

Nosocomial pneumonia, one of the most common hos pital-acquired infectious diseases, is associated with sub stantial morbidity and mortality, approaching 50% in selected patients. Patients with alterations in their tracheobronchial tree or natural host-defense mecha nisms are at increased risk of developing pneumonia. Organisms gain access to the normally sterile tracheo bronchial tree primarily by aspiration of colonized oro pharyngeal gastric secretions. Risk factors for bacterial colonization and the development of nosocomial pneu monia include increased age, elevated pH of gastric con tents, postoperative state, nutritional status, severe underlying disease (for example, chronic obstructive pulmonary disease), administration of corticosteroids or other immunosuppressive therapy, and intubation or mechanical ventilation. High gastric volume may also increase the chance of aspiration of secretions in some high-risk patients.