Nosocomial pneumonia: Problems and progress

Abstract

N osocomial pneumonia is one of the most formidable complications to which the hospitalized patient is prey, with a mortality rate estimated at between 30% and 70%. 1 Although not uncommon on general medical and surgical wards, pneumonia is primarily a disease of the intensive care unit (ICU), where it is the most common nosocomial infection. Patients for whom mechanical-ventilation is required have an incidence of pneumonia nearly 20 times that of nonintubated patients. Crude incidence ratios suggest that some 25% of intubated patients may develop pneumonia according to clinical criteria with rates differing according to the type of ICU. 1 Recent estimates by the Centers for Disease Control put nosocomial pneumonia responsible for an average of 5.9 days of increased length of stay and nearly $6000 in hospital charges. 2 In the nonintubated patient, pneumonia occurs primarily because of aspiration of oropharyngeal-colonizing bacteria into the lungs, which sedatives and neurologic deficits can facilitate. For the patient receiving mechanical ventilation, however, airway defenses are bypassed by numerous tubes such as endotracheal, nasotracheal, and nasogastric tubes. Although the cuffed endotracheal tube is commonly thought to block the aspiration of bacteria-laden, upper airway secretions into the lower respiratory tree, it is an