Severe hospital-acquired pneumonia: a review for clinicians.

Hospital-acquired pneumonia (HAP) is one of the most commonly encountered nosocomial infections. Patients who develop severe HAP experience considerable morbidity and mortality, and the condition results in a substantial expenditure of health care resources. A large body of scientific literature about HAP now exists. This article summarizes the current state of knowledge concerning severe HAP with an emphasis on recent advances in its diagnosis, treatment, and prevention.