Diagnosis of Pulmonary Infections

Two types of pulmonary infections are important in critical care medicine: infections which cause severe alterations of gas exchange and respiratory failure and infections which arise as complications of another critical illness. The former are generally community-acquired infections, while the latter obviously arise within the hospital, usually the intensive care unit (ICU). Organisms responsible for these two types of infection differ and different diagnostic approaches may be required. This chapter will focus on methods for ascertaining the correct diagnosis in seriously ill patients suspected of having either type of respiratory infection.