ABSTRACT
Pneumonia is the most relevant respiratory infection in mechanically ventilated patients. It is defined as the presence of microorganisms in the pulmonary parenchyma leading to the development of an inflammatory response by the host, which may be localized to the lung or may extend systemically. Nosocomial pneumonia (NP) is an infectious process that develops within 48 hours after admission to hospital and was not incubating at the time of hospitalization. Ventilator-associated pneumonia (VAP) is considered a subgroup of NP and is an infectious pulmonary process that develops 48 hours after the presence of an artificial airway and mechanical ventilation (MV). Since a large proportion of the patients who develop NP are intubated and receive MV, most epidemiological and clinical studies on NP have been focused on critically ill patients and those receiving MV. From a clinical point of view, NP is of great importance, both because of its consequences in terms of morbidity and mortality and because of the high costs associated with this condition.
