Ventilator-associated pneumonia is a lung infection that develops in a person who is on a ventilator. A ventilator is a machine that is used to help a patient breathe by giving oxygen through a tube placed in a patient’s mouth or nose, or through a hole in the front of the neck. The most common cause of ventilator-associated pneumonia is micro aspiration of bacteria that colonize the oropharynx and upper airways in seriously ill patients. Ventilator-associated pneumonia includes clinical signs of purulent tracheal discharge, fevers, respiratory distress, and micro-biological signs of the presence of microorganisms along with white blood cells in the tracheal aspirate along with radiological evidence of pneumonia.