 This proposal investigates the utility of exhaled breath condensate fluid EBCF collected from heat moisture exchange HME filters connected to patients endotracheal tubes for early, non-invasive detection of ventilator-associated pneumonia VAP in critically ill or injured ICU patients. The development of pneumonia during mechanical ventilation is the most common healthcare-associated infection in severely injured patients, accounting for substantial morbidity, excess ICU and hospital stay, additional cost and increased mortality. 