Fever > 38.3
Increased FiO2 requirement
Worsening sepsis
Leukocyte count > 10,000 or <5,000
New infiltrate on CXR
Difficult to diagnose with pre-existing infiltrates
Difficult to diagnose with pre-existing infiltrates
Ventilator associated pneumonia
Deterioration After Intubation 
Severe acute respiratory syndrome
ARDS
Aspiration pneumonia and pneumonitis
Pulmonary embolism
Ventilator associated lung injury
Pulmonary infarction