تشخيص ذات الرئة عند مرضى التنفس الاصطناعي

All patients on mechanical ventilation are colonized with gram negative bacteria in upper and lower airways within 74-96 hours, so it's difficult to sort out true pneumonia vs colonization.
for a diagnosis of pneumonia, you should see:

1- new or increasing infiltrate
2- elevated WBC
3- purulent sputum
4- fever or hypothermia