PURPOSE: Ventilator-associated events (VAE) are surveillance paradigms established by the CDC, and they denote three categories of increasing progression from a ventilator-associated condition (VAC), to an infection-related ventilator-associated condition (IVAC), and finally to ventilator-associated pneumonia (VAP). Moreover, the first criteria for VAC can only be met after 2 days of stable daily values (PEEP or FiO2). Following a period of two days of more of instability, additional specific criteria, such as WBCs, temperature, antimicrobial therapy, and a positive culture, would need to be met to move through the remaining categories. Considering VAEs are rather new in critical care, there has been a growing interest in quantifying these definitions for practical application. While a distinction exists between an early onset (the first 4 days) and a late onset (after the 4th day) of VAP, very little information exists on the duration of intubation before a VAE. Furthermore, some studies have looked at the incidence of early onset VAP in the ICU, found that the highest observed number of cases occurred in day 3 and 4 after admission and that the incidence increases with the duration of mechanical ventilation and the median time from ICU admission to the onset of the first episodes was 6 days.