Comparison of multiple definitions for Ventilator-Associated Pneumonia in patients requiring mechanical ventilation for non-pulmonary conditions: preliminary data from PULMIVAP, an Italian multicentre cohort study

Objectives: Compare intensivist-diagnosed VAP (iVAP) with four established definitions, assessing their agreement in detecting new episodes. Methods: Analysis from multicentric prospective study on pulmonary microbiota in patients requiring mechanical ventilation (MV). Data collected were used to compare hypothetical VAP onset according to iVAP with the study consensus criteria, the European Centre for Diseases Control and Prevention definition, and two versions of the latter adjusted for leukocyte count and fever. Results: In our cohort of 186 adult patients, iVAPs were 36.6% (68/186,95%CI=30.0%-44.0%), with an incidence rate of 4.64/100 patient-MVdays, and median MV-day at diagnosis of 6. Forty-seven percent of patients (87/186) were identified as VAP by at least one criterion, with a median MV-day at diagnosis of 5. Agreement between intensivist judgement (iVAP/no-iVAP) and the criteria was highest for the study consensus criteria (50/87, 57.4%), but still one-third of iVAP was not identified and 9% of patients were identified as VAP against intensivist diagnosis. VAP proportion differed among different criteria (25.2-30.1%). Conclusions: Caution is needed evaluating studies describing VAP incidence. Pre-agreed criteria and definitions that capture VAP's evolving nature provide greater consistency, but new clinically-driven definitions are needed to align surveillance and diagnostic criteria with clinical practice.