Justification and background Ventilator-associated complications (VACs) are those complications that develop during a period of intubation of a patient . Pneumonia is the second most frequent infectious complication in the hospital, and ranks first in ICU, whose risk is increased more than 20 times by the presence of invasive mechanical ventilation and is called ventilator-associated pneumonia (VAP) . Whereas the information published regarding VAP in terms of diagnosis, treatment and impact on the outcome of critically ill patients is enormous.Ventilator-associated tracheobronchitis (VAT) incidence is lacking and complicated in part, since the definition remains controversial. In addition, the significance of tracheobronchial colonization as a risk factor for subsequent lower respiratory tract infection remains unclear . The upper and lower airways can become colonized . Several factors have been taken into account and do not differ from those involved in VAT and VAP development in patients under mechanical ventilation.

Definition VAT diagnosis is controversial and represents an actual problem in order to define the real incidence of VAT , There is currently no valid, reliable definition for VAT, and even the most widely-used VAT criteria and definitions are neither sensitive nor specific. The diagnosis of VAT is considered when a patient under invasive mechanical ventilation starts with fever, leukocytosis and new or increased purulent secretions by the endotracheal tube. A particular difficulty with much commonly used VAT definition (in order to distinguish from VAP) is the key point of the absence of pulmonary consolidation. Evidence suggests that chest radiograph findings do not accurately role out VAP. A taskforce on hospital-acquired pneumonia, and VAP has been recently published (European Respiratory Society (ERS), European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and European Society of Intensive Care Medicine (ESICM)). Nosocomial tracheobronchitis definition includes occurrence of purulent tracheal secretion after ≥48 h of hospitalisation or mechanical ventilation plus ≥2 of the following: fever (≥38.5°C) or hypothermia (<36°C), leukocytosis (≥12 × 109/L), significant bacteriologic counts in respiratory secretions (≥103 cfu/mL for protected brush specimen (PBS) and ≥105 cfu/mL for endotracheal aspirates); absence of new pulmonary infiltrates compatible with pneumonia and absence of other causes of fever are mandatory. This definition needs to be further validated and can overdiagnose the incidence of VAT (and overuse of antibiotics) because the positive culture of respiratory secretions is not a mandatory item RATIONALE Given the possible high incidence of VAT, and its importance as a risk factor for VAP, and a potential target to treat in order to reduce VAP incidence, a large multicentre

METHODS This prospective international multicentre observational study will be conducted in 8 countries ((Spain, France, Portugal, Brazil, Argentina, Ecuador, Bolivia and Colombia).) Inclusion criteria 10-20 consecutive admissions with a predictive duration of intubation and mechanical ventilation > 48h.

Exclusion criteria Predicted duration of intubation and mechanical ventilation ≤ 48h. Tracheostomy at ICU admission. Primary objective To determine the incidence of VAT in patients requiring intubation and mechanical ventilation >48h.

Secondary objectives To determine risk factors for VAT. To determine incidence and risk factors for transition from VAT to VAP. To determine microorganisms associated with VAT. To determine the impact of VAT on outcome.

Inclusion Criteria:

• 10-20 consecutive admissions with a predictive duration of intubation and mechanical ventilation > 48h.

Exclusion Criteria:

• Predicted duration of intubation and mechanical ventilation ≤ 48h.
• Tracheostomy at ICU admission.

10-20 consecutive admissions with a predictive duration of intubation and mechanical ventilation > 48h.