Evolution of tracheobronchial colonization following tracheal intubation in neuro-injured ventilated patients: the INSPIRE study

Background Characteristics and course of endotracheal secretions have scarcely been studied in patients under mechanical ventilation (MV) at risk of developing ventilator-associated pneumonia (VAP). Research question Exhaustive description of endotracheal secretions and determination of their predictive value for the diagnosis of VAP during MV. Study design and methods Single-center prospective study in neuro-injured patients requiring MV for at least 7 days. Patients with pulmonary and infectious diseases were ineligible. All endotracheal aspirates (ETA) collected between tracheal intubation and Day7 were analyzed. Macroscopic characteristics and microbiology were assessed. CPIS was calculated daily. A blinded adjudication committee validated all VAP events. Results Forty-eight patients and 1544 ETAs were analyzed. Overall, 81% of the ETA were purulent and 50% were thick. Culture results showed high inter- and intra-individual variability. Ten patients (21%) developed an early VAP. Eight patients (80%) with VAP and 14 (37%) without had a CPIS>6. The day before VAP diagnosis, a 20-mL increase in ETA volume detected a VAP with a sensitivity of 67% and a specificity of 93%. Interpretation Our study provides new information on the course of respiratory colonization in mechanically ventilated patients and suggests that ETA color and aspect, and pathogens kinetics cannot predict VAP. Traditional VAP criteria (CPIS and bacterial load) had also a low diagnostic specificity. Contrariwise, an increase in secretion volume should alert for VAP development.