The leakage of oropharyngeal secretions around high-volume low-pressure tracheal tube cuffs is usually considered as a major risk factor for bacterial tracheal colonization and subsequent development of ventilator-associated pneumonia. The rate of leakage around the cuff is related to the pressure differential across the cuff, namely the difference between the pressure of the subglottic fluid above the cuff and the tracheal pressure under the cuff. Consequently, positive end-expiratory pressure (PEEP) improves the sealing around the cuff towards fluid leakage. However, this preventive effect of PEEP is compromised during prolonged mechanical ventilation by tracheal suctioning manoeuvre, which may enhance fluid leakage, by decreasing tracheal pressure. Indeed, in a benchtop model, a suctioning manoeuvre, without disconnection of the ventilator, induced a constant fluid leakage past a high-volume low-pressure tracheal tube cuff when performed with a high level of suction pressure (- 400 mbar) and a large size of suction catheter size (16 French).

This clinical study aims to confirm these experimental data in patients under mechanical ventilation.

Inclusion Criteria:

• intubated with a Hi-Lo Evac tube since less than 48 hours
• under continuous sedation
• written consent signed

Exclusion Criteria:

• hemodynamic instability
• allergy of blue dye