Endotracheal tube alters host defences, impairs mechanical clearance from the respiratory tract, causes local trauma and inflammation, and allows pooling of secretions around the cuff. The pressure of the endotracheal tube-cuff should be sufficient to prevent the leakage of colonized subglottic secretions into the lower airway [37] . Also, continuous or intermittent suctioning of oropharyngeal and upper respiratory tract secretions above endotracheal cuffs can prevent aspiration. Endotracheal tubes with a separate dorsal lumen above the cuff, designed to suction the subglottic secretions continuously, were found able to decrease the rates of early-onset VAP [124, 125] . However, in another randomised trial, no benefit with continous subglottic suction on the overall VAP frequency was found [126] . It can reduce but not eliminate the volume of fluid aspirated into the lungs. The lack of effect on prevention of late-onset pneumonia and the high cost of these tubes restrict the usage of them.