Evaluation of a Closed Suction System to Remove Secretions From the Endotracheal Tube

Inclusion Criteria: * Patients admitted to an ICU * 18 years old or more * expected to be intubated for more than 48 hours * less than 24 hours from intubation * fraction of inspired oxygen set at the ventilator \<80% Exclusion Criteria: * Current or past participation in another intervention trial conflicting with the present study * expected survival less than 24 hours * Acute severe asthma * Use of Extracorporeal membrane oxygenation (ECMO) or candidates for ECMO * Double lumen endotracheal tube in place * Conditions which pose the patient at high risk if inadvertent endotracheal tube displacement occurs (laryngeal edema, cervical spine trauma, upper airways diseases with difficult reintubation) * other contraindications posed by staff physicians