A new tracheo-bronchial closed-suction system has been recently introduced. The Trach Care catheter can be connected to the endotracheal tube of a patient on mechanical ventilation and be left in place as long as 24 h. Thus, suctioning does not require disconnection from the mechanical ventilator. We evaluated the benefits of this new system in 20 patients receiving mechanical ventilation; ten patients required PEEP of 10 cm H2O and under, while the other ten patients needed PEEP over 10 cm H2O to maintain acceptable oxygenation. PaCO2, arterial oxygen saturation, and alveolar-arterial oxygen tension difference were measured before and after suctioning, using a conventional catheter and the Trach Care closed-suction method. Oxygenation only deteriorated when the open technique was used in patients receiving over 10 cm H2O of PEEP. The changes were statistically, but not clinically, significant. The Trach Care system is approximately 25 times as expensive as conventional suctions catheter, so its use cannot be justified economically. A potential advantage of the technique is preventing the dissemination of contaminated secretions, which are dispersed when the patient is disconnected from the ventilator and inspiratory gas flow persists. While no universal advantage of the closed-suction system was found, potential benefits may be considered on a case-by-case basis.