Closed system endotracheal suctioning maintains lung volume during volume-controlled mechanical ventilation

Objective: A closed suction system (CS) maintains connection with the mecha nical ventilator during tracheal suctioning and is claimed to limit loss in lung volume and oxygenation. We compared changes in lung volume, oxygenati on, airway pressure and hemodynamics during endotracheal suctioning perform ed with CS and with an open suction system (OS). Design: Prospective, randomized study. Setting: Intensive care unit in a university hospital. Patients: We enrolled ten patients, volume-controlled (VC) ventilated with a Siemens Servo 900 ventilator (PaO2/FIO2 192 +/- 70. PEEP 10.7 +/- 3.9 cmH (2)O). Interventions: We performed four consecutive tracheal suction maneuvers, tw o with CS and two with OS, at 20-min intervals. During the suction maneuver s continuous suction was applied for 20 s. Measurements and main results: We measured end-expiratory lung volume chang es (DeltaV(L)) tidal volume (V-Trt), respiratory rate (RR) and minute volum e (V-Ert) by respiratory inductive plethysmography; arterial oxygen saturat ion (SpO(2)), airway pressure and arterial pressure (PA). Loss in lung volu me during OS (DeltaV(L) 1.2 +/- 0.71) was significantly higher than during CS (DeltaV(L) 0.14 +/- 0.1 I). During OS we observed a marked drop in SpO(2 ), while during CS the change was only minor. During CS ventilation was not interrupted and we observed an immediate increase in RR (due to the activa tion of the ventilator's trigger), while V-Trt decreased, V-Ert was maintai ned. Conclusions: Avoiding suction-related lung volume loss can be helpful in pa tients with an increased tendency to alveolar collapse, CS allows auctionin g while avoiding dramatic drops in lung volumes and seems to be safe during the VC ventilation setting that we used.