Fig. 2. Continuous changes of arterial oxygen tension (Pao2; left ) and arterial carbon dioxide tension (Paco2; right ) from the beginning (time 0) to 15 min after endotracheal suctioning in nine patients undergoing at random open and closed-circuit endotracheal suctioning followed by a recruitment maneuver. Pao2and Paco2were sampled every second. Black arrows indicate the beginning of the recruitment maneuver.