Fig. 2.  Representative recording of systemic arterial pressure (Art.P) and airway pressure (Aw.P) in a control pig (A , C ) and a pig with acute respiratory distress syndrome (ARDS) (B , D ) successively ventilated for 20 s with the three investigated ventilatory patterns (i.e. , a tidal volume (V^T) of 10 ml/kg and a respiratory rate of 15 breaths/min [RR15], followed by a V^Tof 6 ml/kg and RR25 and a V^Tof 6 ml/kg and RR15 during baseline (A , B ) and hemorrhage (C , D ). Change in pulse pressure (ΔPP) was small before bleeding in pigs with normal lungs as well as those with ARDS, and it increased significantly during hemorrhagic shock in both groups, but mainly with a V^Tof 10 ml/kg. Please observe that during baseline in pigs with ARDS, airway pressure gradient is more marked during V^T10 and V^T6 RR15 than during V^T6 RR25 but not during hemorrhage (impact of the decrease in ΔP^tpduring bleeding).