Effect of protective ventilation and open lung strategy on extravascular lung water in rabbits with acute respiratory distress syndrome]

To study the effect of protective ventilation and open lung strategy on extravascular lung water index (EVLWI) in rabbits with acute respiratory distress syndrome (ARDS).Saline-lavaged, anesthetized ARDS rabbits were divided into (1) a moderate tidal volume (V(T)) zero positive end-expiratory pressure (PEEP) group (MVZP group): V(T) 12 ml/kg, PEEP 0 cm H2O; (2) a low V(T) zero PEEP group (LVZP group): V(T) 6 ml/kg, PEEP 0 cm H2O; (3) a low V(T) best PEEP group (LVBP group): V(T) 6 ml/kg, PEEP 10 cm H2O; (4) a low V(T) best PEEP + sustained inflation (SI) group (LVBP + SI group): V(T) 6 ml/kg, PEEP 10 cm H2O + SI. EVLWI was measured by single indicator thermodilution technique at baseline, 0, 1, 2 and 3 h.In the MVZP, LVZP, LVBP, and LVBP + SI groups, EVLWI in the ARDS model [(22.3 +/- 5.6), (20.0 +/- 3.8), (25.7 +/- 9.7), (22.5 +/- 6.2) ml/kg, respectively] was significantly higher than those at baseline [(11.3 +/- 2.4), (10.2 +/- 2.4), (10.3 +/- 4.6), (9.7 +/- 2.3) ml/kg, respectively, all P < 0.05]. In the MVZP group, EVLWI at 2 h and 3 h [(32.0 +/- 12.2), (36.2 +/- 12.4) ml/kg] was higher than that of 0 h [(22.3 +/- 5.6) ml/kg, P < 0.05]. In the LVZP group EVLWI at 2 h and 3 h [(27.8 +/- 12.9), (30.3 +/- 13.0) ml/kg] was also higher than that of 0 h [(20.0 +/- 3.8) ml/kg, P < 0.05]. In the LVBP group, EVLWI at 1 h was (18.5 +/- 8.1) ml/kg and was lower than that of 0 h [(25.7 +/- 9.7) ml/kg, P = 0.027]. In the LVBP + SI group, EVLWI at 1, 2, 3 h [(16.8 +/- 6.5), (18.0 +/- 7.1), (15.7 +/- 2.7) ml/kg] was lower than that of 0 h [(22.5 +/- 6.2) ml/kg, all P < 0.05]. There was significant difference among the four groups at 1 h and 3 h (all P < 0.05). At 1 h and 3 h, compared with MVZP group, EVLWI of the LVBP and the LVBP + SI groups were significantly decreased (all P < 0.05). At 3 h, compared with the EVLWI of the LVZP group, EVLWI of the LVBP + SI group was significantly decreased (P < 0.05).Lung protective ventilation and open lung strategy could decrease EVLWI.