肺保护与肺开放通气策略对急性呼吸窘迫综合征家兔血管外肺水的影响

目的探讨肺保护与肺开放通气策略对急性呼吸窘迫综合征(ARDS)血管外肺水(EVLWI)的影响。方法以肺泡灌洗法复制家兔ARDS模型,分为中等潮气量(VT)零呼气末正压(PEEP)组(MVZP组)、小VT零PEEP组(LVZP组)、小VT最佳PEEP组(LVBP组)和小VT最佳PEEP+控制性肺膨胀(SI)组(LVBP+SI组)。采用单指示剂热稀释法测定EVLWI。观察在不同通气条件下0、1、2和3h EVLWI的变化。结果MVZP组、LVZP组、LVBP组和LVBP+SI组EVLWI在基础时分别为(11.3±2.4)、(10.2±2.4)、(10.3±4.6)和(9.7±2.3)ml/kg,达到ARDS模型(0h)时显著升高(22.3±5.6)、(20.0±3.8)、(25.7±9.7)和(22.5±6.2)ml/kg,P均<0.05]。在实验观察3h中,MVZP组在2、3h EVLWI(32.0±12.2)、(36.2±12.4)ml/kg]显著高于0h(22.3±5.6)ml/kg,P均<0.05]。LVZP组在2、3h EVLWI(27.8±12.9)、(30.3±13.0)ml/kg]也显著高于0h(20.0±3.8)ml/kg,P均<0.05];LVBP组1h时EVLWI为(18.5±8.1)ml/kg,与0h(25.7±9.7)ml/kg]比较差异有统计学意义(P=0.027)。LVBP+SI组在1、2、3h各时点EVLWI分别为(16.8±6.5)、(18.0±7.1)、(15.7±2.7)ml/kg,与0h(22.5±6.2)ml/kg]比较显著降低(P均<0.05)。与MVZP组比较,1、3h时LVBP组与LVBP+SI组EVLWI显著降低(P均<0.05)。3hLVBP+SI组EVLWI显著低于LVZP组(P<0.05)。结论肺保护与肺开放通气策略可降低EVLWI,增加肺水清除。

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

OBJECTIVE: 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). METHODS: 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. RESULTS: 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). CONCLUSION: Lung protective ventilation and open lung strategy could decrease EVLWI.