APRV-BIPAP模式对急性肺损伤猪肺复张/开放策略实验研究

Lung recruitment/open maneuvers by APRV-BIPAP ventilation in piglets with acute lung injury

目的探讨压力释放-双相正压通气(APRV/BIPAP)模式下,不同压力组合肺复张/开放(RMs)策略疗效,摸索最佳压力组合,观察对血流动力学等影响。方法大肠杆菌腹腔注射制作猪急性肺损伤(ALI)模型,APRV-BIPAP下,逐步递增压力组合(Phigh/Plow),即RM1(30/15)、RM2(35/20)、RM2(40/25)、RM4(45/30)、RM5(50/35)、RM6(55/40)、RM7(60/45)cm H2O实施RMs,吸气相CT扫描,评价RMs疗效,监测氧合指数(PaO2/FiO2)、血流动力学指标、平均气道压(Pmean)变化。RMs完成后,处死取肺组织行病理学检查。结果健康幼猪8头,成模后CT扫描均显示不同程度肺泡萎陷。随RMs,PaO2/FiO2改善,肺泡萎陷减少,以RM2后改善最明显(P<0.05),但非病变区域有肺泡过度膨胀;随压力递增,心率(HR)增快(P<0.05),平均动脉压(MAP)下降(P<0.05),PIP、Pmean和中心静脉压(CVP)升高(P<0.05),但RMs完成后能恢复到RMs前水平(P>0.05);研究过程中未发生气胸、纵隔气肿等,但病理检查有肺泡过度膨胀和间隔断裂。结论借助APRV-BIPAP模式实施RMs疗效好,35/20 cmH2O是最佳压力组合,对血流动力学和气道压等影响小;一旦RMs获得疗效满意,设置30/15 cm H2O维持20 min,RMs疗效好。

Objective To evaluate lung recruitment/open maneuvers（RMs）by airway pressure release ventilation（APRV）/ biphasic positive airway pressure（BIPAP） mode and explore the best levels of high and low airway pressure combination and the effects on hemodynamic indexes.Methods The model of acute lung injury（ALI） was induced by intraperitoneal injection of E.coli.in piglets.The different pressure combinations（Phigh/Plow） of RMs were increased sequentially on APRV/ BIPAP mode,i.e.RM1（30/15）,RM2（35/20）,RM2（40/25）,RM4（45/30）,RM5（50/35）,RM6（55/40）,RM7（60/45） cm H2O.The efficacy of RMs was evaluated by computed tomography（CT） at inspiratory phase and PaO2/FiO2,hemodynamic indexes and mean pressure of airway（Pmean） were monitored continuously.The piglets were sacrificed when RMs were finished and pulmonary pathological examination was done routinely by optical microscopy.Results Eight piglets with ALI model were established and all of them showed different degrees of alveolar collapse by CT scan.During RMs,the levels of PaO2/FiO2 increased significantly（P0.05） and the area of alveolar collapse decreased significantly（P0.05） too,especially after RM2 was finished（P0.05）.But the alveolar over inflation could be found in some independent or non-lesional areas.The heart rate（HR） increased but mean artery blood pressure（MBP） decreased significantly while the pressure combinations（Phigh/Plow） of RMs increased gradually（P0.05）.Meantime the Pmean and peak inspiratory pressure（PIP） of airway and central venous pressure（CVP） increased significantly（P0.05）.But when RMs were finished,all of these indexes recovered to the pre-RMs levels.Even there were no barotraumas,such as pneumothorax and pneumomediastinum,the alveolar overdistention and interruption of the alveolar separation could still be found by pathological examination.Conclusion RMs could be done well by APRV/BIPAP.Phign/Plow（35/20 cm H2O） would be the best pressure combination with more efficacy of RMs and less influence on hemodynamics,airway pressure indexes,etc.When the effect of RMs was satisfactory enough,setting Phigh/Plow to 30/15 cm H2O for 20 min may maintain the good efficacy of RMs.