大潮气量致急性肺损伤犬呼吸机相关性肺损伤模型的构建

目的建立大潮气量致急性肺损伤（ALI）犬呼吸机相关性肺损伤（VILI）模型。方法健康雄性杂种犬12只用油酸静脉注射法制备犬ALI模型,造模成功后进行支持通气15min过渡,然后随机分为VILI组及对照组行机械通气6 h,每组6只。VILI组潮气量（Vt）=20 mL/kg,对照组Vt=6 mL/kg,两组呼气末正压（PEEP）均为10 cmH2O。动态观察各组血气交换指标变化。通气6 h后取支气管肺泡灌洗液（BALF）作白蛋白浓度检查,取肺组织作病理切片肺损伤评分。结果各组在油酸静脉注射后（2.50±0.80）h达到ALI标准。VILI组在犬机械通气6 h后PaO2、SaO2及氧合指数（OI）较对照组略下降（P〈0.05）,而PaCO2波动不大,且心率、血压波动也较对照组小（P〈0.05）。VILI组BALF中蛋白浓度和肺组织损伤评分均较对照组显著升高（分别P〈0.05,P〈0.01）。结论本实验成功建立了大潮气量致ALI犬VILI模型。

Establishment of Ventilator-Induced Lung Injury Model after High Tidal Volume Ventilation in Dogs with Acute Lung Injury

Objective To establish ventilator-induced acute lung injury（VILI） model induced by high tidal volume ventilation in dogs with acute lung injury（ALI）.Methods 14 male mix-bred dogs were i.v.injected with oleic acid and the arterial oxygen pressure（PaO_2） was monitored.Animals were ventilated with supported model for 15 min while the PaO_2 less than 60 mmHg.Then the animals were randomized into two different Vt MV groups： control group（Vt = 6 mL/kg body weight,n = 6） and VILI group（Vt = 20 mL/kg body weight,n = 6）.The MV lasted for 6 h with a PEEP equals to 10 cm H_2O.PaO_2 was monitored dynamically during the ventilation process.The albumin concentration in BALF and pathological changes of the lung tissue were evaluated in order to determine the lung injury while animals were sacrificed after 6 h MV.Results Dogs were ALI-modeled after（2.50±0.80） hours after oleic acid injection.The pH of dogs in the trial were decreased in the whole trial,but decreased more severe in the control group than in VILI group（P0.01）.PaO_2,SO_2 and oxygenation index（OI）in VILI group were a little lower than that in the non-VILI group.But PaCO_2 and hemodynamics fluctuated less in the VILI group than in non-VILI group（P0.01 and P0.05,respectively）.The albumin concentration of BALF and the lung injury score in VILI group were lower than those in the non-VILI group（P0.05 and P0.01,respectively）.Conclusion A ventilator-induced lung injury model has been successfully established after high tidal volume ventilation in dogs with acute lung injury.