肺内源性与外源性急性呼吸窘迫综合征模型猪的肺复张性比较

Comparison of recruitability of acute respiratory distress syndrome caused by pulmonary and extrapulmonary in pig models

目的应用分层电阻抗成像技术(EIT)比较肺内源性急性呼吸窘迫综合征(ARDSp)和肺外源性急性呼吸窘迫综合征(ARDSexp)模型猪的肺复张性。方法健康巴马猪16只,随机分为ARDSp组和ARDSexp组,每组各8只。采用盐酸气管吸入的方法复制ARDSp模型,油酸静脉滴注的方法复制ARDSexp模型。模型复制成功后,采用肺保护性通气策略进行机械通气并进行一次肺复张,之后保持其他呼吸机参数不变,分别在高低呼气末正压(PEEP)25 cmH2O和5 cmH2O水平下通气1 h,通气结束后进行吸气末和呼气末暂停,记录高低PEEP水平间的复张容积、每个PEEP水平下的氧合情况及血流动力学参数。结果ARDSexp组和ARDSp组模型的复张容积为分别为(1572.8±314.9)ml和(1089.9±224.2)ml,差异有统计学意义(P=0.003)。升高PEEP能够改善ARDSexp的氧合指数,由(214.3±128.6)mmHg提高到(447.5±96.0)mmHg,差异有统计学意义(P=0.004),而ARDSp高低PEEP水平间氧合指数变化不显著,差异无统计学意义[(173.6±112.0)mmHg vs(178.4±128.2)mmHg,P=0.943]。结论ARDSexp和ARDSp模型猪的复张性不同,相比ARDSp,ARDSexp的复张性更好。高PEEP水平可能能够改善ARDSexp的氧合,而对ARDSp的效应相对不显著。

Objective To compare the recruitability between pulmonary(ARDSp)and extrapulmonary acute respiratory distress syndrome(ARDSexp)using electric impedance tomography(EIT)in pig models.Methods Sixteen healthy Bama pigs were randomly divided into ARDSp and ARDSexp group with 8 animals each.ARDSp model was established using alveolar instillation of hydrochloric acid and ARDSexp was injected with oleic acid through atrium venous.After the model was established,the animal received lung protective ventilation.After a recruitment maneuver,low(5 cmH2O)and high(25 cmH2O)PEEP were applied in each animal remaining other setting unchanged for 1 hour.Then an end-inspiratory and end-expiratory occlusion were performed.The recruitment volume(VREC)generated between high and low PEEP was calculated,and the data of oxygenation and hemodynamic were recorded.Results Significant difference was found in VREC between ARDSexp and ARDSp models(P=0.003),and VREC was(1572.8±314.9)ml and(1089.9±224.2)ml,respectively.The ratio of arterial partial pressure of oxygen to inspired oxygen fraction(PaO2/FiO2)increased from(214.3±128.6)mmHg to(447.5±96.0)mmHg(P=0.004)with increasing PEEP in ARDSexp.However,PaO2/FiO2 did not change significantly in ARDSp[(173.6±112.0)mmHg vs(178.4±128.2)mmHg,P=0.943].Conclusion The recruitability between ARDSp and ARDSexp in pig models is different.Compared with ARDSp,ARDSexp may have better recruitability.Higher PEEP may improve the oxygenation of ARDSexp,while the effect on ARDSp is relatively small.