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目的 探求急性肺损伤 (ALI)动物模型在高CO2 通气时病理生理指标的改变机制。方法 2 2只新西兰大白兔随机分为对照组 (C组 )、非高CO2 通气组 (N组 )、高CO2 (8% )通气组 (H组 )。N组和H组通过静脉注射油酸 (0 1ml/kg)复制ALI模型。 3组均机械通气至 3h ,观察生理及病理指标的变化。结果 H组气道峰压显著低于N组 ,动态胸肺顺应性显著高于N组。动脉血氧分压H组明显高于N组 ;H组与N组BALF细胞数、BALF中蛋白含量、肺组织湿重 /干重比差异均有显著性 (P <0 0 5 ) ;肺组织中髓过氧化物酶的含量H组明显低于N组 (P <0 0 5 ) ;H组病理组织学改变较N组明显减轻 (P <0 0 5 ) ;PaCO2 与pH密切相关 ,与PaO2 、动态顺应性均呈正相关 ,与气道峰压呈负相关。结论 机械通气时吸入8%的CO2 所致高碳酸血症对ALI动物模型有保护作用 ,其机制可能与改善了肺力学、减少肺泡中蛋白质渗出 ,减轻多形核白细胞在肺内的扣押及抑制其活性有关。
Objective To explore the mechanism of pathophysiological changes in acute lung injury (ALI) animal model under high CO2 ventilation. Methods Two New Zealand white rabbits were randomly divided into control group (C group), non-hypercapnic CO2 group (N group), and hypercapnic group (H group). N and H groups were replicated with ALI by intravenous injection of oleic acid (0 1 ml / kg). 3 groups were ventilated to 3h, observation of physiological and pathological changes. Results The peak airway pressure of group H was significantly lower than that of group N, and the dynamic compliance of chest and lung was significantly higher than that of group N. The arterial partial pressure of oxygen in group H was significantly higher than that in group N; the number of BALF cells in BALF, protein content in BALF and the ratio of wet weight to dry weight in lung tissue in H group and N group were significantly different (P <0.05) The content of myeloperoxidase in H group was significantly lower than that in N group (P <0.05), and the histopathological changes in H group were significantly reduced compared with N group (P <0 05) , Dynamic compliance were positively correlated, and negative correlation with peak airway pressure. Conclusions Hypercapnia induced by inhalation of 8% CO2 during mechanical ventilation has a protective effect on animal models of ALI. The mechanism may be related to the improvement of lung mechanics, reduction of protein exudation in alveoli, mitigation of polymorphonuclear leukocyte sequestration in the lung, and Inhibit its activity.