目的　观察四氧化二氮 (N2 O4 )和偏二甲基肼 (UDMH)染毒复合冲击伤 (冲毒复合伤 )大鼠血气及病理形态学的变化。　方法　健康雄性Wistar大鼠 168只 ,随机分为 :( 1)UDMH冲毒复合伤组 (BU组 ) ;( 2 )N2 O4 冲毒复合伤组 (BN组 ) ;( 3 )UDMH及N2 O4 冲毒复合伤组 (BUN组 ) ,每组 5 6只大鼠。大鼠在冲击伤后 10min相继吸入UDMH和 (或 )N2 O4 造成重度冲击伤复合中毒模型。于伤前及伤后 3 ,6,12 ,2 4 ,4 8,72h进行血气分析和主要器官病理形态学检查。　结果　BUN组大鼠临床症状进行性加重 ,肺泡内弥漫性充满淡粉色渗出物及大片状出血 ,肺出血和水肿均加重。心肌细胞不同程度浊肿 透明性变 ,可见个别心肌纤维断裂 ,心肌间质疏松及出血水肿 ,心肌病变加重。肝血窦扩张 充血 ,肝细胞浊肿等。三组动物伤后 3～ 12h动脉血氧分压 (PaO2 )均显著下降 ,其中 3～ 6h下降最为显著。BUN组大鼠PaO2 下降持续时间最长 ,恢复较前两组慢。　结论　UDMH及N2 O4 冲毒复合伤时 ,大鼠呼吸系统症状更严重 ,其主要的病理学改变和血气变化也最明显 ,表明这类损伤最难救治 Objective To observe the changes of blood gas and pathomorphology in rats with combined impact injury of nitrogen tetraoxide (N 2 O 4) and dimethyl diallylhydrazine (UDMH). Methods A total of 168 male Wistar rats were randomly divided into three groups: (1) UDMH group (BU group); (2) N2 O4 group; (3) UDMH and N2 O4 Poisoning combined injury group (BUN group), each group of 56 rats. Rats in the impact 10min after inhalation of UDMH and (or) N2 O4 caused severe impact injury poisoning model. Blood gas analysis and major histopathological examination were performed before and after injury at 3, 6, 12, 24, 48, 72h. Results The clinical symptoms of rats in BUN group were aggravated. The alveoli were diffusely filled with light pink exudates and large flakes of hemorrhage, and pulmonary hemorrhage and edema were aggravated. Myocardial cells with varying degrees of opacity transparent change, showing that some myocardial fiber rupture, myocardial interstitial and hemorrhagic edema, increased myocardial disease. Liver sinusoidal dilatation and congestion, hepatocyte swelling and so on. The arterial partial pressure of oxygen (PaO2) decreased significantly from 3 to 12 hours after injury in the three groups of animals, with the most significant decrease in 3 to 6 hours. PaO2 decreased the longest duration in BUN group, and recovered slower than the former two groups. Conclusions UDMH and N2 O4 combined with detoxification have more severe respiratory symptoms and the most obvious pathological changes and blood gas changes, indicating that these injuries are the most difficult to treat