Establishment Of Thoracic Injuries Model In Dogs With Indoor-explosion And Analysis The Early Patho-physiological Changes

Objective:To establish a thoracic injuries model in dogs with indoor-explosion,To observe the changes of related parameters after explosive injuries.To analyze the early patho-physiological changes and to provide new idea and theoretical basis for the early treatment of thoracic blast injuries.Methods:22 healthy dogs (w: 12.71±0.81 kg, no matter the sex) were randomly divided into 4 groups according to the overpressure on the sternum :Group A: 6 dogs, the dynamite dose was 30 g, it was 1m between the dogs, and the spot of blast and the overpressure on the sternum was 730 kPa.Group B: 6 dogs, the dynamite dose was 80 g, it was 1m between the dogs, and the spot of blast and the overpressure on the sternum was 1450 kPa.Group C: 5 dogs, the dynamite dose was 80 g, it was 0.8m between the dogs, and the spot of blast and the overpressure on the sternum was 2840 kPa.Group D:5 dogs without injury are as a control group.The vital sign of the dogs were observed before the blast and 1min, 5min, 10min, 30min, 1h, 2h, 3h, 4h, 5h, 6h after the blast. The parameters of blood gas were analyzed before the blast and 2min, 1h, 6h after the blast, The pulmonary water content, the protein content and the glutathione content of the lungswere measured. The morphological changes under the microscope and the electron-microscope were observed.Results:There was no mortality in group A, The mortality was 33.3%, and 80% in group B and in group C respectively.The dogs in group A were injured slightly, the dogs in group B were injured more serious than dogs in group A and D, the dogs in group C were injuried too serious to be saved.Partial lung tissue was consolidated(the pulmonary alveoli was filled with multiple red cell and leucocyte) in pathological section, the other alveolar space was merged or distended compensately, some pneumonocyte fell off, the blood capillary distended seriously. All the pathological section failed to be found the change of pneumonedema.Conlusion:The most suitable model for thoracic injuries in dogs was with 1450 kPa overpressure on the sternum after explosion. The characteristic changes of indoor-explosive thoracic injuries were showed in this group.Hypoxemia and hypotension were the most prominent patho-physiological changes in early stage. Hypoxia in room and the toxic inhalants might play more important roles in the injuries of the dogs, compared with the reflect wave, which still need future investigation.