| Center of Thoracic and Cardiovascular Surgery, Xijing Hospital The Fourth Military Medical University, Xi'an 710032The incidence of explosive injury in wartime or in peacetime increases, which is due to the character of modern warfare and the increasing accidents of terrorism. The incidence of thoracic explosive injury( TFT ) is high and the injury is severe and complex, it always leads to respiratory and circulation failure and high mortality. It is reported that over 80% of cases of the thoracic injury die on spot and during back-sending period. So the researches on TEI have been attached more attention gradually. Multiple injury factors and mechanisms involve in TEI. So the corresponding animal model of TEI should be established and used for the researches on exploring its mechanisms and clinical treatments. In order to finish parts of the Military Tenth Five-year Dictating Subject, the purpose of this study is to establish an curable animal model of TEI, observe the regulations of pathophysiological changes after TEI, explore its mechanisms and wound characteristics, analyze the causes of early death and then provide the principle and basis for treating TEI.Methods: According to the distance (D) from the rabbits to the explosive center, 38 rabbits were randomly divided into 5 injured groups, which were Group A (D=5cm, n=6), Group B(D=8cm, n=8), Group C (D=12cm, n=8), Group D (D=15cm, n=8) and Group E (D=12cm, n=6), and 1 control group (Group F, n=4) without injury. The former 4 injured groups were exerted with regular treatment after injury and the Group E did not. A special detonator, which can generate fragments and blast wave, was used to be the center of explosion. The rabbits were fixed to the stand with the right side of the body towards the explosive center. The emergent regular treatment after injury included closing the thoracic wall, draining air out of thoracic cavity, and so on. The blood pressure, heart rate, respiratory rate, blood gas and other physiological parameters, ratio of lung water and average survival time, early mortality were monitored and calculated after injury, and pathological examination and wound analysis were done.Results: The early physiological changes after TEI include decrease of heart rate, increase of respiratory rate, decrease of blood pressure and temporary severe increase of CVP. The pathological changes include rupture of heart and great vessels, myocardial contusion, laceration, hemorrhage and edema of lung, hepatic rupture and gastric-enteric perforation. The degree of injury has negative correlation with the injury distance. The nearer the injury distance is, the more serious the injury, the shorter the survival time and the higher the mortality are. In Group A(D=5cm) and B(D=8cm), the early death rate was still 100% through regular treatment. In Group D(D=15cm), the early death rate was 37.5%.In Group C( D=12cm), the rates of blast and fragment injury of lung were 100% and 75% respectively, the early death rate was 100% without treatment, and the rabbitsIB 5 !)icould survive over 210min on average and the mortality decreased to 62.5% through regular treatment. There are 25(73.5%) rabbits which were traumatized by fragments and 34(100%) by blast wave in the 34 injured rabbits. The occurring rate of rib fracture, thoracic cavity bleeding, heart rupture and thoracic-abdomen combined injury was 47.1%, 61.7%, 8.8% and 47.1%respectively.Conclusions: (1) The Group C (D=12cm) can be chosen as the curable animal model of TEL It can be repeated and imitate the wound characteristics of TEI well. (2) Fragment and blast wave are the major injury factors of TEI, which make serious and complex thoracic trauma. This is the obvious characteristics of PEL (3) The multiple and complicated wound are very common in TEI The injury of different organs and factors can be interfered with and thus makes the injury more complex and early mortality higher. (4) This study suggests that the rupture of heart and great vessels, bleeding shock, acute respiratory... |
