A Study On Cervical Vaf Vascular Injury In Early Stages Of Maxillofacial Explosive Injury

In recent years, the incidence of explosive injury has greatly increased both in war times and in peaceful times, and during the detonation maxillofacial region was often involved.Detonation of explosives can generate certain amount of atmosphere with high temperature more than 3000癈 and high velocity more than 7000m/s near the source, which can injure bodies together with the fragments generated by the detonation.The objective of this study is to establish a type of animal model of maxillofacial explosive injury, which increases the standardization of studies on explosive injury. In this study we adopt a novel kind of spherical explosive produced by NINT, and we measure pressures and strains and accelerations with different kinds of sensors and oscilloscopes. Pressures outside and inside of soft tissues can be precisely measured, as well as strains and accelerations of bones.In the animal models of maxillofacial explosive injury with the novel explosives, parameters of all kinds can be measured precisely. The model can be duplicated conveniently and through which we can better studies on animal maxillofacial explosive injury. We suggest using the explosive of 0.125g TNT equivalent, with the radius of 2.5 nun, in rabbit models of maxillofacial explosive injury. When 0.125g TNT equivalent explosive detonates 2 nun away from skin of maxillofacial region , the peak value of the pressure on the skin is 842MPa, and the time of thepeak is 2.6ps, and the pressure lasts only 19.6|as. The peak value of the pressure on the common carotid artery is 34MPa, and the time of the peak is 2.6us, and the pressure lasts only 14.8|us.Both walls of veins and arteries were damaged. Endothelial cells of some part of the vessels disappear and thrombosis was found in external jugular veins after injury. Crevice or cavity can be found in tunica medium, which may account for the possible reasons of pseudo-aneurysm formation after injury.The studies show TXB2 and 6-keto-PGFiu levels and the ratio of them in plasma, lung and brain tissues changes during the early stage of maxillofacial explosive injury. The stable metabolites of thromboxane A2(TXA2)and prostacyclin(PGl2), TXB2 and 6-keto-PGF] ?,in the blood serum were measured before and after injury. TXB2 and 6-keto-PGFi a levels and the ratio significantly increased after injury, and reached the peaks at 6h or 24h after injury, and reduced to the normal levels at the third day. During maxillofacial explosive injury, the increase of TXA2 and PGI2 levels and the ratio is owing to the damage of capillary endothelia in soft tissues near the wound or in lungs or in brain, and the activation of platelets, then thrombus can form in blood vessels.