Study On Ballistic Characteristics Of Fragment Wounds At High Altitude And Its Primary Surgery Treatment

Objective: Fragment wounds were the most frequently encountered wounds in the modern warfare. The characteristics of environment at high altitude,which were low barometric,low partial pressure of oxygen, low temperature and complicated topography, had important effect on the treatment of war wounds at high altitude. Study on the ballistic characteristics of fragment wounds at high altitude and its early surgery treatment would help to improve the level of war wounds treatment in the conflict at high altitude.Medthods: (1) The study was made up of two parts: high altitude group (Lhasa, 3658m above sea level) and plain control group (Chongqing, 351m above sea level). The velocities of different shapes fragments were measured at the firing distance of 10m and 20m. After those fragments were fired at the soap targets, exit/entry areas of wound tract, volumes of cavity, the maximum diameters of cavity and shapes of wound tract were measured. The steel balls (1.03g, firing range 20m) and the steel triangle fragments (0.37g, firing range 10m) were shot at the hind legs of pigs with smoothbore rifle, respectively. Tissue partial pressure of oxygen (tPo2) in muscle around wound tract and the serum creatine kinase (CK) were assayed before wounding and 6h after wounding. Exit/entry areas of wound tract, volume of cavity and mass of necrotic tissue excised (METE) were measured at 6h after wounding; Muscle samples, which were take off wound tract, were respectively tested for pathological examination, Succinate dehydrogenase (SDH) and ATPase activity measure and bacterial culture. Then the pigs were killed, and their gross pathological changes were observed. (2) The steel balls (1.03g, firing range 10m) were shot at the hind legs of pigs, and then these swines were randomly assigned into local medication group and oral medication group. At 1h after wounding, sustained release carriers (containing 0.025g cinrofloxacin and 0.060g tinidazole) were put into those wounds. Muscle samples taken off from wound tracts, were tested for bacterial culture at 0h, 24h and 48h after wounding, and were assayed for SDH and ATPase activity measure at 24h and 48h after wounding. Dressings were changed at 48h after wounding, necrotic tissue was excised and weighed, and then after taken out of sustained releases carriers from wounds were sutured. The instance of wounds healing was observed at 8 day after wounding. Been given 0.250g cinrofloxacin and 0.500g tinidazole (take orally, two times everyday), but not sustained release carriers, the other managements of the oral medication group were the same with the local medication group.Results: The velocities of fragment at high altitude were much higher than plain, the attenuation of fragment velocities was slower than plain. Exit/entry areas of wound tract, volume of cavity and the maximum diameter of cavity of soap shot by fragment at high altitude were all obvious bigger than plain. The biological effect of fragment at high altitude was different from plain, which was the volume of cavity vs. unit of track length and METE vs. unit of track length in high altitude group, were both obvious bigger; the pathological changes of muscle tissue round wound track were more serious; the tPo2, SDH and ATPase activity of muscle tissue round wound track were evident lower; the decline of CK activity in high altitude group was evident bigger. The amount of bacteria in muscle tissue round wound track in high altitude group was similar to plain group. Compared with oral medication group, the METE of swine in local medication group was obvious lower; at 24h and 48h after wounding SDH and ATPase activity of tract tissue was much higher, but bacterial amount was obvious lower; the instance of wound healing at 48h and 8 days after in local medication group was much better.Conclusions: (1) Because the air is rareness, gravitational acceleration is small and the velocities attenuation of fragment was slow at high altitude, so the velocities of fragment in high altitude were faster than plain, cavity effects...