| Hemorrhagic shock,fire-arm injury and seawater immersion are the main reasons that lead to the death of soldiers in marine war.With emphasis on the interest of sea,the incidence of marine war treads to increase.The studies on seawater immersion injury are rare,especially about fire-arm injury combined with hemorrhagic shock immersed in seawater.The effects of seawater immersion on fire-arm injury combined with hemorrhagic shock is unclear. Therefore,we carried on the project,so as to find out the effects of seawater immersion on experimental animals subjected to fire-arm injury combined with hemorrhagic shock.The model of dogs and rats subjected to fire-arm injury combined with hemorrhagic shock were utilized in this experiment, hemorheological parameters and plasm osmotic pressure were determined in dogs at pre-shock,1h,3h,5h after 21℃ seawater immersion,hemodynamic parameters were determined in rats at pre-shock,shock,10min,30min,1h,3h,5h after immersion in 15℃,21℃,31℃ seawater and in fresh water,normal saline,land control group respectively.After 5 hours immersion in 21℃ seawater,the RCR and membrance fluidity of myocardial cell mitochondia, the activity of Na+-K+-ATPaseand the MDA in myocardial tissue,the activity of plasm LDH were determined.The main results and conclusions are as follows:1. There was a significant increase in plasma viscosity(VP),casson viscosity(VC),haematocrit(Hct), Casson yield stress(CYS),erythrocyteaggregation index(EAI) and plasma osmotic pressure(POP) in dogs subjected to fire-arm injury combined with hemorrhagic shock after seawater immersion as compared with land control group(p<0.05 or 0.01). There was a significant decrease in erythrocyte deformability index (EDI). These results indicated that seawater immersion increased the blood viscosity.2. In the early stage of 21℃ seawater immersion, the MAP,±dp/dt /max and LVSP in rats subjected to fire-arm injury combined with hemorrhagic shock were transiently increased,but with prolonging of immersion's time,the HR,±dp/dt/max and LVSP in rats of seawater group were significantly decreased as compared with land control group(p<0.05 or 0.01). These results showed that seawater immersion could disturb the hemodynamic status in rats subjected to fire-arm injury combined with hemorrhagic shock.3. After 5 hours immersion in 21℃ seawater, the RCR, membrance fluidity of myocardial cell mitochondia and the activity of Na+-K+-ATPase in myocardium tissue were markedly decreased(p<0.05,vs land control group),but the content of MDA in myocardium tissue and the activity of plasm LDH were significantly increased(p<0.05,vs land control group).These results indicated that 21℃ seawater immersion can aggravate injury in rats subjected to fire-arm injury combined with hemorrhagic shock.4. Immersed in different temperature conditions, the hemodynamic parameters of rats immersed in 15℃ seawater rapidly decreased as compared with other groups. After 1 hour immersed in 15℃ seawater,the MAP, HR, ±dp/dt/max of rats subjected to fire-arm injury combined with hemorrhagic shock were significantly decreased(p<0.05 or 0.01,compared with those of rats immersed in 21℃ or 31℃ seawater). In the fist one hour immersion in 31℃seawater, the hemodynamic parameters were superior to others groups. but after 3 hours of immersion, the MAP,HR,±dp/dt/maxand LVSP were markedly lower than those in rats immersed in 21℃ seawater(p<0.05 or 0.01). These results suggested that temperature of seawater played an important role in the changes of hemodynamic parameters in rats immersed in seawater. 5. After immersion, the MAP, HR, ±dp/dt/max and LVSP in rats immersed in normal saline were superior to those that rats immersed in fresh water, there were significant differences in HR, +dp/dt/max at 10 minutes,1 hour,3 hours after immersion (p<0.05 or 0.01).There also was a significant difference in -dp/dt/max of rats immered in normal saline at 30 minutes,1 hour,3 hours after immersion in normal saline as compared with those...
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