| Objective: In modern war at sea and landing battle,the naval vessel and landing force were often attacked by missiles, bombs, etc. Burn-blast combined injury would become much more common than before, and may be immersed in the hyperosmotic, basic and cold seawater containing marine bacteria. Studying on the features of burn-blast combined injury with seawater immersion would help to improve the early resuscitative effect.Methods: The models of burn-blast combined injury with seawater immersion were developed in local dogs combined with 10% II° burn injury and light blast injury on their right lungs before immersed in seawater for 4 hours. (1) The dogs with burn-blast combined injury were randomly assigned to two groups: immersion and unimmersion (burn-blast-only). In immersion group, the dogs were immersed in seawater for 4 hours, keeping the head and front limbs out of water, then were taken out from seawater and dried with warm wind. Changes of hemodynamic, hemorrheologic, acid-base balance electrolyt balance, osmotic pressure and blood-gas analysis were monitored before and 4h, 7h, 10h, 20h, 28h after wound. The morphologic changes in heart and lung tissue were observed after the experiment was finished. The treatments in unimmersion group were the same as those in immersion group except unimmersion. (2) The dogs with burn-blast combined injury and seawater immersion were randomly assigned to two groups: resuscitation I and resuscitation II. Resuscitation was performed promptly after the dog's beingtaken out from water, respectively by means of Parkland formula (lactatedRinger's solution 4 ml/kg/%burn for 24 hours) and the improved protocol (lactated Ringer's solution 2.5 mllkg/%burn plus colloid solution hetastarch 0.5 ml/kg/%burn for 24 hours, redressing acidosis powerfully, using antibioltic early). The record time points and parametes were the same as those of immersion group.Results: Compared with unirnrnersion group, immersion's post-trauma mortality and shock rate were much higher. Hypothermia, severe metabolic acidosis, hypernatremia, hyperchloremia and hyperosmolality were found only in immersion group. And blood viscosity, erythrocyte rigidity and aggregation became much worse, bacteriemia was discovered earlier in immersion group than that in unimmersion. After resuscitation with Parkland formula, the mortality was significantly decreased, and the production of urine was generously increased, but metabolic acidosis, hypernatremia, hyperchloremia and hyperosmolality were not effectively restored. Nevertheless, the resuscitation with improved protocol not only decreased the mortality and the shock rate, increase the mean artery pressure (MAP), cardiac index (CI), stroke volum index (SVI) significantly, but also decreased blood viscosity, erythrocyte rigidity index (RI) and aggregation index (AI), effectively restored metabolic acidosis and hyperosmolality, reduced the infection rate.Conclusions: (1) The experimental models of bum-blast combined injury with seawater immersion had been successfully developed. (2) The results suggested that seawater immersion after burn-blast combined injury would aggravate the injury 1 or 2 grades, turn light injury into heavy injury, and heighten mortality and shock rate, so all of the burn-blast combined injuries with seawater immersion for more than 4 hours should be considered to be heavy injury, and given the first aid. (3) The post-trauma mortality of burn-blast combined injury with seawater immersion was the highest within the first 10 hours after injury, this period should be regarded as the goldenresuscitation time. (4) Seawater immersion after bum-blast combined injury would cause severe homodynamic changes, allo-microcirculation, circulation related anoxia, metabolic acidosis, hypernatremia, hyperchloremia and hyperosmolality, and its injuries obviously have subsequent effect. (5) Redressing acidosis powerfully and using antibioltic early would be much more necessary.
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