Effect of seawater immersion on plasma osmotic pressure and electrolyte balance following open chest trauma

Objective: To explore the effect of seawater immersion on serum osmotic pressure and electrolytes balance following chest trauma in dogs. Methods: Twenty five healthy adult dogs were used in the experiment. A canine model of right open pneumothorax was established by chest puncturing on all animals. Animals were divided into three groups: a control group (n=10) with chest trauma without any immersion; a seawater group (n=10) immersed in seawater after chest trauma and a normal saline group (n=5) immersed in normal saline solution following chest trauma. Blood samples were taken at different time intervals to determine plasma osmotic pressure and electrolytes. The hemodynamic changes were also recorded. Results: Mortality in the seawater group was much higher than that of the control group and the normal saline group. The mean survival time in the seawater group lasted only 45 minutes, while in the control group and the normal saline group the average survival time was more than 4 hours (P< 0.01 ). One of the most important causes of death was hypernatremia and high osmolality. Severe electrolytes imbalance was observed in seawater group. Hypernatremia and high osmolality were the most significant factors of high mortality in the seawater group. Conclusions: Seawater immersion after chest trauma appears to be associated with severe electrolyte imbalance as well as high osmotic pressure. These may be the risk factors leading to fatal outcome.