Hypernatremia deepens the demarcating borderline of leukocytic infiltration in the burn wound.

The influence of hypernatremia on progressive burn wound necrosis was evaluated in a second-degree burn model. The depth of the burned tissue sloughed off was measured in a comparative study in the rat (contact burn injury with a metal plate, 70 degrees C for 5 s). Rats in the hypernatremic group were treated with an intraperitoneal fluid injection of hypernatremic saline (10 ml, 850 mEq/l). Control rats were injected with hyponatremic saline (10 ml, 100 mEq/l). On the fourth postburn day specimens were harvested and compared. The greatest depth of leukocytic infiltration (percent of total dermal thickness) was measured. The average depths were significantly different. In zone 1 (from the normal skin edge to 5 mm inside the wound) the average depth in the hypernatremic group was 38.0 +/- 9.3 percent of the dermal depth and in the control group 9.5 +/- 1.2 percent. In zone II (from 5 to 10 mm inside the wound) the hypernatremic group sloughed off at 64.0 +/- 11.8 percent and the control group at 12.5 +/- 2.1 percent. The hypernatremic group showed a deeper demarcating borderline of leukocytic infiltration than the control rats. The wound depth progression may be caused by an osmotic injury.