Causes and time course of acute hemolysis after burn injury in the rat.

Thermal injury can cause acute red blood cell damage and destruction, but the mechanisms of these effects are not well described. To investigate the red blood cell abnormalities that occur after burn injury we studied the time course of red blood cell changes that are seen early after burn injury. Male Sprague-Dawley rats were divided into control, sham-burn, and burn (30% total body surface area full-thickness) groups. Plasma-free hemoglobin, erythrocyte osmotic fragility, and red blood cell membrane deformability were measured in the first 8 hours after burn injury. Plasma-free hemoglobin was significantly increased 1 hour after injury. It fell promptly but remained significantly higher than the control value at 4 and 8 hours after burn injury. Osmotic fragility was also significantly increased when compared with control values, whereas membrane deformability was less than control values for the duration of the experiment. This study identifies an early hemolytic effect of burn injury and documents red blood cell changes in osmotic fragility and membrane deformability that may contribute to accelerated red blood cell loss later in the course of burn management.