Combined Smoke Inhalation and Scald Burn in the Rat

The combination of burn injury with smoke inhalation from fires significantly increases mortality. The mechanism of increased mortality is poorly understood but has been associated with multiple organ dysfunction syndrome, including cardiac dysfunction. Impaired cardiac function correlates with decreased survival in burn patients. We investigated smoke inhalation from burning cotton combined with a 40% body surface area, third-degree burn during the first 4 hours after injury in rats. In the early phase after injury, burn caused a significant rise in lung neutrophil infiltration but no increase in lung water. Smoke led to a rise in lung water but only a mild increase in neutrophil infiltration. Combined smoke and burn did not increase neutrophil accumulation or lung water above that which occurred with either injury alone. Only in combined smoke and burn was there a drop in cardiac output and stroke volume with pulmonary edema and lung neutrophil influx.