A model for thermal gradients during renal vascular anastomoses

Quantitative knowledge of warm ischemic intervals is of special importance in organ transplantation. Warm ischemia as a function of time is deleterious to tissue survival. In a laboratory model of a preserved transplantable organ, we determined thermal gradients in pig kidneys similar in size to human kidneys. Sixteen nonviable porcine kidneys cooled to 0 degrees C were placed in an artificial "iliac fossa." The posterior renal wall was in contact with the normothermic fossa. The anterior renal wall was exposed to the ambient temperature of the "operating room." The temperature of both walls was monitored for a minimum of 2 hr. Temperature changes relative to time and kidney weight were studied. The temperature of the posterior wall rises above 20 degrees C within 5 to 10 min; the anterior wall attains this temperature within 30 to 40 min. The thermal gradient between the two walls is significantly greater for larger kidneys (200 g) than for smaller kidneys (100 g). Implications for biochemical pathology are discussed.