Mammalian cells do not possess intrinsic tolerance to hypoxia or ischemia. Hypothermia can suppress cellular metabolism and the chemical reactions that drive the detrimental effects of hypoxia and ischemia. However, hypothermia also nonspecifically inhibits vital enzymatic processes required for maintaining cellular integrity and tissue homeostasis. Therefore, reducing ischemia time and exposure to hypothermia during organ transplantation is desirable. The traditionally accepted upper limit for total ischemia in lung allografts is about 6 hours.1 Longer ischemia has been shown to decrease lung allograft function.2 Contrastingly, other studies,3 including the article by Grimm and colleagues,4 argue that prolonged ischemia more than 6 hours might not impact short- or long-term outcomes.
Bharat A. Prolonged Lung Allograft Ischemia and Posttransplant Outcome. JAMA Surg. 2015;150(6):554. doi:10.1001/jamasurg.2015.0416