A Whole-body Cooling Strategy in Uncontrolled Donation After Circulatory Death: Insights From a Porcine Ex Vivo Lung Perfusion Model

Background. Prolonged warm ischemia in uncontrolled donation after circulatory death (uDCD) potentially increases the risk of graft dysfunction in lung transplantation. To address this concern, a noninvasive, whole-body cooling approach was developed using a specialized liquid refrigerant at −21 °C. The aim of this study was to investigate whether this method reduces lung temperature and improves lung function in uDCD donors. Methods. Fifteen pigs were randomly assigned to 3 groups. In the study group (n = 5), the entire donor body was submerged in a basin containing a coolant of −21 °C, and chest compression was performed during 90 min of warm ischemia. In the sham group (n = 5), neither body cooling nor chest compression was performed during 90 min of warm ischemia. Lungs were evaluated by cellular ex vivo lung perfusion (EVLP) after 5 h of additional cold ischemia. Lungs in the donation after brain death (DBD) group (n = 5) were perfused after 1 h of cold ischemia. Results. Tracheal temperature decreased to 28.5 °C in the study group and remained at 38.1 °C in the sham group. Lungs in the study group showed higher transplant suitability with significantly higher PaO 2 /FiO 2 , and lower peak inspiratory pressure during EVLP than those in the sham group (all P < 0.05). The study group had a significantly higher ATP level, a relatively lower hypoxia-inducible factor-1α level, and lower percentage of apoptotic cells than the sham group. Conclusions. This novel cooling approach effectively reduced lung temperature during warm ischemia, resulting in improved lung function during EVLP. These data suggest that this method could mitigate ischemia–reperfusion injury in uDCD donors, expanding the donor lung pool.