High-flow endobronchial cooled humidified air protects non-heart-beating donor rat lungs against warm ischemia

Objective: Lungs from non-heart-beating donors for transplantation require protection against warm ischemic damage. Minimally invasive techniques are required to reduce organ damage during the warm ischemic period because invasive surgical procedures are often not feasible at this time. This study investigated the preservative effect of high-flow endobronchial cooled humidified air during warm ischemia in non-heart-beating donor rat lungs. Methods: Fourteen animals were divided into a Cooling group (n = 7), which received cooled air/saline spray during a 2-hour warm ischemic period, and a Control group (n = 7), which received no cooling. After ischemia the lungs were reperfused on an isolated lung perfusion apparatus. Results: Endobronchial temperatures in the Cooling and Control groups were 8°C and 36°C at 10 minutes, and 5°C and 35°C at 20 minutes, respectively (P < .0001). Lung core and surface temperatures in the Cooling group were also lower than those in the corresponding Control group (P < .0001). After reperfusion, pulmonary arterial pressure (P = .003) and peak airway pressure (P = .002) were lower in the Cooling group than in the Control group. Higher pulmonary venous Po₂ (P = .02), higher adenosine triphosphate levels (P = .01), and lower wet/dry lung weight ratio (P = .003) were seen in the Cooling group compared with the Control group. Conclusions: High-flow endobronchial cooled humidified air can decrease lung temperature and improve post-ischemic pulmonary function and adenosine triphosphate levels in non-heart-beating donor lungs.