Effects of Initial Low Flow Reperfusion and Surfactant Administration on the Viability of Perfused Cadaveric Rat Lungs

Abstract.

To expand the cadaveric lung donor pool, protecting the endothelium and alveoli from warm ischemia and reperfusion injury is important. The effects of initial low flow reperfusion and surfactant administration were studied in non–heart-beating donor lungs. The rat heart-lung bloc was excised immediately (group 1) or 30 min (groups 2–4) after euthanasia (n= 6 in each group). The graft was ventilated and reperfused (50 ml/min) immediately after excision for 1 h in groups 1 and 2. In groups 3 and 4, the reperfusion flow rate was increased gradually to 50 ml/min, while ensuring that the pulmonary arterial pressure did not exceed 40 mmHg. Then the graft was reperfused for 1 h. Surfactant was introduced into the airway in group 4 before reperfusion. Airway pressure (AWP) and pulmonary arterial pressure were monitored during reperfusion. After reperfusion, the wet/dry weight ratio (W/D) of the right lung was calculated, and histologic examination using trypan blue staining of the left lung was performed. In group 2, lung failure appeared in all animals during reperfusion. In group 3, although all lungs were reperfused for 1 h, AWP and W/D were higher than in group 1. In group 4, AWP and W/D were lower than in group 3. Histologic examination showed that surfactant administration had attenuated the alveolar cell death. To avoid damage caused by high pulmonary arterial pressure associated with graft reperfusion, iniital low flow reperfusion was beneficial in cadaveric lungs. Surfactant administration before reperfusion was effective in preventing pulmonary edema.