Low-potassium solution for lung preservation in the setting of high-flow reperfusion

Background. We previously demonstrated that standard preservation using Euro-Collins solution impairs lung function in the setting of high-flow reperfusion because of potassium-induced vasoconstriction. Preservation strategies for single-lung transplantation are an important factor in patients with pulmonary hypertension. This study investigates the hypothesis that low-potassium preservation solution will improve function of lungs subjected to high-flow reperfusion. Methods. Twenty-one New Zealand white rabbit lungs were harvested and studied on an isolated, blood-perfused model of lung function after 4 hours of cold ischemia at 4°C. Control lungs were preserved with 50 mL/kg of cold saline solution flush (group 1). Experimental lungs were preserved with low-potassium solution (group II) or Euro-Collins solution (group III) at similar temperatures and volumes. Results. The pulmonary arteriovenous oxygen gradient at the end of the 30-minute high-flow reperfusion period was significantly higher in group II compared with group III (121.3 ± 19.2 mm Hg versus 31.1 ± 4.2 mm Hg; p < 0.001). The pulmonary vascular resistance was significantly lower in group II than in group III (46.3 ± 1.8 × 103 dynes · s · cm−5 versus 79.8 ± 8.4 × 103 dynes · s · cm−5; p < 0.01). The percent decrease in dynamic airway compliance in group III was significantly greater than in groups I and II (−51.0% ± 13.3% versus −10.2% ± 3.4% and −11.2% ± 2.8%, respectively; p < 0.001). Similarly, the wet to dry ratio of the lungs in group III was significantly greater than in groups I and II (13.9 ± 2.3 versus 5.9 ± 0.2 and 6.0 ± 0.4, respectively; p < 0.001). Conclusions. These data demonstrate that a low-potassium preservation solution yields improved lung function after high-flow reperfusion in an ex vivo rabbit lung model. Lung preservation should be aimed at the clinical setting.