L-Arginine administration during reperfusion improves pulmonary function

Background. Nitric oxide is crucial to the maintenance of vascular homeostasis. Because nitric oxide levels decline upon lung reperfusion, infusion of L-arginine, a nitric oxide precursor, during reperfusion might prove effective at ameliorating reperfusion injury. Methods. Neonatal piglet heart-lung blocks were preserved with Euro-Collins solution for 12 hours, rewarmed at room temperature for 1 hour, and reperfused for 10 minutes with either whole blood (n = 5), whole blood containing L-arginine (10 mmol/L; n = 6), or leukocyte-depleted blood (n = 6) on an isolated, blood-perfused, working heart-lung circuit. After the initial 10 minutes, all blocks received whole blood for 4 hours. Control blocks were continuously perfused on the circuit without intervening ischemia (n = 6). Results. The partial pressure of oxygen in the whole blood group (113.8 ± 33.1 mm Hg) was significantly less than in controls (417.3 ± 6.2 mm Hg; p < 0.01). Lung compliance was significantly less in the whole blood group (0.8 ± 0.2 mL/cm H₂O) than in controls (2.9 ± 0.4 mL/cm H₂O; p < 0.01). The L-arginine and leukocyte-depleted blood groups showed no significant difference from controls. Conclusions. L-Arginine infusion during reperfusion improves pulmonary function, making it a simple alternative to leukocyte depletion.