Abstract: AIM:To evaluate the protective effect of pulmonary perfusion with hypothermic HTK solution on lung function after cardiopulmonary bypass in corrections of tetralogy of Fallot. METHODS: Twenty-four consecutive infants with tetralogy of Fallot were randomly divided into perfusion group (n=12) and control group (n=12). Oxygen index, alveolar-arterial O2 gradient, serum levels of malondialdehyde, endothelin-1, sICAM-1, and P-selectin were measured before commencement and serially for 48 h after termination of bypass. RESULTS: Oxygenation values were better preserved in perfusion group than in control group. The trend revealed significant differences in serum levels of malondialdehyde, endothelin-1, sICAM-1, and P-selectin between groups. Serum levels of malondialdehyde, sICAM-1, and P-selectin tended to increase after bypass in control group, but remained at a low level in perfusion group. Serum levels of endothelin-1 increased significantly from 12 h after bypass in both groups and the levels in control group were significantly higher than those in perfusion group. CONCLUSIONS: This study suggests that pulmonary perfusion with hypothermic HTK solution during cardiopulmonary bypass relieves lung injury in infants with tetralogy of Fallot.