In the present study, the levels of interleukin-6 (IL-6), malondialdehyde (MDA), and endothelin-1 (ET-1) in the serum and the change of oxygen index (OI) and respiratory index (RI) were measured to investigate the effect of PAP with HTK on lung protection in infant with CHD after CPB. Here, IL6 is linked to coronary artery disorder.