目的　探讨小儿先天性心脏病心脏手术期间血浆肾上腺髓质素 (AM )的变化规律。方法　选择中低温体外循环 (CPB)心脏手术患儿 10例 ,分别于全麻诱导后 10min、阻断主动脉前即刻、阻断主动脉后5min、开放主动脉后 5min、术后 3h采集动脉血 ,采用特异性放射免疫方法测定血浆AM浓度。结果　CPB开始患儿血浆AM即逐渐增高 ,开放主动脉后血浆AM浓度显著增高 (P <0 .0 5 ) ,术后 3h进一步升高(P <0 .0 1) ,且净增值 (△AM)与CPB时间呈显著正相关 (r =0 .89,P <0 .0 1)。结论　小儿心脏手术期间血浆AM浓度增高 ,可能与拮抗心脏手术期间外周血管阻力增加或调节围术期的体液、电解质平衡稳态有关。 Objective To investigate the changes of plasma adrenomedullin (AM) during cardiac surgery in children with congenital heart disease. Methods 10 children undergoing cardiopulmonary bypass (CPB) were included in this study. They were given 10 min after induction of anesthesia, immediately before aorta occlusion, 5 min after occlusion of the aorta, 5 min after opening of the aorta and 3 h after the operation , Using specific radioimmunoassay method for the determination of plasma AM concentration. Results Plasma AM was gradually increased in children with CPB. Plasma AM was significantly increased after aortic opening (P <0.05), increased at 3 hours after surgery (P <0. 01) ) Had significant positive correlation with CPB time (r = 0.89, P <0.01). Conclusion The increase of plasma AM concentration during pediatric cardiac surgery may be related to the increase of peripheral vascular resistance during cardiopulmonary bypass or the perioperative fluid and electrolyte homeostasis.