儿童体外循环中内生性一氧化氮浓度的变化

目的　一氧化氮(NO)是内皮细胞分泌的扩血管因子，测定NO代谢产物及NO合成酶的浓度可反映内生性NO的变化。方法　分别于手术前、体外循环降温结束、升温开始和停体外循环时测定两者的浓度。结果　术前NO代谢产物及NO合成酶的浓度分别为50．2±10．6μmol／L和34．5±8．9μmol／L，降温结束时，两者浓度均显著降低。此后略有升高，升温以后都显著增加，分别达60．8±20．4μmol／L和45．3±13．2μmol／L。结论　本实验显示，体外循环中内生性NO升高，特别在升温阶段升高明显。这同升温阶段炎症反应加剧，炎症因子浓度增高有关。

Concentrations of Nitric Oxide during Cardiopulmonary Bypass in Children

Objective Nitric oxide (NO) is an endothelium- derived vasodilator. Measuringthe concentrations of NO synthase and NO metabolic products may reflect the changes of endogenousNO. Methods At the time of preoperation, cooling end, warming beginning and cardiopulmonarybypass stop, we measured the concentrations of NO synthase and NO metabolic products in 20 childrenwith congenital heart disease. Results Before CPB, the concentrations of NO synthase and NOmetabolic products were 50.2 ± 10.6 μmol/L and 34.5 ± 8.9 μmol/L, respectively. They decreasedduring cooling and increased slightly in the hypothermic phase. While warming, they increased signifi-cantly to 60.8 ± 20.4 μmol/L and 45.3 ± 13.2 μmol/L. Conclusion The concentrations of NO syn-thase and NO metabolic products were elevated during cardiopulmonary bypass especially in the warmingphase. It suggested that they might be affected by the inflammatory and reperfusion reactions whichwere more serious during warming than any other phases in cardiopulmonary bypass.