体温变化对先天性心脏病小儿体外循环中脑氧供需平衡的影响

Effects of Temperature Change on the Balance of Cerebral Oxygen Supply and Demand in Children of Congenital Heart Disease during Cardiopulmonary Bypass

目的观察体温变化对先天性心脏病手术小儿体外循环(CPB)期间脑氧供需平衡的影响。方法选择室间隔缺损心内修复术小儿15例,分别在CPB降温期和复温期不同体温时点(T0～T7)同时抽取桡动脉和颈内静脉球部血行血气分析,计算脑氧代谢指标,包括动脉内氧含量(CaO2)、静脉内氧含量(CjvO2)、动静脉血氧含量差(AVDO2)、脑氧摄取率(CEO2),并同时检测乳酸及血糖水平。结果降温期各体温时点与基础值T0比较,颈静脉球血氧饱和度(SjvO2)显著升高(P<0.01),CaO2、AVDO2、CEO2显著降低(P<0.01);复温期各体温时点与降温期T3比较,SjvO2显著降低(P<0.01),AVDO2、CEO2均显著升高(P<0.01)。结论体温是影响先天性心脏病手术小儿CPB期间脑氧供需平衡的重要因素,降温期脑氧耗量明显降低,而复温期明显升高,较易发生脑氧供需失衡。

Objective To investigate the effects of temperature change on the balance of cerebral oxygen supply and demand in children of congenital heart disease during cardiopulmonary bypass. Methods Fifteen children of ventricular septal defect aged from four to nine years old were enrolled in the present study. Blood samples were collected simultaneously from the radial artery and jugular bulb respectively at different temperature points during hypothermic and rewarming phase of CPB for blood gas analysis and further calculation of cerebral oxygen consumption,including oxygen content of artery (CaO2),oxygen content of jugular bulb venous (CjvO2),the arterio-venous oxygen content difference (AVDO2)and cerebral extraction rate of oxygen (CEO2). At the same time,the content of blood glucose and lactic acid of the same blood sample were measured. Results Compared with data of baseline,jugular bulb venous oxygen saturation (SjvO2)was significantly higher (P < 0.01)and CaO2,AVDO2 and CEO2 were significantly lower (P < 0.01)during hypothermic phase of CPB. Compared with data of hypothermic phase,SjvO2 was significantly lower (P < 0.01),however,AVDO2 and CEO2 were significantly higher during rewarming phase of CPB (P < 0.01). Conclusion Temperature is an important factor influencing the balance of cerebral oxygen supply and demand during CPB in children of congenital heart disease suffered cardiac surgery. The cerebral oxygen consumption is significantly lower during hypothermic phase,while higher during rewarming phase of CPB. The imbalance of cerebral oxygen supply and demand occurs easily during rewarming phase of CPB.