体外循环时体温变化对全身和脑氧代谢的影响

Comparison of the effects of temperature change on systemic and cerebral oxygen metabolism during cardiopulmonary bypass

目的 :研究体外循环体温变化对全身和脑氧代谢状况的影响。方法 :用比色方法测定瓣膜置换患者体外循环 (CPB)中不同鼻咽温 (NPT)时的血浆乳酸浓度 ,血气分析仪测定动脉血、混合静脉血、颈静脉球部血的氧含量并计算动 -静脉的氧含量差值、全身和脑的氧摄取率。结果 :CPB全过程中血浆乳酸浓度呈进行性升高 ,复温时更明显。降温时全身和脑的氧耗量明显降低 ,复温时均升高 ,脑的氧耗量升高更为明显。 结论 :体外循环中体温是影响氧耗量的一个重要因素 ,各体温点都有不同程度的氧供需失衡 。

Objective: To study the effects of body temperature change on systemic and cerebral oxygen metabolism during cardiopulmonary bypass(CPB). Methods: In patients undergoing heart valve replacement, lactic acid was measured through colorimetry and using a blood gas analyzer to measure oxygen content of artery, pulmonary artery and jugular bulb at different nasopharyngeal temperatures (NPT) during CPB. Then systemic/cerebral arterial venous oxygen content differences and oxygen extraction rate were calculated. Results: The concentration of blood plasm lactic acid continualy increased during CPB, especially during rewarming phase. During hypothermia systemic/cerebral arterial venous oxygen content differences and oxygen extraction were reductive but they were increasing during rewarming time, especially in the case of the cerebrum. Conclusion: Body temperature change is an important factor that influences oxygen supply and oxygen demand at different NPT, but the cerebral imbalance during rewarming time needs special attention. [