目的观察异丙酚对中低温体外循环心肺转流术(CPB)期间脑氧合的影响。方法心内直视手术患者17例随机分为芬太尼组和异丙酚组，通过监测动脉、颈内静脉血和混合静脉血氧含量以及乳酸浓度，计算全身和脑动静脉氧含量差、氧摄取率和动静脉乳酸浓度差，分析异丙酚对CPB期间脑氧合的影响。结果两组复温过程中动静脉氧含量差和氧摄取率均较低温时升高；异丙酚组在CPB过程中动脉-颈内静脉血氧含量差和脑的氧摄取率要高于芬太尼组(P0.05)。CPB全过程中两组血乳酸浓度均进行性升高。结论CPB期间应用异丙酚麻醉并不能明显改善脑氧合。CPB期间脑保护机理有其复杂性一面，不能仅停留于氧代谢平衡方面。“,”Objective To observe the effects of propofo1 on cerebral oxygenation during hypothermia cardiopulmonary bypass(CPB).Methods Seventeen patients undergoing heart surgery were randomlydivided in two groups: fentanyl group arid propofol group. The oxygen content and the concentration of blood plasma lactic acid of artery, jugular venous bulb and pulmonary artery were monitored in the patients undergoing heart valve replacement at different nasopharyngeal temperatures. The arterial-venous oxygen content difference, oxygen extraction rate of cerebrum and total body were calculated. Results In two groups, arterial-venous differences and oxygen extraction rates during rewarming Were both higher than those during hypothemnia period. In propofol group, arterial-jugular venous difference and oxygen extraction were higher than those in fentanyl group(P0.05). The concentration of lactic acid in plasrn was increased in both groups during CPB. Conclnsion Propofol cannot amehiorate cerebral oxygenation imbalance during CPB, especially during rewarming period. Cerebral protection involves many aspects including the improvement in the balance of oxygen delivery and consumption.