海滩椅位肩关节成形术时两种不同麻醉方式对脑氧供需平衡的影响

Effects of Different Anesthetic Protocol on Global Cerebral Supply and Demand Under Shoulder Athroplasty in Beach Chair Position

目的探讨海滩椅位肩关节手术七氟烷-氧化亚氮麻醉与丙泊酚-瑞芬太尼麻醉对患者颈静脉球血氧饱和度(SjvO2)和局部脑组织氧饱和度(SctO2)的影响,并评价两者之间的关系。方法择期行肩关节手术患者48例,按照随机数字表法分为七氟烷-氧化亚氮麻醉(S组,n=24)和丙泊酚-瑞芬太尼麻醉(P组,n=24)。麻醉诱导气管插管成功后仰卧位和体位变至海滩椅位后的不同时间点测定平均动脉血压、心率以及SjvO2和SctO2。结果两组平均动脉压均明显下降,但S组在体位变动后10min内较P组高(P<0.05);两组SjvO2均明显下降,下降幅度S组低于P组(12%±10%vs 23%±9%,P<0.01);S组SjvO2<50%和平动脉压低于50mmHg的发生率低于P组(P<0.05),但两组间SctO2低于基础值20%的比例无明显差异。结论肩关节成形术时七氟烷-氧化亚氮麻醉较丙泊酚-瑞芬太尼麻醉均能提供足够的脑氧供,但SjvO2反映脑氧供需平衡变化比SctO2更加敏感可靠。

Objective To study the effects of different anesthetics （ sevoflurane - nitrous oxide vs propofol - remifentanil） on cere- bral oxygenation and systemic hemodynamics in patients undergoing shoulder anthroplasty in beach chair position （BCP）. Jugular venous bulb oxygen saturation （SjvO2 ） and regional cerebral tissue oxygen saturation （SctO2 ） were determined while patients were placed from the supine to BCP. Methods Forty eight patients scheduled for shoulder surgery in BCP were randomly assigned to receive sevoflurane - nitrous oxide （Group S） or propofol -remifentanil （Group P） anesthesia. Mean arterial pressure and heart rate, as well as SjvO2and SctO2 , were measured before （postinduction baseline in supine position） and after BCP. Results Mean arterial pressure decreased by BCP in both groups. It was, however, significantly higher in group S than in group P at 7 to 8min after the positioning. SjvO2 also significantly decreased after BCP in both groups, the magnitude of which was lower in group S than in group P. The incidences of SjvO2 〈 50% and mean arterial pressure less than 50mmHg were lower in group S, but SctO2and the incidence of cerebral desaturation （ more than 20% decrease from baseline） did not significantly differ between the groups. Conclusion Both anesthetic protocols can provide sufficient oxygenation in patients undergoing shoulder anthroplasty in BCP. Furthermore, SjvO2 is a more reliable indicator reflecting cerebral supply and demand balance or potential cerebral ischemia than SctO2in BCP.