过度通气对控制性降压下颅内动脉瘤夹闭术中脑氧代谢的影响

目的:研究过度通气对控制性降压下颅内动脉瘤夹闭术中脑氧代谢的影响。方法:择取颅内动脉瘤患者36例,ASAⅠ～Ⅱ级,随机分为正常通气组(A组,PaCO235～40mmHg)、轻度通气组(B组,PaCO230～35mmHg)和中度通气组(C组,PaCO225～30mmHg)。各组应用硝酸甘油控制性降压,降压幅度在基础值的20%～25%,在降压达到目标值15min后进行过度通气。各组于降压前(T0)、降压达到目标血压15min后(T1)、过度通气使PaCO2达到各组预定值15min后(T2)、MAP恢复且PaCO2恢复到35～40mmHg后15min(T3)抽取桡动脉血和颈内静脉血进行血气分析,计算动脉血氧含量(CaO2)、静脉血氧含量(CjvO2)、动脉-静脉血氧含量差(Da-jvO2)和脑氧摄取率(CERO2)。结果:与T0比较,各组T1、T2时MAP显著降低(P<0.05),T3时MAP差异无统计学意义(P>0.05)。与T0比较,A组和B组其余时点各项指标差异无统计学意义(P>0.05);与T0比较,C组各时点CaO2差异无统计学意义(P>0.05),T2时C组CjvO2明显降低(P<0.05)、Da-jvO2和CERO2显著升高(P<0.05)。结论:控制性降压下颅内动脉瘤夹闭术中保持PaCO2在(30±2)mmHg时脑氧代谢障碍,维持PaCO2在(35±2)mmHg以上是安全的。

Effect of artificial hyperventilation on cerebral oxygenation and metabolism under controlled hypotention during intracranial aneurysm surgery

Objective To investigate the effect of various degree of artificial hyperventilation on cerebral oxygenation and metabolism under controlled hypotention during intracranial aneurysm surgery.Methods thirty-six patients(ASAⅠ-Ⅱ) scheduled for intracranial aneurysm surgery were divided into there groups according to PaCO2:hypotention and PaCO2(40 ± 2) mmHg(group A),hypotention and PaCO2(35 ± 2) mmHg(group B) and hypotention and PaCO2(30 ± 2) mmHg(group C).Arterial and jugular venous blood samples were taken before hypotention(T0),after hypotention for 15 min(T1),artificial ventilation for 15 min(T2),and at the end of hypotention and artificail ventilation(T3).The arterial oxygen concent(CaO2),jugular venous oxgen conent(CjvO2),arterial and jugular bulb venous 02 content difference(Da-jvO2) and cerebral oxygen extraction rate(CERO2) were calculated.Results Compared with T0,MAP has significantly decreased at T1 and T2(P < 0.05) and there was no difference at T3 between groups(P > 0.05).Compared with T0,CaO2 has no difference at all points in group C(P > 0.05),CjvO2 decreased significantly at T2 in group C(P < 0.05),Da-jvO2 and CERO2 have increased significantly at T2 in group C(P < 0.05).Conclusion Keeping PaCO2(30 ± 2) mmHg leads to disorder of cerebral oxygen metabolism and it is safe to keep PaCO2(35 ± 2) mmHg during intracranial aneurysm surgery.