摘要目的 观察呼气末正压通气对全身麻醉腹腔镜胃癌根治术患者脑血流动力学的影响.方法 择期行全身麻醉腹腔镜胃癌根治术的患者80例,美国麻醉医师协会(ASA)分级Ⅰ～Ⅱ级,采用随机数字表法分为A、B组,每组40例.A组通气参数:潮气量(VT)8ml/kg,呼吸频率(RR) 12次/分,呼气末正压(PEEP)5 cmH2O(1 cmH2O=0.098 kPa).B组通气参数:VT 8 ml/kg,RR 12次/分.于气腹前(T0)、气腹后30 min(T1)、气腹后1 h(T2)、气腹后2h(T3)时记录大脑中动脉平均血流速度(Vm)、平均动脉压(MAP)、心率(HR)、经皮测血氧饱和度(SpO2)、呼气末二氧化碳分压(PetCO2)变化,分别抽取各时点桡动脉血、颈内静脉球部血进行血气分析,记录动脉血氧分压(PaO2)、动脉血二氧化碳分压(PaCO2)、动脉血氧饱和度(SaO2)、血红蛋白(Hb)浓度;颈内静脉血氧分压(PjvO2)和颈内静脉血氧饱和度(SjvO2),根据Fick公式分别计算脑动脉和颈内静脉血氧含量(CjvO2)及其差值(Da-jvO2).结果 与气腹前比较,两组气腹后Vm、SjvO2、PaCO2在各时间点明显升高(P＜0.05).但是A组Vm、SjvO2、PaCO2的上升趋势较B组更为缓和,A组PaCO2在T1、T2分别为(35.5±2.7)、(40.7±3.5)mmHg,明显低于B组的(39.9±3.1)、(49.4±4.7)mmHg(P＜0.05),而Vm在T3为(68.9±8.1)cm/s,明显低于B组的(87.9 ±9.6) cm/s(P ＜0.05).与气腹前比较,气腹后2h两组Da-jvO2明显下降(P＜0.05),组间比较,A组下降幅度明显大于B组(P＜0.05).结论 低水平呼气末正压通气对全身麻醉腹腔镜胃癌根治术患者手术期间能有效降低术中的高二氧化碳血症,维持患者脑血流动力学的稳定,从而改善脑的过度灌注状态,改善患者的脑血流量和脑氧供需平衡.

abstractsObjective To observe the effects of low levels of positive end expiratory pressure on cerebral hemodynamics in patients with gastric cancer undergoing laparoscopic radical resection surgery under general anesthesia.Methods 80 patients (ASA Ⅰ-Ⅱ),scheduled to undergo laparoscopic radical gastrostomy,were randomly divided into group A,and group B,each group had 40 cases.The ventilation parameters of group A:tidal volume (VT):8 ml/kg,respiratory rate (RR):12 min,positive end expiratory pressure (PEEP):5 cmH2O (1 cmH2O =0.098 kPa).Group B was:VT:8 ml/kg,RR:12 min.Recording the average blood flow velocity in the middle cerebral artery (Vm),mean arterial pressure (MAP),heart rate (HR),transcutaneous oxygen saturation (SpO2),end-tidal carbon dioxide pressure (PetCO2) of the two group before pneumoperitoneum (T0),30 min after pneumoperitoneum (T1),1 hours (T2) and 2 hours (T3) after pneumoperitoneum.Blood samples of jugular bulb and radial artery were obtained at each time point for blood gas analysis,detection the arterial oxygen pressure (PaO2),arterial carbon dioxide pressure (PaCO2),arterial oxygen saturation (SaO2),hemoglobin concentration (Hb),internal jugular venous blood oxygen partial pressure (PjvO2),internal jugular venous oxygen saturation (SjvO2),jugular venous oxygen content (CjvO2),and arterial-jugular venous oxygen content difference (Da-jvO2).Results Compared with T0,the Vm,SjvO2,PaCO2 of the two groups increased significantly at each time point (P ＜ 0.05).But the Vm,SjvO2 of group A at T2 was significantly lower than that in group B (P ＜ 0.05),and the PaCO2 of group A at T1 and T2 were (35.5 ± 2.7),(40.7 ±3.5) mmHg respectively,which significantly lower than that of group B [(39.9 ± 3.1),(49.4 ±4.7) mmHg,P ＜0.05].And the Vm of group A at T2 was (68.9 ±8.1) cm/s,significantly lower than that of group B (P ＜ 0.05).Compared with T0,the Da-jvO2 at T2 of two groups decreased significantly (P ＜0.05),and between the two groups,A group decreased significantly than that in B group (P ＜0.05).Conclusion The low level of positive end expiratory pressure in patients undergoing laparoscopic radical gastrostomy with general anesthesia can effectively reduce the hypercapnia during operation,and improve cerebral hyperperfusion state,so as to improve the cerebral blood flow and improve cerebral oxygen supply and demand balance.