颈部腔镜手术中CO2压力对脑血流影响的实验研究

目的:通过脑氧代谢探讨颈部腔镜手术中 CO2 充气压力对兔脑血流量(CBF)的影响及意义。方法:运用CO2 气建立和维持兔颈部的手术空间,实验动物分成 4 组,每组 6 只,分别维持 0 mmHg(对照组)、4 mmHg、8 mmHg、12 mmHg气压。动态监测平均动脉压(MAP)、心率(HR)、中心静脉压(CVP)变化。分析观察颈内静脉血氧分压(PjvO2)、颈静脉氧饱和度(SjvO2 )、脑动 静脉血氧含量差(Ca jvDO2 )变化。结果:12 mmHg气压组 150min CVP增为(7.54±0.23)cmH2O(P<0.05),而 MAP基本不变。8 mmHg气压组、12 mmHg气压组 150 minPjvO2、SjvO2 与对照组和4 mmHg比较分别下降(P<0.05)。各实验组Ca jvDO2 上升(P<0.05)。8 mmHg以上气压组有超微细胞学改变。结论:颈部腔镜手术中 CO2 压力影响颈静脉回流是导致 CBF改变的主要原因。CO2压力可以引起脑充血、缺氧反应、脑组织变性。

Effects of Carbon Dixide Insufflation on Cerebral Blood Flow during Endoscopic Neck Surgery with Pressure in Rabbits Model

Objective: To study the effect and its significance on cerebral blood flow(CBF) by analyzing cerebral oxygenation during endoscopic neck surgery with carbon dioxide insufflation in rabbits model. Methods: Twenty-four rabbits, 6 in each group, underwent endoscopic neck surgery. Insufflation was performed with CO_2 pressure at 0 mmHg(sham), 4 mmHg, 8 mmHg and 12 mmHg. Mean artery pressures (MAP), heart rate (HR) and central venous pressure (CVP) were monitored dynamically during insufflation. The changes in PjvO_2(oxygen pressure of jugular blood), SjvO_2 (oxygen saturation of jugular blood) and Ca-jvDO_2(cerebral ateriovenous difference of oxygen)were observed. Results: After 150 min, CVP of the 12 mmHg group with CO_2 insufflation pressure significantly increased to 7.54±0.23 cmH_2O(P<0.05), while MAP without significant changes. PjvO_2 and SjvO_2 of the 8 mmHg group and of the 12 mmHg group was greatly decreased respectively compared with those of the sham group and the 4 mmHg group after 150 min (P< 0.05 ). Ca-jvDO_2 of every CO_2 insufflation group improved obviously (P<0.05) compared with that of the sham group. The cerebral tissue had significant changes in the cytologic analysis when the CO_2 insufflation pressure was higher than 8 mmHg. Conclusion: Carbon dioxide insufflation pressure influences jugular venous circumfluence during endoscopic neck surgery, which is a key reason for the changes of CBF. The CO_2 insufflation pressures can cause the cerebral hyperaemia, hypoxia and cerebral tissue denaturation.