硬膜外阻滞对肠系膜下动脉血流的影响

Effect of epidural anesthesia on blood flow of the inferior mesenteric artery

目的研究胸段硬膜外阻滞对肠系膜下动脉血流的影响。方法18例ASA I或II级直肠癌或乙状结肠癌根治术患者采用全身麻醉与硬膜外阻滞联合麻醉。术中连续监测MAP和CVP。全麻诱导前行T10～11硬膜外穿刺置管。手术开腹暴露肠系膜下动脉。于硬膜外给药前、给药后MAP降至60mm Hg、迅速扩容使CVP升至给药前、注射麻黄碱后MAP升至硬膜外给药前水平4个时点用多普勒超声直接测量肠系膜下动脉内径(D)、最大流速(Vmax)、最小流速(Vmin)、平均血流速度(Vmean)、阻力指数(RI)、搏动指数(PI)以及速度积分(FVI),并计算血流量(Q)。结果胸段硬膜外阻滞使Q在实验不同时点均有不同程度的上升。MAP与PI具有良好的相关性(P<0.05);CVP与Vmean、FVI具有良好的相关性(P<0.05)。结论肠系膜下动脉的灌注受MAP、CVP的影响,硬膜外阻滞可以增加肠系膜下动脉血流量。

Objective To investigate the effect of epidural anesthesia on blood flow of the inferior mesenteric artery. Methods General anesthesia combined with thoracic epidural anesthesia was used in 18 patients （ASA class Ⅰ or Ⅱ） undergoing radical operation for rectal or sigmoid cancer. Mean arterial pressure（MAP） and central venous pressure（CVP） were monitored during operation. Epidural catheter was placed before induction of general anesthesia. After the inferior mesenterie artery was exposed, the Doppler ultrasonic measurements were performed directly before epidural block,at the time points for MAP decreased to about 60 mm Hg, CVP increased to the preoperative level with volume expansion and MAP increased to the level before epidural block after ephedrine injection. The relationship between the inferior mesenteric artery blood flow （Q） and MAP or CVP was analyzed. Results During epidural block, Q was increased significantly, MAP was closely correlated with pulsation index（H） （r=0.99, P〈0. 05）, and CVP was closely correlated with the mean velocity of blood（Vmean） and the flow velocity integrity（FVI） （P〈0. 05）. Conclusion The perfusion of the inferior mesenteric artery was related to MAP and CVP. Epidural block can increase the perfusion of the inferior mesenteric artery.