内毒素血症对腹腔内脏血流影响的实验研究

Effects of endotoxemia on splanchnic blood flow

目的观察在内毒素血症状态下,肠系膜上动脉、肝动脉、门静脉血流以及肝动脉缓冲效应(hepatic arterial barffer response,HABR)的变化。方法 24头雌性猪(21～35kg),随机分为二组。一组静脉持续注入大肠杆菌内毒素,为内毒素组(n=12);一组静脉注入生理盐水,为对照组(n=12)。通过7F Swan-Ganz 右心漂浮导管和超声流量探头监测心排出量(CO)、肺动脉楔压(Ppaw),记录肝动脉(Qha)、门静脉(Qpv)和肠系膜七动脉(Qmsa)血流。通过阻断门静脉血流的方法检测HABR,采用肝动脉血流的变化值(△Qha)/门静脉血流变化值(△Qpv)的方式表示 HABR(△Qha/△Qpv)。结果静脉持续注射内毒素后,心率明显加快。内毒素组 CO 在1h 明显增加(与基础值比较 P≤0.05),MAP 和 CO 在6、8h 明显下降(与对照组比较差异显著,P≤0.01)。在注射内毒素后,Qha 由(0.05±0.03)ml/(kg·min)降至(0.01±0.01)ml/(kg·min)(P≤0.01),Qpv 由(0.26±0.06)ml/(kg·min)降至(0.18±0.09)ml/(kg·min)(P≤0.05),Qmsa 由(0.15±0.03)ml/(kg·min)降至(0.05±0.04)ml/(kg·min)(P≤0.01),ΔQha/ΔQpv由(0.16±0.12)降至(0.04±0.04)(P≤0.01)。对照组未发生上述改变。结论在静脉持续注射内毒素的情况下,实验动物表现出由高血流动力学到低血流动力学的变化,同时内脏血流进行性减少;HABR 功能减退,难以发挥维持肝血流量的作用。

Objective To investigate the changes of blood flow of superior mesenteric artery, hepatic artery, portal vein and hepatic arterial buffer response （HABR）. Methods Twenty-four pigs weighing 21-35 kg were divided into the endotoxemia group （n= 12） and control group （n= 12）. The animals in the endotoxemia group received continuous intravenous infusion of E. coli endotoxin and those in the control group received that of normal saline. The pulmonary arterial wedge pressure, cardiac output, superior mesenteric arterial flow, hepatic arterial flow and portal venous flow were recorded via Swan-Ganz catheter and ultrasound transit time flow probe. Results During the infusion of endotoxin, the heart rate significantly increased and CO elevated at the 1st h （P≤0. 05） and CO, MAP decreased at the 6th, and 8th h as compared with the control group （P≤0. 01）. In the endotoxemia group, Qha decrease from （0. 05±0.03）ml/（kg·min） to （0.01±0.01）ml/（kg ·min） （P≤ 0.01）, Qpv decreased from （0. 26±0.06）ml/（kg ·min） to （0.18±0.09）ml/（kg·min） （P≤0. 05）, Qmsa decreased from （0. 15±0.03）ml/（kg ·min） to （0.05±0. 04）ml/（kg ·min） （P≤0. 01） and AQha/AQpv decreased from （0. 16±0.12） to （0. 04±0.04） （P≤0.01）. There were no significant changes in these parameters in the control group. Conclusions During the continuous infusion of endotoxin, hemodynamics changes from hyperdynamic state to hypodynamic one. Meanwhile, the splanchnic blood flow is in low state. The decreased HABR losses the function of maintaining the liver blood flow.