内毒素休克犬的肾脏血流动力学变化

Changes of renal hemodynamics in dogs with endotoxemic shock

目的探讨内毒素休克（ES）时肾脏血流动力学的动态变化及其在急性肾损伤（AKI）发病中的作用。方法经肺动脉导管注射大肠杆菌内毒素建立犬的ES-AKI模型；肺动脉导管及脉搏指数连续心输出量（PICCO）监测全身血流动力学，超声血流量仪监测左肾动脉肾血流量（RBF）变化；定时留取血尿标本检测血气、肾功及生化指标。HE染色观察肾脏病理改变。结果注射内毒素后，心输出量（CO）和RBF波动较对照组大，但组间差异无统计学意义；犬平均动脉压（MAP）、外周血管阻力（SVR）和肾血管阻力（RVR）均明显下降（P〈0．05）；血管外肺水（EVLW）明显升高（P〈0．05）；尿量在2h显著下降（P〈0．05），后有所恢复。肌酐清除率（CCr）明显下降[由0h的（101．2±19．3）ml／min降至6h的（29．2±15．7）ml／min，（P〈0．01）]，血清肌酐（SCr）缓慢上升（P〈0．05）；尿的N-乙酰葡萄糖苷酶（NAG）升高[（67．0±9．5）μmol／L升至6h的（98．0±18．9）p,mol／L，（P〈0．01）]。相关分析显示RBF与CO（R2=0．630，P=0．001）呈正相关，而与MAP无明显相关性（R2=0．009，P=0．758）。CCr与MAP呈正相关（R2=0．415，P=0．003）而与RBF及CO均无明显相关性（P〉0．05）；MAP在100～180mmHg范围内，CCr与MAP在内毒素休克组呈正相关（R2=0．780，P=0．000），在对照组不相关。肾脏自身调节曲线右移。结论内毒素休克时肾血流量与心输出量呈正相关；内毒素休克早期，肾脏压力灌注明显下降，而流量灌注可无明显改变；内毒素休克早期肾脏的自身调节曲线右移，容易发生急性肾损伤。

Objective To explore the changes of renal hemodynamic in dogs with endotoxemic shock （ES） and their potential roles in acute kidney injury （AKI）. Methods Canine endotoxic shock model was induced by an infusion of lipopolysaccharide of Escherichia coli through pulmonary artery catheter （PAC）. Systemic hemodynamics and left renal blood flow （RBF） was monitored by PAC, pulse index continuous cardiac output （PiCCO） and ultrasonic blood flow meter. Blood and urine specimens were harvested timely for blood gas analysis, renal function tests and biochemical detection. Results Hemodynamics ： CO and RBF fluctuated widely but without any significance （ P 〉 0. 05 ）. The values of mean arterial pressure （ MAP）, systemic vascular resistance （ SVR）, renal vascular resistance （RVR） and 2-hour urine volume significantly decreased （ all P 〈 0. 05 ） while extravascular lung water （ EVLW ） increased markedly （ P 〈 0. 05 ）. Renal function ： There was a drop in CCr, urine osmotic pressure and an elevation in SCr and NAG. RBF was correlated positively with CO （RE = 0. 630, P = 0. 001 ）. However, it bad no correlation with MAP （ RE = 0. 009, P = 0. 758 ）. CCr was correlated positively with MAP （ RE = 0. 415, P=0. 003）. However, it had no correlation with RBF or CO （P 〉0. 05 ）. The auto-regulation curve of GFR had a shift to the fight. Conclusion RBF is positively correlated with cardiac output in endotoxin shock. Renal pressure perfusion may decrease obviously without any noticeable change of renal flow perfusion. The shift of renal auto-regulation under pressure perfusion occurs at the early stage of septic shock.