Effect of bypass flow rate of portosystemic bypass on the visceral organs in acute portal vein occlusion

本研究的目的是在急性门静脉阻塞（PVO）期间，使用肝素包被导管Anthrone确定门静脉系统旁路的临界流速（BFR）。各实验组麻醉犬的BFR控制在门静脉流量的10%（1组）、30%（2组）、50%（3组）。观察各组血液动力学和生化变化。随着BFR的降低，门静脉压（P_<pv>）升高，1组为47.1 mmHg， 2组为26.8 mmHg， 1组和2组肠系膜上动脉流量（F_<sma>）均显著降低。而P_<sma>组的变化可忽略不计。因此，BFR与P_<pv>呈负相关（r=-0.911， P<0.0001），与F_<sma>呈正相关（r=0.875， P<0.0001）。随着BFR的降低，门静脉红细胞压积升高，1组为54.5%，2组为50.3%。PVO 2小时后，门静脉血pH值降低，1组为7.210,2组为7.337。门静脉血CPK-BB水平与肠绝缘程度密切相关。综上所述，维持2小时PVO的临界BFR必须在门静脉流量的10% ~ 30%之间，在2小时PVO以上的肠系膜器官绝缘方面，50% BFR就足够了。

The object of this study was to determine the critical flow rate (BFR) of the portosystemic bypass, using heparin coated catheter Anthrone, during acute portal vein occlusion (PVO). BFR was controlled at 10% (Group 1) , 30% (Group 2), 50% (Group 3) of the portal flow in the individual experimental groups of anesthetized dogs. Hemodynamic and biochemical changes were observed during 2 hours in each group.With decreased BFR, portal venous pressure (P_<pv>) increased, with 47.1 mmHg in Group 1 and 26.8 mmHg in Group 2, and superior mesenteric arterial flow (F_<sma>) decreased remarkably in both Group 1 and Group 2. However, P_<sma> showed negligible changes in Group 3. Thus, negative correlation between BFR and P_<pv> (r=-0.911, P<0.0001), and positive correlation between BFR and F_<sma> (r=0.875, P<0.0001) were found respectively. With decreased BFR, portal venous blood hematocrit increased, with 54.5% in Group 1 and 50.3% in Group 2. Following 2 hours PVO, pH levels of portal venous blood were reduced, with 7.210 in Group 1 and 7.337 in Group 2. CPK-BB levels of portal venous blood correlated well to the degree of intestinal insultation.In conclusions, the critical BFR must be between 10% and 30% of portal flow for life sustaining up to 2 hours PVO, and 50% BFR is sufficient enough in more than 2 hours PVO, in the aspect of mesenteric organ insultation.