The Effect Of Different Levels Of CVP On Hemodynamics,Metabolism Of Oxygen And Hepatic Venous Bleeding In Bama Miniature Pigs

Objective:To investigate the best security value of low central venous pressure(LCVP) through the animal experiment,and provide the evidences of theory for the safety during the clinical application of LCVP technology in operation.Method:1.50 healthy and clean Bama miniature pigs were selected and purchased from the Animal Research Institute of Guangxi University.They were divided into eight groups randomly(CVP 0 - 2O Group;CVP 1-<2cmH₂O Group;CVP 2 - <3cmH₂O Group;CVP 3 - <4cmH₂O Group;CVP 4 - <5cmH₂O group;CVP 5 - <6cmH₂O Group;CVP 6 - <7cmH₂O Group; CVP 7 - <8cmH₂O group),there were 6 Bama miniature pigs in each group.2. After general anesthesia,hemodynamic monitoring was carried out by the catheters of femoral artery,internal jugular vein and Swan-Ganz.At the same time,the retrograde catheter of internal jugular vein was prepared.3.Left liver lobe was resected partially during laparotomy,left hepatic vein was catheterized. Hepatic vein pressure and the amount of hepatic vein bleeding in unit time were observed during the different level of CVP.4.NTG was infused by micro-infusion pump,to control the CVP of groups.5.Blood samples were collected from femoral artery,pulmonary artery and internal jugular vein,sent to blood gas analysis.6.HP multi-function monitoring system was applied to calculate the hemodynamics index:Cardiac index(CI),the metabolism of oxygen index:systemic and brain oxygen delivery(DO₂),oxygen consumption (VO₂),oxygen extract ratio(O₂ER) et al.Results:1.48 animal models were established successfully,the successful model rate of CVP was 96%.2.The effects of different levels of CVP on hemodynamics:â‘ There was no significant difference of heat rate CHR) in different groups(P>0.05).â‘¡The MAP,CO and CI in the groups of CVP <2 cmH₂O decreased obviously compared with the other groups of C VP≥2cmH₂O (p <0.05),there was no significant difference among the other groups of CVP≥2cmH₂O(p>0.05).3.The effects of different levels of CVP on systemic metabolism of oxygen:â‘ There was no significant difference of Hb,SaO₂ and CaO₂ in different groups of CVP(p>0.05).The DO₂ in the group of CVP<2 cmH₂O decreased obviously compared with the other groups of CVP≥2cmH₂O (p<0.05),there was no significant difference(p>0.05) among the other groups of CVP≥2cmH₂O.â‘¡The SvO₂,CvO₂,VO₂ of the group of CVP <1cmH₂O in systemic mixed venous and intracranial venous blood was less than the other groups of CVP≥1cmH₂O(p<0.05),the O₂ER was higher than the other groups of CVP≥1cmH₂O(p<0.05),whereas the differences among the other groups of CVP≥1cmH₂O were no significant(p>0.05).4.The effects of different levels of CVP on hepatic venous bleeding:â‘ Hepatic venous bleeding in the group of CVP <3cmH₂O was less than the other groups of CVP≥3cmH₂O,in the group of CVP <5cmH₂O was less than the other groups of CVP≥5cmH₂O(p <0.05); There was no significant difference in the groups of CVP <3cmH₂O(p> 0.05), There was no significant difference in the groups of CVP≥5cmH₂O(p> 0.05).â‘¡There was a high degree of linear positive correlation between hepatic venous pressure and CVP(r = 0.985,p<0.01);There was a high degree of linear positive correlation between the volume of hepatic venous bleeding and CVP (r= 0.933,p<0.01).Conclusion:1.The stability of hemodynamics and metabolism of oxygen can be maintained at the level of CVP≥2cmH₂O.2.The level of CVP at 3cmH₂O and 5cmH₂O are the critical points to reduce hepatic venous bleeding. There is a high degree of linear relationship between hepatic venous pressure, hepatic venous bleeding volume and CVP.The lower CVP and hepatic venous pressure is got,the less amount of hepatic veins bleeding is obtained.3.The level of CVP at 2 - <3cmH₂O is the best security value,could be applied to reduce the hepatic venous bleeding,while the stability of hemodynamics and metabolism of oxygen could be maintained.