The Effect Of Different Level Of Low Central Venous Pressure On Hemodynamics And Blood Loss In Pig Animal Model Of Injury Of Hepatic Vein

Objective:To observe the effect of different level of low central venous pressure on hemodynamics and blood loss in pig animal model of injury of hepatic vein,and evaluate the best security value of LCVP.Method:30 Bama miniature pigs were randomly divided into 5 groups with 6 pigs in each group:group A,group B,group C,group D and group E.After anesthesia,an arterial catheter was placed in the left femoral artery for continuously measure the arterial blood pressure.A single lumen venous catheter was placed in the right internal jugular vein for measure CVP and infusion.A Swan-Ganz catheter was placed through the right femoral vein for measure CO,PCWP,SPAP,DPAP and MPAP.After openning the abdominal cavity,partial liver of the left lobe were resected,and isolated the left hepatic vein.An outer sheath catheter of Swan-Ganz catheter for measured the velocity of blood loss from left vein was placed in the left hepatic vein 3 centimeter.After the model established,cardiac output(CO) was measured,and the heart rate(HR), mean arterial pressure(MAP),Mean pulmonary arterial pressure(MPAP), pulmonary capillary wedge pressure(PCWP) and so on were recorded, and the cardiac index(CI),systemic vascular resistance(SVR) and pulmonary vascular resistance(PVR) were calculated.Different doses of nitroglycerin were infused with micro-infusion pump to control the CVP at the following different levels:group A at 0mmHg,group B at 1mmHg, group C at 2mmHg,group D at 3mmHg and group E at 4mmHg.After the CVP were stable for 10 minutes,hemodynamic indexes were recorded and calculated again,and the hepatic venous pressure was measured through the outer sheath catheter.And then the outer sheath catheter was put in Axillary midline and openned for 30 seconds,and the blood loss from the left hepatic vein were collected.Results:1.Animal models establishment2 pigs were given up because endotracheal intubation or placement of Swan-Ganz catheter defeat.The success ratio of anesthesia was 94%. The success ratio of animal model of LCVP was 100%.2.The effects of different levels of LCVP on haemodynamicsIn all groups,the HR before controlled LCVP were no significant difference compared with that after controlled LCVP,and there were no significant difference among the 5 groups(P＞0.05).Before controlled LCVP,the MAP,CO,CI and MPAP were no significant difference among the 5 groups.After controlled LCVP,the MAP,CO,CI and MPAP in group A and group B were significant decreased than that before controlled LCVP(P＜0.05 ).In group C,group D and group E,there were no significant difference in MAP,CO,CI and MPAP after controlled LCVP,compared with that before controlled LCVP.After controlled LCVP,the MAP,CO,CI and MPAP in group A and group B were significant lower than that in group C,group D and group E.Before controlled LCVP,the SVR and PVR were no significant difference among the 5 groups.After controlled LCVP,the SVR and PVR in group A and group B were significant increased than that before controlled LCVP(P＜0.05).In group C,group D and group E,there were no significant difference the SVR and PVR after controlled LCVP, compared with that before controlled LCVP.After controlled LCVP,the SVR and PVR in group A and group B were significant higher than that in group C,group D and group E.Before controlled LCVP,the PCWP were no significant difference among the 5 groups.After controlled LCVP,the PCWP in group A, group B and group C were significant decreased than that before controlled LCVP(P＜0.05) In group D and group E,there were no significant difference in PCWP after controlled LCVP,compared with that before controlled LCVP.After controlled LCVP,the PCWP in group A,group B and group C were significant lower than that in group D and group E.3.The effect of different level of LCVP on the blood loss during injury of hepatic vein.The CVP and the hepatic venous pressure was positively correlated (r=0.985,P＜0.01) The blood loss and the CVP was positively correlated(r=0.923,P＜0.01).The velocity of blood loss in group A, group B,group C,group D and group E were 8.5±2.25ml/30s,16.3±2.06 ml/30s,24.54±3.39 ml/30s,27.2±3.25 ml/30s and 43.6±6.62 ml/30s respectively.The blood loss were significant difference in group comparison,group E＞group D and group C＞group B＞group A(P＜0.05). Conclusion:Controlled low central venous pressure can be effective in reducing blood loss in injury of hepatic vein of pigs.As maintaining a relatively stable hemodynamic circumstances,controlled of LCVP at 2mmHg～3mmHg can maximum reduce the blood loss in injury of hepatic vein in Bama miniature pigs.