Assessment Of Stroke Volume Variation For Changes Of Volume By Using APCO

Objective:To observe the sensibility of SVV and CVP when the volume is change during induction period of general anesthesia for patients.Methods:Forty patients scheduled for elective orthopaedics operation were investigated.The forty patients were divided into two groups randomly.The patients of GroupⅠwere general anesthaetized and mechanical ventilated.Then bloodletting was been made as follows:5% whole body circulation, 5% whole body circulation.Then infused 6%HES 130/0.4 step by step, 5% whole body circulation, 5% whole body circulation.There were four steps all together.Each step was implemented after 5 min when the hemodynamics was stable. The patients of GroupⅡwere general anesthetized and mechanical ventilated. Then infused 6%HES 130/0.4 step by step, 5% whole body circulation, 5% whole body circulation. There were two steps all together. Each step was also implemented after 5 min when the hemodynamics was stable. Many indexes were signed such as APCO,SVV,CVP,HR,SVR,MBP etal.Statistical analysis was performed with t test and correlation analysis.Results:During hypovolemia, the central venous pressure (CVP) didn't change significantly along with the blood volume decrease, and changes in cardiac index were correlated lowly to in CVP(r=0.400, P<0.05),while changes in blood volume were not correlated to in CVP(r=-0.258, P>0.05). During hypovolemia, CVP increased significantly after the blood volume increase 10%; changes in cardiac index revealed no significant correlation to changes in CVP(r=0.207,P>0.05), while changes in blood volume were correlated lowly to in CVP(r=-0.341,r2=0.116, P<0.05). During hypervolemia, along with blood volume increase, CVP didn't change significantly; changes in cardiac index revealed no significant correlation to changes in CVP (r=0.200,P>0.05), while changes in blood volume were not correlated to in CVP(r=-0.069, P>0.05).During hypovolemia, the stroke volume variation (SVV)increased significantly along with the blood volume reduction, and changes in cardiac index were significantly correlated to changes in SVV(r=0.605,P<0.01),besides changes in blood volume were significantly correlated to changes in SVV(r=-0.559, P<0.01). During hypovolemia, SVV decreased significantly along with the blood volume induction; changes in cardiac index were significantly correlated to changes in SVV(r=0.651, P<0.01), besides changes in blood volume were significantly correlated to changes in SVV(r=- 0.530, P<0.01). During hypervolemia, along with blood volume increase, SVV didn't change obviously; changes in cardiac index revealed no significant correlation to changes in SVV (r=0.067,P>0.05),while changes in blood volume were not correlated to in CVP(r=-0.044 ,P>0.05).Conclutions:1.CVP can not reflect the changes of volume.2.SVV is useful indicator of hyporolemia ,but not of hypervolemia.