| Objective:To evaluate the accuracy of stroke volume variation(SW)in fluid responsiveness monitoring for patients undergoing off-pump coronary atery bypass grafting, and to observe the changes of hemodynamic indexes before and after thoracotomy. To study the performance of SVV following trendelenburg position and alteration of tidal volume. By present study,the ability of SW in guiding the volume therapy in OPCABG are to be evaluated.Methods:43 patients referred for elective OPCABG were enrolled in present study. Central venous catheter and pulmonary artery catheter were inserted after anesthesia induction and CVP, PCWP,CO,CI,SV,SVI were mornitored continuously. SW was observed by Flotrac/Vigileo system. All patients were under general anesthesia and mechanical ventilation. To observed the influence of body position to S W,the hemodynamic indexes were recorded after anesthesia induction and trendelenburg(30°) position.To observed the influence of tidal volume to SW, the hemodynamic indexes were recorded under the contition of 6ml/kg and 10ml/kg tidal volumes as well as points of thoracotomy and pericardiotomy. To study the ability of SW for mornitoring the fluid responsiveness, two volume expansion(VE) tests with hydroxyethyl starch 130/0.4 and sodium chloride injection 6ml/kg were accomplished before and after OPCABG respectively. Every index was recorded before and after VE. According to if cardiac index alteration(ACI) was less than 10%, all patients were divided into two groups:responder group whoseΔCI were =10%after VE and inresponder group whoseΔCI were<10%after VE. Observed the relationship between the indexes before VE(indexes at baseline) andΔSVV. All hemodynamic data in present study were recorded at 3 min following stable hemodynamic status achieving.Results:After the trendenlenburg postion, SBP,DBP,MAP,CVP,PCWP,SVI,CO,CI and SV increased significantly; SW decreased significantly. SBP,DBP,MAP and SW were different significantly between responder group and inresponder group.Following tidal volume was adjusted from 6ml/kg to 10ml/kg,the indexes didn't change significantly.Following the first VE, CVP,CO,CI increased significantly, meanwhile the SBP,MAP,DBP,SW decreased significantly. CO,SV,CI were lower in responder group than in inresponder group. SW was higher in responder group than in inresponder group. There was a significant relationship between SW at baseline andΔCI(r=0.420,P<0.01), and there was also a significant relationship betweenΔSVV andΔCI(r=-0.540,P<0.01). These results demonstrated that the ability of SVV to predict fluid responsiveness was significantly better than other indexes, andΔSW was useful for evaluating the fluid responsiveness before OPCABG. The threshold SW value of 10.5%discriminated between respond-er group and in-responder group with a sensitivity of 59.30%and a specificity of 81.20%befo-re OPCABG.Following the second VE, SBP,MAP,PCWP,CVP,CO,CI,SV,SVI increased significantly, SVV decreased significantly. CO,SV,CI were lower inresponder group than in inresponder group. SVV was higher inresponder group than in inresponder group. There was a significant relationship between SW at baseline andΔCI(r=0.391,P<0.01), and there was also a significant re-lationship betweenΔSVV andΔCI(r=-0.666,P<0.01). These results demonstrated that the ability of SW to predict fluid responsiveness was significantly better than the other indexes, andΔSW was useful for evaluating the fluid respons-iveness after OPCABG. The threshold SW value of 10.5%discriminated bet-ween responder group and inresponder group with a sensitivity of 92.60%and a specificity of 87.50%after OPCABG.Conclusion:The filling pressure like CVP and PCWP are limited in moni toring fluid responsiveness for patients undergoing OPCABG. SW obtained fr om the Foltrac/Vigileo system can monitor fluid responsiveness exactly before and after OPCABG, so it is suitable for guiding the fluid therapy in OPCABG...
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