每搏输出量变异度监测非体外循环冠状动脉旁路移植术患者血容量变化的准确性

目的 评价每搏输出量变异度(SVV)监测非体外循环冠状动脉旁路移植术患者血容量变化的准确性.方法 择期行非体外循环冠状动脉旁路移植术患者21例,性别不限,年龄44～77岁,体重43～93 kg,ASA分级Ⅱ或Ⅲ级.开胸打开心包,待血液动力学稳定5 min时(T1),以0.25ml·kg-1·min-1的速率静脉输注6％羟乙基淀粉130/0.4氯化钠注射液7 ml/kg.于T1和输注完毕后10min(T2)时记录HR、MAP、CVP、体循环血管阻力(SVR)、体循环血管阻力指数(SVRI)、SVV、每搏输出量指数(SVI)和CI,并计算变化率(△HR、△MAP、△CVP、△SVR、△SVV、△SVI和△CI).△HR、△MAP、△CVP、△SVR、△SVV与△SVI进行Pearson相关性分析.以△SVI≥25％为扩容有效的标准,绘制HR、MAP、CVP、SVR、SVV监测血容量变化的ROC曲线,计算曲线下面积及其95％可信区间.结果 与T1时比较,T2时CVP、SVI、CO和CI升高,SVRI和SVV降低(P＜0.01),MAP和HR差异无统计学意义(P＞0.05).△HR、△SVR与△SVI均呈负相关,相关系数分别为-0.737和- 0.480(P＜ 0.05)；△CVP、△MAP、△SVV与△SVI无相关性(P＞0.05).ROC曲线分析结果显示:SVV的诊断阈值为8.8％,灵敏度为52.6％,特异度为100.0％.ROC曲线下面积及其95％可信区间为0.579(0.346 ～ 0.812).结论 SVV不能准确地监测非体外循环冠状动脉旁路移植术患者的血容量变化.

Accuracy of stroke volume variation in monitoring blood volume in patients undergoing off-pump coronary artery bypass grafting

Objective To evalute the accuracy of stroke volume variation (SVV) in monitoring blood volume in patients undergoing off-pump coronary artery bypass grafting.Methods Twenty-one ASA Ⅱ or Ⅲ patients of both sexes aged 44-77 yr undergoing off-pump coronary artery bypass grafting were enrolled in this study.Anesthesia was induced with midazolam,etomidate,fentanyl,rocuronium and dolicaine and maintained with target-controlled infusion of propofol,infusion of remifentanil,intermittent iv injetion of atracurium and inhalation of sevoflurane.The patients were mechanically ventilated (VT 8 ml/kg,RR 12 bpm,I:E 1:2,PEEP 0,FiO2 80％ ).PEr CO2 was maintained at 35-44 mm Hg.Radial artery was cannulated and connected to FloTrac pressure transducer and Vigileo monitor.6％ hydroxyethyl starch 130/0.4 sodium chloride solution 7 ml/kg was infused at a rate of 0.25 ml· kg- 1 1· min- 1 at 5 min of haemodynamics stabilization after pericardiotomy (T1).HR,MAP,CVP,systemic vascular resistance (SVR),systemic vascular nesistance index (SVRI),SVV,stroke volume index (SVI)and CI were recorded at T1 and at 10 min after loading dose (T2).The change rate of HR(△HR),MAP(△MAP),CVP(△CVP),SVR(△SVR),SVV(△SVV),SVI(△SVI) and CI(△CI) were calculated.△SVI≥25％ was considered effective volume expansion.The ROC curves for HR,MAP,CVP,SVR and SVV in determining the volume expansion efficacy were plotted.The area under the curves and 95 ％ confidence interval were calculated.Results Compared with T1,CVP,SVI,CO and CI were significantly increased,SVRI and SVV decreased at T2 (P ＜ 0.01).There was no significant difference in MAP and HR between T1 and T2(P ＞0.05).△SVI was negatively correlated with △HR and △SVR ( r =- 0.737,r =- 0.480,P ＜ 0.05).△SVI was not correlated with △CVP,△MAP and( P ＞ 0.05).The change in SVI was determined by SVV 8.8％ (sensitivity =52.6％,specificity =100.0％ ).The area under the curve for SVV and 95％ confidence interval were 0.579(0.346-0.812).Conclusion SVV can not be used to accuratelymonitor the changes in blood volume in patients undergoing off-pump coronary artery bypass grafting.