脉压变异度和每搏量变异度在室间隔缺损患儿术中预测容量反应的探讨

Prediction of fluid responsiveness by pulse pressure variation and stroke volume variation in children with ventricular septal defect during cardiac surgery

目的探讨右侧小切口室间隔缺损修补术患儿在开胸状态下,脉压变异度(PPV)和每搏量变异度(SVV)是否可以预测容量反应,以及二者的准确性的差异。方法 56例年龄(1.2±1.0)岁,体重(8.7±2.0) kg行室间隔缺损修补术的患儿,在体外循环结束后,机械通气条件为吸入氧浓度50%,潮气量10 ml/kg,呼吸频率16～25次/min,使PETCO2维持在30～35 mm Hg。拔出主动脉插管之后进行容量负荷试验,以30 ml/(kg·h)速度输注5%白蛋白或血浆15 min。记录容量负荷试验前、后PPV和SVV,同时记录心率(HR)、收缩压(SBP)、舒张压(DBP)、每搏指数(SVI)、心指数(CI)、压力升支最大速率(dp/dtmax)、体循环阻力指数(SVRI)。根据容量负荷试验后CI的变化将所有患儿分为两个组,CI增加≥15%为有反应组,否则为无反应组。绘制受试者特征曲线(ROC)比较PPV、SVV预测容量反应准确性。结果有反应组患儿共27例,无反应组患儿共29例。容量负荷试验前有反应组PPV、SVV明显高于无反应组,均P <0.01。ROC分析以PPV和SVV预测容量反应的准确性分别为0.89和0.78。PPV的诊断阈值为18%,敏感性为83%,特异性为81%; SVV的诊断阈值为18. 5%,敏感性为83%,特异性为62%。容量负荷试验前有反应组SBP、DBP、CI(均P <0.01)、SVI(P <0.05)明显低于无反应组。容量负荷试验后有反应组SBP、DBP、SVI、CI、dp/dtmax均明显上升(均P <0.01),SBP、CI高于无反应组(P <0.05)。容量负荷试验前PPV和SVV均与ΔSBP(P <0.0001)、ΔDBP(P <0.05)、ΔCI(P <0.0001)、ΔSVI(P <0.0001)呈正相关,与ΔSVRI呈负相关(P <0.05)。结论在室间隔缺损患儿修补术中,容量管理对于维护血流动力学稳定十分重要。开胸状态下,PPV、SVV能够预测容量反应及指导容量管理,且PPV更准确。

Objective To evaluate whether pulse pressure variation (PPV) and stroke volume variation (SVV) could predict fluid responsiveness in children with ventricular septal defect undergoing surgical repair through right subaxillary minithoractomy.Methods A total of 56 children ( mean age: 1.2±1.0 years,mean weight: 8.7±2.0 kg) undergoing ventricular septal defect repair were enrolled. After cardiopulmonary bypass,mechanical ventilation was set with 50% of inspired oxygen,10 ml / kg of tidal volume and a respiratory rate of 16-25 times per minute,maintaining the PETCO2 value at 30-35 mmHg. After aortic cannulation removal,volume loading test was performed with 5% albumin or blood plasma at 30 ml /(kg·h) for 15 minutes. PPV and SVV were recorded along with heart rate (HR) ,systolic blood pressure (SBP),diastolic blood pressure (DBP) ,stroke volume index (SVI) ,cardiac index (CI),the maximal rate of pressure upstroke (dp/ dtmax) and systemic vascular resistance index (SVRI) before and after fluid loading. Children were divided into two groups according to CI changes after volume loading test,patients were considered as responders (Group R) to fluid loading when CI increased ≥15%,otherwise non-responders (Group NR).Receiver operating curve (ROC) analysis was established to compare the accuracy of PPV and SVV to predict fluid responsiveness. Results Group R consisted of 27 children and Group NR consisted of 29 children. Before volume loading test,PPV and SVV in Group R were higher than those in Group NR (P<0.01) . By ROC analysis,the accuracy to predict fluid responsiveness was 0.89 for PPV and 0.78 for SVV,respectively. The cut off value for PPV was 18% with a sensitivity of 83% and a specificity of 81%,the cut off value for SVV was 18.5% with a sensitivity of 83% and a specificity of 62%. Before fluid loading,SBP,DBP,CI (all P<0.01) ,SVI (P<0.05) in Group R were lower than those in Group NR. After fluid loading,SBP,DBP,SVI,CI and dp/dtmax in Group R increased significantly (all P<0.01) . SBP and CI were higher than those in Group NR (P<0.05) . PPV and SVV before volume loading were positively correlated with ΔSBP (P<0.0001) , ΔDBP (P<0.05) ,ΔCI (P<0.0001) and ΔSVI (P<0.0001) ,while negatively correlated with SVRI(P<0.05) . Conclusion Fluid management plays an important role to maintain hemodynamic stability in children with ventricular septal defect undergoing surgery. Under open chest conditions,PPV and SVV are predictive of fluid responsiveness and useful for guiding fluid management,with PPV being more accurate.