每搏输出量变异度监测不同潮气量通气时全麻患者血容量变化的准确性

目的 评价每搏输出量变异度(SVV)监测不同潮气量通气时全麻患者血容量变化的准确性.方法 择期行胃肠手术的全麻患者50例,年龄31～59岁,ASAⅠ或Ⅱ级,随机分为2组:常规潮气量组(C组,n=20)和小潮气量组(L组,n=30).C组潮气量(VT)8 ml/kg,呼吸频率(RR)12次/min,呼气末正压力0,吸入氧浓度80%,氧流量2 L/min,行间歇正压通气;L组VT 6 ml/kg,RR16次/min,余同c组.气管插管后10 min,两组均以0.3 ml·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,输注后开始手术.于输注前(T1)和输注后10 min(T2)时记录MAP、HR、CVP、体循环血管阻力(SVR)、SVV和每搏指数(SI),并计算其变化率.绘制各项血液动力学指标监测血容量变化的ROC曲线.结果 ROC曲线结果 分析显示:以SI变化率≥25%为监测血容量变化的标准时,SVV的诊断周值为9.5%,C组SVV>9.5%监测血容量变化的灵敏度为100%,特异度为57.1%;L组SVV>9.5%监测血容量变化的灵敏度为91.3%,特异度为71.4%.ROC曲线下面积显示:两组SVV监测血容量变化的准确性高于MAP、HR、CVP、SVR.结论 在常规潮气量(8 ml/kg)和小潮气量(6 ml/kg)/机械通气时,SVV均可准确地监测全麻患者血容量变化.

Accuracy of stroke volume variation in monitoring blood volume in patients ventilated with different tidal volumes under general anesthesia

Objective To evaluate the accuracy of stroke volume variation(SVV)in monitoring the blood volume in patients ventilated with different tidal volunes under general anesthesia.Methods Fifty ASAⅠ or Ⅱ patients of both sexes aged 31-59 yr undergoing elective gamointesfinal surgery were randomly divided into 2 groups:conventional tidal volume group(group C,n=20)and low tidal volume group(group L,n=30).All the pailents were ventilated with intermittent positive-prssure ventilation(IPPv).The ventilatory parametem were kept unchanged during the study:tidal volume(VT)8 ml/kg,respiratory late(RR)12 bpm,positive end expiratory pressure(PEEP)0,fractional inspired oxygen(FiO2)80%,oxygen flow 2.0 Umin in group C; VT 6 ml/kg,RR 16 bpm,PEEP 0,FiO2 80%,oxygen flow 2.0 Umin in group L;airway pressure< 15 cm H2O,Prr CO2 35-45 mitt Hg and SpO2 98%-100%.6%hydroxyethyl starch 130/0.4 sodium chloride solution 7 ml/kg was infused intravenously 10 min after endotracheal intubafion at a rate of 0.3 ml·kg-1·min-1 in both groups.and then the surgery was began.MAP,HR,CVP,systemic vascular resistance(SVR),SVV and stroke index(SI) were recorded before(TI)and at 10 mln after the infusion of hydroxyethyl starch(T2),and the change rate was calculated.ROC curves of changes in blood volume monitm by hemodynamic parameters were plotted.Results The analysis result8 of ROC curve showed that:when the change rate of SI≥25%was used as the criteria for assessing the changes in blood volume,diagnostic threshold of SVV was 9.5%;when SVV>9.5%.the sensitivity and specificity of blood volume monitoring were 100%and 57.1%respectively in group C;when SVV>9.5%.the sensitivity and specificity of blood volunle monitoring were 91.3%and 71.4% respectively in group L. The area under BOC curve showed that the accuracy of SVV in blood volume monitoring was better than that of MAP, HR, CVP and SVB in both groups. Conclusion SVV can be used to accurately monitor the changes in blood volume in mechanically ventilated patients with conventional tidal volume (8 ml/kg) or low tidal volume (6 ml/kg).