Tran Henry, Froese Norbert, Dumont Guy, Lim Joanne, Ansermino J Mark
Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, V6H 3V4, Canada.
J Clin Monit Comput. 2007 Feb;21(1):1-6. doi: 10.1007/s10877-006-9051-y. Epub 2006 Nov 11.
Intravascular volume loading is used to optimize cardiac output in children following weaning from cardiopulmonary bypass. Central venous pressure (CVP) is frequently used to titrate fluid administration but it is often misleading in predicting fluid responsiveness. Variation in the arterial pressure waveform is exaggerated in patients with deficient intravascular volume and has been shown to be a good predictor of fluid responsiveness in adults following cardiac surgery. The aim of this study was to compare the measures of variation in blood pressure as a guide to volume loading in children following cardiopulmonary bypass.
After ethical approval, we collected continuous real-time measurements from 25 children during volume loading after cardiopulmonary bypass. Subjects with moderate or severe tricuspid incompetence or who did not require volume loading during weaning from cardiopulmonary bypass were excluded from the study. Unstable readings were excluded from analysis. Systolic Pressure Variation (SPV), Pulse Pressure Variation (PPV) and Systolic Volume Variation (SVV) were retrospectively calculated before and after each bolus of fluid. Fluid responsiveness was classified as a change in blood pressure of > or =80 mmHg/L/m(2).
Forty-four boluses were analyzed from the 25 children. Respiratory variables were similar. CVP was a poor predictor of fluid responsiveness and a negative relationship between change in blood pressure and Delta Down was observed. Performance in predicting fluid responsiveness as measured by the areas under the ROC curves were CVP (0.58), PPV (0.67), SPV (0.74) and SVV (0.74).
Variation in blood pressure was a better guide to volume loading in children than CVP. Delta down was not useful in predicting fluid responsiveness in children with open chests following bypass surgery. SPV and SVV require further testing in prospective clinical trials.
在小儿体外循环撤机后，血管内容量负荷用于优化心输出量。中心静脉压（CVP）常被用于滴定液体输注，但它在预测液体反应性方面常常具有误导性。血管内容量不足的患者动脉压波形变化会被放大，并且已被证明是心脏手术后成人液体反应性的良好预测指标。本研究的目的是比较血压变化指标作为小儿体外循环后容量负荷指导的效果。
经伦理批准后，我们在25名小儿体外循环后容量负荷期间收集了连续实时测量数据。患有中度或重度三尖瓣关闭不全或在体外循环撤机期间不需要容量负荷的受试者被排除在研究之外。不稳定读数被排除在分析之外。在每次推注液体前后回顾性计算收缩压变异（SPV）、脉压变异（PPV）和收缩期容积变异（SVV）。液体反应性被分类为血压变化≥80 mmHg/L/m²。
对25名小儿的44次推注进行了分析。呼吸变量相似。CVP是液体反应性的较差预测指标，并且观察到血压变化与Δ下倾之间存在负相关。通过ROC曲线下面积测量的预测液体反应性的性能分别为：CVP（0.58）、PPV（0.67）、SPV（0.74）和SVV（0.74）。
对于小儿容量负荷，血压变化比CVP是更好的指导指标。Δ下倾在预测体外循环手术后开胸小儿的液体反应性方面无用。SPV和SVV需要在前瞻性临床试验中进一步测试。
