Background

Many maneuvers assessing fluid responsiveness (minifluid challenge, lung recruitment maneuver, end-expiratory occlusion test, passive leg raising) are considered as positive when small variations in cardiac index, stroke volume index, stroke volume variation or pulse pressure variation occur. Pulse contour analysis allows continuous and real-time cardiac index, stroke volume, stroke volume variation and pulse pressure variation estimations. To use these maneuvers with pulse contour analysis, the knowledge of the minimal change that needs to be measured by a device to recognize a real change (least significant change) has to be studied. The aim of this study was to evaluate the least significant change of cardiac index, stroke volume index, stroke volume variation and pulse pressure variation obtained using pulse contour analysis (ProAQT^®, Pulsion Medical System, Germany).

Methods

In this observational study, we included 50 mechanically ventilated patients undergoing neurosurgery in the operating room. Cardiac index, stroke volume index, pulse pressure variation and stroke volume variation obtained using ProAQT^® (Pulsion Medical System, Germany) were recorded every 12 s during 15-min steady-state periods. Least significant changes were calculated every minute.

Results

Least significant changes statistically differed over time for cardiac index, stroke volume index, pulse pressure variation and stroke volume variation (p < 0.001). Least significant changes ranged from 1.3 to 0.7% for cardiac index, from 1.3 to 0.8% for stroke volume index, from 10 to 4.9% for pulse pressure variation and from 10.8 to 4.3% for stroke volume variation.

Conclusion

To conclude, the present study suggests that pulse contour analysis is able to detect rapid and small changes in cardiac index and stroke volume index, but the interpretation of rapid and small changes of pulse pressure variation and stroke volume variation must be done with caution.

中文翻译：

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评估脉搏轮廓分析衍生参数的最小有效变化

背景

当心脏指数，中风量指数，中风量变化或脉搏压力变化发生微小变化时，许多评估体液反应性的方法（微流挑战，肺复张动作，呼气末闭塞试验，被动抬腿）被认为是积极的。脉搏轮廓分析可进行连续和实时的心脏指数，搏动量，搏动量变化和脉压变化估算。为了将这些动作与脉冲轮廓分析一起使用，必须研究必须由设备测量以识别实际变化（最小变化）的最小变化的知识。这项研究的目的是评估使用脉搏轮廓分析（ProAQT）获得的心脏指数，中风量指数，中风量变化和脉压变化的最小显着变化^®，Pulsion医疗系统，德国）。

方法

在这项观察性研究中，我们纳入了50名在手术室接受神经外科手术的机械通气患者。使用ProAQT获得心脏指数，每搏量指数，脉搏压力变化和每搏输出量变化^®（压出性医疗系统，德国）在15分钟稳定状态期间记录每12秒。每分钟计算最少的显着变化。

结果

随时间推移，心脏指数，中风量指数，脉压变化和中风量变化的统计学差异最小（p  <0.001）。心脏指数的最小显着变化范围为1.3到0.7％，搏动量指数的最小变化为1.3到0.8％，脉压变化的数值为10到4.9％，搏动量变化为10.8到4.3％。

结论

总而言之，本研究表明脉搏轮廓分析能够检测出心脏指数和中风量指数的快速和小变化，但是对脉压变化和中风量变化的快速和小变化的解释必须谨慎。