Pybus David Andrew
St. George Private Hospital, 1 South St., Kogarah, NSW, 2217, Australia.
J Clin Monit Comput. 2019 Feb;33(1):53-63. doi: 10.1007/s10877-018-0145-0. Epub 2018 Apr 28.
Spectral analysis of the arterial pressure waveform, using specialized hardware, has been used for the retrospective calculation of the 'Spectral Peak Ratio' (SPeR) of the respiratory and cardiac arterial spectral peaks. The metric can quantify the cardiovascular response to volume loading by analysing the effect of changing tidal volume (indexed to body weight) (V) on pulse pressure variability. In this pilot study, the feasibility of real-time SPeR calculation, using a mobile computer which was wirelessly connected to the patient monitor, was evaluated by examining the determinants of SPeR in 60 cardiac-surgical patients. In 30 patients undergoing aortic valve replacement (AVR), graded cyclical changes in ventricular loading were induced by increasing V over 2 min, while performing spectral analysis at 1 Hz, before and after AVR. A strong, linear correlation between SPeR and V was found and the slope of the regression line (β) changed significantly after AVR. The change in β correlated with the width of the preoperative vena contracta. In another 30 patients, SPeR at constant V was calculated at 1 Hz during passive leg raising. β fell significantly on leg raising. The mean arterial pressure change during the manoeuvre was linearly related to the change in β. Real-time spectral analysis of the arterial waveform was easily accomplished. The regression of SPeR on V was linear. β appeared to represent the slope of the cardiac response curve at the venous return curve equilibrium point. Measurements were possible at a significantly lower V than the equivalent time domain metrics.
利用专门硬件对动脉压波形进行频谱分析，已用于回顾性计算呼吸和心脏动脉频谱峰值的“频谱峰值比”（SPeR）。该指标可通过分析潮气量（以体重为指标）（V）变化对脉压变异性的影响，来量化心血管对容量负荷的反应。在这项初步研究中，通过检查60例心脏手术患者的SPeR决定因素，评估了使用无线连接到患者监护仪的移动计算机进行实时SPeR计算的可行性。在30例行主动脉瓣置换术（AVR）的患者中，在AVR前后，通过在2分钟内增加V来诱发心室负荷的分级周期性变化，同时以1Hz的频率进行频谱分析。发现SPeR与V之间存在强线性相关性，并且AVR后回归线的斜率（β）发生了显著变化。β的变化与术前缩流宽度相关。在另外30例患者中，在被动抬腿期间以1Hz的频率计算恒定V时的SPeR。抬腿时β显著下降。操作期间的平均动脉压变化与β的变化呈线性相关。动脉波形的实时频谱分析很容易完成。SPeR对V的回归是线性的。β似乎代表静脉回流曲线平衡点处心脏反应曲线的斜率。在比等效时域指标显著更低的V下即可进行测量。
