King David H, Paulson William D, Al-Qaisi Mo, Taylor Michael G, Panayiotopoulos Yiannis, Abeygunarsekara Sumith, Chan Anthony, Ali Galil, Chemla Eric S
1 Renal Unit, Broomfield Hospital, Chelmsford, Essex - UK.
J Vasc Access. 2015 May-Jun;16(3):211-7. doi: 10.5301/jva.5000324. Epub 2015 Jan 30.
Dialysis venous pressure monitoring has been widely recommended as a surveillance method but has not been shown to improve access outcomes in randomised controlled trials. The method has been impaired by the need to either turn off the blood pump or to derive the static venous pressure from the venous pressure measured with the dialysis pump running. We have developed a unique algorithm which converts Doppler-shifted spectral information derived from unscaled pulsatile blood flow waveforms into an estimate of mean blood pressure (MBP) at the point of ultrasound insonation.
We have devised the unique expression shown here: MBP = MAP/(1 + Pff/Vff) where MAP is the mean arterial pressure, Pff = (systolic - diastolic)/MAP measured on the contralateral arm and Vff = spectral maximum - minimum/mean. Venous conductance (VC) can be measured by combining this pressure data with Duplex ultrasound blood flow data. A new device BlueDop™ has been used to illustrate the potential clinical value of non-invasive static pressure ratio (SPRn) in a monitoring role. Duplex and BlueDop™ technology were tested in an arterio-venous fistula (AVF) study in which VC, Q and SPRn were compared. Thresholds used for detection of ≥60% venous stenosis were VC <10 mL min-1 mm Hg-1, Q <500 mL min-1, SPRn >0.56.
The following accuracy was achieved: VC = 96%, Q = 92%, SPRn = 76% with similar accuracy in predicting premature thrombosis.
A new algorithm has been described and its in vivo accuracy in estimating mean 'pressure from flow' has been confirmed. Two new variables and a new dedicated instrument BlueDop™ have been demonstrated in clinical use.
透析静脉压力监测作为一种监测方法已被广泛推荐，但在随机对照试验中尚未显示能改善血管通路结局。该方法因需要关闭血泵或在透析泵运行时从测量的静脉压力中获取静态静脉压力而受到影响。我们开发了一种独特的算法，可将从未缩放的脉动血流波形导出的多普勒频移光谱信息转换为超声探测点处的平均血压（MBP）估计值。
我们设计了此处所示的独特表达式：MBP = MAP/(1 + Pff/Vff)，其中MAP是平均动脉压，Pff =（收缩压 - 舒张压）/对侧手臂测量的MAP，Vff = 光谱最大值 - 最小值/平均值。静脉电导（VC）可通过将此压力数据与双功超声血流数据相结合来测量。一种新型设备BlueDop™已被用于说明无创静态压力比（SPRn）在监测中的潜在临床价值。在一项动静脉内瘘（AVF）研究中测试了双功和BlueDop™技术，比较了VC、Q和SPRn。用于检测≥60%静脉狭窄的阈值为VC <10 mL min-1 mm Hg-1、Q <500 mL min-1、SPRn >0.56。
实现了以下准确率：VC = 96%，Q = 92%，SPRn = 76%，在预测过早血栓形成方面准确率相似。
已描述了一种新算法，并证实了其在体内估计平均“血流压力”的准确性。两种新变量和一种新型专用仪器BlueDop™已在临床应用中得到展示。
