Lambermont B, Gerard P, Detry O, Kolh P, Potty P, D'orio V, Marcelle R
Hemodynamics Research Center (HemoLiège), University of Liège, Belgium.
Acta Anaesthesiol Scand. 1998 Jul;42(6):717-20. doi: 10.1111/j.1399-6576.1998.tb05307.x.
Pressure measuring systems using fluid-filled catheters can result in the recording of distorted pressure waveforms. It results in phase delay, overestimation of systolic and, to a lesser extent, of diastolic pressure. We designed and evaluated a method to correct this pressure waveform distortion using an appropriate transfer equation obtained from the dynamic response of the fluid-filled catheter. This transfer equation is based on the principle that a fluid-filled catheter recording system is considered as an underdamped dynamic system fully characterized by its natural frequency (omega n) and damping ratio (zeta).
Pressure waveforms, simultaneously recorded in vitro or in vivo by a fluid-filled catheter (Pc) and a micromanometer-tipped catheter (Pref), were used to validate the method. Dynamic response of the catheter used was obtained from a fastflush test. The corrected signal (Ppred) was obtained using omega n, zeta and the following transfer equation: d2Pc/dt2 + 2 omega n zeta dPc/dt + omega n 2Pc = C Ppred (t) After correction of Pc, Ppred was compared, using a linear regression, with Pref taken as reference.
Our results showed that Ppred was fitted to Pref with excellent coefficient correlation (0.99). The mean error and the standard error of estimate were respectively -1.16 mmHg and 1.4 mmHg.
This new method can convert the distorted pressure waveforms transmitted by any fluid-filled catheters into high-fidelity signals. It suppresses the phase delay and the over-estimation of systolic pressure induced by fluid-filled catheters.
使用充液导管的压力测量系统可能会导致记录的压力波形失真。这会导致相位延迟，收缩压被高估，舒张压在较小程度上也被高估。我们设计并评估了一种方法，通过从充液导管的动态响应中获得的适当传递方程来校正这种压力波形失真。该传递方程基于这样一个原理，即充液导管记录系统被视为一个欠阻尼动态系统，其完全由固有频率（ωn）和阻尼比（ζ）来表征。
使用充液导管（Pc）和微测压头导管（Pref）在体外或体内同时记录的压力波形来验证该方法。所用导管的动态响应通过快速冲洗试验获得。校正信号（Ppred）使用ωn、ζ和以下传递方程获得：d2Pc/dt2 + 2ωnζdPc/dt + ωn2Pc = C Ppred(t) 在对Pc进行校正后，使用线性回归将Ppred与作为参考的Pref进行比较。
我们的结果表明，Ppred与Pref拟合良好，相关系数极佳（0.99）。估计的平均误差和标准误差分别为-1.16 mmHg和1.4 mmHg。
这种新方法可以将任何充液导管传输的失真压力波形转换为高保真信号。它抑制了充液导管引起的相位延迟和收缩压的高估。
