Schwid H A, Taylor L A, Smith N T
Department of Anesthesiology, University of Washington School of Medicine, Seattle 98195.
J Clin Monit. 1987 Oct;3(4):220-8. doi: 10.1007/BF03337375.
Simultaneous measurements of aortic and radial artery pressures are reviewed, and a model of the cardiovascular system is presented. The model is based on resonant networks for the aorta and axillo-brachial-radial arterial system. The model chosen is a simple one, in order to make interpretation of the observed relationships clear. Despite its simplicity, the model produces realistic aortic and radial artery pressure waveforms. It demonstrates that the resonant properties of the arterial wall significantly alter the pressure waveform as it is propagated from the aorta to the radial artery. Although the mean and end-diastolic radial pressures are usually accurate estimates of the corresponding aortic pressures, the systolic pressure at the radial artery is often much higher than that of the aorta due to overshoot caused by the resonant behavior of the radial artery. The radial artery dicrotic notch is predominantly dependent on the axillo-brachial-radial arterial wall properties, rather than on the aortic valve or peripheral resistance. Hence the use of the radial artery dicrotic notch as an estimate of end systole is unreliable. The rate of systolic upstroke, dP/dt, of the radial artery waveform is a function of many factors, making it difficult to interpret. The radial artery waveform usually provides accurate estimates for mean and diastolic aortic pressures; for all other measurements it is an inadequate substitute for the aortic pressure waveform. In the presence of low forearm peripheral resistance the mean radial artery pressure may significantly underestimate the mean aortic pressure, as explained by a voltage divider model.
本文回顾了同时测量主动脉和桡动脉压力的方法，并提出了一种心血管系统模型。该模型基于主动脉和腋-肱-桡动脉系统的共振网络。所选择的模型很简单，以便清晰地解释观察到的关系。尽管模型简单，但它能产生逼真的主动脉和桡动脉压力波形。结果表明，动脉壁的共振特性在压力波从主动脉传播到桡动脉的过程中会显著改变压力波形。虽然桡动脉的平均压和舒张末期压力通常是相应主动脉压力的准确估计值，但由于桡动脉的共振行为导致的过冲，桡动脉的收缩压往往远高于主动脉的收缩压。桡动脉重搏切迹主要取决于腋-肱-桡动脉壁的特性，而不是主动脉瓣或外周阻力。因此，将桡动脉重搏切迹用作收缩末期估计值是不可靠的。桡动脉波形的收缩期上升速率dP/dt受多种因素影响，难以解释。桡动脉波形通常能准确估计主动脉的平均压和舒张压；对于所有其他测量，它都不能充分替代主动脉压力波形。如分压模型所解释的，在前臂外周阻力较低的情况下，桡动脉平均压可能会显著低估主动脉平均压。
