A Novel Theory: Measuring the Real-Time-Based Arterial Properties via Vascular Loading Decoupling Technique

Abstract

This paper presents a decoupling theory named as Vascular Loading Decoupling Technique (VLDT), extended from the beat-based Tissue Control Method (TCM), for noninvasive measurement of real-time-based intra-arterial blood pressure and dynamic compliance of blood vessel. Both VLDT and TCM are based upon the decoupling theory to cause the arterial pulsation without the influence from surrounding tissues and measure the variations of the vascular diameter at critical depth. Meanwhile, the AC part of blood pressure is lost, that is, the reference pressure for AC controller is absent as well. To remedy this problem, VLDT employs Step-Hold control rules and cubic spline curve fitting technique to estimate the reference pressure, identify the impedance of blood vessel, and calculate the AC control gain at Hold stage, then track the AC part of blood pressure and compute the real-time arterial blood pressure at Step stage by turns, which makes the real time measurement feasible; moreover, the dynamic compliance of blood vessel can be extracted from real-time impedances of blood vessel. Since the compliance of blood vessel is decoupled from surrounding tissues, it is valuable for diagnosing the severity of vascular sclerosis. The simulation results showed that the VLDT approach is superiority over TCM. This could provide new prospective to circulatory medicine research.