Ratio-Independent Arterial Stiffness-Based Blood Pressure Estimation

Abstract

Blood pressure is one of the crucial vital signs that still lacks measurement accuracy in clinical environments. It is reported by physicians that automated non-invasive blood pressure measurement devices, which are usually based on the oscillometric method, do not provide accurate estimation of blood pressure. This problem has been addressed in this work by incorporating arterial stiffness in blood pressure measurement. Pulse transit time is first used to estimate arterial stiffness parameters. Afterwards, these parameters are fixed into a model of the oscillometric envelope which can then be used to curve fit measured data using only four free parameters: systolic, diastolic, mean blood pressure and minimum lumen area. The proposed individualized technique is independent of any experimentally determined ratio, commonly used in existing oscillometric methods. The accuracy of the proposed technique is evaluated by comparing with (1) the same model without incorporation of arterial stiffness (i.e. a purely oscillometric technique), and (2) Omron device measurements. The results are promising and meet the criteria recommended by the ANSI/AAMI SP - 10 standard for non-invasive blood pressure measurement techniques.