Abstract
In this paper, we discuss an ARX (AuoRegressive eXogenous) model concerned with the acceleration and the blood pressure for some healthy volunteers at the emergency brake of an ambulance. Recently, a problem that patients die in the ambulance, that is called DOA (Dead On Arrival), is getting attention. The reason for DOA is not only the development of patient's disease or lack of prehospital treatment but also the vibration of the ambulance. We have already had a result that the blood pressure of a finger changes when the ambulance accelerates or decelrates. As the blood pressure variation may cause serious damage for a patient who has circulatory disease, it is necessary to put a system which absorbs the vibration to reduce the blood pressure variation on the ambulance. To design the system, we propose an ARX model which can be formed using only the experimental data of the acceleration and the blood pressure variation without mechanical characteristics of a human body. We use a tilting bed to measure the relation between the blood pressure and the acceleration of gravity acting from head to leg of a human body, and developed the models of several order. As a result, we have confirmed that a 3rd order ARX model can quantitatively explain the transitional variation of the blood pressure at the deceleration of the ambulance.
