Evaluation of Cardiovascular Stress Reaction Using HPCD Method on a Beat-by-beat Basis

Abstract

In order to establish a bionic model/system in cardiovascular fields, comprehension of hemodynamics is important. In this study, a novel beat-by-beat hemodynamic system evaluation method named “beat-by-beat HPCD method” is proposed and evaluated.　Gregg’s theoretically driven model of hemodynamics which was called “HPCD method” is improved by using non-invasive and beat-by-beat cardiovascular measurement of mean blood pressure and cardiac output. Continuous beat-by-beat measurements of MBP and CO were done on three healthy male subjects during three hours. In the measurement, a five minutes cold pressor test was executed in each subject and also each subject did exercise using a bicycle ergometer in five minutes and walked during 15 minutes. Measured beat-by-beat MBP and CO can derive beat-by-beat HP (hemodynamic profile) and CO (compensation deficit). Then, beat-by-beat changes clearly observed from plots on HP axis and CD axis plane. More vascular response can be observed on cold pressor and more myocardial response can be observed on ergometer exercise. During walking period, the response is intermediate between cold pressor and ergometer exercise. Finally, the proposed method can be considered as applicable to evaluate cardiovascular bionic system especially on evaluation of a person being subjected to stress. Keywords: hemodynamics; stress; cardiovascular system; hemodynamic profile and compensation deficit model