Detection of Echinocyte during Perfusion with Oxygenator Based on Continuous Blood Viscosity Monitoring

Steady-State Model of Pressure-Flow Characteristics Modulated by Occluders in Cardiopulmonary Bypass Systems

“…A glycerin solution and a human erythrocyte turbid solution were employed as working fluids. Glycerol solution was substituted for human blood as a more readily available working fluid, based on our previous reports [22][23][24]. Each fluid was perfused in the CPB system, and the viscosities were measured using a vibrating viscometer (SV-10; A & D. Co., Ltd., Tokyo, Japan).…”

“…As reported, the relationship between the differential pressure and Reynolds number can be applied to viscous fluids in general differential pressure flow meters, from which the flow rate from the fluid differential pressure can be obtained using an orifice plate based on Bernoulli's theorem [19]- [21]. Based on these reports, a system that can continuously monitor blood viscosity by measuring the differential pressure and flow rate of the oxygenator was proposed [22]- [24]. Additionally, a mathematical model that can express the relationship between the blood flow rate and differential pressure for perfused viscous fluids was also proposed [25][26][27].…”

“…We propose an exponential model to address the relationships between the opening ratio of the occluder and the differential pressure. Combining this model with the previous model [22][23][24]26], which links differential pressure and flow rate, allows the estimation of the flow rate from the opening ratio of the occluder. The following experiments were carried out to determine the model parameters.…”