Discrete Two-Degree-of-Freedom Control for Hemodynamic Optimization: Circulatory Simulation Study with Baroreflex...

The baroreflex mechanism supports hemodynamic stability, but its function is often impaired under conditions such as heart failure. In drug therapy for heart failure, the causal mechanisms determining hemodynamics become more complicated due to combined pharmacological and uncertain baroreflex effects. The purpose of this paper is to propose a cli- nically feasible hemodynamic control system that compensates for individual variability caused by the baroreflex mechanism.We propose a discrete two-degree-of-freedom (2DoF) control framework that combines feedforward and feedback components. The feedforward component aims to improve the immediate response by utilizing pre-modeled pharmacological effects, while feedback accommodates uncertain baroreflex effects through disturbance suppression. First, a discrete model of our drug therapy system represents steady-state properties of pharmacological effects and the circulatory equilibrium theory, describing the hemodynamic response to drug inputs. The optimal drug inputs are then calculated as solutions to a nonlinear constrained optimization problem, which enables ex- plicit consideration of the requirements of clinical practice, e.g., control of key cardiovascular parameters and hemodynamics, circulatory equilibrium mechanisms, drug dosage limitations, contraindicated drugs, and physician preferences.In evaluation, a hemodynamic simulator was developed to model the circulatory system and the effects of pharmacological and baroreflex modulation. When applying the above control strategy, the simulation results demonstrate that our proposed controller can achieve the desired control under cases of both normal and impaired baroreflex response.Clinical relevance - This paper shows that 2DoF control can achieve hemodynamic immediacy through feedforward components while reducing baroreflex uncertainty through feedback's disturbance suppression effect.