Modeling the hemodynamic response to dopamine in acute heart failure

A nonlinear descriptive single-input-multiple-output (SIMO) model of the hemodynamic response (cardiac output and mean arterial pressure) in acute ischemic heart failure to the inotropic drug dopamine was developed to facilitate the design of closed-loop control systems. The structure of the cardiac-output component is a first order system with a sigmoidal relationship, while the mean-arteria-pressure component is a first-order system with a threshold. Overall, the model gave good approximations of mean empirical responses. Parameter identification was performed on positive step (drug on) and negative step (drug off) testing using multiple (2 mcg/kg/min-6 mcg/kg/min) infusions of dopamine in a canine model of acute ischemic heart failure. Parameter estimation utilized a least-squares objective function and a linearized form of the step response of the model in the time domain.