Control of rocuronium-induced neuromuscular blockade via online identification of a two-parameters Wiener model*

A closed-loop controller for rocuronium-induced neuromuscular blockade using the first twitch of a train-of-four electromyographic stimulation as the measured signal is presented. Central to this development is the use of a two-parameters Wiener model, previously proposed to atracurium. The controller includes recursive parameters identification by an EKF, inversion of the nonlinearity using the current nonlinear parameter estimate and a pole placement controller for the exactly linearized system. Numerical tests on the performance of this adaptive structure were carried out on a bank of 500 simulated standard PK/PD models. The developed controller steers the neuromuscular blockade to a desired reference, tracking a constant or varying profile. It is also able to deal with parameter-varying systems and works well in noisy scenarios. These capabilities are crucial when testing this structure in a real clinical environment.