Model-based adaptive closed-loop feedback control of atracurium-induced neuromuscular blockade.

Closed-loop control of atracurium-induced neuromuscular blockade by a model-based adaptive feedback algorithm is described. Mean offsets (+/- s.d.) from setpoints at 50, 70 and 90% neuromuscular blocks using the Relaxograph were 1.1 +/- 1.3, 0.2 +/- 0.7 and 0.1 +/- 0.4%, respectively. Correspondingly, the mean steady-state rates of infusion of atracurium were 0.20 +/- 0.06, 0.25 +/- 0.03 and 0.39 +/- 0.10 mg.kg-1.h-1. The described controller provides reasonable control of atracurium dosing at different degrees of neuromuscular blockade. It gives a solution to the problem of adapting pharmacokinetic and pharmacodynamic data to individuals when using population mean data as starting values for drug therapy.