PERFORMANCE ASSESSMENT OF A FUZZY CONTROLLER FOR ATRACURIUM-INDUCED NEUROMUSCULAR BLOCK

The performance of a fuzzy controller for atracurium-induced neuromusc ular block was assessed. Ten ASA I or II patients undergoing surgery a nticipated to last at least 120 min were studied. A Datex Relaxograph was used to monitor neuromuscular block. Initially the T1 set point wa s set at 10% of baseline for at least 30 min (phase I). The T1 set poi nt was then increased to 20% and then returned to 10% for two further periods of at least 30 min duration (phases II and III), The mean (so) of the mean T1 error in 10 patients for phases I, II and III were 1.1 (1.4)%, -0.43 (1.2)% and 0.28 (0.94)%, respectively. The results show that a simple fuzzy logic controller can provide good accuracy with i nsensitivity to set point changes despite the considerable inter-indiv idual variation in infusion rate required.