Real-time fuzzy control of mean arterial pressure in postsurgicalpatients in an intensive care unit

摘要

The authors have developed a fuzzy control system to provideclosed-loop control of mean arterial pressure (MAP) in postsurgicalpatients in a cardiac surgical intensive care unit setting, byregulating sodium nitroprusside infusion. The core of the controlalgorithms is a nonlinear proportional-integral (PI) controller, whichprecisely represents the simplest fuzzy controller. Theproportional-gain and integral-gain are adjusted continuously accordingto the error and rate change of the error of MAP. Twelve postoperativepatients who exhibited elevated MAP following coronary artery bypassgrafting procedures took part in the study. The length of time thattwelve patients were on the fuzzy control system ranged from 1 h 45 minto 18 h 7 min. The total fuzzy-controller run time was 95 h 13 min.Clinical results showed that the average percentage of time in which MAPstayed between 90% and 110% of the MAP setpoint was 89.31%, with astandard deviation of 4.96%