Design of an assistive anaesthesia drug delivery control using knowledge based systems

Manual methods used during anaesthesia, to decide and deliver the quantity of drug, required significant effort from the clinical standpoint not guaranteeing an optimal performance. Delivering adequate anaesthesia requires precise automation in anaesthesia drug delivery system which will improve the patient safety, reduce the cost due to minimal consumption of drug and will help in early post-operative recovery. The present study discusses a fuzzy proportional-integral-derivative (fuzzy PID) based controller to suggest the change in quantity of isoflurane to be delivered to the patient, for the maintenance of the desired anaesthetic depth, as targeted by the anaesthesiologist. Depth of Hypnosis (DoH) of the patient is measured using BIS™ index and is used as the measured variable in the controller designed for the maintenance of anaesthesia during surgery. The fuzzy PID controller efficiently deals with the nonlinearity of physiological systems.