Hierarchical rule-based and self-organizing fuzzy logic control for depth of anaesthesia

A multistage hierarchical fuzzy control system with a multiechelon structur e for depth of anaesthesia (DOA) is described in this paper, There are four echelons that monitor, control, interpret, and assess the whole surgical o peration. Echelon 1 is a measurement and control action level that involves instrument sensing (i.e., Dinamap), anaesthetist observations [i.e., measu rement of sweating (SW), lacrimation (LA), and pupil response (PR)I and a s yringe pump (i.e., Graseby pump). Echelon 2 is an interpretation level that involves interpreting systolic arterial pressure (SAP) and heart rate (HR) to provide the primary DOA (PDOA), interpreting SW, LA, and PR to provide the degree of lightness (DOL) and interpreting bolus drug effects to estima te the sensitivity of patients (SOP), Echelon 3 is a regulation level that involves controlling the drug from either a hand-crafted anaesthetists' rul e-base or a self-organizing fuzzy logic controller (SOFLC) algorithm; plann ing the drug profile to avoid long recovery; and managing alarm situations, Finally, echelon 4 is an assessment level that assesses the whole surgical procedure according to patient recovery time, Testing this system in clini cal trials as an intelligent adviser has provided a preliminary proof-of-co ncept of the applicability of this hierarchical structure for DOA managemen t.