FPGA Implementation of Explicit Model Predictive Control for Closed Loop Control of Depth of Anesthesia*

In past years, many advanced control strategies on numerous embedded platforms have been proposed and investigated to evaluate the effects of drugs dosing during closed loop control of anesthesia for a patient undergoing surgery. In today's era of automation, operating rooms are extremely complex and crowded, which often results in complex configurations, computer based control, and cable clutter. In this paper, we present a Field Programmable Gate Array (FPGA) based Explicit Model Predictive Control (EMPC) scheme to reduce the hardware size and to improve the quality control of anesthesia with simple configurations. We introduce an FPGA-based implementation of Binary Search Tree (BST) algorithm to evaluate a piecewise affine (PWA) control law, using customized 32-bit oating-point arithmetic. The FPGA-based EMPC strategy is tested for four-compartmental Pharmacokinetic-Pharmacodynamic (PK-PD) patient model to regulate the Bispectral Index (BIS) as a measure of Depth of Anesthesia (DoA) by controlling the drug infusion rate. The real-time simulation results for variable BIS set-point tracking are achieved with Xilinx's Vertex 4 XC4VLX25-10FF668 FPGA.