Model predictive control using MISO approach for drug co-administration in anesthesia

In this paper, a model predictive control system for the depth of hypnosis is proposed and analyzed. This approach considers simultaneous co-administration of the hypnotic and analgesic drugs and their effect on the Bispectral Index Scale (BIS). The control scheme uses the nonlinear multiple-input–single-output (MISO) model to predict the remifentanil influence over the propofol hypnotic effect. Then, it exploits a generalized model predictive control algorithm and a ratio between the two drugs in order to provide the optimal dosage for the desired BIS level, taking into account the typical constraints of the process. The proposed approach has been extensively tested in simulation, using a set of patients described by realistic nonlinear pharmacokinetic/pharmacodynamic models, which are representative of a wide population. Additionally, an exhaustive robustness evaluation considering inter- and intra-patient variability has been included, which demonstrates the effectiveness of the analyzed control structure

On the Use of FOPID Controllers for Maintenance Phase of General Anesthesia

This paper investigates the performance achievable with a fractional-order PID regulator controlling the Depth of Hypnosis (measured via the Bispectral Index Scale) through the administration of propofol during the maintenance phase of total intravenous anesthesia. In particular, two different methodologies were applied to tune the controller: in the first case, genetic algorithms (GAs) were used to minimize the integrated absolute error, while in the second case, the isodamping approach-a method that targets phase margin invariance with respect to the process dc gain-was employed. In both cases, the performance was extensively analyzed and compared with that of a standard PID controller by simulating multiple patients through a Monte Carlo method. The results demonstrate that a fractional-order PID controller can be effectively used to control the Depth of Hypnosis, but the improvement with respect to a standard PID controller is marginal

Event-Based control of depth of hypnosis in anesthesia

Background and Objective: In this paper, we propose the use of an event-based control strategy for the closed-loop control of the depth of hypnosis in anesthesia by using propofol administration and the bispectral index as a controlled variable. Methods: A new event generator with high noise-filtering properties is employed in addition to a PIDPlus controller. The tuning of the parameters is performed off-line by using genetic algorithms by considering a given data set of patients. Results: The effectiveness and robustness of the method is verified in simulation by implementing a Monte Carlo method to address the intra-patient and inter-patient variability. A comparison with a standard PID control structure shows that the event-based control system achieves a reduction of the total variation of the manipulated variable of 93% in the induction phase and of 95% in the maintenance phase. Conclusions: The use of event based automatic control in anesthesia yields a fast induction phase with bounded overshoot and an acceptable disturbance rejection. A comparison with a standard PID control structure shows that the technique effectively mimics the behavior of the anesthesiologist by providing a significant decrement of the total variation of the manipulated variable

A gain-scheduled PID controller for propofol dosing in anesthesia

6siA gain-scheduled proportional-integral-derivative controller is proposed for the closed-loop dosing of propofol in anesthesia (with the bispectral index as a controlled variable). In particular, it is shown that a different tuning of the parameters should be used during the infusion and maintenance phases. Further, the role of the noise filter is investigated.nonenonePadula, F.; Ionescu, C.; Latronico, N.; Paltenghi, M.; Visioli, A.; Vivacqua, G.Padula, Fabrizio; Ionescu, C.; Latronico, Nicola; Paltenghi, M.; Visioli, Antonio; Vivacqua, Giuli

Linear MPC for anesthesia process with external predictor

In this paper we present a new model predictive control system for the depth of hypnosis in general anesthesia. The depth of hypnosis is measured by the Bispectral Index Scale signal and controlled through propofol administration. The proposed control scheme is based on an external predictor that, by exploiting the Wiener structure of the pharmacokinetic/pharmacodynamic model of propofol, compensates for the process nonlinearity and increases the system robustness by means of an additional filter. The performance of the developed control scheme is evaluated through an extensive simulation study, which considers inter-patient and intra-patient variability by applying a Monte Carlo technique. The obtained results show that the proposed methodology is effective in both the induction and maintenance phases

Individualized PID tuning for maintenance of general anesthesia with propofol and remifentanil coadministration

In this paper we propose a methodology for a patient-individualized tuning of the parameters of a proportional–integral–derivative (PID) controller that regulates the depth of hypnosis in the maintenance phase of general anesthesia. In particular, we consider a PID controller employed in a closed-loop multiple-input–single-output (MISO) control system for propofol and remifentanil coadministration. Simulation results show that the approach provides an increased robustness with respect to both intra-patient and inter-patient compared to a population-based tuning. This is obtained at the cost of a slight decrement of the controller bandwidth that causes a minor increment of the time required to reject disturbances

Optimized PID controller for propofol and remifentanil coadministration: Influence of opioid-hypnotic balance

In the practice of total intravenous anesthesia, the regulation of the balance between opioid and hypnotic drugs is fundamental since it has a significant impact on depth of hypnosis and hemodynamics. Therefore, in the implementation of a fully automated control system for anesthesia, this aspect must be considered. In a recently devised PID-based control scheme for propofol and remifentanil coadministration, the opioid-hypnotic balance is handled by imposing a ratio between the infusion rates of these two drugs. The anesthesiologist can choose the most suitable balance during each phase of surgery by changing the ratio. The aim of this paper is to evaluate and discuss the benefits that this solution can bring in the clinical practice. In order to do so, the proposed solution has been tested in simulation by using a recently devised open source patient simulator that takes into account both anesthetic and hemodynamic variables. Simulation results show that the proposed approach automatically induces and maintains the desired depth of hypnosis and, furthermore, it gives the anesthesiologist the possibility to better manage the patient's hemodynamics by selecting the most appropriate opioid-hypnotic balance for each situation

Individualized PID tuning for maintenance of general anesthesia with propofol

In this paper we investigate a novel tuning methodology for a patient-individualized selection of the parameters of a proportional-integral-derivative (PID) controller that regulates the maintenance phase of general anesthesia. In particular, the knowledge of demographic data is exploited to determine the values of the parameters for each specific patient. The proposed approach is focused on the closed-loop administration of propofol by using the Bispectral Index Scale as controlled variable. Simulation results suggest that, with respect to a previously devised population-based PID tuning approach, the new methodology is more robust with respect to both intra-patient and inter-patient variability, at the cost of a slight decrement in the controller bandwidth

Experimental results of an event-based PID control system for propofol and remifentanil coadministration

This paper presents the first experimental results obtained with an event-based PID regulator for closed-loop control of general anesthesia. The control system exploits the bispectral index scale as feedback variable and regulates the coadministration of propofol and remifentanil. The experiments have been conducted on fourteen patients under conditions that are representative of the routine clinical practice. The results obtained show that the performance of the event-based control system is consistent with the standards of care. In particular, a noise-free infusion profile is obtained, which mimics the behavior of the anesthesiologist and reduces the control effort on the infusion pumps. This makes the control system easy to apply and to supervise since its behavior is intuitive for the anesthesiologist. Thus, the proposed solution represent a step forward for the acceptance and diffusion of closed-loop control systems in the routine clinical practice